
<PAGE>   1

     AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 27, 2001

                                                 REGISTRATION NO. 333-
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            ------------------------

                                    FORM S-3
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                            ------------------------

                              CALPINE CORPORATION
             (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

<TABLE>
<S>                                  <C>                                  <C>
              DELAWARE                               4911                              77-0212977
 (STATES OR OTHER JURISDICTIONS OF       (PRIMARY STANDARD INDUSTRIAL               (I.R.S. EMPLOYER
   INCORPORATION OR ORGANIZATION)        CLASSIFICATION CODE NUMBERS)           IDENTIFICATION NUMBERS)
</TABLE>

                          50 WEST SAN FERNANDO STREET
                           SAN JOSE, CALIFORNIA 95113
                                 (408) 995-5115
  (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF
                   REGISTRANTS' PRINCIPAL EXECUTIVE OFFICES)

                                PETER CARTWRIGHT
      CHAIRMAN, PRESIDENT AND CHIEF EXECUTIVE OFFICER, CALPINE CORPORATION
                          50 WEST SAN FERNANDO STREET
                           SAN JOSE, CALIFORNIA 95113
                                 (408) 995-5115
 (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                             OF AGENT FOR SERVICE)

                                   COPIES TO:

<TABLE>
<S>                                                   <C>
               BRUCE C. BENNETT, ESQ.                                 JOSEPH A. COCO, ESQ.
                 COVINGTON & BURLING                        SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP
             1330 AVENUE OF THE AMERICAS                                FOUR TIMES SQUARE
              NEW YORK, NEW YORK 10019                              NEW YORK, NEW YORK 10036
                   (212) 841-1000                                        (212) 735-3000
</TABLE>

    APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: From time
to time after the effective date of this Registration Statement as determined by
market conditions.
    If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box:  [ ]
    If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than securities offered only in connection with dividend or interest
reinvestment plans, please check the following box:  [X]
    If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering:  [ ]
    If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering:  [ ]
    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box:  [ ]

                        CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
- ---------------------------------------------------------------------------------------------------------------------------------
                                                                           PROPOSED            PROPOSED
                                                                            MAXIMUM             MAXIMUM
               TITLE OF EACH CLASS                   AMOUNT TO BE       OFFERING PRICE         AGGREGATE           AMOUNT OF
         OF SECURITIES TO BE REGISTERED              REGISTERED(1)        PER UNIT(1)      OFFERING PRICE(1)   REGISTRATION FEE
- ---------------------------------------------------------------------------------------------------------------------------------
<S>                                               <C>                 <C>                 <C>                 <C>
 Zero-Coupon Convertible Debentures Due April 30,
   2021 of Calpine Corporation(2)................      1,000,000           $1,000.00        $1,000,000,000         $250,000
- ---------------------------------------------------------------------------------------------------------------------------------
 Common Stock, par value $.001 per share, of
   Calpine Corporation...........................         (3)                 (3)                 (3)                 (3)
- ---------------------------------------------------------------------------------------------------------------------------------
 Total...........................................         --                  --            $1,000,000,000         $250,000
- ---------------------------------------------------------------------------------------------------------------------------------
</TABLE>

(1) Estimated solely for the purpose of determining the registration fee in
    accordance with Rule 457(o) under the Securities Act and exclusive of
    accrued interest and dividends, if any.
(2) $1,000,000,000 in aggregate principal amount of Calpine Corporation's
    Zero-Coupon Convertible Debentures Due April 30, 2021 (the "Debentures")
    were issued by Calpine Corporation on April 30, 2001 in an offering exempt
    from registration under Section 4(2) of the Securities Act of 1933 and Rule
    144A thereunder. Pursuant to a Registration Rights Agreement, dated April
    30, 2001, Calpine Corporation is obligated to file this Registration
    Statement to permit registered resales of the Debentures and related common
    stock from time to time by holders thereof.
(3) The Debentures are convertible into common stock, par value $.001 per share
    (the "Common Stock") of Calpine Corporation at an initial conversion rate of
    13.2714 shares of Common Stock per $1,000 principal amount at maturity of
    the Debentures (or a total of 13,271,400 shares of Common Stock assuming
    conversion of all of the Debentures), subject to adjustment under certain
    circumstances. Shares of Common Stock issued upon conversion of the
    Debentures will be issued without the payment of additional consideration.
    Pursuant to Rule 457(i) of the Securities Act, no registration fee is
    attributable to the Common Stock registered hereby.

    THE REGISTRANTS HEREBY AMEND THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANTS
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OF 1933 OR UNTIL THIS REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(a),
MAY DETERMINE.

- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
<PAGE>   2

THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. WE MAY
NOT SELL THESE SECURITIES UNTIL THE REGISTRATION STATEMENT FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION RELATING TO THESE SECURITIES IS EFFECTIVE.
THIS PROSPECTUS IS NOT AN OFFER TO SELL THESE SECURITIES AND IS NOT SEEKING AN
OFFER TO BUY THESE SECURITIES IN ANY STATE WHERE THE OFFER OR SALE IS NOT
PERMITTED.

                   SUBJECT TO COMPLETION, DATED JULY 27, 2001

PROSPECTUS

                                 $1,000,000,000

                              CALPINE CORPORATION

                 Zero-Coupon Convertible Debentures Due April 30, 2021
                            ------------------------
[CALPINE LOGO]

THE SECURITIES

    The Zero-Coupon Convertible Debentures Due April 30, 2021, or the
Debentures, represent Calpine Corporation's senior unsecured obligations. The
Debentures are convertible into shares of our common stock, par value $.001, as
described below. We will not pay interest on the Debentures unless an upward
interest adjustment becomes payable. The issue price represents a yield to
maturity of 0% per annum unless an upward interest adjustment becomes payable.

    An upward interest adjustment to the yield to maturity on the Debentures
equivalent to 7.25% per annum may be made on April 30, 2004, 2006, 2008, 2011 or
2016. An upward interest adjustment will be made on each upward interest
adjustment date if the trading price of the Debentures is less than 98% of the
accreted value as of such upward interest adjustment date for 20 out of the last
30 New York Stock Exchange trading days ending 90 days prior to such upward
interest adjustment date. If an upward interest adjustment is in effect for a
particular semi-annual period, we will pay a portion of the upward interest
adjustment as cash interest at a rate of 0.25% per annum or 0.125% per
semi-annual period, of the accreted value as of the beginning of the applicable
semi-annual period and the remaining interest of 7.0% per annum will be accrued
and payable at the earlier of maturity or the redemption or repurchase of the
Debentures. "Accreted Value" means, as of any date, the sum of the issue price
of the Debentures and the accrued and unpaid interest as of such date (excluding
any accrued and unpaid interest which will be paid as cash interest).

    If an upward interest adjustment is in effect during a semi-annual period,
other than a semi-annual period immediately preceding an upward interest
adjustment date, and the trading price of the Debentures is greater than or
equal to 98% of the accreted value as of the next following interest payment
date for 20 out of the last 30 NYSE trading days ending on such interest payment
date, the upward interest adjustment will be adjusted downward on such interest
payment date, such that, from and including such date, the Debentures will cease
to accrue interest unless and until there is a subsequent upward interest
adjustment. If an upward interest adjustment is in effect during a semi-annual
period immediately preceding an upward interest adjustment date, a downward
interest adjustment will be made on the next upward interest adjustment date if
the trading price of the Debentures is greater than or equal to 98% of the
accreted value as of such upward interest adjustment date for 20 out of the last
30 NYSE trading days ending 90 days prior to such upward interest adjustment
date. If a downward interest adjustment is made, no upward interest adjustment
may be made until the next upward interest adjustment date.

    We will not pay cash interest on the Debentures prior to maturity unless an
upward interest adjustment occurs or we elect to do so following a tax event.

    On or after April 30, 2004, we may redeem for cash all or part of the
Debentures at a redemption price equal to the issue price plus any accrued and
unpaid interest to the redemption date. On April 30, 2002, 2004, 2006, 2008,
2011 and 2016 any holder may require us to repurchase such holder's Debentures.
The initial repurchase price will be $1,000 per Debenture, but will be higher if
an upward interest adjustment applies for one or more semi-annual periods. We
may choose to pay the repurchase price in cash or shares of our common stock or
a combination of cash and shares of our common stock, except in 2016, when we
may only pay the repurchase price in cash. The Debentures will mature on April
30, 2021, unless earlier redeemed or repurchased. At maturity, we will pay the
accreted value of the Debentures in cash.

    The Debentures are convertible at the option of the holder into shares of
our common stock at a conversion rate of 13.2714 shares of common stock per
$1,000 principal amount at maturity of the Debentures, subject to adjustment
upon certain events. This is equivalent to an initial conversion price of $75.35
per share of common stock based on the issue price of the Debentures.

    The Debentures are evidenced by global notes deposited with a custodian for
and registered in the name of a nominee of The Depository Trust Company, or DTC.
Except as described in this prospectus, beneficial interests in the global notes
will be shown on, and the transfers thereof will be effected only through,
records maintained by DTC and its direct and indirect participants.

    The Debentures are eligible for trading in the Private Offerings, Resale and
Trading through Automatic Linkages (PORTAL) Market of the National Association
of Securities Dealers, Inc.

THE OFFERING

    The Debentures and the common stock issuable upon conversion of the
Debentures may be offered and sold from time to time pursuant to this prospectus
by the holders of those securities or by their transferees, pledgees, donees or
successors (all of which we refer to as selling holders).

    The securities may be sold by the selling holders directly to purchasers or
through agents, underwriters or dealers. The names of any selling holders,
agents, underwriters or dealers involved in the sale of the securities, and the
agent's commission, dealer's purchase price or underwriter's discount, if any,
will be provided in supplements to this prospectus. The selling holders will
receive all of the proceeds from the sale of the securities and will pay all
underwriting discounts and selling commissions, if any, applicable to any sale.
We are responsible for the payment of all other expenses incident to the offer
and sale of the securities. The selling holders and any broker-dealers, agents
or underwriters that participate in the distribution of the securities may be
deemed to be "underwriters" within the meaning of the Securities Act, and any
commission received by them and any profit on the resale of the securities
purchased by them may be deemed to be underwriting commissions or discounts
under the Securities Act.

    Calpine's common stock is traded on The New York Stock Exchange under the
symbol "CPN." On July 26, 2001, the last reported sales price of the common
stock on that exchange was $36.89.

    INVESTING IN THE DEBENTURES INVOLVES RISKS. SEE "RISK FACTORS" ON PAGE 17.

    NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR PASSED UPON THE
ADEQUACY OR ACCURACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

                The date of this prospectus is          , 2001.
<PAGE>   3

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
SUMMARY.....................................................    4
RISK FACTORS................................................   17
WHERE YOU CAN FIND MORE INFORMATION.........................   18
FORWARD-LOOKING STATEMENTS..................................   19
CONSOLIDATED RATIO OF EARNINGS TO FIXED CHARGES.............   20
USE OF PROCEEDS.............................................   20
SELLING HOLDERS.............................................   21
PLAN OF DISTRIBUTION........................................   22
PRICE RANGE OF COMMON STOCK.................................   23
DIVIDEND POLICY.............................................   23
CAPITALIZATION..............................................   24
SECURITIES OFFERED..........................................   25
DESCRIPTION OF DEBENTURES...................................   26
REGISTRATION RIGHTS.........................................   43
DESCRIPTION OF CAPITAL STOCK................................   45
CERTAIN UNITED STATES FEDERAL INCOME TAX CONSEQUENCES.......   49
LEGAL MATTERS...............................................   55
INDEPENDENT AUDITORS........................................   55
</TABLE>

                           -------------------------

     This document is called a prospectus and is part of a registration
statement that we filed with the SEC using a "shelf" registration or continuous
offering process. Under this shelf process, selling holders may from time to
time sell the securities described in this prospectus in one or more offerings.

     This prospectus provides you with a general description of the securities
that the selling holders may offer. Each time a selling holder sells securities,
the selling holders are required to provide you with a prospectus supplement
containing specific information about the selling holder and the terms of the
securities being offered. That prospectus supplement may include additional risk
factors or other special considerations applicable to those securities. The
prospectus supplement may also add, update or change information in this
prospectus. If there is any inconsistency between the information in this
prospectus and any prospectus supplement, you should rely on the information in
that prospectus supplement. You should read both this prospectus and any
prospectus supplement together with the additional information described under
the heading "Where You Can Find More Information."

     The registration statement containing this prospectus, including the
exhibits to the registration statement, provides additional information about us
and the securities offered under this prospectus. The registration statement,
including the exhibits, can be read at the SEC web site or at the SEC offices
mentioned under the heading "Where You Can Find More Information."

     You should rely only on the information incorporated by reference or
provided in this prospectus and the prospectus supplement. We have not
authorized anyone to provide you with different information. We are not making
an offer or soliciting a purchase of these securities in any jurisdiction in
which the offer or solicitation is not authorized or in which the person making
the offer or solicitation is not qualified to do so or to anyone to whom it is
unlawful to make the offer or solicitation. You should not assume that the
information in this prospectus or the prospectus supplement is accurate as of
any date other than the date on the front of the document.

                                        2
<PAGE>   4

     The prospectus incorporates business and financial information about us
that is not included in or delivered with the document. YOU MAY REQUEST AND
OBTAIN THIS INFORMATION FREE OF CHARGE BY WRITING OR TELEPHONING US AT THE
FOLLOWING ADDRESS: CALPINE CORPORATION, 50 WEST SAN FERNANDO STREET, SAN JOSE,
CALIFORNIA 95113, ATTENTION: LISA M. BODENSTEINER, ASSISTANT SECRETARY,
TELEPHONE: (408) 995-5115.

     Unless we have indicated otherwise, references in this prospectus to
"Calpine," "we," "us," and "our" or similar terms are to Calpine Corporation and
its consolidated subsidiaries, unless the context requires otherwise.

                                        3
<PAGE>   5

                                    SUMMARY

     This summary highlights information contained elsewhere or incorporated by
reference in this prospectus. This summary is not complete and does not contain
all of the information that you should consider before investing in the
Debentures. You should carefully read the entire prospectus, including the risk
factors, the financial statements and the documents incorporated by reference.

     All information in this prospectus reflects the 2 for 1 stock split that
became effective on October 7, 1999, the 2 for 1 stock split that became
effective on June 8, 2000 and the 2 for 1 stock split that became effective on
November 14, 2000.

                                  THE COMPANY

     Calpine is a leading independent power company engaged in the development,
acquisition, ownership and operation of power generation facilities and the sale
of electricity predominantly in the United States. We have experienced
significant growth in all aspects of our business over the last five years.
Currently, we own interests in 56 power plants having a net capacity of 8,615
megawatts. We also have 25 gas-fired projects under construction having a net
capacity of 14,092 megawatts and have announced plans to develop 33 gas-fired
projects (power plants and expansions of current facilities) with a net capacity
of 17,750 megawatts. Upon completion of the projects under construction, we will
have interests in 80 power plants located in 23 states and Canada, having a net
capacity of 22,707 megawatts. Of this total generating capacity, 96% will be
attributable to gas-fired facilities and 4% will be attributable to geothermal
facilities. As a result of our expansion program, our revenues, cash flow,
earnings and assets have grown significantly over the last five years, as shown
in the table below. Financial information in this summary does not reflect any
impact on Calpine's financial position or results of operations that will result
from our business combination under the pooling of interests method of
accounting consummated on April 19, 2001 with Encal Energy Ltd.

<TABLE>
<CAPTION>
                                                                      COMPOUND ANNUAL
                                                1996        2000        GROWTH RATE
                                                ----        ----      ---------------
                                                 (IN MILLIONS)
<S>                                           <C>         <C>         <C>
Total Revenue...............................  $  214.6    $2,282.8           81%
EBITDA......................................     110.7       825.9           65%
Net Income..................................      18.7       323.5          104%
Total Assets................................   1,031.4     9,737.3           75%
</TABLE>

     Since our inception in 1984, we have developed substantial expertise in all
aspects of the development, acquisition and operation of power generation
facilities. We believe that the vertical integration of our extensive
engineering, construction management, operations, fuel management, power
marketing and financing capabilities provides us with a competitive advantage to
successfully implement our acquisition and development program and has
contributed to our significant growth over the past five years.

     We are a corporation organized and existing under the laws of the State of
Delaware. Our principal executive office is located at 50 West San Fernando
Street, San Jose, California 95113. Our registered office is located at 9 East
Loockerman Street, Dover, Delaware 19901, c/o National Registered Agents, Inc.

                CONSOLIDATED RATIOS OF EARNINGS TO FIXED CHARGES

<TABLE>
<CAPTION>
                                        THREE MONTHS
      YEAR ENDED DECEMBER 31,          ENDED MARCH 31,
- ------------------------------------   ---------------
1996   1997    1998    1999    2000         2001
- -----  -----   -----   -----   -----        ----
<S>    <C>     <C>     <C>     <C>     <C>
1.46x  1.72x   1.69x   1.77x   2.04x        1.37x
</TABLE>

                                        4
<PAGE>   6

                                   THE MARKET

     The power industry represents the third largest industry in the United
States, with an estimated end-user market of over $215 billion of electricity
sales in 2000 produced by an aggregate base of power generation facilities with
a capacity of approximately 860,000 megawatts. In response to increasing
customer demand for access to low-cost electricity and enhanced services, new
regulatory initiatives have been and are continuing to be adopted at both the
state and federal level to increase competition in the domestic power generation
industry. The power generation industry historically has been largely
characterized by electric utility monopolies producing electricity from old,
inefficient, high-cost generating facilities selling to a captive customer base.
Industry trends and regulatory initiatives have transformed the existing market
into a more competitive market where end-users purchase electricity from a
variety of suppliers, including non-utility generators, power marketers, public
utilities and others.

     There is a significant need for additional power generating capacity
throughout the United States, both to satisfy increasing demand, as well as to
replace old and inefficient generating facilities. Due to environmental and
economic considerations, we believe this new capacity will be provided
predominantly by gas-fired facilities. We believe that these market trends will
create substantial opportunities for efficient, low-cost power producers that
can produce and sell energy to customers at competitive rates.

     In addition, as a result of a variety of factors, including deregulation of
the power generation market, utilities, independent power producers and
industrial companies are disposing of power generation facilities. To date,
numerous utilities have sold or announced their intentions to sell their power
generation facilities and have focused their resources on the transmission and
distribution business segments. Many independent producers operating a limited
number of power plants are also seeking to dispose of their plants in response
to competitive pressures, and industrial companies are selling their power
plants to redeploy capital in their core businesses.

                                    STRATEGY

     Our strategy is to continue our rapid growth by capitalizing on the
significant opportunities in the power market, primarily through our active
development and acquisition programs. In pursuing this growth strategy, we
utilize our management and technical knowledge to implement a fully integrated
approach to the acquisition, development and operation of power generation
facilities. This approach uses our expertise in design, engineering,
procurement, finance, construction management, fuel and resource production,
acquisition, operations and power marketing, which we believe provides us with a
competitive advantage. The key elements of our strategy are as follows:

     - Development of new and expansion of existing power plants. We are
       actively pursuing the development of new and expansion of our existing
       highly efficient, low-cost, gas-fired power plants to replace old and
       inefficient generating facilities and meet the demand for new generation.

     - Acquisition of power plants. Our strategy is to acquire power generating
       facilities that meet our stringent criteria, provide significant
       potential for revenue, cash flow and earnings growth and provide the
       opportunity to enhance the operating efficiencies of the plants.

     - Enhancement of existing power plants. We continually seek to maximize the
       power generation and revenue potential of our operating assets and
       minimize our operating and maintenance expenses and fuel costs.

                                        5
<PAGE>   7

                              RECENT DEVELOPMENTS

     In addition to the recent developments described below, please see the
recent developments described in Calpine's Annual Report on Form 10-K for the
year ended December 31, 2000, our Quarterly Report on Form 10-Q for the quarter
ended March 31, 2001 and our Current Reports on Form 8-K dated April 19, 2001,
June 26, 2001, July 6, 2001, July 12, 2001 and July 26, 2001 which are
incorporated by reference in this prospectus.

     Second Quarter 2001 Earnings.  On July 26, 2001, we announced earnings for
the quarter ended June 30, 2001. Net income from recurring operations (before
deduction of nonrecurring merger costs incurred in connection with the Encal
pooling of interests transaction) was $132.2 million for the quarter ended June
30, 2001, representing a 122% increase over 2000 second quarter net income of
$59.5 million. Diluted earnings per share from recurring operations (before
deduction of nonrecurring merger costs of $0.07 per share) for the second
quarter rose 95% to $0.39 per share, from $0.20 per share for the same period
last year. Revenue for the quarter increased 284% to $1.6 billion, from $417
million a year ago. Total assets at June 30, 2001 were approximately $16.0
billion as compared to $10.3 billion at December 31, 2000. As a result of the
completion of the Encal pooling of interests transaction, the financial results
for the quarter and six months ended June 30, 2000, and for the quarter ended
March 31, 2001 have been restated to include Encal. Earnings for the quarter and
six months ended June 30, 2001, benefited primarily from the continued execution
of our program to own and operate low-cost generating facilities in key power
markets throughout the United States and Calpine Energy Services' successful
power systems program.

     Acquisitions.  On April 19, 2001, Calpine closed the acquisition of all of
the common shares of Encal Energy Ltd. (which was thereafter merged with and
into Calpine Canada Resources Ltd.), a Calgary, Alberta-based natural gas and
petroleum exploration and development company, through a stock-for-stock
exchange in which Encal shareholders received, in exchange for each share of
Encal common stock, .1493 shares of Calpine common equivalent shares (called
"exchangeable shares") of Calpine's subsidiary, Calpine Canada Holdings Ltd. A
total of 16,603,633 exchangeable shares were issued to Encal shareholders in
exchange for their Encal common stock. Each exchangeable share is exchangeable
for one share of our common stock. The aggregate value of the transaction is
approximately U.S. $1.1 billion, including the assumed indebtedness of Encal.
With the addition of Encal's assets, which currently produce approximately 230
million cubic feet of gas equivalent ("mmcfe") per day, net of royalties,
Calpine's net production increased to 390 mmcfe per day in North America, enough
to fuel approximately 2,300 megawatts of Calpine's power fleet.

     On May 15, 2001, we announced that our wholly-owned subsidiary, Canada
Power Holdings Ltd., had entered into a letter of intent to acquire from British
Columbia-based Westcoast Energy, Inc. a 100% interest in Westcoast's 250
megawatt facility located on Vancouver Island and a 50% interest in its 50
megawatt facility located in Ontario for approximately U.S.$255 million. The
acquisition is expected to close in the third quarter of this year and is
subject to final documentation and third party and regulatory approvals.

     On July 5, 2001, we announced an agreement to acquire a 1,200 megawatt
natural gas-fired power plant at Saltend near Hull, Yorkshire, England from
Entergy Wholesale Operations for approximately L560 million (approximately
U.S.$800 million at current exchange rates). The Saltend facility, a
cogeneration facility, provides electricity and steam for BP Chemical's Hull
Works plant under a 15-year agreement. The balance of Saltend facility's
electricity output is sold into the deregulated UK power market. The Saltend
transaction will be our first acquisition of a power facility in Europe. The
acquisition is expected to close in the third quarter of this year and is
subject to third party approvals.

     On July 10, 2001, we announced an agreement to acquire approximately 85% of
the voting stock of Michael Petroleum Corporation, a Houston, Texas-based
natural gas exploration and
                                        6
<PAGE>   8

development company, for approximately $270 million and the assumption of $49.5
million of debt. The acquisition includes 204 billion cubic feet equivalent of
proven natural gas reserves currently producing 43 mmcfe per day and an
inventory of high quality, low risk drilling locations within a 94,000 acreage
position in close proximity to our South Texas Magic Valley and Hidalgo Energy
Centers. The acquisition is expected to close August 15, 2001.

     Turbine Contract.  On April 19, 2001, we announced the purchase of 35 model
7FB and 11 model 7FA gas-fired turbines from GE Power Systems. We expect to take
delivery of five turbines in 2002, with the remainder of the contract to be
filled by the end of 2005. With this purchase, we have firm orders in place for
the delivery of 203 turbines which, when operated in a combined-cycle
configuration, will produce approximately 50,000 megawatts of baseload capacity.

     Securities.  On April 25, 2001, Calpine Canada Energy Finance ULC ("Energy
Finance"), our indirect wholly-owned subsidiary, issued $1.5 billion in
aggregate principal amount of its 8 1/2% Senior Notes Due 2008. The Senior Notes
Due 2008 are fully and unconditionally guaranteed by us.

     On June 7, 2001, we redeemed all $105 million in aggregate outstanding
principal amount of our 9 1/4% Senior Notes Due 2004 at a redemption price of
100% of the principal amount of the Senior Notes Due 2004, plus accrued interest
to the redemption date.

     California Power Market.  The deregulation of the California power market
has produced significant unanticipated results in the past year. The
deregulation froze the rates that utilities can charge their retail and business
customers in California and prohibited the utilities from buying power on a
forward basis, while wholesale power prices were not subjected to limits.

     In the past year and a half, a series of factors have reduced the supply of
power to California, which has resulted in wholesale power prices that have been
significantly higher than historical levels. Several factors contributed to this
increase. These included:

     - significantly increased volatility in prices and supplies of natural gas;

     - an unusually dry fall and winter in the Pacific Northwest, which reduced
       the amount of available hydroelectric power from that region (typically,
       California imports a portion of its power from this source);

     - the large number of power generating facilities in California nearing the
       end of their useful lives, resulting in increased downtime (either for
       repairs or because they have exhausted their air pollution credits and
       replacement credits have become too costly to acquire on the secondary
       market); and

     - continued obstacles to new power plant construction in California, which
       deprived the market of new power sources that could have, in part,
       ameliorated the adverse effects of the foregoing factors.

     As a result of this situation, two major California utilities that are
subject to the retail rate freeze, including Pacific Gas & Electric Company
("PG&E"), have faced wholesale prices that far exceed the retail prices they are
permitted to charge. This has led to significant under-recovery of costs by
these utilities. As a consequence, these utilities have defaulted under a
variety of contractual obligations, including payment obligations to power
generators. PG&E has defaulted on payment obligations to Calpine under Calpine's
long-term qualifying facility ("QF") contracts, which are subject to federal
regulation under the Public Utility Regulatory Policies Act of 1978, as amended
("PURPA"). The PG&E QF contracts are in place at 11 of our facilities and
represent nearly 600 megawatts of electricity for Northern California customers.

     PG&E Bankruptcy Proceedings.  On April 6, 2001, PG&E filed for bankruptcy
protection under Chapter 11 of the United States Bankruptcy Code. As of April 6,
2001, Calpine had recorded

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<PAGE>   9

approximately $266 million in accounts receivable with PG&E under our QF
contracts, plus a $69 million note receivable not yet due and payable. Calpine
is currently selling power to PG&E pursuant to our long-term QF contracts, and
PG&E is paying on a current basis for these purchases since its bankruptcy
filing. With respect to the receivables recorded under these contracts on July
6, 2001, Calpine announced that it had entered into a binding agreement with
PG&E to modify all of Calpine's QF contracts with PG&E and that, based upon such
modification, PG&E had agreed to assume all of the QF contracts. Under the terms
of this agreement, Calpine will continue to receive its contractual capacity
payments under the QF contracts, plus a five-year fixed energy component of
approximately 5.37 cents per kilowatt-hour. In addition, all past due
receivables under the QF contracts will be elevated to administrative priority
status in the PG&E bankruptcy proceeding and will be paid to Calpine, with
interest, upon the effective date of a confirmed plan of reorganization.
Administrative claims enjoy priority over payments made to the general unsecured
creditors in bankruptcy. The bankruptcy court approved the agreement on July 12,
2001. We cannot predict when the bankruptcy court will confirm a plan of
reorganization for PG&E.

     CPUC Proceedings Regarding QF Contract Pricing.  Our QF contracts with PG&E
provide that the California Public Utilities Commission ("CPUC") has the
authority to determine the appropriate utility "avoided cost" to be used to set
energy payments for certain QF contracts, including those for all of our QF
plants in California which sell power to PG&E. Section 390 of the California
Public Utility Code provided QFs the option to elect to receive energy payments
based on the California Power Exchange ("PX") market clearing price. In
mid-2000, our QF facilities elected this option and were paid based upon the PX
zonal day ahead clearing price ("PX Price") from summer 2000 until January 19,
2001, when the PX ceased operating a day ahead market. Since that time, the CPUC
has ordered that the price to be paid for energy deliveries by QFs electing the
PX Price shall be based on a natural gas cost-based "transition formula." The
CPUC has conducted proceedings (R. 99-11-022) to determine whether the PX Price
was the appropriate price for the energy component upon which to base payments
to QFs which had elected the PX based pricing option. The CPUC has issued a
proposed decision to the effect that the PX price was the appropriate price for
energy payments under the California Public Utility Code. However, a final
decision has not been issued to date. Therefore, it is possible that the CPUC
could order a payment adjustment based on a different energy price
determination. We believe that the PX Price was the appropriate price for energy
payments but there can be no assurance that this will be the outcome of the CPUC
proceedings.

     California Long-Term Supply Contracts.  California has adopted legislation
permitting it to issue long-term revenue bonds to provide funding for wholesale
purchases of power. The bonds will be repaid with the proceeds of payments by
retail customers over time. The California Department of Water Resources ("DWR")
sought bids for long-term power supply contracts in a publicly announced
auction. Calpine successfully bid in that auction and signed several long-term
power supply contracts with DWR.

     On February 7, 2001, we announced the signing of a 10-year, $4.6 billion
fixed-price contract with DWR to provide electricity to the State of California.
Calpine committed to sell up to 1,000 megawatts of electricity, with initial
deliveries of 200 megawatts starting October 1, 2001, which increases to 1,000
megawatts by January 1, 2004. The electricity will be sold directly to DWR on a
24-hour, 7-day-a-week basis. This contract is contingent upon our satisfaction,
in our sole discretion, that adequate provisions have been made by DWR to assure
us of full payment under the terms of that contract (including the terms and
conditions of any bonds issued by DWR to provide funds for payment of its
obligations under the contract).

     On February 28, 2001, we announced the signing of two long-term power sales
contracts with DWR. Under the terms of the first contract, a $5.2 billion,
10-year, fixed-price contract, Calpine committed to sell up to 1,000 megawatts
of generation. Initial deliveries began July 1, 2001 with 200 megawatts and
increase to 1,000 megawatts by as early as July 2002. Under the
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<PAGE>   10

terms of the second contract, a 20-year contract totaling up to $3.1 billion,
Calpine will supply DWR with up to 495 megawatts of peaking generation,
beginning with 90 megawatts as early as August 2001, and increasing up to 495
megawatts as early as August 2002. Each of these contracts is also contingent
upon our satisfaction, in our sole discretion, that adequate provisions have
been made by DWR to assure us of full payment under the terms of that contract
(including, but not limited to, the terms and conditions of any bonds issued by
DWR to provide funds for payment of its obligations under that contract).

     FERC Investigation into California Wholesale Markets.  In response to the
increase in wholesale energy prices in the California markets, on June 28, 2000,
the Board of Governors of the California Independent System Operator (the
"ISO"), which controls the long-distance high-voltage power lines that deliver
electricity throughout California and the adjoining states, reduced the price
cap applicable to the ISO's wholesale energy and ancillary services markets from
$750/MWh to $500/MWh. The ISO subsequently reduced the price cap to $250/MWh
effective August 7, 2000. During this period, however, the PX maintained a
separate price cap set at a much higher level applicable to the "day-ahead" and
"day-of" markets administered by the PX. On August 23, 2000, the Federal Energy
Regulatory Commission ("FERC") denied a complaint filed August 2, 2000 by San
Diego Gas & Electric Company ("SDG&E") that sought to extend the ISO's $250
price cap to all California energy and ancillary service markets, not just the
markets administered by the ISO. However, in its order denying the relief sought
by SDG&E, FERC instructed its staff to initiate an investigation of the
California power markets and to report its findings to FERC and held further
hearing procedures in abeyance pending the outcome of this investigation. Under
FERC regulations, QF contracts are exempt from regulation under the Federal
Power Act, which is the legislation that provides the authority for FERC to
investigate the California power markets and frame equitable relief with respect
to the California wholesale markets. Therefore, any such relief will only apply
to sales by Calpine in the short-term market. None of Calpine's receivables
related to power produced under its long-term QF contracts with PG&E should be
affected by any FERC findings pursuant to the proceedings described below. See
"Government Regulation -- Federal Energy Regulation -- Federal Power Act
Regulation" set forth in our Annual Report on Form 10-K for the year ended
December 31, 2000, which is incorporated by reference in this prospectus.

     On November 1, 2000, FERC released a Staff Report detailing the results of
the staff investigation, together with an "Order Proposing Remedies for
California Wholesale Markets" (the "November 1 Order"). In the November 1 Order,
FERC found that the California power market structure and market rules were
seriously flawed, and that these flaws, together with short supply relative to
demand, resulted in unusually high energy prices. The November 1 Order proposed
specific remedies to the identified market flaws, including (a) imposition of a
so-called "soft" price cap at $150/MWh to be applied to both the PX and ISO
markets, which would allow bids above $150/MWh to be accepted, but would subject
such bids to certain reporting obligations requiring sellers to provide cost
data and/or identify applicable opportunity costs and specifying that such bids
may not set the overall market clearing price; (b) elimination of the
requirement that the California utilities sell into and buy from the PX; (c)
establishment of independent non-stakeholder governing boards for the ISO and
the PX; and (d) establishment of penalty charges for scheduling deviations
outside of a prescribed range. In the November 1 Order FERC established October
2, 2000, the date 60 days after the filing of the SDG&E complaint, as the
"refund effective date." Under the November 1 Order, rates charged for service
after that date through December 31, 2002 will remain subject to refund if
determined by FERC not to be just and reasonable. While FERC concluded that the
Federal Power Act and prior court decisions interpreting that act strongly
suggested that refunds would not be permissible for charges in the period prior
to October 2, 2000, it noted that it was willing to explore proposals for
equitable relief with respect to charges made in that period.

                                        9
<PAGE>   11

     On December 15, 2000, FERC issued a subsequent order that affirmed in large
measure the November 1 Order (the "December 15 Order"). Various parties have
filed requests for administrative rehearing and for judicial review of aspects
of FERC's December 15 Order. The outcome of these proceedings, and the extent to
which FERC or a reviewing court may revise aspects of the December 15 Order or
the extent to which these proceedings may result in a refund of or reduction in
the amounts charged by the Company's subsidiaries for power sold in the ISO and
PX markets, cannot be determined at this time.

     On June 19, FERC ordered price mitigation in 11 states in the western
United States in an attempt to reduce the dependence of the California market on
the spot markets in favor of longer-term committed energy supplies. The order
provides for price mitigation in the spot market throughout the 11-state western
region during "reserve deficiency hours," which is when operating reserves in
California fall below 7%. This price will be a single market clearing price
based upon the marginal operating cost of the last unit dispatched by the
California ISO. In addition, FERC implemented price mitigation in non-reserve
deficiency hours, which will be set at 85% of the market clearing price during
the last reserve deficiency period. These price mitigation procedures went into
effect on June 20, 2001 and will remain in effect until September 30, 2002.

     The retention by FERC of a market-based, rather than a cost-of-service
based, rate structure, will enable us to continue to realize benefits from our
efficient, modern power plants. We believe that Calpine's marginal costs will
continue to be below any price cap imposed by FERC, whether during reserve
deficiency hours or at other times. Therefore, we believe that FERC's mitigation
plan will not have a material adverse effect on Calpine's financial condition or
results of operations.

     FERC also ordered all sellers and buyers in wholesale power markets
administered by the California ISO, as well as representatives of the State of
California, to participate in a settlement conference before a FERC
administrative judge. The settlement discussions were intended to resolve all
issues that remain outstanding to resolve past accounts, including sellers'
claims for unpaid invoices, and buyers' claims for refunds of alleged
overcharges, for past periods. The settlement discussions began on June 25, 2001
and ended on July 9, 2001. The Chief Administrative Law Judge issued his report
and recommendation to FERC on July 12, 2001. On July 25, 2001, FERC ordered an
expedited fact-finding hearing to calculate refunds for spot market transactions
in California. The hearing must be completed within 45 days from the date the
California ISO provides certain critical data for the purpose of developing the
factual basis needed to implement the refund methodology and order refunds.
While it is not possible to predict the amount of any refunds until the hearings
take place, based upon the information available at this time, we do not believe
that this proceeding will result in a material adverse effect on Calpine's
financial condition or results of operations.

                          PRINCIPAL EXECUTIVE OFFICES

     Our principal executive offices are located at 50 West San Fernando Street,
San Jose, California 95113. Our telephone number is (408) 995-5115, and our home
page on the world wide web is at http://www.calpine.com. The contents of our
website are not part of this prospectus.

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<PAGE>   12

                                  THE OFFERING

     The Debentures being registered were originally issued and sold to Goldman,
Sachs & Co. (the "Initial Purchaser"). The Initial Purchaser simultaneously sold
the Debentures in transactions exempt from the registration requirements of the
Securities Act to persons reasonably believed by them to be qualified
institutional buyers as defined in Rule 144A under the Securities Act.

SECURITIES REGISTERED...........   $1,000,000,000 aggregate initial principal
                                   amount of Zero-Coupon Convertible Debentures
                                   Due April 30, 2021 (the "Debentures") and
                                   13,271,400 shares of common stock (subject to
                                   adjustments described in this prospectus).

ISSUE PRICE.....................   Each Debenture was issued at $1,000 per
                                   Debenture.

MATURITY........................   April 30, 2021.

RANKING.........................   The Debentures are senior unsecured
                                   obligations of Calpine and rank equally with
                                   all of our existing and future senior
                                   unsecured indebtedness.

INTEREST ADJUSTMENT.............   An upward interest adjustment to the yield at
                                   maturity on the Debentures equivalent to
                                   7.25% per annum (an "Upward Interest
                                   Adjustment") will be made on April 30, 2004,
                                   2006, 2008, 2011 or 2016 (each an "Upward
                                   Interest Adjustment Date") if the Trading
                                   Price (as defined below) of the Debentures is
                                   less than 98% of the Accreted Value as of
                                   such Upward Interest Adjustment Date for 20
                                   out of the last 30 NYSE trading days ending
                                   90 days prior to such Upward Interest
                                   Adjustment Date. If an Upward Interest
                                   Adjustment is in effect for a particular
                                   semi-annual period, we will pay a portion of
                                   the Upward Interest Adjustment as cash
                                   interest at a rate of 0.25% per annum (0.125%
                                   per semi-annual period) of the Accreted Value
                                   as of the beginning of the applicable
                                   semi-annual period and the remaining interest
                                   (7.0% per annum) will be accrued and payable
                                   at the earlier of maturity or the redemption
                                   or repurchase of the Debentures.

                                   If an Upward Interest Adjustment is in effect
                                   during a semi-annual period (other than a
                                   semi-annual period immediately preceding an
                                   Upward Interest Adjustment Date) and the
                                   Trading Price of the Debentures is greater
                                   than or equal to 98% of the Accreted Value as
                                   of the next following interest payment date
                                   for 20 out of the last 30 NYSE trading days
                                   ending on such interest payment date, the
                                   Upward Interest Adjustment will be adjusted
                                   downward on such interest payment date (such
                                   adjustment, a "Downward Interest
                                   Adjustment"), such that, from and including
                                   such date, the Debentures will cease to
                                   accrue interest unless and until there is a
                                   subsequent Upward Interest Adjustment. If an
                                   Upward Interest Adjustment is in effect
                                   during a semi-annual period immediately
                                   preceding an Upward Interest Adjust-

                                        11
<PAGE>   13

                                   ment Date, a Downward Interest Adjustment
                                   will be made on the next Upward Interest
                                   Adjustment Date if the Trading Price of the
                                   Debentures is greater than or equal to 98% of
                                   the Accreted Value as of such Upward Interest
                                   Adjustment Date for 20 out of the last 30
                                   NYSE trading days ending 90 days prior to
                                   such Upward Interest Adjustment Date. If a
                                   Downward Interest Adjustment is made in
                                   accordance with the preceding sentence, no
                                   Upward Interest Adjustment may be made until
                                   the next Upward Interest Adjustment Date.
                                   Upward Interest Adjustment Dates may occur on
                                   April 30, 2004, 2006, 2008, 2011 or 2016.

CASH INTEREST PAYMENT...........   We will not pay cash interest on the
                                   Debentures unless an Upward Interest
                                   Adjustment is in effect or we elect to do so
                                   following a Tax Event (as defined below),
                                   each as described below. If an Upward
                                   Interest Adjustment is in effect for a
                                   particular semi-annual period, we will pay a
                                   portion of the Upward Interest Adjustment as
                                   cash interest at a rate of 0.25% per annum
                                   (0.125% per semi-annual period), of the
                                   Accreted Value as of the beginning of the
                                   applicable semi-annual period. If we elect to
                                   pay cash interest upon the occurrence of a
                                   Tax Event, the amount of cash interest
                                   payable for each semi-annual period will be
                                   determined based on the Restated Principal
                                   Amount (as defined below). Cash interest, if
                                   any, will be paid semi-annually in arrears on
                                   each April 30 and October 30 to the holders
                                   of record of the Debentures as of the
                                   preceding April 15 and October 15,
                                   respectively.

CONVERSION RIGHTS...............   For each Debenture surrendered for
                                   conversion, a holder will receive 13.2714
                                   shares of our common stock. This represents
                                   an initial conversion price of $75.35 per
                                   share of common stock. The conversion ratio
                                   and the equivalent conversion price may be
                                   adjusted for certain reasons, but will not be
                                   adjusted for accrued interest. Upon
                                   conversion, holders will not receive any cash
                                   payment representing accrued interest.
                                   Instead, accrued interest will be deemed paid
                                   in full by the common stock received by
                                   holders on conversion.

                                   Holders may surrender Debentures for
                                   conversion into common stock at any time
                                   prior to 5:00 p.m., New York City time, on
                                   April 29, 2021. Debentures called for
                                   redemption may be surrendered for conversion
                                   until the close of business in New York City
                                   on the business day immediately preceding the
                                   redemption date.

REDEMPTION OF THE DEBENTURES AT
OUR
  OPTION........................   On or after April 30, 2004, we may redeem for
                                   cash all or part of the Debentures at any
                                   time, upon not less than 30 nor more than 60
                                   days notice by mail to holders of Debentures,
                                   for a cash price equal to the issue price
                                   plus any accrued and unpaid interest to the
                                   redemption date or, if we elected to pay cash
                                   interest on the

                                        12
<PAGE>   14

                                   Debentures following a Tax Event, the
                                   Restated Principal Amount, plus any accrued
                                   and unpaid cash interest through the
                                   redemption date.

PURCHASE OF DEBENTURES AT YOUR
  OPTION........................   You have the right to require us to
                                   repurchase the Debentures on April 30, 2002,
                                   2004, 2006, 2008, 2011 and 2016. In each
                                   case, the repurchase price payable will be
                                   equal to the issue price plus any accrued and
                                   unpaid interest to the repurchase date, or,
                                   if we elected to pay cash interest on the
                                   Debentures following a Tax Event, the
                                   Restated Principal Amount, plus any accrued
                                   and unpaid cash interest through the
                                   repurchase date. We may choose to pay the
                                   repurchase price in cash or shares of our
                                   common stock, or a combination of cash and
                                   shares of our common stock, except on April
                                   30, 2016 when we may only pay the repurchase
                                   price in cash.

TAX EVENT.......................   We have the option, under limited
                                   circumstances, to elect to pay cash interest
                                   at a rate of 7.25% per annum on the
                                   Debentures from and after the date a Tax
                                   Event occurs instead of accruing interest
                                   pursuant to an Upward Interest Adjustment.
                                   Such cash interest would only be payable
                                   during periods in which an Upward Interest
                                   Adjustment is in effect. If we make such an
                                   election, the principal amount on which we
                                   pay interest will be restated (the "Restated
                                   Principal Amount") and will be equal to the
                                   issue price plus accrued and unpaid interest
                                   payable pursuant to an Upward Interest
                                   Adjustment to the date on which we exercise
                                   our option to commence paying cash interest.
                                   See "Description of Debentures -- Tax Event."

CHANGE IN CONTROL...............   If we undergo a change in control, you will
                                   have the option to require us to repurchase
                                   all of your Debentures not previously called
                                   for redemption or any portion thereof for
                                   cash or, at our option, registered shares of
                                   our common stock (which are valued at 95% of
                                   the average closing prices of our common
                                   stock for the five NYSE trading days
                                   immediately preceding and including the third
                                   NYSE trading day prior to the repurchase
                                   date). We will pay a repurchase price equal
                                   to the issue price plus any accrued and
                                   unpaid interest to the repurchase date, or,
                                   if we elected to pay cash interest on the
                                   Debentures following a Tax Event, the
                                   Restated Principal Amount, plus any accrued
                                   and unpaid cash interest through the
                                   repurchase date. See "Description of
                                   Debentures -- Change in Control."

EVENTS OF DEFAULT...............   If there is an event of default on the
                                   Debentures, an amount equal to the issue
                                   price plus any accrued and unpaid interest
                                   may be declared immediately due and payable.
                                   These amounts automatically become due and
                                   payable in some circumstances.

                                        13
<PAGE>   15

                                   The following are events of default with
                                   respect to the Debentures:

                                   - our failure for 30 days to pay when due any
                                     interest on the Debentures (after any
                                     Upward Interest Adjustment or after our
                                     election to pay cash interest on the
                                     Debentures following a Tax Event);

                                   - our failure to pay principal of the
                                     Debentures (or, if we have elected to pay
                                     cash interest on the Debentures following a
                                     Tax Event, the Restated Principal Amount)
                                     and accrued interest (including any
                                     interest payable pursuant to an Upward
                                     Interest Adjustment) at maturity, upon
                                     redemption, repurchase or following a
                                     change in control, when the same becomes
                                     due and payable;

                                   - our material failure to comply with any of
                                     our covenants or agreements in the
                                     Debentures or the Indenture (as defined in
                                     this prospectus) for 30 days after written
                                     notice is given by the Trustee (as defined
                                     below) or by the holders of at least 25% in
                                     principal amount of all outstanding
                                     Debentures;

                                   - our default under any of our other
                                     instruments of indebtedness with an
                                     outstanding principal amount of $50,000,000
                                     or more, individually or in the aggregate,
                                     which has caused the holders of such
                                     indebtedness to declare such indebtedness
                                     due and payable prior to its stated
                                     maturity;

                                   - our failure to pay when due any portion of
                                     principal under any of our other
                                     instruments of indebtedness, which default
                                     is individually or in an aggregate
                                     principal amount exceeding $50,000,000 and
                                     continues unremedied or unwaived for more
                                     than 30 days; and

                                   - certain events involving the bankruptcy,
                                     insolvency or reorganization of Calpine.

REGISTRATION RIGHTS.............   Pursuant to a registration rights agreement
                                   entered into in connection with the initial
                                   offering of the Debentures to the Initial
                                   Purchaser, we have agreed to use our best
                                   efforts to keep the registration statement,
                                   of which this prospectus is a part,
                                   continuously effective and useable (subject
                                   to certain exceptions) until the earliest of
                                   (1) two years, (2) the expiration of the
                                   period referred to in Rule 144(k) of the
                                   Exchange Act (or any successor provision
                                   thereto) with respect to the Debentures and
                                   common stock issuable upon conversion of the
                                   Debentures that are covered by the
                                   registration statement or (3) the sale of all
                                   of the Debentures and common stock issuable
                                   upon conversion of the Debentures that are
                                   covered by the registration statement.

                                   Additional interest will accrue on the
                                   Debentures if we are not in compliance with
                                   these requirements. See

                                        14
<PAGE>   16

                                   "Registration Rights" for a further
                                   discussion of our obligations to maintain the
                                   effectiveness of the registration statement
                                   of which this prospectus is a part.

TAX.............................   Each holder agreed in the Indenture, for U.S.
                                   federal income tax purposes, to treat the
                                   Debentures as "contingent payment debt
                                   instruments" and to be bound by our
                                   application of the Treasury regulations that
                                   govern contingent payment debt instruments,
                                   including our determination that the rate at
                                   which interest will be deemed to accrue for
                                   federal income tax purposes will be 9.44% per
                                   annum, which is the rate comparable to the
                                   rate at which we would borrow on a
                                   noncontingent, nonconvertible borrowing.
                                   Based on the agreement(i) each holder will be
                                   required to accrue interest on a constant
                                   yield to maturity basis at that rate, with
                                   the result that a holder will recognize
                                   taxable income significantly in excess of
                                   cash received while the Debentures are
                                   outstanding, and (ii) a holder will recognize
                                   ordinary income upon a conversion of a
                                   Debenture into our stock equal to the excess,
                                   if any, between the value of the stock
                                   received on the conversion and the sum of the
                                   original purchase price of the Holder's
                                   Debenture and accrued but unpaid interest.
                                   Non-U.S. Holders should be aware that special
                                   tax consequences may apply to them due to the
                                   fact that we believe we are likely to be a
                                   "United States real property holding
                                   corporation." See discussion below under
                                   "Certain United States Federal Income Tax
                                   Consequences -- Non-U.S. Holders" and
                                   "-- Foreign Investment in Real Property Tax
                                   Act."

                                   The proper application of the regulations
                                   that govern contingent payment debt
                                   instruments to a holder of a Debenture is
                                   uncertain in a number of respects, and if our
                                   treatment were successfully challenged by the
                                   Internal Revenue Service, it might be
                                   determined that, among other differences, a
                                   holder should have accrued interest income at
                                   a lower rate, should not have recognized
                                   income or gain upon the conversion, and
                                   should not have recognized ordinary income
                                   upon a taxable disposition of its Debenture.
                                   In addition, if the Internal Revenue Service
                                   successfully asserts that the Debentures are
                                   not debt, Non-U.S. Holders would generally be
                                   subject to a 30% United States federal
                                   withholding tax on payments of contingent
                                   interest made in respect of the Debentures.
                                   See "Certain United States Federal Income Tax
                                   Consequences."

                                   HOLDERS SHOULD CONSULT THEIR TAX ADVISORS
                                   REGARDING THE FEDERAL, STATE, LOCAL AND
                                   FOREIGN TAX CONSEQUENCES OF AN INVESTMENT IN
                                   DEBENTURES AND WHETHER AN INVESTMENT IN THE
                                   DEBENTURES IS ADVISABLE IN LIGHT OF THE

                                        15
<PAGE>   17

                                   AGREED UPON TAX TREATMENT AND THE HOLDER'S
                                   PARTICULAR TAX SITUATION.

USE OF PROCEEDS.................   The net proceeds of this offering will be
                                   used to extinguish certain project finance
                                   debt and for working capital and general
                                   corporate purposes.

BOOK-ENTRY FORM.................   The Debentures have been issued in book-entry
                                   form and are represented by permanent global
                                   certificates deposited with, or on behalf of,
                                   DTC and registered in the name of a nominee
                                   of DTC. Beneficial interests in any of the
                                   securities will be shown on, and transfers
                                   will be effected only through, records
                                   maintained by DTC or its nominee and any such
                                   interest may not be exchanged for
                                   certificated securities, except in limited
                                   circumstances. See "Description of
                                   Debentures -- Book-Entry System."

ABSENCE OF MARKET FOR THE
  DEBENTURES....................   The Debentures were initially sold in
                                   transactions exempt from the registration
                                   requirements of the Securities Act. As a
                                   result of the effectiveness of the
                                   registration statement of which this
                                   prospectus is a part, the Debentures are no
                                   longer restricted securities under the
                                   Securities Act. However, there is currently
                                   no market for the Debentures. Although the
                                   Initial Purchaser informed us at the time of
                                   the initial offering and sale of the
                                   Debentures that it planned to make a market
                                   in the Debentures, the Initial Purchaser is
                                   not obligated to do so, and they may
                                   discontinue any such market making at any
                                   time without notice. Accordingly, we cannot
                                   assure you as to the development or liquidity
                                   of any market for the Debentures.

TRADING.........................   Our common stock is listed on the New York
                                   Stock Exchange under the symbol "CPN." The
                                   common stock issuable upon conversion of the
                                   Debentures has been listed on the New York
                                   Stock Exchange.

                                        16
<PAGE>   18

                                  RISK FACTORS

     Investing in these Debentures involves risk. In addition to the risk
factors described in Calpine's Annual Report on Form 10-K for the year ended
December 31, 2000 and in our Quarterly Report on Form 10-Q for the quarter ended
March 31, 2001, which are incorporated by reference in this prospectus, and the
other information contained in this prospectus, you should carefully consider
the risk factors described below before making an investment decision. The risks
and uncertainties described below and incorporated by reference are not the only
risks we face. Additional risks and uncertainties not presently known to us or
that we currently deem immaterial may also impair our business operations.

                           RISKS RELATING TO CALPINE

     Please see the risk factors described in Calpine's Annual Report on Form
10-K for the year ended December 31, 2000 for a description of the risks
relating to Calpine.

                        RISKS RELATING TO THE DEBENTURES

WE MAY BE UNABLE TO REPAY THE DEBENTURES WHEN DUE OR REPURCHASE THE DEBENTURES
WHEN WE ARE REQUIRED TO DO SO.

     At final maturity, the entire outstanding principal amount of the
Debentures will become due and payable, plus accrued and unpaid interest, if
any. At any accelerated maturity prior to final maturity, the issue price plus
any accrued and unpaid interest, if any, will become due and payable. A holder
may also require us to repurchase all or a portion of that holder's Debentures
at certain times during the term of the Debentures including if a Change of
Control (as defined in this prospectus) occurs. At maturity or at any time when
a holder may require us to repurchase Debentures, we may not have sufficient
funds or may be unable to arrange for additional financing to pay the amount
due.

     Our borrowing arrangements or agreements relating to indebtedness to which
we may become a party may limit our ability to repay or repurchase the
Debentures with cash. Our failure to repay or repurchase any tendered Debentures
or Debentures due upon maturity would constitute an event of default under the
Indenture. Any such default, in turn, may cause a default under the terms of our
other indebtedness.

BECAUSE THERE IS NO PUBLIC MARKET FOR THE DEBENTURES, YOU MAY NOT BE ABLE TO
RESELL THE DEBENTURES EASILY OR AT A FAVORABLE PRICE.

     There is no public market for the Debentures and we are not certain of:

     - the liquidity of any market that may develop;

     - the ability of the holders to sell their Debentures; or

     - the price at which holders would be able to sell their Debentures.

     If such a market were to develop, the Debentures could trade at prices that
may be higher or lower than the issue price to the public plus any accrued
interest, depending on many factors, including prevailing interest rates, the
market for similar debentures and our financial performance.

     The Initial Purchaser advised us at the time of the initial offering and
sale of the Debentures that it planned to make a market in the Debentures. The
Initial Purchaser is not obligated, however, to make a market in the Debentures,
and the Initial Purchaser may discontinue any such market-making activity at any
time at its sole discretion. In addition, such market-making activity will be
subject to the limits imposed by the Securities Act of 1933 and the Securities
Exchange Act of 1934. Accordingly, no assurance can be given as to the
development or liquidity of any market for the Debentures.

                                        17
<PAGE>   19

                      WHERE YOU CAN FIND MORE INFORMATION

     We file annual, quarterly and current reports, proxy statements and other
information with the SEC. You may obtain any document we file with the SEC at
the SEC's public reference rooms in Washington, D.C., Chicago, Illinois and New
York, New York. You may obtain information on the operation of the SEC's public
reference facilities by calling the SEC at 1-800-SEC-0330. You can request
copies of these documents, upon payment of a duplicating fee, by writing to the
SEC at its principal office at 450 Fifth Street, N.W., Washington, D.C.
20549-1004. Our SEC filings are also accessible through the Internet at the
SEC's Web site at http://www.sec.gov.

     The SEC permits us to "incorporate by reference" into this prospectus the
information in documents we file with it, which means that we can disclose
important information to you by referring you to those documents. The
information incorporated by reference is considered to be a part of this
prospectus, and later information that we file with the SEC will update and
supersede this information. We incorporate by reference the documents listed
below and any future filings we make with the SEC under Section 13(a), 13(c),
14, or 15(d) of the Securities Exchange Act of 1934, as amended, until the
offering is completed:

     - Calpine's Annual Report on Form 10-K for the year ended December 31,
       2000;

     - Calpine's Quarterly Report on Form 10-Q for the quarter ended March 31,
       2001;

     - Calpine's Current Reports on Form 8-K dated February 6, 2001, April 9,
       2001, April 19, 2001, April 26, 2001, June 26, 2001, July 6, 2001, July
       12, 2001, July 16, 2001 and July 26, 2001; and

     - the description of Calpine's common stock contained in Calpine's
       Registration Statement on Form 8-A (File No. 001-12079), filed with the
       SEC on August 20, 1996, pursuant to Section 12 of the Securities Exchange
       Act of 1934, as amended.

     If you request a copy of any or all documents incorporated by reference,
then we will send to you the copies requested at no charge. However, we will not
send exhibits to such documents, unless such exhibits are specifically
incorporated by reference in such documents. You should direct requests for such
copies to: Calpine Corporation, 50 West San Fernando Street, San Jose,
California 95113, attention: Lisa M. Bodensteiner, Assistant Secretary,
telephone: (408) 995-5115.

     We have filed with the SEC a registration statement on Form S-3 under the
Securities Act, covering the securities described in this prospectus. This
prospectus does not contain all of the information included in the registration
statement. Any statement made in this prospectus concerning the contents of any
contract, agreement or other document is only a summary of the actual contract,
agreement or other document. If we have filed any contract, agreement or other
document as an exhibit to the registration statement, you should read the
exhibit for a more complete understanding of the document or matter involved.
Each statement regarding a contract, agreement or other document is qualified in
its entirety by reference to the actual document.

                                        18
<PAGE>   20

                           FORWARD-LOOKING STATEMENTS

     Some of the statements contained in this prospectus and incorporated by
reference into this prospectus are forward-looking statements within the meaning
of Section 27A of the Securities Act and Securities 21E of the Securities
Exchange Act and are subject to the safe harbor created by the Private
Securities Litigation Reform Act of 1995. These statements include declarations
regarding our or our management's intents, beliefs or current expectations. In
some cases, you can identify forward-looking statements by terminology such as
"may," "will," "should," "expects," "plans," "anticipates," "believes,"
"estimates," "predicts," "potential," or "continue" or the negative of such
terms or other comparable terminology. Any forward-looking statements are not
guarantees of future performance and actual results could differ materially from
those indicated by the forward-looking statements. Forward-looking statements
involve known and unknown risks, uncertainties, and other factors that may cause
our or our industry's actual results, levels of activity, performance, or
achievements to be materially different from any future results, levels of
activity, performance, or achievements expressed or implied by such forward-
looking statements.

     Among the important factors that could cause actual results to differ
materially from those indicated by such forward-looking statements are:

     - changes in government regulations, including pending changes in
       California and anticipated deregulation of the electric energy industry;

     - commercial operations of new plants that may be delayed or prevented
       because of various development and construction risks, such as a failure
       to obtain financing and the necessary permits to operate or the failure
       of third-party contractors to perform their contractual obligations;

     - cost estimates are preliminary and actual costs may be higher than
       estimated;

     - the assurance that Calpine will develop additional plants;

     - a competitor's development of lower-cost generating gas-fired power
       plants;

     - the risks associated with marketing and selling power from power plants
       in the newly competitive energy market;

     - the risks associated with marketing and selling combustion turbine parts
       and components in the competitive combustion turbine parts market;

     - the risks associated with engineering, designing and manufacturing
       combustion turbine parts and components;

     - delivery and performance risks associated with combustion turbine parts
       and components attributable to production, quality control, suppliers and
       transportation;

     - the successful exploitation of an oil or gas resource that ultimately
       depends upon the geology of the resource, the total amount and costs to
       develop recoverable reserves and operations factors relating to the
       extraction of natural gas;

     - the uncertainty of the California power market. We are working closely
       with a number of parties to resolve the current uncertainty. This is an
       ongoing process and, therefore, the outcome cannot be predicted. It is
       possible that any such outcome will include changes in government
       regulations, business and contractual relationships or other factors that
       could materially affect us; however, we believe that a final resolution
       will not have a material adverse impact on us; and

     - other risks identified from time to time in our reports and registration
       statements filed with the SEC, including the risk factors identified in
       "Risk Factors" and in our Annual Report on

                                        19
<PAGE>   21

Form 10-K for the year ended December 31, 2000 and Quarterly Report on Form 10-Q
for the quarter ended March 31, 2001, which are incorporated by reference in
this prospectus.

     Although we believe that the expectations reflected in the forward-looking
statements are reasonable, we cannot guarantee future results, levels of
activity, performance or achievements. Moreover, neither we nor any other person
assumes responsibility for the accuracy and completeness of such statements. We
are under no duty to update any of the forward-looking statements after the date
of this prospectus to conform such statements to actual results.

                CONSOLIDATED RATIO OF EARNINGS TO FIXED CHARGES

<TABLE>
<CAPTION>
                                        THREE MONTHS
      YEAR ENDED DECEMBER 31,          ENDED MARCH 31,
- ------------------------------------   ---------------
1996   1997    1998    1999    2000         2001
- -----  -----   -----   -----   -----        ----
<S>    <C>     <C>     <C>     <C>     <C>
1.46x  1.72x   1.69x   1.77x   2.04x        1.37x
</TABLE>

     For purposes of computing our consolidated ratio of earnings to fixed
charges, earnings consist of pretax income before adjustment for minority
interests in our consolidated subsidiaries or income or loss from equity
investees, plus fixed charges, amortization of capitalized interest, and
distributed income of equity investees, reduced by interest capitalized and the
minority interest in pretax income of subsidiaries that have not incurred fixed
charges. Fixed charges consist of interest expensed and capitalized (including
amortized premiums, discounts and capitalized expenses related to indebtedness),
an estimate of the interest within rental expense, and the distributions on the
company-obligated mandatorily redeemable convertible preferred securities of
subsidiary trusts ("HIGH TIDES"(SM)). This information does not reflect any
impact on Calpine's financial position or results of operations that will result
from our business combination under the pooling of interest method of accounting
consummated on April 19, 2001 with Encal Energy Ltd.

                                USE OF PROCEEDS

     The selling holders will receive all of the net proceeds of the resale of
the Debentures, and the common stock issuable upon conversion of the Debentures.
We will not receive any of the proceeds from the resale of any of those
securities.

                                        20
<PAGE>   22

                                SELLING HOLDERS

     The Debentures were originally issued and sold to the Initial Purchaser.
The Initial Purchaser immediately sold the Debentures in transactions exempt
from the registration requirements of the Securities Act to persons reasonably
believed by them to be qualified institutional buyers as defined in Rule 144A
under the Securities Act.

     The selling holders may from time to time offer and sell pursuant to this
prospectus any or all of the Debentures and the common stock issuable upon
conversion of the Debentures. Any selling holder may also elect not to sell any
Debentures or common stock issuable upon conversion of the Debentures held by
it. The term "selling holder" includes the holders listed below and the
beneficial owners of the Debentures and their transferees, pledgees, donees or
other successors. Only those Debentures and shares of common stock issuable upon
conversion of the Debentures listed below may be offered for resale by the
selling holders pursuant to this prospectus.

     The selling holders may offer and sell any or all of the Debentures and the
common stock issuable upon conversion of the Debentures listed below by using
this prospectus. Because the selling holders may offer all or only some portion
of the Debentures or the common stock issuable upon conversion of the Debentures
listed in the table, no estimate can be given as to the amount of those
securities that will be held by the selling holders upon termination of any such
sales. In addition, the selling holders identified in the table below may have
sold, transferred or disposed of all or a portion of their Debentures or shares
of common stock issuable upon conversion of the Debentures since the date on
which they provided the information regarding their ownership of those
securities included in this prospectus.

     The following table sets forth recent information with respect to the
selling holders of the Debentures and the respective number of Debentures and
shares of common stock issuable upon conversion of the Debentures beneficially
owned by each selling holder that may be offered for such selling holder's
account pursuant to this prospectus. We prepared the table based on information
supplied to us by the selling holders.

<TABLE>
<CAPTION>
                                                              AGGREGATE PRINCIPAL
                                                              AMOUNT AT MATURITY
                       SELLING HOLDER                            OF DEBENTURES
                       --------------                         -------------------
<S>                                                           <C>
[to come]

</TABLE>

     To our knowledge, none of the selling holders has, or has had within the
past three years, any position, office or other material relationship with
Calpine or any of its predecessors or affiliates, except that Goldman, Sachs &
Co. acted as the Initial Purchaser of the Debentures and acts as an adviser to
Calpine from time to time with respect to other matters.

                                        21
<PAGE>   23

                              PLAN OF DISTRIBUTION

     The Debentures and the common stock issuable upon conversion of the
Debentures may be offered and sold from time to time to purchasers directly by
the selling holders. Alternatively, the selling holders may from time to time
offer those securities to or through underwriters, broker-dealers or agents, who
may receive compensation in the form of underwriting discounts, concessions or
commissions from the selling holders or the purchasers of the securities for
whom they act as agents. The selling holders and any underwriters,
broker-dealers or agents that participate in the distribution of the securities
may be deemed to be "underwriters" within the meaning of the Securities Act, and
any profit on the sale of such securities and any discounts, commissions,
concessions or other compensation received by any such underwriter,
broker-dealer or agent may be deemed to be underwriting discounts and
commissions under the Securities Act.

     The securities may be sold from time to time in one or more transactions at
fixed prices, at prevailing market prices at the time of sale, at varying prices
determined at the time of sale or at negotiated prices. The sale of the
securities may be effected in transactions, which may involve crosses or block
transactions:

     - on any national securities exchange or quotation service on which the
       securities may be listed or quoted at the time of sale,

     - in the over-the-counter market,

     - in transactions otherwise than on such exchanges or in the
       over-the-counter market, or

     - through the writing and exercise of options.

     At the time a particular offering of the securities is made, if required, a
prospectus supplement will be distributed, which will set forth the names of the
selling holders, the aggregate amount and type of securities being offered and
the terms of the offering, including the name or names of any underwriters,
broker-dealers or agents, any discounts, commissions and other terms
constituting compensation from the selling holders and any discounts,
commissions or concessions allowed or reallowed to paid broker-dealers.

     To comply with the securities laws of certain jurisdictions, if applicable,
the securities will be offered or sold in such jurisdictions only through
registered or licensed brokers or dealers. In addition, in certain jurisdictions
the securities may not be offered or sold unless they have been registered or
qualified for sale in such jurisdictions or any exemption from registration or
qualification is available and is complied with.

     The selling securityholders and any other person participating in such
distribution will be subject to applicable provisions of the Securities Exchange
Act and the rules and regulations thereunder, including, without limitation,
Regulation M of the Exchange Act, which may limit the timing of purchases and
sales of any of the offered securities by the selling securityholders and any
other such person. Furthermore, Regulation M may restrict the ability of any
person engaged in the distribution of the offered securities to engage in
market-making activities with respect to the particular offered securities being
distributed. All of the foregoing may affect the marketability of the offered
securities and the ability of any person or entity to engage with respect to the
offered securities.

     Pursuant to a registration rights agreement, we have borne all fees and
expenses incurred in connection with the registration of the securities, except
that selling holders will pay all broker's commissions and underwriting
discounts and commissions, if any, in connection with any sales effected
pursuant to this prospectus. The selling holders will be indemnified by us
against certain civil liabilities, including certain liabilities under the
Securities Act or the Securities Exchange Act or otherwise, or alternatively
will be entitled to contribution in connection with those liabilities.

                                        22
<PAGE>   24

                          PRICE RANGE OF COMMON STOCK

     Our common stock is traded on the New York Stock Exchange under the symbol
"CPN." Public trading of the common stock commenced on September 20, 1996. Prior
to that, there was no public market for the common stock. The following table
sets forth, for the periods indicated, the high and low sale price per share of
the common stock on the New York Stock Exchange. The information in the
following table reflects the 2 for 1 stock split that became effective on
October 7, 1999, the 2 for 1 stock split that became effective on June 8, 2000
and the 2 for 1 stock split that became effective on November 14, 2000.

<TABLE>
<CAPTION>
                                                          HIGH        LOW
                                                         -------    -------
<S>                                                      <C>        <C>
1999
  First Quarter........................................  $ 4.672    $ 3.157
  Second Quarter.......................................    7.375      4.391
  Third Quarter........................................   11.969      6.852
  Fourth Quarter.......................................   16.375     10.633
2000
  First Quarter........................................  $30.750    $16.094
  Second Quarter.......................................   35.219     18.125
  Third Quarter........................................   52.250     32.250
  Fourth Quarter.......................................   52.969     32.250
2001
  First Quarter........................................  $ 58.04    $ 29.00
  Second Quarter.......................................    57.35      36.20
  Third Quarter (through July 26, 2001)................    46.00      32.50
</TABLE>

     As of July 26, 2001, there were approximately 844 holders of record of our
common stock. On July 26, 2001, the last sale price reported on the NYSE for our
common stock was $36.89 per share.

                                DIVIDEND POLICY

     We do not anticipate paying any cash dividends on our common stock in the
foreseeable future because we intend to retain our earnings to finance the
expansion of our business and for general corporate purposes. In addition, our
ability to pay cash dividends is restricted under certain of our indentures and
our other debt agreements. Future cash dividends, if any, will be at the
discretion of our board of directors and will depend upon, among other things,
our future operations and earnings, capital requirements, general financial
condition, contractual restrictions and such other factors as the board of
directors may deem relevant.

                                        23
<PAGE>   25

                                 CAPITALIZATION

     The following table sets forth, as of March 31, 2001, (1) our actual
consolidated capitalization; and (2) the consolidated capitalization of Calpine
as adjusted to reflect the net effect of (a) our acquisition of WRMS
Engineering, Inc. on April 3, 2001, including the issuance of our common stock
in connection therewith, (b) our business combination with Encal, including the
issuance of our common stock upon exchange of the exchangeable securities
offered thereby, (c) the sale of $1.5 billion in aggregate principal amount of
Energy Finance's 8 1/2% Senior Notes Due 2008, guaranteed by us and the use of
proceeds thereof, (d) the sale of $1.0 billion in aggregate principal amount of
the Debentures offered hereby and the use of proceeds thereof and (e) the
redemption of $105 million in aggregate principal amount of our 9 1/4% Senior
Notes Due 2004. The adjustments do not reflect normal day-to-day operations.
This table should be read in conjunction with the consolidated financial
statements and related notes thereto and the unaudited pro forma combined
condensed financial statements and related notes thereto incorporated by
reference in this prospectus.

<TABLE>
<CAPTION>
                                                                   MARCH 31, 2001
                                                              -------------------------
                                                                ACTUAL      AS ADJUSTED
                                                                ------      -----------
                                                                     (UNAUDITED)
                                                                   (IN THOUSANDS,
                                                                EXCEPT SHARE AMOUNTS)
<S>                                                           <C>           <C>
SHORT-TERM DEBT:
  Notes payable and borrowings under lines of credit,
     current portion........................................  $      851    $       851
  Project financing, current portion........................      91,571          1,177
  Capital lease obligation, current portion.................       2,050          2,050
  Zero-Coupon Convertible Debentures Due 2021...............          --      1,000,000
                                                              ----------    -----------
                                                                  94,472      1,004,078
LONG-TERM DEBT:
  Notes payable and borrowings under lines of credit, net of
     current portion........................................     133,955          7,713
  Project financing, net of current portion.................   1,646,564        841,958
  Senior notes..............................................   3,701,750      5,096,750
  Capital lease obligation, net of current portion..........     208,840        209,065
                                                              ----------    -----------
     Total long-term debt...................................   5,691,109      6,155,486
                                                              ----------    -----------
  Company-obligated mandatorily redeemable convertible
     preferred securities of subsidiary trusts..............   1,122,686      1,122,686
Minority interests..........................................      41,180         41,180
                                                              ----------    -----------
STOCKHOLDERS' EQUITY:
  Preferred stock, $.001 par value:
  10,000,000 shares authorized; no shares outstanding,
     actual, and one share outstanding, as adjusted.........          --             --
                                                              ----------    -----------
  Common stock, $.001 par value: 1,000,000,000 shares
     authorized, 285,113,768 shares outstanding, actual, and
     301,868,577 shares outstanding, as adjusted............         285            302
  Additional paid-in capital................................   1,734,202      1,938,183
  Retained earnings.........................................     631,394        607,413
  Accumulated other comprehensive loss......................     (56,694)       (77,344)
                                                              ----------    -----------
     Total stockholders' equity.............................   2,309,187      2,468,554
                                                              ----------    -----------
     Total capitalization...................................  $9,258,634    $10,791,984
                                                              ==========    ===========
</TABLE>

                                        24
<PAGE>   26

                               SECURITIES OFFERED

     Using this prospectus, selling holders may offer for sale the Debentures
and the common stock into which the Debentures are convertible. We registered
all of these securities under the Securities Act using a "shelf" registration
statement. This shelf registration statement allows the selling holders to offer
and sell any combination of these securities. Each time selling holders offer
securities during the period of time that we are required by the Registration
Rights Agreement to keep the shelf registration statement effective, such
selling holder must provide this prospectus, which names the selling holders and
describes the specific securities offered. This prospectus may be amended or
supplemented by one or more prospectus supplements, which may provide new
information or update the information in this prospectus.

                                        25
<PAGE>   27

                           DESCRIPTION OF DEBENTURES

     We issued the Debentures under an indenture (the "Indenture") between the
Company and Wilmington Trust Company, as trustee (the "Trustee").

     In this section, references to "Calpine," "we," "our" or "us" refer solely
to Calpine Corporation and not its subsidiaries.

GENERAL

     The Debentures are senior unsecured obligations of Calpine, are limited to
an aggregate initial principal amount of $1,000,000,000, plus accrued interest
pursuant to any Upward Interest Adjustments. The Debentures will mature on April
30, 2021. The Debentures rank equally with all of our existing and future senior
unsecured indebtedness.

     We issued the Debentures at a price to investors of $1,000 per Debenture.
We will not pay interest on the Debentures unless an Upward Interest Adjustment
becomes payable or we elect to do so following a Tax Event. The maturity value
of each Debenture may exceed $1,000 in the event an Upward Interest Adjustment
becomes payable on the Debentures. The issue price represents a yield to
maturity of 0% per annum unless an Upward Interest Adjustment occurs. The
Debentures issued only in denominations of $1,000 principal amount and multiples
of $1,000 principal amount.

     You have the option, at any time on or prior to 5:00 p.m., New York City
time, on April 29, 2021, unless previously redeemed or otherwise repurchased by
Calpine, to convert your Debentures into shares of our common stock at a
conversion rate of 13.2714 shares of common stock per $1,000 principal amount of
the Debentures. This is equivalent to an initial conversion price of $75.35 per
share of common stock based on the price to investors of the Debentures. The
conversion rate is subject to adjustment if certain events occur. Upon
conversion, you will receive only shares of common stock. You will not receive
any cash payment for any accrued interest to the conversion date. To calculate
earnings per share following this offering, we will be using the as-converted
method to account for the potential dilutive effect of the Debentures.

     Each holder agreed in the Indenture, for U.S. federal income tax purposes,
to treat the Debentures as "contingent payment debt instruments" and to be bound
by our application of the Treasury regulations that govern contingent payment
debt instruments, including our determination that the rate at which interest
will be deemed to accrue for federal income tax purposes will be 9.44% per
annum, which is the rate comparable to the rate at which the Issuer would borrow
on a noncontingent, nonconvertible borrowing. Based on the agreement, (i) each
holder will be required to accrue interest on a constant yield to maturity basis
at that rate, with the result that a holder will recognize taxable income
significantly in excess of cash received while the Debentures are outstanding,
and (ii) a holder will recognize ordinary income upon a conversion of a
Debenture into our common stock equal to the excess, if any, between the value
of the common stock received on the conversion and the sum of the original
purchase price of the holder's Debenture and accrued but unpaid interest.
However, the proper application of the regulations that govern contingent
payment debt instruments to a holder of a Debenture is uncertain in a number of
respects, and if our treatment were successfully challenged by the Internal
Revenue Service, it might be determined that, among other differences, a holder
should have accrued interest income at a lower rate, should not have recognized
income or gain upon the conversion, and should not have recognized ordinary
income upon a taxable disposition of its Debenture. In addition, if the Internal
Revenue Service successfully asserts that the Debentures are not debt, Non-U.S.
Holders would generally be subject to a 30% Unites States federal withholding
tax on payments of contingent interest made in respect of the Debentures. See
"Certain United States Federal Income Tax Consequences."

                                        26
<PAGE>   28

     HOLDERS SHOULD CONSULT THEIR TAX ADVISORS REGARDING THE TAX TREATMENT OF
THE DEBENTURES AND WHETHER A PURCHASE OF THE DEBENTURES IS ADVISABLE IN LIGHT OF
THE AGREED UPON TAX TREATMENT AND THE INVESTOR'S PARTICULAR TAX SITUATION.

INTEREST ADJUSTMENT

     An Upward Interest Adjustment (equivalent to 7.25% per annum) may be made
on April 30, 2004, 2006, 2008, 2011 or 2016. An Upward Interest Adjustment will
be made on each Upward Interest Adjustment Date if the Trading Price of the
Debentures is less than 98% of the Accreted Value as of such Upward Interest
Adjustment Date for 20 out of the last 30 NYSE trading days ending 90 days prior
to such Upward Interest Adjustment Date. If an Upward Interest Adjustment is in
effect for a particular semi-annual period, we will pay a portion of the Upward
Interest Adjustment as cash interest at a rate of 0.25% per annum (0.125% per
semi-annual period) of the Accreted Value as of the beginning of the applicable
semi-annual period and the remaining interest (7.0% per annum) will be accrued
and payable at the earlier of maturity or the redemption or the repurchase of
the Debentures. We will pay cash interest on each April 30 and October 30 for
which an Upward Interest Adjustment is in effect, to the holders of record on
the preceding April 15 and October 15, respectively. Interest will be determined
on the basis of a 360-day year, consisting of twelve 30-day months.

     If an Upward Interest Adjustment is in effect during a semi-annual period
(other than a semi-annual period immediately preceding an Upward Interest
Adjustment Date) and the Trading Price of the Debentures is greater than or
equal to 98% of the Accreted Value as of the next following interest payment
date for 20 out of the last 30 NYSE trading days ending on such interest payment
date, the Upward Interest Adjustment will be subject to a Downward Interest
Adjustment on such interest payment date, such that from and including such date
the Debentures will cease to accrue interest unless and until there is a
subsequent Upward Interest Adjustment. If an Upward Interest Adjustment is in
effect during a semi-annual period immediately preceding an Upward Interest
Adjustment Date, a Downward Interest Adjustment will be made on the next Upward
Interest Adjustment Date if the Trading Price of the Debentures is greater than
or equal to 98% of the Accreted Value as of such Upward Interest Adjustment Date
for 20 out of the last 30 NYSE trading days ending 90 days prior to such Upward
Interest Adjustment Date. If a Downward Interest Adjustment is made, no Upward
Interest Adjustment may be made until the next Upward Interest Adjustment Date.

     The "Trading Price" of the Debentures on any date of determination means
the average of the secondary market bid quotations per Debenture obtained by the
bid solicitation agent for $10,000,000 principal amount at maturity of the
Debentures at approximately 3:30 p.m., New York City time, on such determination
date from three independent nationally recognized securities dealers we select,
provided that if at least three such bids are not obtained by the bid
solicitation agent, but two such bids are obtained, then the average of the two
bids shall be used, and if only one such bid is obtained by the bid solicitation
agent, this one bid shall be used. If the bid solicitation agent cannot obtain
at least one bid for $10,000,000 principal amount at maturity of the Debentures
from a nationally recognized securities dealer or in our reasonable judgment,
the bid quotations are not indicative of the secondary market value of the
Debentures, then the Trading Price of the Debentures will equal (a) the
then-applicable conversion rate of the Debentures multiplied by (b) the closing
price on the NYSE of our common stock on such determination date.

     The bid solicitation agent will initially be The Bank of New York. We may
change the bid solicitation agent, but the bid solicitation agent will not be
our affiliate. The bid solicitation agent will solicit bids from securities
dealers that are believed by us to be willing to bid for the Debentures.

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<PAGE>   29

     In the event of any Upward Interest Adjustment, we will disseminate a press
release not later than three business days prior to the relevant Upward Interest
Adjustment Date through Dow Jones & Company, Inc. or Bloomberg Business News
containing this information and publish the information on our Website on the
World Wide Web or through such other public medium as we may use at that time.

TAX EVENT

     We have the option, under limited circumstances, to elect to pay cash
interest at a rate of 7.25% per annum on the Debentures from and after the date
a Tax Event occurs instead of accruing interest pursuant to an Upward Interest
Adjustment. Such cash interest would only be payable during periods in which an
Upward Interest Adjustment is in effect. If we make such an election, the
principal amount on which we pay interest will be restated and will be equal to
the issue price plus accrued and unpaid interest payable pursuant to an Upward
Interest Adjustment to the date on which we exercise our option to commence
paying cash interest. The Restated Principal Amount will be the amount due at
maturity. If we elect this option, interest will be based on a 360-day year,
consisting of twelve 30-day months. Interest will accrue from the date we
exercise our option to declare the occurrence of a Tax Event and will be payable
semi-annually in arrears on each April 30 and October 30 to the holders of
record on the preceding April 15 and October 15, respectively.

     The term "Tax Event" means the receipt by us of an opinion of a nationally
recognized independent tax counsel experienced in such matters to the effect
that as a result of:

     - any amendment to or change (including any announced prospective change
       (which will not include a proposed change), provided that a Tax Event
       will not occur more than 90 days before the effective date of any
       prospective change) in the laws (or any regulations thereunder) of the
       United States or any political subdivision or taxing authority of the
       United States or any political subdivision; or

     - any judicial decision or official administrative pronouncement, ruling,
       regulatory procedure, notice or announcement, including any notice or
       announcement of intent to adopt such procedures or regulations (an
       "Administrative Action"); or

     - any amendment to or change in the administrative position or
       interpretation of any Administrative Action or judicial decision that
       differs from the theretofore generally accepted position, in each case,
       by any legislative body, court, governmental agency or regulatory body,
       irrespective of the manner in which such amendment or change is made
       known, which amendment or change is effective or such Administrative
       Action or decision is announced, in each case, on or after the date of
       original issuance of the Debenture;

there is more than an insubstantial risk that interest, including original issue
discount, payable on the Debentures either:

     (1) would not be deductible on a current accrual basis; or

     (2) would not be deductible under any other method, in whole or in part, by
         us for United States federal income tax purposes.

INTEREST

     We will not pay cash interest on the Debentures unless there is an Upward
Interest Adjustment in effect or if we elect to do so following a Tax Event.
Interest will be based on a 360-day year, consisting of twelve 30-day months,
and will be payable semi-annually in arrears on each April 30 and October 30.
Cash interest as a result of an Upward Interest Adjustment will be paid at the
rate of 0.25% per annum (0.125% per semi-annual period). Cash interest following
a Tax Event and our election to pay the interest in cash will be paid at a rate
of 7.25% per

                                        28
<PAGE>   30

annum on the Debentures during any period in which an Upward Interest Adjustment
is in effect. The record date for the payment of cash interest to holders will
be April 15 and October 15 of each year. We will give notice to the holders of
the Debentures, no later than 30 days prior to each record date, of the amount
of cash interest to be paid as of the next interest payment date. We will pay
interest on the Debentures by check mailed to the address of the registered
holders of the Debentures as of the record date relating to each interest
payment date.

     You should be aware that interest, including any adjustments occurring as a
result of an Upward Interest Adjustment, accruing for the period you hold the
Debentures must be included in your gross income for federal income tax purposes
in accordance with the Treasury Regulations governing debt instruments providing
for contingent payments. For more information, see the discussion below in the
section captioned "Certain United States Federal Income Tax Consequences."

REDEMPTION RIGHTS

     We must repay the Debentures at their stated maturity on April 30, 2021,
unless earlier redeemed. The circumstances in which we may, or we are required
to, redeem the Debentures prior to their stated maturity are described below.

     We have the right to redeem the Debentures in whole or in part, at any time
or from time to time, on or after April 30, 2004 upon not less than 30 nor more
than 60 days' notice by mail to holders of the Debentures for a cash price equal
to the issue price plus any accrued and unpaid interest to the redemption date.

     If we decide to redeem fewer than all of the outstanding Debentures, the
Trustee will select the Debentures to be redeemed by such method as the Trustee
considers fair and appropriate and which may provide for the selection for
redemption of portions of the Debentures.

     If we have previously exercised our option to pay cash interest instead of
accruing interest on the Debentures following a Tax Event, the redemption price
will be equal to the Restated Principal Amount plus any accrued and unpaid cash
interest through the redemption date. See "-- Tax Event."

     If the Trustee selects a portion of your Debentures for partial redemption
and you convert a portion of the same Debentures, the converted portion will be
deemed to be the portion selected for redemption. Each Debenture selected for
redemption will be redeemed in whole.

     In the event of any redemption in part, we will not be required to:

     - issue, register the transfer of or exchange any Debenture during a period
       beginning at the opening of business 15 days prior to the mailing of the
       relevant notice of redemption and ending at the close of business on the
       day of mailing of the notice, or

     - register the transfer of or exchange any Debenture so selected for
       redemption, in whole or in part, except the unredeemed portion of any
       Debenture being redeemed in part.

CONVERSION RIGHTS

     You may surrender your Debentures for conversion into common stock at any
time prior to 5:00 p.m., New York City time, on April 29, 2021. You may convert
each Debenture, pursuant to the initial conversion ratio, into 13.2714 shares of
our common stock (equivalent to an initial conversion price of $75.35 per share
of common stock). The conversion ratio and the equivalent conversion price in
effect at any given time are referred to in this prospectus as the applicable
conversion ratio and the applicable conversion price, respectively, and will be
subject to adjustment as described below. If a Debenture has been called for
redemption, you will be entitled to convert the Debenture from the date of
notice of the redemption until the close of business on the business day
immediately preceding the date of redemption. You may convert

                                        29
<PAGE>   31

fewer than all of your Debentures so long as the Debentures converted are a
multiple of $1,000 principal amount.

     Upon conversion of any Debentures you will not receive any cash payment
representing accrued interest with respect to the converted Debentures. Instead,
upon conversion we will deliver to you a fixed number of shares of common stock
and any cash payment to account for fractional shares. The cash payment for
fractional shares will be based on the closing price of our common stock on the
NYSE trading day immediately prior to the conversion date. Delivery of shares of
common stock will be deemed to satisfy our obligation to pay the principal
amount of the Debentures, including accrued interest. Accrued interest will be
deemed paid in full rather than canceled, extinguished or forfeited. We will not
adjust the conversion ratio to account for the accrued interest.

     If you wish to exercise your conversion right, you must deliver an
irrevocable conversion notice, together, if the Debentures are in certificated
form, with the certificated security, to the conversion agent who will, on your
behalf, convert the Debentures into shares of our common stock. You may obtain
copies of the required form of the conversion notice from the conversion agent.

     Based upon our treatment of the Debentures for U.S. federal income tax
purposes, as discussed above, a holder would be required to recognize ordinary
income upon a conversion of a Debenture into our common stock equal to the
excess, if any, between the value of the stock received on the conversion and
the sum of the original purchase price of the holder's Debenture and accrued but
unpaid interest. For a more detailed discussion, see "Certain United States
Federal Income Tax Consequences."

     The conversion rate will be subject to adjustment upon the following
events:

     - the payment of dividends and other distributions payable exclusively in
       our common stock on our common stock;

     - the issuance to all holders of our common stock of rights or warrants
       that allow the holders to purchase shares of our common stock at less
       than the current market price; provided that no adjustment will be made
       if holders of the Debentures may participate in the transaction on a
       basis and with notice that our board of directors determines to be fair
       and appropriate or in some other cases;

     - subdivisions or combinations of our common stock;

     - the payment of dividends and other distributions to all holders of our
       common stock, consisting of evidences of our indebtedness, securities or
       capital stock, cash or assets, except for those rights or warrants
       referred to in the second bullet point above and dividend and other
       distributions paid exclusively in cash; provided that no adjustment will
       be made if all holders of the Debentures may participate in the
       transactions;

     - the payment to holders of our common stock in respect of a tender or
       exchange offer, other than an odd-lot offer, by us or any of our
       subsidiaries for our common stock to the extent that the offer involves
       aggregate consideration that, together with (1) any cash and the fair
       market value of any other consideration payable in respect of any tender
       offer by us or any of our subsidiaries for shares of our common stock
       consummated within the preceding 12 months not triggering a conversion
       price adjustment and (2) all-cash distributions to all or substantially
       all stockholders made within the preceding 12 months not triggering a
       conversion price adjustment, exceeds an amount equal to 12.5% of the
       market capitalization of our common stock on the expiration date of the
       tender offer; and

     - the distribution to all or substantially all holders of our common stock
       of all-cash distributions in an aggregate amount that, together with (1)
       any cash and the fair market value of any other consideration payable in
       respect of any tender offer by us or any of our

                                        30
<PAGE>   32

       subsidiaries for shares of our common stock consummated within the
       preceding 12 months not triggering a conversion price adjustment and (2)
       all other all-cash distributions to all or substantially all holders of
       our common stock made within the preceding 12 months not triggering a
       conversion price adjustment, exceeds an amount equal to 12.5% of the
       market capitalization of our common stock on the business day immediately
       preceding the day on which we declare the distribution.

     The applicable conversion price will not be adjusted:

     - upon the issuance of any shares of our common stock pursuant to any
       present or future plan providing for the reinvestment of dividends or
       interest payable on securities of Calpine and the investment of
       additional optional amounts in shares of our common stock under any plan,

     - upon the issuance of any shares of our common stock or options or rights
       to purchase those shares pursuant to any present or future employee,
       director or consultant benefit plan or program of Calpine,

     - upon the issuance of any shares of our common stock pursuant to any
       option, warrant, right, or exercisable, exchangeable or convertible
       security outstanding as of the date the Debentures were first issued, or

     - upon the issuance of any rights, any distribution of separate
       certificates representing the rights, any exercise or redemption of any
       rights or any termination or invalidation of the rights, pursuant to our
       stockholders rights plan.

     We may increase the conversion rate for at least 20 days, so long as the
increase is irrevocable during that 20-day period. No adjustment in the
applicable conversion price will be required unless the adjustment would require
an increase or decrease of at least 1% of the applicable conversion price. If
the adjustment is not made because the adjustment does not change the applicable
conversion price by more than 1%, then the adjustment that is not made will be
carried forward and taken into account in any future adjustment. Except as
specifically described above, the applicable conversion price will not be
subject to adjustment in the case of the issuance of any of our common stock, or
securities convertible into or exchangeable for our common stock.

     If you submit your Debenture for conversion after we have elected to
exercise our option to pay cash interest instead of accruing interest following
a Tax Event or if we are required to make a cash payment pursuant to an Upward
Interest Adjustment, after a record date and prior to the opening of business on
the next interest payment date (except for Debentures or portions of Debentures
called for redemption on a redemption date on a date in such period), you must
pay funds equal to the interest payable on the converted principal amount.

REPURCHASE RIGHT

     You have the right to require us to repurchase your Debentures on April 30,
2002, 2004, 2006, 2008, 2011 and 2016. We will be required to repurchase any
outstanding Debentures for which you deliver a written repurchase notice to the
paying agent. This notice must be delivered during the period beginning at any
time from the opening of business on the date that is 20 business days prior to
the relevant repurchase date until the close of business on the last business
day prior to such repurchase date. If the repurchase notice is given and
withdrawn during the period, we will not be obligated to repurchase the related
Debentures. Our repurchase obligation will be subject to some additional
conditions. Also, our ability to satisfy our repurchase obligations may be
affected by the factors described in "Risk Factors" under the caption "We May Be
Unable to Repay the Debentures When Due or Repurchase the Debentures When We Are
Required to Do So."

     The repurchase price payable will be equal to the issue price plus any
accrued and unpaid interest to such repurchase date.

                                        31
<PAGE>   33

     We may choose, in our sole discretion, to pay the repurchase price in cash
or shares of our common stock, or a combination of cash and shares of our common
stock except on April 30, 2016 when we may only pay the repurchase price in
cash. For a discussion of the tax treatment of a holder receiving cash, shares
of our common stock or any combination thereof, see "Certain United States
Federal Income Tax Consequences."

     If we have previously exercised our option to pay cash interest instead of
accruing interest on the Debentures following a Tax Event, the repurchase price
will be the Restated Principal Amount plus any accrued and unpaid cash interest
through the repurchase date. See "-- Tax Event."

     If we choose to pay the repurchase price, in whole or in part, in shares of
our common stock or a combination of cash and shares of our common stock, we
will be required to give notice on a date not less than 20 business days prior
to each repurchase date to all holders at their addresses shown in the register
of the registrar, and to beneficial owners as required by applicable law (i.e.
if no notice is given, we will pay the repurchase price with cash), stating
among other things:

     - whether we will pay the repurchase price of the Debentures in cash, in
       shares of our common stock, or any combination thereof, and specifying
       the percentages of each;

     - if we elect to pay with common stock, the method of calculating the price
       of the common stock; and

     - the procedures that holders must follow to require us to repurchase their
       Debentures.

     If we pay with shares of our common stock, they will be valued at 100% of
the market price for our common stock.

     The "market price" means the average of the sale prices of our common stock
on the NYSE for the five NYSE trading day period ending on the third business
day prior to the applicable repurchase date (if the third business day prior to
the applicable repurchase date is a NYSE trading day, or if not, then on the
last NYSE trading day prior to the third business day), appropriately adjusted
to take into account the occurrence, during the period commencing on the first
of the NYSE trading days during the five NYSE trading day period and ending on
the repurchase date, of some events that would result in an adjustment of the
conversion rate with respect to our common stock.

     The "sale price" of our common stock on any date means the closing per
share sale price on the NYSE (or if no closing sale price is reported, the
average of the bid and ask prices or, if more than one in either case, the
average of the average bid and the average asked prices) on that date as
reported on the NYSE.

     Your notice electing to require us to repurchase your Debentures must
state:

     - if certificated Debentures have been issued, the Debentures certificate
       numbers, or if not certificated, your notice must comply with appropriate
       DTC procedures;

     - the portion of the principal amount of Debentures to be repurchased, in
       multiples of $1,000;

     - that the Debentures are to be repurchased by us pursuant to the
       applicable provisions of the Debentures; and

     - in the event we elect, pursuant to the notice that we are required to
       give, to pay the repurchase price in shares of common stock, in whole or
       in part, but the repurchase price is ultimately to be paid to the holder
       entirely in cash because any of the conditions to payment of the
       repurchase price or portion of the repurchase price in shares of common

                                        32
<PAGE>   34

       stock is not satisfied prior to the close of business on the last day
       prior to the repurchase date, as described below, whether the holder
       elects:

          (1) to withdraw the repurchase notice as to some or all of the
              Debentures to which it relates, or

          (2) to receive cash in respect of the entire repurchase price for all
              Debentures or portions of Debentures subject to the repurchase
              notice.

     If the holder fails to indicate the holder's choice with respect to the
election described in the final bullet point above, the holder will be deemed to
have elected to receive cash in respect of the entire repurchase price for all
Debentures subject to the repurchase notice in these circumstances. For a
discussion of the tax treatment of a holder receiving cash instead of shares of
common stock, see "Certain United States Federal Income Tax Consequences."

     You may withdraw any repurchase notice by a written notice of withdrawal
delivered to the paying agent prior to the close of business on the last day
prior to the repurchase date. The notice of withdrawal must state:

     - the principal amount of the withdrawn Debentures;

     - if certificated Debentures have been issued, the certificate numbers of
       the withdrawn Debentures, or if not certificated, your notice must comply
       with appropriate DTC procedures; and

     - the principal amount, if any, which remains subject to the repurchase
       notice.

     If we elect to pay the repurchase price, in whole or in part, in shares of
common stock, the number of shares to be delivered by us will be equal to the
portion of the repurchase price to be paid in common stock divided by the market
price of one share of common stock as determined by us in our repurchase notice.
We will pay cash based on the market price for all fractional shares.

     Because the market price of our common stock is determined prior to the
applicable repurchase date, holders of Debentures bear the market risk with
respect to the value of the common stock to be received from the date the market
price is determined to the repurchase date. We may pay the repurchase price or
any portion of the repurchase price in shares of common stock only if the
information necessary to calculate the market price is published in a daily
newspaper of national circulation or is otherwise publicly available (e.g., by
dissemination on the World Wide Web or by other public means).

     Upon determination of the actual number of shares of common stock to be
paid upon repurchase of the Debentures, we will disseminate a press release not
later than three business days prior to the relevant interest payment date
through Dow Jones & Company, Inc. or Bloomberg Business News containing this
information and publish the information on our Website on the World Wide Web or
through such other public medium as we may use at that time.

     A holder must either effect book-entry transfer or deliver the Debentures,
together with necessary endorsements, to the office of the paying agent after
delivery of the repurchase notice to receive payment of the repurchase price.
You will receive payment on the later of the repurchase date or the time of
book-entry transfer or the delivery of the Debentures. If the paying agent holds
money or securities sufficient to pay the repurchase price of the Debentures on
the business day following the repurchase date, then:

     - the Debentures will cease to be outstanding;

     - interest, including any interest payable pursuant to an Upward Interest
       Adjustment (including any cash interest) will cease to accrue; and

                                        33
<PAGE>   35

     - all other rights of the holder will terminate.

     This will be the case whether or not book-entry transfer of the Debentures
is made or whether or not the Debentures are delivered to the paying agent.

     We will comply with the provisions of Rule 13e-4 and any other tender offer
rules under the Securities Exchange Act which may be applicable at the time. We
will file Schedule TO or any other schedule required in connection with any
offer by us to repurchase the Debentures at your option.

RANKING

     The Debentures constitute senior debt, rank equally with all of our
existing and future senior unsecured debt, and rank senior to any future
subordinated indebtedness.

     We currently conduct substantially all our operations through our
subsidiaries, and our subsidiaries generate substantially all of our operating
income and cash flow. As a result, distributions or advances from our
subsidiaries are the principal source of funds necessary to meet our debt
service obligations. Contractual provisions or laws, as well as our
subsidiaries' financial condition and operating requirements, may limit our
ability to obtain cash from our subsidiaries that we require to pay our debt
service obligations, including payments on the Debentures. In addition, holders
of the Debentures will have a junior position to the claims of creditors of our
subsidiaries on their assets and earnings. As of March 31, 2001, our
subsidiaries had approximately $1.7 billion of project finance debt, without
giving effect to the anticipated use of proceeds, to which the Debentures would
have been structurally subordinated.

CHANGE IN CONTROL

     If a Change in Control as defined below occurs, a holder of Debentures will
have the right, at its option, to require us to repurchase all of its Debentures
not previously called for redemption, or any portion of the principal amount
thereof, that is equal to $1,000 or an integral multiple of $1,000. The price we
are required to pay is equal to the issue price plus any accrued and unpaid
interest to such repurchase date, or, if we elected to pay cash interest on the
Debentures following a Tax Event, the Restated Principal Amount plus any accrued
and unpaid cash interest through the repurchase date.

     At our option, instead of paying the repurchase price in cash, we may pay
the repurchase price in registered shares of our common stock valued at 95% of
the average of the closing prices of our common stock for the five NYSE trading
days immediately preceding and including the third NYSE trading day prior to the
repurchase date. We may only pay the repurchase price in our common stock if we
satisfy conditions provided in the Indenture.

     Within 30 days after the occurrence of a Change in Control, we are
obligated to give to the holders of Debentures notice of the Change in Control
and of the repurchase right arising as a result of the Change in Control. We
must also deliver a copy of this notice to the Trustee. To exercise the
repurchase right, a holder of Debentures must deliver on or before the 30th day
after the date of our notice irrevocable written notice to the Trustee of the
holder's exercise of its repurchase right, together with the Debentures with
respect to which the right is being exercised. We are required to repurchase the
Debentures on the date that is 45 days after the date of our notice.

     A Change in Control will be deemed to have occurred at the time after the
Debentures are originally issued that any of the following occurs:

          (1) any person, including any syndicate or group deemed to be a
     "person" under Section 13(d)(3) of the Exchange Act, acquires beneficial
     ownership, directly or indirectly, through a purchase, merger or other
     acquisition transaction or series of transactions, of

                                        34
<PAGE>   36

     shares of our capital stock entitling the person to exercise 50% or more of
     the total voting power of all shares of our capital stock that is entitled
     to vote generally in elections of directors, other than an acquisition by
     us, any of our subsidiaries or any of our employee benefit plans; or

          (2) we merge or consolidate with or into any other person, any merger
     of another person into us, or we convey, sell, transfer or lease all or
     substantially all of our assets to another person, other than any
     transaction:

        - that does not result in any reclassification, conversion, exchange or
          cancellation of outstanding shares of our capital stock, or

        - pursuant to which the holders of our common stock immediately prior to
          the transaction have the entitlement to exercise, directly or
          indirectly, 50% or more of the total voting power of all shares of
          capital stock entitled to vote generally in the election of directors
          of the continuing or surviving corporation immediately after the
          transaction, or

        - which is effected solely to change our jurisdiction of incorporation
          and results in a reclassification, conversion or exchange of
          outstanding shares of our common stock solely into shares of common
          stock of the surviving entity.

     However, a Change in Control will not be deemed to have occurred if either
(A) the closing price per share of our common stock on the NYSE for any five
NYSE trading days within the period of 10 consecutive NYSE trading days ending
immediately after the later of the Change in Control or the public announcement
of the Change in Control, in the case of a Change in Control relating to an
acquisition of capital stock, or the period of 10 consecutive NYSE trading days
ending immediately before the Change in Control, in the case of Change in
Control relating to a merger, consolidation or asset sale, equals or exceeds
105% of the conversion price of the Debentures in effect on each of those NYSE
trading days or (B) all of the consideration (excluding cash payments for
fractional shares and cash payments made pursuant to dissenters' appraisal
rights) in a merger or consolidation otherwise constituting a Change in Control
under clause (1) and/or clause (2) above consists of shares of common stock
traded on a national securities exchange or quoted on the Nasdaq National Market
(or will be so traded or quoted immediately following the merger or
consolidation) and as a result of the merger or consolidation the Debentures
become convertible into such common stock.

     For purposes of these provisions:

     - the conversion price is equal to $1,000 divided by the conversion rate;

     - whether a person is a "beneficial owner" will be determined in accordance
       with Rule 13d-3 under the Exchange Act; and

     - "person" includes any syndicate or group that would be deemed to be a
       "person" under Section 13(d)(3) of the Exchange Act.

     Rule 13e-4 under the Exchange Act requires the dissemination of prescribed
information to security holders in the event of an issuer tender offer and may
apply in the event that the repurchase option becomes available to the holders
of Debentures. We will comply with this rule to the extent it applies at that
time.

     The definition of Change in Control includes a phrase relating to the
conveyance, transfer, sale, lease or disposition of "all or substantially all"
of our assets. There is no precise, established definition of the phrase
"substantially all" under applicable law. Accordingly, the ability of a holder
of Debentures to require us to repurchase its notes as a result of the
conveyance, transfer, sale, lease or other disposition of less than all of our
assets may be uncertain.

                                        35
<PAGE>   37

     The foregoing provisions would not necessarily provide the holders of
Debentures with protection if we are involved in a highly leveraged or other
transaction that may adversely affect the holders.

     If a Change in Control were to occur, we may not have enough funds to pay
the Change in Control repurchase price. See "Risk Factors" under the caption "We
May Be Unable to Repay the Debentures When Due or Repurchase the Debentures When
We Are Required to Do So." In addition, we have, and may in the future incur,
other indebtedness with similar change in control provisions permitting its
holders to accelerate or to require us to repurchase our indebtedness upon the
occurrence of similar events or on some specified dates. If we fail to
repurchase the Debentures when required following a Change in Control, we will
be in default under the Indenture.

MERGER AND SALES OF ASSETS BY CALPINE

     We may not consolidate with or merge with or into any other person or sell,
assign, convey, transfer, or lease or otherwise dispose of all or substantially
all of our properties and assets as an entirety to any person unless:

     - we shall be the surviving corporation;

     - the person formed by the consolidation or into which we are merged or the
       person to which our properties and assets are so sold, assigned,
       conveyed, transferred, leased or otherwise disposed of, shall be a
       corporation, organized and existing under the laws of the United States,
       any State within the United States or the District of Columbia and shall
       expressly assume, in a form reasonably satisfactory to the Trustee, all
       of our obligations under the Indenture and the Debentures; and

     - immediately after giving effect to the transaction, no event of default
       with respect to the Debentures will have occurred and be continuing.

EVENTS OF DEFAULT

     The following are events of default with respect to the Debentures (each,
an "Event of Default"):

     - default for 30 days in payment of any interest installment due and
       payable on the Debentures (after any Upward Interest Adjustment or any
       election by us to pay cash interest on the Debentures following a Tax
       Event);

     - default in payment of principal of the Debentures (or, if we have elected
       to pay cash interest on the Debentures following a Tax Event, the
       Restated Principal Amount) and accrued interest (including any interest
       payable pursuant to an Upward Interest Adjustment) at maturity, upon
       redemption, repurchase or following a change in control, when the same
       becomes due and payable;

     - material default in our performance of any other covenants or agreements
       in the Debentures or the Indenture which default continues for 30 days
       after the date on which written notice of such default is given to us by
       the Trustee or to us and Trustee by the holders of at least 25% in
       principal amount of the then outstanding Debentures;

     - default by us under any instrument or instruments under which there is or
       may be secured or evidenced any of our indebtedness (other than the
       Debentures) having an outstanding principal amount of $50,000,000 (or its
       equivalent in any other currency or currencies) or more, individually or
       in the aggregate, that has caused the holders thereof to declare such
       indebtedness to be due and payable prior to its stated maturity, unless
       such declaration has been rescinded within 30 days;

                                        36
<PAGE>   38

     - default in the payment of the principal of any bond, debenture, note or
       other evidence of our indebtedness, in each case for money borrowed, or
       in the payment of principal under any mortgage, indenture, agreement or
       instrument under which there may be issued or by which there may be
       secured or evidenced any indebtedness of ours for money borrowed, which
       default for payment of principal is individually or in an aggregate
       principal amount exceeding $50,000,000 (or its equivalent in any other
       currency or currencies) when such indebtedness becomes due and payable
       (whether at maturity, upon redemption or acceleration or otherwise), if
       such default shall continue unremedied or unwaived for more than 30 days
       after the expiration of any grace period or extension of the time for
       payment applicable thereto; and

     - certain events of bankruptcy, insolvency and reorganization.

     The Indenture requires that we file annually with the Trustee a certificate
describing any default by us in the performance of any conditions or covenants
that has occurred under the Indenture and its status. We must give the Trustee,
within 30 days after the occurrence thereof, written notice of any event which
with the giving of notice or lapse of time or both would become an Event of
Default described in the fourth, fifth and sixth bullet points above.

     The Indenture provides that if an Event of Default (other than an Event of
Default relating to certain events of bankruptcy, insolvency and reorganization)
occurs and is continuing with respect to the Debentures, either the Trustee or
the registered holders of at least 25% in aggregate principal amount of the
Debentures, may declare the issue price plus accrued and unpaid interest on the
Debentures to be due and payable immediately. If an Event of Default relating to
certain events of bankruptcy, insolvency or reorganization occurs, the issue
price plus accrued and unpaid interest on the Debentures will become immediately
due and payable without any action on the part of the Trustee or any holder. At
any time after a declaration of acceleration, but before a judgment or decree
for payment of money has been obtained, if all Events of Default with respect to
the Debentures have been cured or waived (other than the nonpayment of the issue
price or accrued and unpaid interest on the Debentures which has become due
solely by reason of the declaration of acceleration), then the declaration of
acceleration shall be automatically annulled and rescinded.

     A holder of Debentures may pursue any remedy under the Indenture only if:

     - the holder gives the Trustee written notice of a continuing Event of
       Default for the Debentures;

     - the holders of at least 25% in principal amount of the outstanding
       Debentures make a written request to the Trustee to pursue the remedy;

     - the holder offers to the Trustee security and indemnity reasonably
       satisfactory to the Trustee against any loss, liability or expense;

     - the Trustee fails to act for a period of 60 days after receipt of notice,
       request and offer of security or indemnity; and

     - during that 60-day period, the holders of a majority in principal amount
       of the Debentures do not give the Trustee a direction inconsistent with
       the request.

     This provision does not, however, affect the right of a holder of
Debentures to sue for enforcement of payment of the principal of or interest,
including Liquidated Damages (as defined below) on the holder's Debenture on or
after the respective due dates expressed or provided for in its Debenture or the
holder's right to convert its Debenture in accordance with the Indenture.

     The Trustee is entitled under the Indenture, subject to the duty of the
Trustee during a default to act with the required standard of care, to be
indemnified before proceeding to exercise any right or power under the Indenture
at the direction of the registered holders of the

                                        37
<PAGE>   39

Debentures or which requires the Trustee to expend or risk its own funds or
otherwise incur any financial liability. The Indenture also provides that the
registered holders of a majority in principal amount of the outstanding
Debentures may direct the time, method and place of conducting any proceeding
for any remedy available to the Trustee or exercising any trust or power
conferred on the Trustee with respect to the Debentures. The Trustee, however,
may refuse to follow any such direction that the Trustee determines is unduly
prejudicial to the rights of other registered holders of the Debentures, or
would involve the Trustee in personal liability; provided that the Trustee may
take any other action deemed proper by it that is not inconsistent with such
direction.

     The Indenture provides that while the Trustee generally must mail notice of
a default or Event of Default to the registered holders of the debt securities
of any series issued under the Indenture within 90 days of the Trustee's actual
knowledge of the occurrence, the Trustee may withhold notice of any default or
Event of Default (except in payment on the debt securities) if the Trustee in
good faith determines that the withholding of such notice is in the interest of
the registered holders of that series of debt securities.

MODIFICATION AND WAIVER

     We may amend or supplement the Indenture if the holders of a majority in
principal amount of the Debentures consent to it. Without the consent of the
holder of each Debenture affected, however, no modification may:

     - reduce the amount of Debentures whose holders must consent to an
       amendment, supplement or waiver;

     - reduce the rate of interest or change the time for payment of interest on
       the Debentures;

     - make any change in the method of determining whether an Upward Interest
       Adjustment shall be made for a semi-annual period;

     - reduce the issue price of the Debentures or change its stated maturity;

     - make any change in any redemption or repurchase right to the detriment of
       such holder;

     - make payments on the Debentures payable in currency or consideration
       other than as originally stated in the Debentures;

     - impair the holder's right to receive payment of principal and interest on
       the Debentures or to institute suit for the enforcement of any payment on
       the Debentures;

     - make any change in the percentage of principal amount of Debentures
       necessary to waive compliance with some provisions of the Indenture or to
       make any change in this provision for modification; or

     - waive a continuing default or Event of Default regarding any payment on
       the Debentures.

     We may amend or supplement the Indenture or waive any provision of it
without the consent of any holders of Debentures in some circumstances,
including:

     - to cure any ambiguity, omission, defect or inconsistency;

     - to provide for the assumption of our obligations under the Indenture by a
       successor upon any merger, consolidation or asset transfer permitted
       under the Indenture;

     - to provide for uncertificated Debentures in addition to or in place of
       certificated Debentures or to provide for bearer Debentures;

     - to provide any security for or guarantees of the Debentures;

     - to comply with any requirement to effect or maintain the qualification of
       the Indenture under the Trust Indenture Act of 1939;

                                        38
<PAGE>   40

     - to add covenants that would benefit the holders of Debentures or to
       surrender any rights we have under the Indenture; or

     - to make any change that does not adversely affect the rights of any
       holder of the Debentures, including, without limitation, changing any
       payment record dates as necessary to conform to the then current market
       practice.

     The holders of a majority in principal amount of the outstanding Debentures
may waive any existing or past default or Event of Default. Those holders may
not, however, waive any default or Event of Default in any payment of principal
or interest on any Debenture or compliance with a provision that cannot be
amended or supplemented without the consent of each holder affected.

CALCULATIONS IN RESPECT OF DEBENTURES

     We will be responsible for making all calculations called for under the
Debentures. These calculations include, but are not limited to, determinations
of the market prices of the Debentures and of our common stock, accrued interest
payable on the Debentures, the Accreted Value of the Debentures, the Restated
Principal Amount of the Debentures and the Accreted Conversion Price of the
Debentures. We will make all these calculations in good faith and, absent
manifest error, our calculations will be final and binding on holders of
Debentures. We will provide a schedule of our calculations to the Trustee, and
the Trustee is entitled to rely upon the accuracy of our calculations without
independent verification. The Trustee will forward our calculations to any
holder of Debentures upon the request of that holder.

LIMITATIONS OF CLAIMS IN BANKRUPTCY

     If a bankruptcy proceeding is commenced in respect of us, the claim of a
holder of Debentures is, under Title 11 of the United States Code, limited to
the issue price of the Debentures plus accrued interest from the date of issue
to the commencement of the proceeding.

GOVERNING LAW

     The Indenture and the Debentures will be governed by, and construed in
accordance with, the laws of the State of New York.

TRUSTEE

     Wilmington Trust Company will initially act as Trustee and paying agent for
the Debentures. Wilmington Trust Company currently acts as trustee under:

     - an indenture with Calpine and Calpine's subsidiary, Calpine Capital Trust
       III, dated as of August 9, 2000,

     - an indenture with Calpine dated as of August 10, 2000, and

     - an indenture with Calpine's subsidiary, Calpine Canada Energy Finance
       ULC, pursuant to which Calpine has guaranteed Senior Notes issued by such
       subsidiary.

     A number of Calpine's series of debt securities are presently outstanding
under certain of the above indentures. We may have in the future other
relationships with Wilmington Trust Company.

     If an Event of Default occurs and is continuing, the Trustee will be
required to use the degree of care and skill of a prudent man under the
circumstances in the conduct of his own affairs. The Trustee will become
obligated to exercise any of its powers under the Indenture at the request of
any of the holders of any Debentures only after those holders have offered the
Trustee indemnity reasonably satisfactory to it.

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<PAGE>   41

     If the Trustee becomes one of our creditors, it will be subject to
limitations in the Indenture on its rights to obtain payment of claims or to
realize on some property received for any such claim, as security or otherwise.
The Trustee is permitted to engage in other transactions with us. If, however,
it acquires any conflicting interest, it must eliminate that conflict or resign.

FORM, EXCHANGE, REGISTRATION AND TRANSFER

     We issued the Debentures in registered form, without interest coupons. We
will not charge a service charge for any registration of transfer or exchange of
the Debentures. We may, however, require the payment of any tax or other
governmental charge payable for that registration.

     Debentures are exchangeable for other Debentures, for the same total
principal amount and for the same terms but in different authorized
denominations in accordance with the Indenture. Holders may present Debentures
for registration of transfer at the office of the security registrar or any
transfer agent we designate. The security registrar or transfer agent will
effect the transfer or exchange when it is satisfied with the documents of title
and identity of the person making the request.

     We have appointed the Trustee as security registrar for the Debentures. We
may at any time rescind that designation or approve a change in the location
through which any registrar acts. We are required to maintain an office or
agency for transfers and exchanges in each place of payment. We may at any time
designate additional registrars for the Debentures.

     In the case of any redemption, the security registrar will not be required
to register the transfer or exchange of any Debentures either:

     - during a period beginning 15 days prior to the mailing of the relevant
       notice of redemption and ending on the close of business on the day of
       mailing of the notice, or

     - if the Debentures have been called for redemption, in whole or in part,
       except the unredeemed portion of any Debentures being redeemed in part.

PAYMENT AND PAYING AGENTS

     Payments on the Debentures will be made in U.S. dollars at the office of
the Trustee. At our option, however, we may make payments by check mailed to the
holder's registered address or, with respect to global Debentures, by wire
transfer. We will make interest payments to the person in whose name the
Debentures is registered at the close of business on the record date for the
interest payment.

     The Trustee is designated as our paying agent for payments on Debentures.
We may at any time designate additional paying agents or rescind the designation
of any paying agent or approve a change in the office through which any paying
agent acts.

     Subject to the requirements of any applicable abandoned property laws, the
Trustee and paying agent shall pay to us upon written request any money held by
them for payments on the Debentures that remain unclaimed for two years after
the date upon which that payment has become due. After payment to us, holders
entitled to the money must look to us for payment. In that case, all liability
of the Trustee or paying agent with respect to that money will cease.

NOTICES

     Except as otherwise described in this prospectus, notice to registered
holders of the Debentures will be given by mail to the holders at the addresses
as they appear in the security register. Notices will be deemed to have been
given on the date of such mailing.

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<PAGE>   42

REPLACEMENT OF DEBENTURES

     We will replace any Debentures that become mutilated, destroyed, stolen or
lost at the expense of the holder upon delivery to the Trustee of the mutilated
Debentures or evidence of the loss, theft or destruction satisfactory to us and
the Trustee. In the case of lost, stolen or destroyed Debentures, indemnity
satisfactory to the Trustee and us may be required at the expense of the holder
of the Debentures before a replacement note will be issued.

PAYMENT OF STAMP AND OTHER TAXES

     We will pay all stamp and other duties, if any, which may be imposed by the
United States or any political subdivision thereof or taxing authority thereof
or therein with respect to the issuance of the Debentures. We will not be
required to make any payment with respect to any other tax, assessment or
governmental charge imposed by any government or any political subdivision
thereof or taxing authority thereof or therein.

BOOK-ENTRY SYSTEM

     The Debentures are represented by one or more Global Securities (each a
"Global Security"). Each Global Security is deposited with, or on behalf of, DTC
and registered in the name of a nominee of DTC. Except under circumstances
described below, the Debentures have been issued in definitive form.

     Upon the issuance of a Global Security, DTC will credit on its book-entry
registration and transfer system the accounts of persons designated by the
underwriter with the respective principal amounts of the Debentures represented
by the Global Security. Ownership of beneficial interests in a Global Security
will be limited to persons that have accounts with DTC or its nominee
("participants") or persons that may hold interests through participants.
Ownership of beneficial interests in a Global Security will be shown on, and the
transfer of that ownership will be effected only through, records maintained by
DTC or its nominee (with respect to interests of persons other than
participants). The laws of some states require that some purchasers of
securities take physical delivery of the securities in definitive form. Such
limits and such laws may impair the ability to transfer beneficial interests in
a Global Security.

     So long as DTC or its nominee is the registered owner of a Global Security,
DTC or its nominee, as the case may be, will be considered the sole owner or
holder of the Debentures represented by that Global Security for all purposes
under the Indenture. Except as provided below, owners of beneficial interests in
a Global Security will not be entitled to have Debentures represented by that
Global Security registered in their names, will not receive or be entitled to
receive physical delivery of Debentures in definitive form and will not be
considered the owners or holders thereof under the Indenture. Principal and
interest payments, if any, on Debentures registered in the name of DTC or its
nominee will be made to DTC or its nominee, as the case may be, as the
registered owner of the relevant Global Security. Neither our company, the
Trustee, any paying agent nor the registrar for the Debentures will have any
responsibility or liability for any aspect of the records relating to, or
payments made on account of beneficial interests in, a Global Security or for
maintaining, supervising or reviewing any records relating to such beneficial
interests.

     We expect that DTC or its nominee, upon receipt of any payment of principal
or interest, if any, will credit immediately participants' accounts with
payments in amounts proportionate to their respective beneficial interests in
the principal amount of the relevant Global Security as shown on the records of
DTC or its nominee. We also expect that payments by participants to owners of
beneficial interests in a Global Security held through these participants will
be governed by standing instructions and customary practices, as is the case
with securities held for the accounts of customers in bearer form or registered
in "street name," and will be the responsibility of the participants.

                                        41
<PAGE>   43

     If DTC is at any time unwilling or unable to continue as a depositary and a
successor depositary is not appointed by us within 90 days, we will issue
Debentures in definitive form in exchange for each entire Global Security. In
addition, we may at any time and in our sole discretion determine not to have
Debentures represented by Global Securities and, in such event, will issue
Debentures in definitive form in exchange for each entire Global Security
relating to the Debentures. In any such instance, an owner of a beneficial
interest in a Global Security will be entitled to physical delivery in
definitive form of Debentures represented by the Global Security equal in
principal amount to such owner's beneficial interest and to have the Debentures
registered in its name. Debentures so issued in definitive form will be issued
as registered Debentures in denominations of $1,000 and multiples thereof,
unless otherwise specified by us.

                                        42
<PAGE>   44

                              REGISTRATION RIGHTS

     We entered into a registration rights agreement with the Initial Purchaser
(the "Registration Rights Agreement"). In the Registration Rights Agreement we
agreed, for the benefit of the holders of the Debentures and the shares of
common stock issuable upon conversion of the Debentures (together, the
"Registrable Securities") that we would, at our expense:

     - file with the SEC, within 90 days after the date the Debentures were
       originally issued, a shelf registration statement covering resales of the
       Registrable Securities;

     - use our best efforts to cause the shelf registration statement to be
       declared effective under the Securities Act within 180 days after the
       date the Debentures were originally issued, subject to our right to
       postpone having the shelf registration statement declared effective for
       an additional 90 days in limited circumstances; and

     - use our best efforts to keep effective the shelf registration statement
       until two years after the date the Debentures were issued or, if earlier,
       until there are no outstanding Registrable Securities (the "Effectiveness
       Period").

     We may suspend the use of the prospectus that is part of the shelf
registration statement in connection with the sales of Registrable Securities
during prescribed periods of time for reasons relating to the acquisition or
divestiture of assets, pending corporate developments, and similar events. We
will provide to each holder of Registrable Securities copies of the prospectus
that is a part of the shelf registration statement, notify each holder when the
shelf registration statement has become effective and take certain other actions
required to permit public resales of the Registrable Securities.

     We may, upon written notice to all the holders of Registrable Securities,
postpone having the shelf registration statement declared effective, for a
reasonable period not to exceed 90 days if we possess material non-public
information, the disclosure of which would have a material adverse effect on us
and our subsidiaries, taken as a whole. Notwithstanding any such postponement,
additional interest ("Liquidated Damages") will accrue on the Debentures (or on
the common stock into which any Debentures have been converted) if either of the
following events ("Registration Defaults") occurs:

     - on or prior to 90 days following the date the Debentures were originally
       issued, a shelf registration statement has not been filed with the SEC;
       or

     - on or prior to 180 days following the date the Debentures were originally
       issued, the shelf registration statement is not declared effective.

     In that case, Liquidated Damages will accrue on the Registrable Securities
from and including the day following the Registration Default to but excluding
the day on which the Registration Default has been cured. Liquidated Damages
will be paid semi-annually in arrears, with the first semi-annual payment due on
the first interest payment date following the date of such Registration Default.
Liquidated Damages accrue either on the principal amount of the Debentures on
the date following the Registration Default or based on the Accreted Conversion
Price (as defined below) on the day following the Registration Default (whether
or not any Debentures remain outstanding after that date). "Accreted Conversion
Price" shall mean, as of any date, the Accreted Value divided by the number of
shares of our common stock issuable upon conversion of a Debenture on such date.

     The rates at which Liquidated Damages will accrue will be as follows:

     - 0.25% of the principal amount of the Debentures (or the Accreted
       Conversion Price) to and including the 90th day after the Registration
       Default; and

     - 0.50% of the principal amount of the Debentures (or the Accreted
       Conversion Price) from and after the 91st day after the Registration
       Default.

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<PAGE>   45

     We have agreed in the Registration Rights Agreement to use our best efforts
to cause the shares of common stock issuable upon conversion of the Debentures
to be listed on the NYSE or other stock exchange or trading system on which our
common stock primarily trades on or prior to the Effective Time of the shelf
registration statement.

     This summary of certain provisions of the Registration Rights Agreement may
not contain all the information important to you. You may request from us a copy
of the Registration Rights Agreement.

CALCULATIONS IN RESPECT OF DEBENTURES

     We will be responsible for making all calculations called for under the
Debentures. These calculations include, but are not limited to, determinations
of the market prices of the Debentures and of our common stock, accrued interest
payable on the Debentures, the Accreted Value of the Debentures, the Restated
Principal Amount of the Debentures and the Accreted Conversion Price of the
Debentures. We will make all these calculations in good faith and, absent
manifest error, our calculations will be final and binding on holders of
Debentures. We will provide a schedule of our calculations to the Trustee, and
the Trustee is entitled to rely upon the accuracy of our calculations without
independent verification. The Trustee will forward our calculations to any
holder of Debentures upon the request of that holder.

LIMITATIONS OF CLAIMS IN BANKRUPTCY

     If a bankruptcy proceeding is commenced in respect of us, the claim of a
holder of Debentures is, under Title 11 of the United States Code, limited to
the issue price of the Debentures plus accrued interest from the date of issue
to the commencement of the proceeding.

GOVERNING LAW

     The Indenture and the Debentures will be governed by, and construed in
accordance with, the laws of the State of New York.

                                        44
<PAGE>   46

                          DESCRIPTION OF CAPITAL STOCK

     Our authorized capital stock consists of 1,000,000,000 shares of common
stock, $.001 par value, and 10,000,000 shares of preferred stock, $.001 par
value. The following summary is qualified in its entirety by the provisions of
our certificate of incorporation and by-laws, which have been incorporated by
reference as exhibits to the Registration Statement of which this prospectus
constitutes a part. The information provided below reflects the 2 for 1 split of
our common stock that became effective on October 7, 1999, the 2 for 1 split of
our common stock that became effective on June 8, 2000 and the 2 for 1 split of
our common stock that became effective on November 14, 2000.

COMMON STOCK

     The holders of common stock are entitled to one vote per share on all
matters to be voted upon by stockholders. Subject to preferences that may be
applicable to any outstanding preferred stock, the holders of common stock are
entitled to receive ratably such dividends, if any, as may be declared from time
to time by the board of directors out of legally available funds. See
"-- Dividend Policy." In the event of our liquidation, dissolution or winding
up, the holders of common stock are entitled to share ratably in all assets
remaining after payment of liabilities, subject to prior liquidation rights of
preferred stock, if any, then outstanding. The common stock has no preemptive or
conversion rights or other subscription rights. There are no redemption or
sinking fund provisions applicable to the common stock. All shares of common
stock to be outstanding upon the redemption or exchange of the exchangeable
shares will be fully paid and non-assessable. Pursuant to a rights agreement
entered into in June of 1997, our shares of common stock outstanding prior to
the occurrence of events specified in the rights agreement have certain
preferred share purchase rights, which are set forth in more detail in the
rights agreement which is available from us upon request as described in "Where
You Can Find More Information." See "-- Anti-Takeover Effects of Provisions of
the Certificate of Incorporation, Bylaws, Rights Plan and Delaware Law -- Rights
Plan."

DIVIDEND POLICY

     We do not anticipate paying any cash dividends on our common stock in the
foreseeable future because we intend to retain our earnings to finance the
expansion of our business and for general corporate purposes. In addition, our
ability to pay cash dividends is restricted under certain of our indentures and
our other debt agreements. Future cash dividends, if any, will be at the
discretion of our board of directors and will depend upon, among other things,
our future operations and earnings, capital requirements, general financial
condition, contractual restrictions and such other factors as the board of
directors may deem relevant.

PREFERRED STOCK

     As of July 26, 2001, there was one share of preferred stock outstanding.
Our board of directors has the authority, without further vote or action by the
stockholders, to issue from time to time up to 10,000,000 shares of preferred
stock in one or more series, and to fix the rights, preferences, privileges,
qualifications, limitations and restrictions granted to or imposed upon any
wholly unissued shares of undesignated preferred stock, including without
limitation dividend rights, if any, voting rights, if any, and liquidation and
conversion rights, if any. Our board of directors has the authority to fix the
number of shares constituting any series and the designations of such series
without any further vote or action by the stockholders. Our board of directors,
without stockholder approval, can issue preferred stock with voting and
conversion rights which could adversely affect the voting power of the holders
of our common stock. The issuance of preferred stock may have the effect of
delaying, deferring or preventing a change in control of our company, or could
delay or prevent a transaction that might otherwise give our

                                        45
<PAGE>   47

stockholders an opportunity to realize a premium over the then prevailing market
price of the common stock.

     Our board of directors has authorized the issuance of up to 1,000,000
shares of Series A Participating Preferred Stock, par value $.001 per share,
pursuant to a rights plan adopted by Calpine's board of directors on June 5,
1997. As of July 26, 2001, no shares of our participating preferred stock were
outstanding. A description of the rights plan and the participating preferred
stock is set forth under "-- Anti-Takeover Effects of Provisions of the
Certificate of Incorporation, Bylaws and Delaware Law -- Rights Plan," below.

     Upon consummation of the Encal acquisition, a series of preferred stock of
Calpine, consisting of one share, was designated as special voting preferred
stock of Calpine, having a par value of $.001 per share, and a liquidation
preference of $.001. Except as otherwise required by law or our certificate of
incorporation, the one share of special voting preferred stock possesses a
number of votes for the election of directors and on all other matters submitted
to a vote of Calpine's stockholders equal to the number of outstanding Calpine
common equivalent shares issued by our wholly-owned subsidiary from time to time
and not owned by us or any entity controlled by us. The holders of our common
stock and the holder of the share of special voting preferred stock vote
together as a single class on all matters on which holders of common stock are
eligible to vote. In the event of our liquidation, dissolution or winding-up,
all outstanding Calpine common equivalent shares will automatically be exchanged
for shares of our common stock, and the holder of the special voting preferred
stock will not be entitled to receive any of our assets available for
distribution to our stockholders. The holder of the share of special voting
preferred stock will not be entitled to receive dividends. The share of special
voting preferred stock was issued to CIBC Mellon Trust Company, as trustee under
a voting and exchange trust agreement among us, Calpine Canada Holdings Ltd. and
the trustee. At such time as the one share of special voting preferred stock has
no votes attached to it because there are no Calpine common equivalent shares
outstanding not owned by us or an entity controlled by us, the one share of
special voting preferred stock will be canceled.

ANTI-TAKEOVER EFFECTS OF PROVISIONS OF THE CERTIFICATE OF INCORPORATION, BYLAWS
AND DELAWARE LAW

  Certificate of Incorporation and Bylaws

     Our certificate of incorporation and bylaws provide that our board of
directors is classified into three classes of directors serving staggered,
three-year terms. The certificate of incorporation also provides that directors
may be removed only by the affirmative vote of the holders of two-thirds of the
shares of our capital stock entitled to vote, voting together as a single class.
Any vacancy on the board of directors may be filled only by vote of the majority
of directors then in office. Further, the certificate of incorporation provides
that any business combination (as therein defined) requires the affirmative vote
of the holders of two-thirds of the shares of our capital stock entitled to
vote, voting together as a single class. The certificate of incorporation also
provides that all stockholder actions must be effected at a duly called meeting
and not by a consent in writing. The by-laws provide that our stockholders may
call a special meeting of stockholders only upon a request of stockholders
owning at least 50% of Calpine's capital stock. These provisions of the
certificate of incorporation and bylaws could discourage potential acquisition
proposals and could delay or prevent a change in control of our company. These
provisions are intended to enhance the likelihood of continuity and stability in
the composition of the board of directors and in the policies formulated by the
board of directors and to discourage certain types of transactions that may
involve an actual or threatened change of control of our company. These
provisions are designed to reduce our vulnerability to an unsolicited
acquisition proposal. The provisions also are intended to discourage certain
tactics that may be used in proxy fights. However, such provisions could have
the effect of discouraging others from making tender offers for our shares and,
as a consequence, they also may inhibit fluctuations in the

                                        46
<PAGE>   48

market price of our shares that could result from actual or rumored takeover
attempts. Such provisions also may have the effect of preventing changes in our
management.

  Rights Plan

     On June 5, 1997, we adopted a stockholders' rights plan to strengthen our
ability to protect our stockholders. The rights plan is designed to protect
against abusive or coercive takeover tactics that are not in the best interests
of Calpine or its stockholders. To implement the rights plan, we declared a
dividend of one preferred share purchase right for each outstanding share of our
common stock held on record as of June 18, 1997, and directed the issuance of
one preferred share purchase right with respect to each share of our common
stock that shall become outstanding thereafter until the rights become
exercisable or they expire as described below. Each right initially represents a
contingent right to purchase, under certain circumstances, one one-thousandth of
a share, called a "unit," of our Series A Participating Preferred Stock, par
value $.001 per share, at a price of $80.00 per unit, subject to adjustment. The
rights become exercisable and trade independently from our common stock upon the
public announcement of the acquisition by a person or group of 15% or more of
our common stock, or ten days after commencement of a tender or exchange offer
that would result in the acquisition of 15% or more of our common stock. Each
unit purchased upon exercise of the rights will be entitled to a dividend equal
to any dividend declared per share of common stock and will have one vote,
voting together with the common stock. In the event of our liquidation, each
share of the participating preferred stock will be entitled to any payment made
per share of common stock.

     If we are acquired in a merger or other business combination transaction
after a person or group has acquired 15% or more of our common stock, each right
will entitle its holder to purchase at the right's exercise price a number of
the acquiring company's shares of common stock having a market value of twice
the right's exercise price. In addition, if a person or group acquires 15% or
more of our common stock, each right will entitle its holder (other than the
acquiring person or group) to purchase, at the right's exercise price, a number
of fractional shares of our participating preferred stock or shares of our
common stock having a market value of twice the right's exercise price.

     The rights expire on June 18, 2007, unless redeemed earlier by us. We can
redeem the rights at a price of $.01 per right at any time before the rights
become exercisable, and thereafter only in limited circumstances.

  Delaware Anti-Takeover Statute

     Calpine is subject to Section 203 of the Delaware General Corporation Law
("Section 203"), which, subject to certain exceptions, prohibits a Delaware
corporation from engaging in any business combination with any interested
stockholder for a period of three years following the date that such stockholder
became an interested stockholder, unless: (1) prior to such date, the board of
directors of the corporation approved either the business combination or the
transaction that resulted in the stockholder becoming an interested stockholder;
(2) upon consummation of the transaction that resulted in the stockholder
becoming an interested stockholder, the interested stockholder owned at least
85% of the voting stock of the corporation outstanding at the time the
transaction commenced, excluding for purposes of determining the number of
shares outstanding those shares owned (x) by persons who are directors and also
officers and (y) by employee stock plans in which employee participants do not
have the right to determine confidentially whether shares held subject to the
plan will be tendered in a tender or exchange offer; or (3) on or subsequent to
such date, the business combination is approved by the board of directors and
authorized at an annual or special meeting of stockholders, and not by written
consent, by the affirmative vote of at least 66 2/3% of the outstanding voting
stock that is not owned by the interested stockholder.

                                        47
<PAGE>   49

     Section 203 defines the term business combination to include: (1) any
merger or consolidation involving the corporation or any of its direct or
indirect majority-owned subsidiaries and the interested stockholder; (2) any
sale, transfer, pledge or other disposition of 10% or more of the assets of the
corporation or any of its direct or indirect majority-owned subsidiaries
involving the interested stockholder; (3) subject to certain exceptions, any
transaction that results in the issuance or transfer by the corporation of any
stock of the corporation or any of its direct or indirect majority-owned
subsidiaries of any stock of the corporation or that subsidiary to the
interested stockholder; (4) any transaction involving the corporation or any of
its direct or indirect majority-owned subsidiaries that has the effect of
increasing the proportionate share of the stock of any class or series of the
corporation or that subsidiary beneficially owned by the interested stockholder;
or (5) the receipt by the interested stockholder of the benefit of any loans,
advances, guarantees, pledges or other financial benefits provided by or through
the corporation or any of its direct of indirect majority-owned subsidiaries. In
general, Section 203 defines an interested stockholder as any entity or person
beneficially owning 15% or more of the outstanding voting stock of the
corporation and any entity or person affiliated with or controlling or
controlled by such entity or person.

                                        48
<PAGE>   50

             CERTAIN UNITED STATES FEDERAL INCOME TAX CONSEQUENCES

     The following is a summary of the material United States federal income tax
consequences of the purchase, ownership and disposition of the Debentures and
common stock into which the Debentures may be converted. Unless otherwise
stated, this summary deals only with Debentures or common stock held as capital
assets by U.S. Holders. As used in this prospectus, "U.S. Holders" are any
beneficial owners of the Debentures or common stock, that are, for United States
federal income tax purposes: (1) citizens or residents of the United States, (2)
corporations created or organized in or under the laws of the United States, any
state thereof or the District of Columbia, (3) estates, the income of which is
subject to United States federal income taxation regardless of its source, or
(4) trusts if (A) a court within the United States is able to exercise primary
supervision over the administration of the trust and (B) one or more United
States persons have the authority to control all substantial decisions of the
trust. As used in this prospectus, "Non-U.S. Holders" are holders of the
securities that are, for United States federal income tax purposes (1)
nonresident alien individuals; (2) foreign corporations; or (3) foreign estates
or trusts that are not subject to United States federal income taxation on their
worldwide income. If a partnership (including for this purpose any entity
treated as a partnership for United States federal income tax purposes) is a
beneficial owner of Debentures or common stock, the treatment of a partner in
the partnership will generally depend upon the status of the partner and upon
the activities of the partnership. A holder of Debentures or common stock that
is a partnership and partners in such partnership should consult their tax
advisors about the United States federal income tax consequences of holding and
disposing of the Debentures or common stock, as the case may be. This summary
does not deal with special classes of holders such as banks, thrifts, real
estate investment trusts, regulated investment companies, insurance companies,
dealers in securities or currencies, or tax-exempt investors and does not
discuss Debentures or common stock held as part of a hedge, straddle, "synthetic
security" or other integrated transaction. This summary also does not address
the tax consequences to U.S. expatriates, persons who own, directly or
indirectly, 10% or more of our voting power or persons that have a functional
currency other than the U.S. dollar or the tax consequences to shareholders,
partners or beneficiaries of a holder of the Debentures or common stock.
Further, it does not include any description of any alternative minimum tax
consequences, United States federal estate or gift tax laws or the tax laws of
any state or local government or of any foreign government that may be
applicable to the Debentures or common stock.

     This summary applies only to the Initial Purchaser that purchases
Debentures at their "issue price." The "issue price" of the Debentures will
equal the first price at which a substantial amount of the Debentures is sold
for cash to the public, not including sales to bond houses, brokers or similar
persons or organizations acting in the capacity of underwriters, placement
agents or wholesalers. This summary is based on the Internal Revenue Code of
1986, as amended, the Treasury regulations promulgated thereunder and
administrative and judicial interpretations thereof, all as of the date hereof,
and all of which are subject to change and differing interpretations, possibly
on a retroactive basis. No statutory, administrative or judicial authority
directly addresses the treatment of the Debentures or instruments similar to the
Debentures for United States federal income tax purposes. Therefore, there can
be no assurance that the Internal Revenue Service (the "IRS") will not challenge
one or more of the conclusions described in this prospectus, and Calpine has not
obtained, nor does Calpine intend to obtain, a ruling from the IRS with respect
to the United States federal income tax consequences of acquiring, holding or
disposing of the Debentures or the common stock.

     You should consult with your own tax advisor regarding the federal, state,
local and foreign income, franchise, personal property, and any other tax
consequences of the purchase, ownership and disposition of the Debentures and
the common stock.

                                        49
<PAGE>   51

CLASSIFICATION OF THE DEBENTURES

     Pursuant to the terms of the Indenture, we and each holder of the
Debentures agreed, for United States federal income tax purposes, to treat the
Debentures as indebtedness for United States federal income tax purposes subject
to the regulations governing contingent payment debt instruments and to be bound
by our application of those regulations to the Debentures, including our
determination of the rate at which interest will be deemed to accrue on the
Debentures for United States federal income tax purposes. The remainder of this
discussion assumes that the Debentures will be treated in accordance with that
agreement and our determinations. However, the proper United States federal
income tax treatment of a holder of a Debenture is uncertain in various
respects, and no assurance can be given that the IRS will not assert that the
Debentures should be treated differently or that such an assertion would not
prevail. Such treatment by the IRS and a court could affect the amount, timing
and character of income, gain or loss in respect of an investment in Debentures.
In particular, it might be determined that a holder should have accrued interest
income at a lower rate, should not have recognized income or gain upon the
conversion and should have recognized capital gain upon a taxable disposition of
its Debenture. In addition, if the IRS successfully asserts that the Debentures
are not debt, Non-U.S. Holders would generally be subject to a 30% United States
federal withholding tax on payments of contingent interest made in respect of
the Debentures.

U.S. HOLDERS

  Accrual of Interest on the Debentures

     Under the rules governing contingent payment debt obligations, a United
States person generally will be required to accrue interest income on the
Debentures, in the amounts described below, regardless of whether the U.S.
Holder uses the cash or accrual method of tax accounting. Accordingly, U.S.
Holders would likely be required to include interest in taxable income in each
year in excess of the stated yield to maturity of the Debentures and in excess
of any contingent interest payments actually received in that year.

     A U.S. Holder must accrue an amount of ordinary income, as original issue
discount for United States federal income tax purposes, for each accrual period
prior to and including the maturity date of the Debentures that equals:

     - the product of (i) the adjusted issue price (as defined below) of the
       Debentures as of the beginning of the accrual period; and (ii) the
       comparable yield to maturity (as defined below) of the Debentures,
       adjusted for the length of the accrual period;

     - divided by the number of days in the accrual period; and

     - multiplied by the number of days during the accrual period that the U.S.
       Holder held the Debentures.

     The issue price of a Debenture is the first price at which a substantial
amount of the Debentures is sold to the public, excluding bond houses, brokers
or similar persons or organizations acting in the capacity of underwriters,
placement agents or wholesalers. The adjusted issue price of a Debenture is its
issue price at the beginning of the first accrual period, and for any accrual
period after the first accrual period will be the sum of the issue price
increased by any interest income previously accrued, determined without regard
to any positive or negative adjustments to interest accruals described below and
decreased by the projected amounts of any payments with respect to the
Debentures.

     Under the rules governing contingent payment debt obligations, we are
required to establish the "comparable yield" for the Debentures. We have
determined that the comparable yield for the Debentures is the annual yield we
would incur, as of the initial issue date, on a fixed rate nonconvertible debt
security with no contingent payments, but with terms and conditions

                                        50
<PAGE>   52

otherwise comparable to those of the Debentures including the level of
subordination, term, timing of payments and general market conditions, but
excluding any adjustments for liquidity or the riskiness of the contingencies
with respect to the Debentures. Accordingly, we have determined the comparable
yield to be 9.44% per annum compounded semi-annually.

     We are required to provide to U.S. Holders, solely for United States
federal income tax purposes, a schedule of the projected amounts of payments on
the Debentures. This schedule must produce the comparable yield. Our
determination of the projected payment schedule for the Debentures includes
estimates for payments of contingent interest and an estimate for a payment at
maturity taking into account the conversion feature. The comparable yield and
schedule of projected payments is set forth in the Indenture. U.S. Holders may
also obtain the projected payment schedule by submitting a written request for
it to Rick Barazza, Vice-President, Investor Relations, Calpine Corporation, 50
West San Fernando Street, San Jose, CA 95113.

     THE COMPARABLE YIELD AND THE SCHEDULE OF PROJECTED PAYMENTS ARE NOT
DETERMINED FOR ANY OTHER PURPOSE OTHER THAN FOR THE DETERMINATION OF A U.S.
HOLDER'S INTEREST ACCRUALS AND ADJUSTMENTS THEREOF IN RESPECT OF THE DEBENTURES
FOR UNITED STATES FEDERAL INCOME TAX PURPOSES AND DO NOT CONSTITUTE A PROJECTION
OR REPRESENTATION REGARDING THE ACTUAL AMOUNTS PAYABLE TO U.S. HOLDERS OF THE
DEBENTURES.

  Adjustments to Interest Accruals on the Debentures

     A U.S. Holder will be required to recognize additional interest income
equal to the amount of any net positive adjustment, i.e., the excess of actual
payments over projected payments, in respect of the Debentures for a taxable
year. If a U.S. Holder incurs a net negative adjustment, i.e., the excess of
projected payments over actual payments, in respect of the Debentures for a
taxable year, the net negative adjustment will (a) reduce the U.S. Holder's
interest income on the Debentures for that taxable year, and (b) to the extent
of any excess after the application of (a), give rise to an ordinary loss to the
extent of the U.S. Holder's interest income on the Debentures during the prior
taxable years, reduced to the extent such interest was offset by prior negative
adjustments.

     A net negative adjustment is not subject to the two percent floor
limitation imposed on miscellaneous itemized deductions under Section 67 of the
Internal Revenue Code.

  Sale, Exchange, Conversion or Redemption

     Generally, the sale, exchange or conversion of Debentures, or the
redemption of Debentures for cash, will result in taxable gain or loss to a U.S.
Holder. In addition, as described above, our calculation of the comparable yield
and the schedule of projected payments for the Debentures includes the receipt
of stock upon conversion of Debentures into our common stock as a contingent
payment with respect to the Debentures. Accordingly, we intend to treat the
receipt of our common stock by a U.S. Holder upon the conversion of Debentures,
or upon the redemption of Debentures where we elect to pay in common stock, as a
contingent payment under the contingent payment debt rules. As described above,
holders are generally bound by our determination of the comparable yield and the
schedule of projected payments. Under this treatment, a sale or exchange, or
such a redemption, or conversion will also result in taxable gain or loss to the
U.S. Holder. The amount of gain or loss on a taxable sale, exchange or
redemption will be equal to the difference between (a) the amount of cash plus
the fair market value of any other property received by the U.S. Holder,
including the fair market value of any common stock received, in the conversion
or redemption and (b) the U.S. Holder's adjusted tax basis in the Debentures. A
U.S. Holder's adjusted tax basis in Debentures will generally be equal to the
U.S. Holder's original purchase price for the Debentures, increased by any
interest income previously accrued by the U.S. Holder (determined without regard
to any positive or negative

                                        51
<PAGE>   53

adjustments to interest accruals described above), and decreased by the amount
of any projected payments on the Debentures to the U.S. Holder. Gain recognized
upon a sale, exchange, conversion or redemption of Debentures will generally be
treated as ordinary interest income; any loss will be ordinary loss to the
extent of interest previously included in income, and thereafter, capital loss
(which will be long-term if the Debentures are held for more than one year). The
deductibility of net capital losses by individuals and corporations is subject
to limitations.

     A U.S. Holder's tax basis in our common stock received upon a conversion of
Debentures or upon a holder's exercise of a put right that we elect to pay in
common stock will equal the then current fair market value of such common stock.
The U.S. Holder's holding period for the common stock received will commence on
the day immediately following the date of conversion or redemption.

  Distributions on Common Stock

     If a U.S. Holder converts the Debentures into common stock, in general,
distributions on the common stock that are paid out of our current or
accumulated earnings and profits, as defined for United States federal income
tax purposes, will constitute dividends and will be includible in income by a
holder and taxable as ordinary income when received or accrued, in accordance
with that holder's method of accounting for United States federal income tax
purposes. If a distribution exceeds our current and accumulated earnings and
profits, the excess will be treated first as a tax-free return of the U.S.
Holder's investment, up to the holder's basis in the common stock. Any remaining
excess will be treated as capital gain.

  Constructive Dividends

     If at any time we make a distribution of property to our stockholders that
would be taxable to the stockholders as a dividend for federal income tax
purposes and, in accordance with the anti-dilution provisions of the Debentures,
the conversion rate of the Debentures is increased, such increase may be deemed
to be the payment of a taxable dividend to holders of the Debentures. For
example, an increase in the exchange rate in the event of distribution of our
evidence of indebtedness or our assets or an increase in the event of an
extraordinary cash dividend will generally result in deemed dividend treatment
to holders of the Debentures, but generally an increase in the event of stock
dividends or the distribution of rights to subscribe for common stock will not.

  Sale or Exchange of Common Stock

     In general, a U.S. Holder will recognize capital gain or loss upon the sale
or exchange of the common stock equal to the difference between the amount
realized on such sale or exchange and such holder's adjusted tax basis in such
shares. The deductibility of net capital losses by individuals and corporations
is subject to limitations. Holders should consult their tax advisors regarding
the treatment of capital gains and losses.

NON-U.S. HOLDERS

     The rules governing United States federal income taxation of Non-U.S.
Holders are complex and no attempt will be made in this prospectus to provide
more than a summary of such rules. Non-U.S. Holders should consult with their
own tax advisors to determine the effect of federal, state, local and foreign
income tax laws, as well as treaties, with regard to an investment in the
Debentures and common stock, including any reporting requirements and, in
particular, the proper application of the United States federal withholding tax
rules.

                                        52
<PAGE>   54

  Payments Made With Respect to the Debentures

     Although the matter is not free from doubt, the 30% United States federal
withholding tax will not apply to any payment to a Non-U.S. Holder of principal
or interest (including amounts taken into income as interest under the accrual
rules described above under "-- U.S. Holders" and amounts attributable to the
common stock received upon a conversion of the Debentures) on Debentures,
provided that: (i) the Non-U.S. Holder does not own, actually or constructively,
10% or more of the total combined voting power of all classes of our stock
entitled to vote; (ii) the Non-U.S. Holder is not a controlled foreign
corporation related, directly or indirectly, to us through stock ownership;
(iii) the Non-U.S. Holder is not a bank which acquired the Debentures in
consideration for an extension of credit made pursuant to a loan agreement
entered into in the ordinary course of business; (iv) the Debentures and our
common stock are actively traded within the meaning of Section
871(h)(4)(c)(v)(I) of the Internal Revenue Code and the Non-U.S. Holder's
holdings are deemed not to be a United States real property interest within the
meaning of Section 897(c)(1) of the Internal Revenue Code (as described below
under "-- Foreign Investment in Real Property Tax Act"); and (v) either (A) the
beneficial owner of Debentures certifies to us or our paying agent on IRS Form
W-8BEN, under penalties of perjury, that it is not a United States person and
provides its name, address and certain other information or (B) the beneficial
owner holds its Debentures through certain foreign intermediaries or certain
foreign partnerships and such holder satisfies certain certification
requirements.

     If the Non-U.S. Holder cannot satisfy the requirements described above,
payments of interest (including amounts taken into income under the accrual
rules described above under "-- U.S. Holders" and amounts attributable to the
common stock received upon a conversion of the Debentures) will be subject to
the 30% United States federal withholding tax unless the Non-U.S. Holder
provides us with a properly executed (1) IRS Form W-8BEN (or successor form)
claiming an exemption from or reduction in withholding under an applicable tax
treaty or (2) IRS Form W-8ECI (or successor form) stating that interest paid on
the Debentures is not subject to withholding tax because it is effectively
connected with the Non-U.S. Holder's conduct of a trade or business in the
United States. In addition, if the Debentures are not actively traded, within
the meaning of Section 871(h)(4)(C)(v)(I) of the Internal Revenue Code, any cash
interest attributable to an Upward Interest Adjustment will be subject to a 30%
United States federal withholding tax, unless the Non-U.S. Holder can satisfy
condition (1) or (2) described in the preceding sentence.

     If a Non-U.S. Holder of the Debentures is engaged in a trade or business in
the United States, and if interest on the Debentures is effectively connected
with the conduct of such trade or business, the Non-U.S. Holder, although exempt
from the withholding tax discussed in the preceding paragraphs, will generally
be subject to regular United States federal income tax on interest and on any
gain realized on the sale or exchange of the Debentures in the same manner as if
it were a U.S. Holder. Such a Non-U.S. Holder will be required to provide to the
withholding agent a properly executed IRS Form W-8ECI (or successor form) in
order to claim an exemption from withholding tax. In addition, if such a
Non-U.S. Holder is a foreign corporation, such Non-U.S. Holder may be subject to
a branch profits tax equal to 30% (or such lower tax rate provided by an
applicable treaty) of its effectively connected earnings and profits for the
taxable year, subject to certain adjustments.

  Sale or Exchange of Debentures or Common Stock

     Subject to the discussion below regarding "Foreign Investment in Real
Property Tax Act," a Non-U.S. Holder will generally not be subject to United
States federal income or withholding tax with respect to gain upon the sale,
exchange, or other disposition (other than a conversion) of Debentures or common
stock, unless: (1) the income or gain is "U.S. trade or business income," which
means income or gain that is effectively connected with the conduct by the Non-
U.S. Holder of a trade or business, or, in the case of a treaty resident,
attributable to a

                                        53
<PAGE>   55

permanent establishment or a fixed base, in the United States; (2) such Non-U.S.
Holder is an individual who is present in the United States for 183 days or more
in the taxable year of disposition and certain other conditions are met; (3)
such Non-U.S. Holder is subject to tax pursuant to the provisions of the
Internal Revenue Code applicable to certain United States expatriates; or (4) in
the case of an amount which is attributable to original issue discount, the
Non-U.S. Holder does not meet the conditions for exemption from United States
federal withholding tax described above.

     U.S. trade or business income of a Non-U.S. Holder will generally be
subject to regular United States income tax in the same manner as if it were
realized by a U.S. Holder. Non-U.S. Holders that realize U.S. trade or business
income with respect to the Debentures or common stock should consult their tax
advisors as to the treatment of such income or gain. In addition, U.S. trade or
business income of a Non-U.S. Holder that is a corporation may be subject to a
branch profits tax at a rate of 30%, or such lower rate provided by an
applicable income tax treaty.

  Distributions on Common Stock

     A Non-U.S. Holder of our common stock will generally be subject to United
States federal withholding tax at a 30% rate (or lower rate provided under any
applicable income tax treaty) on distributions by us with respect to our common
stock that are treated as dividends paid (and on dividends deemed paid on the
Debentures or common stock, as described above under "U.S.
Holders -- Constructive Dividends"). Except to the extent that an applicable tax
treaty otherwise provides, generally a Non-U.S. Holder will be taxed in the same
manner as a U.S. Holder on dividends paid (or deemed paid) that are effectively
connected with the Non-U.S. Holder's conduct of a trade or business in the
United States, and a corporate Non-U.S. Holder may also be subject to a United
States branch profits tax at a 30% rate or such lower rate as may be specified
in an applicable income tax treaty.

FOREIGN INVESTMENT IN REAL PROPERTY TAX ACT

     Under the Foreign Investment in Real Property Tax Act, any person who
acquires a "United States real property interest" (as described below) from a
foreign person must deduct and withhold a tax equal to 10% of the amount
realized by the foreign transferor. In addition, a foreign person who disposes
of a United States real property interest generally is required to recognize
gain or loss that is subject to United States federal income tax. A "United
States real property interest" generally includes any interest (other than an
interest solely as a creditor) in a United States corporation unless it is
established under specific procedures that the corporation is not (and was not
for the prior five-year period) a "United States real property holding
corporation." We believe that we are likely to be classified as a "United States
real property holding corporation" and we can give no assurance that we will not
continue to be classified as a United States real property holding corporation.
However, so long as our stock is regularly traded on an established securities
market, an exemption should apply to the Debentures and the common stock except
(i) in the case of Debentures, if the Debentures are or become regularly traded,
with respect to a Non-U.S. Holder that owns more than 5% of the Debentures, and
(ii) otherwise, and in the case of the common stock, with respect to a Non-U.S.
Holder whose beneficial and/or constructive ownership of common stock exceeds 5%
of the total fair market value of the common stock.

     Any investor that may approach or exceed the 5% ownership threshold
discussed above, either alone or in conjunction with related persons, should
consult its own tax advisor concerning the United States tax consequences that
may result. A Non-U.S. Holder who sells or otherwise disposes of common stock
may be required to inform its transferee whether such common stock constitutes a
United States real property interest.

                                        54
<PAGE>   56

BACKUP WITHHOLDING AND INFORMATION REPORTING

  U.S. Holders

     Payments of interest or dividends made by us on, or the proceeds of the
sale or other disposition of, the Debentures or shares of common stock may be
subject to information reporting and U.S. federal backup withholding tax
(currently 30.5%) if the recipient of such payment fails to supply an accurate
taxpayer identification number or otherwise fails to comply with applicable
United States information reporting or certification requirements. Any amount
withheld from a payment to a U.S. Holder under the backup withholding rules is
allowable as a credit against the holder's U.S. federal income tax, provided
that the required information is furnished to the IRS.

  Non-U.S. Holders

     A Non-U.S. Holder may be required to comply with certification procedures
to establish that the holder is not a U.S. person in order to avoid backup
withholding tax requirements with respect to our payments of principal and
interest, including cash payments in respect of original issue discount, on the
Debentures. In addition, we must report annually to the IRS and to each Non-U.S.
Holder the amount of any dividends paid to, and the tax withheld with respect
to, such holder, regardless of whether any tax was actually withheld. Copies of
these information returns may also be made available under the provisions of a
specific treaty or agreement to the tax authorities of the country in which the
Non-U.S. Holder resides.

TAX EVENT

     The modification of the terms of the Debentures by us upon a Tax Event
could possibly alter the timing of income recognition by the holders with
respect to the payments of interest due after the option exercise date.

THE PROPER TAX TREATMENT OF A HOLDER OF DEBENTURES IS HIGHLY UNCERTAIN IN A
NUMBER OF RESPECTS. HOLDERS SHOULD CONSULT THEIR TAX ADVISORS REGARDING THE
FEDERAL, STATE, LOCAL AND FOREIGN TAX CONSEQUENCES OF AN INVESTMENT IN THE
DEBENTURES AND WHETHER AN INVESTMENT IN THE DEBENTURES IS ADVISABLE IN LIGHT OF
THE AGREED UPON TAX TREATMENT AND THE HOLDER'S PARTICULAR TAX SITUATION.

                                 LEGAL MATTERS

     The validity of the Debentures and any common stock issuable upon
conversion of the Debenture offered hereby will be passed upon for us by
Covington & Burling, New York, New York.

                              INDEPENDENT AUDITORS

     The financial statements incorporated by reference in this prospectus and
elsewhere in this registration statement have been audited by Arthur Andersen
LLP, independent public accountants, as indicated in their reports with respect
thereto, and are included herein in reliance upon the authority of said firm as
experts in giving such reports.

                                        55
<PAGE>   57

                                    PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

     The following table sets forth the costs and expenses payable by Calpine in
connection with resales of the securities being registered. All amounts are
estimates subject to future contingencies except the SEC registration statement
filing fee.

<TABLE>
<S>                                                           <C>
SEC Registration Statement Filing Fee.......................  $250,000
Legal Fees and Expenses.....................................  $ 50,000
Accounting Fees and Expenses................................  $  7,500
Printing Fees...............................................  $100,000
Transfer Agent Fees.........................................  $  5,000
Miscellaneous...............................................  $ 10,000
                                                              --------
Total.......................................................  $422,500
</TABLE>

- -------------------------

ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

     Section 145 of the General Corporation Law of the State of Delaware (the
"Delaware Law") empowers a Delaware corporation to indemnify any persons who
are, or are threatened to be made, parties to any threatened, pending or
completed legal action, suit or proceedings, whether civil, criminal,
administrative or investigative (other than action by or in the right of such
corporation), by reason of the fact that such person was an officer or director
of such corporation, or is or was serving at the request of such corporation as
a director, officer, employee or agent of another corporation or enterprise. The
indemnity may include expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement actually and reasonably incurred by such person in
connection with such action, suit or proceeding, provided that such officer or
director acted in good faith and in a manner he reasonably believed to be in or
not opposed to the corporation's best interests, and, for criminal proceedings,
had no reasonable cause to believe his conduct was unlawful. A Delaware
corporation may indemnify officers and directors in an action by or in the right
of the corporation under the same conditions, except that no indemnification is
permitted without judicial approval if the officer or director is adjudged to be
liable to the corporation in the performance of his duty. Where an officer or
director is successful on the merits or otherwise in the defense of any action
referred to above, the corporation must indemnify him against the expenses which
such officer or director actually and reasonably incurred.

     In accordance with Delaware Law, the certificate of incorporation of
Calpine Corporation ("Calpine") contains a provision to limit the personal
liability of the directors of Calpine for violations of their fiduciary duty.
This provision eliminates each director's liability to Calpine or its
stockholders for monetary damages except (i) for any breach of the director's
duty of loyalty to Calpine or its stockholders, (ii) for acts or omissions not
in good faith or which involve intentional misconduct or a knowing violation of
law, (iii) under Section 174 of the Delaware Law providing for liability of
directors for unlawful payment of dividends or unlawful stock purchases or
redemptions, or (iv) for any transaction from which a director derived an
improper personal benefit. The effect of this provision is to eliminate the
personal liability of directors for monetary damages for actions involving a
breach of their fiduciary duty of care, including any such actions involving
gross negligence. The certificate of incorporation further provides that, if the
Delaware Law is amended to further reduce the liability of a corporation's
directors for breaches of

                                       II-1
<PAGE>   58

fiduciary duty, then a director of Calpine shall not be liable for any such
breach to the fullest extent permitted by the laws as so amended.

     Article Ten of the bylaws of Calpine provides for indemnification of the
officers and directors of Calpine to the fullest extent permitted by applicable
law.

     Calpine has entered into indemnification agreements with its directors and
officers. These agreements provide substantially broader indemnity rights than
those provided under the Delaware Law and the Calpine's bylaws. The
indemnification agreements are not intended to deny or otherwise limit
third-party or derivative suits against Calpine or its directors or officers,
but if a director or officer were entitled to indemnity or contribution under
the indemnification agreement, the financial burden of a third-party suit would
be borne by Calpine, and Calpine would not benefit from derivative recoveries
against the director or officer. Such recoveries would accrue to the benefit of
Calpine but would be offset by Calpine's obligations to the director or officer
under the indemnification agreement. In addition, the directors of Calpine are
insured under officers and directors liability insurance policies.

     Reference is made to Section 5 of the Registration Rights Agreement
incorporated by reference as Exhibit 4.1 hereto for a description of the
indemnification arrangements in connection with the registration of the
Debentures under the Securities Act of 1933.

ITEM 16. EXHIBITS

<TABLE>
<CAPTION>
EXHIBIT
NUMBER                            DESCRIPTION
- -------                           -----------
<C>       <S>
   3.1    Amended and Restated Certificate of Incorporation of Calpine
          Corporation(a)
   3.2    Certificate of Correction of Calpine Corporation(b)
  *3.3    Certificate of Amendment of Amended and Restated Certificate
          of Incorporation of Calpine Corporation
   3.4    Certificate of Designation of Series A Participating
          Preferred Stock of Calpine Corporation(b)
   3.5    Amended Certificate of Designation of Series A Participating
          Preferred Stock of Calpine Corporation(b)
  *3.6    Amended Certificate of Designation of Series A Participating
          Preferred Stock of Calpine Corporation
   3.7    Certificate of Designation of Special Voting Preferred Stock
          of Calpine Corporation(c)
   3.8    Amended and Restated By-laws of Calpine Corporation(d)
  *4.1    Registration Rights Agreement, dated April 30, 2001 by and
          between Calpine Corporation and the Initial Purchaser
   4.2    Rights Agreement, dated as of June 5, 1997, between Calpine
          Corporation and First Chicago Trust Company of New York, as
          rights agent(e)
  +5.1    Opinion of Covington & Burling
  +8.1    Opinion of Thelen Reid & Priest LLP as to certain tax
          matters
 *12.1    Statement Regarding Computation of Ratios
 *23.1    Consent of Arthur Andersen LLP, independent public
          accountants
 +23.2    Consent of Covington & Burling (included in opinion filed as
          exhibit 5.1)
 +23.3    Consent of Thelen Reid & Priest LLP
 *24.1    Power of Attorney of Officers and Directors of Calpine
          Corporation (as set forth on the signature pages of this
          Registration Statement)
 *25.1    Statement of Eligibility of Trustee
</TABLE>

- -------------------------
 *  Filed herewith.

 +  To be filed.

                                       II-2
<PAGE>   59

(a) Incorporated by reference to Calpine Corporation's Registration Statement on
    Form S-3 (Registration No. 333-40652) filed with the SEC on June 30, 2000.

(b) Incorporated by reference to Calpine Corporation's Annual Report on Form
    10-K dated December 31, 2000, filed with the SEC on March 15, 2001.

(c) Incorporated by reference to Calpine Corporation's Quarterly Report on Form
    10-Q for the quarter ended March 31, 2001, filed with the SEC on May 15,
    2001.

(d) Incorporated by reference to Calpine Corporation's Registration Statement on
    Form S-1 (Registration No. 333-07497).

(e) Incorporated by reference to Calpine's Registration Statement on Form 8-A
    filed with the SEC on June 18, 1997 and amended by the Corporation's
    Registration Statement on Form 8-A/A filed with the SEC on June 24, 1997
    (File No. 001-12079).

ITEM 17. UNDERTAKINGS

     The undersigned registrant hereby undertakes:

          (1) To file, during any period in which offers or sales are being
     made, a post-effective amendment to this registration statement to include
     any material information with respect to the plan of distribution not
     previously disclosed in the registration statement or any material change
     to such information in the registration statement.

          (2) That, for the purpose of determining any liability under the
     Securities Act of 1933, each such post-effective amendment shall be deemed
     to be a new registration statement relating to the securities offered
     therein, and the offering of such securities at that time shall be deemed
     to be the initial bona fide offering thereof.

          (3) To remove from registration by means of a post-effective amendment
     any of the securities being registered which remain unsold at the
     termination of the offering.

          (4) If the registrant is a foreign private issuer, to file a
     post-effective amendment to the registration statement to include any
     financial statements required by Rule 3-19 of Regulation S-X under the
     Securities Act of 1933 at the start of any delayed offering or throughout a
     continuous offering. Financial statements and information otherwise
     required by Section 10(a)(3) of the Act need not be furnished, provided,
     that the registrant includes in the prospectus, by means of a
     post-effective amendment, financial statements required pursuant to this
     paragraph (4) and other information necessary to ensure that all other
     information in the prospectus is at least as current as the date of those
     financial statements. Notwithstanding the foregoing, with respect to
     registration statements on Form F-3, a post-effective amendment need not be
     filed to include financial statements and information required by Section
     10(a)(3) of the Act or Rule 3-19 of Regulation S-X if such financial
     statements and information are contained in periodic reports filed with or
     furnished to the Commission by the registrant pursuant to Section 13 or
     Section 15(d) of the Securities Exchange Act of 1934 that are incorporated
     by reference in the Form F-3.

     The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934, (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in the
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

                                       II-3
<PAGE>   60

     The undersigned registrant hereby undertakes to deliver or cause to be
delivered with the prospectus, to each person to whom the prospectus is sent or
given, the latest annual report, to security holders that is incorporated by
reference in the prospectus and furnished pursuant to and meeting the
requirements of Rule 14a-3 under Rule 14c-3 under the Securities Exchange Act of
1934; and, where interim financial information required to be presented by
Article 3 of Regulation S-X is not set forth in the prospectus, to deliver, or
cause to be delivered to each person to whom the prospectus is sent or given,
the latest quarterly report that is specifically incorporated by reference in
the prospectus to provide such interim financial information.

     Insofar as indemnification for liabilities arising under the Securities Act
of 1933 may be permitted to directors, officers and controlling persons of the
registrant pursuant to the foregoing provisions, or otherwise, the registrant
has been advised that in the opinion of the SEC such indemnification is against
public policy as expressed in the Securities Act of 1933 and is, therefore,
unenforceable. In the event that a claim for indemnification against such
liabilities (other than the payment by the registrant of expenses incurred or
paid by a director, officer or controlling person of the registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by them is against public
policy as expressed in the Securities Act of 1933 and will be governed by the
final adjudication of such issue.

                                       II-4
<PAGE>   61

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing this Registration Statement on Form S-3 and has duly
caused this registration statement to be signed on its behalf by the
undersigned, thereunto duly authorized in the City of San Jose, State of
California, on this 25th day of July, 2001.

                                          CALPINE CORPORATION

                                          By:      /s/ ANN B. CURTIS
                                            ------------------------------------
                                                        Ann B Curtis
                                                  Executive Vice President
                                                and Chief Financial Officer

                               POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS:

     That the undersigned officers and directors of Calpine Corporation do
hereby constitute and appoint Peter Cartwright and Ann B. Curtis, and each of
them, the lawful attorney and agent or attorneys and agents with power and
authority to do any and all acts and things and to execute any and all
instruments which said attorneys and agents, or either of them, determine may be
necessary or advisable or required to enable Calpine Corporation to comply with
the Securities Exchange Act of 1934, as amended, and any rules or regulations or
requirements of the Securities and Exchange Commission in connection with this
Registration Statement on Form S-3. Without limiting the generality of the
foregoing power and authority, the powers granted include the power and
authority to sign the names of the undersigned officers and directors in the
capacities indicated below to this Registration Statement or amendments or
supplements thereto, and each of the undersigned hereby ratifies and confirms
all that said attorneys and agents, or either of them, shall do or cause to be
done by virtue hereof. This Power of Attorney may be signed in several
counterparts.

     IN WITNESS HEREOF, each of the undersigned has executed this Power of
Attorney as of the date indicated opposite the name.

     Pursuant to the requirements of the Securities Exchange Act of 1934, this
Registration Statement on Form S-3 has been signed below by the following
persons on behalf of the Registrant and in the capacities and on the dates
indicated.

<TABLE>
<CAPTION>
                      SIGNATURE                                     TITLE                    DATE
                      ---------                                     -----                    ----
<C>                                                    <C>                               <S>
                /s/ PETER CARTWRIGHT                      Chairman, President, Chief     July 25, 2001
- -----------------------------------------------------   Executive Officer and Director
                  Peter Cartwright

                  /s/ ANN B. CURTIS                    Executive Vice President, Chief   July 25, 2001
- -----------------------------------------------------   Financial Officer and Director
                    Ann B. Curtis

              /s/ CHARLES B. CLARK, JR.                 Vice President and Controller,   July 25, 2001
- -----------------------------------------------------      Chief Accounting Officer
                Charles B. Clark, Jr.
</TABLE>

                                       II-5
<PAGE>   62

<TABLE>
<CAPTION>
                      SIGNATURE                                     TITLE                    DATE
                      ---------                                     -----                    ----

<C>                                                    <C>                               <S>
                 /s/ KENNETH T. DERR                               Director              July 25, 2001
- -----------------------------------------------------
                   Kenneth T. Derr

                /s/ JEFFREY E. GARTEN                              Director              July 25, 2001
- -----------------------------------------------------
                  Jeffrey E. Garten

                                                                   Director
- -----------------------------------------------------
                  Gerald Greenwald

                                                                   Director
- -----------------------------------------------------
                   Susan C. Schwab

               /s/ GEORGE J. STATHAKIS                             Director              July 25, 2001
- -----------------------------------------------------
                 George J. Stathakis

                 /s/ JOHN O. WILSON                                Director              July 25, 2001
- -----------------------------------------------------
                   John O. Wilson
</TABLE>

                                       II-6
<PAGE>   63

                                 EXHIBIT INDEX

<TABLE>
<CAPTION>
EXHIBIT
NUMBER                            DESCRIPTION
- -------                           -----------
<C>       <S>
   3.1    Amended and Restated Certificate of Incorporation of Calpine
          Corporation(a)
   3.2    Certificate of Correction of Calpine Corporation(b)
  *3.3    Certificate of Amendment of Amended and Restated Certificate
          of Incorporation of Calpine Corporation
   3.4    Certificate of Designation of Series A Participating
          Preferred Stock of Calpine Corporation(b)
   3.5    Amended Certificate of Designation of Series A Participating
          Preferred Stock of Calpine Corporation(b)
  *3.6    Amended Certificate of Designation of Series A Participating
          Preferred Stock of Calpine Corporation
   3.7    Certificate of Designation of Special Voting Preferred Stock
          of Calpine Corporation(c)
   3.8    Amended and Restated By-laws of Calpine Corporation(d)
  *4.1    Registration Rights Agreement, dated April 30, 2001 by and
          between Calpine Corporation and the Initial Purchaser
   4.2    Rights Agreement, dated as of June 5, 1997, between Calpine
          Corporation and First Chicago Trust Company of New York, as
          rights agent(e)
  +5.1    Opinion of Covington & Burling
  +8.1    Opinion of Thelen Reid & Priest LLP as to certain tax
          matters
 *12.1    Statement Regarding Computation of Ratios
 *23.1    Consent of Arthur Andersen LLP, independent public
          accountants
 +23.2    Consents of Covington & Burling (included in opinion filed
          as exhibit 5.1)
 +23.3    Consent of Thelen Reid & Priest LLP
 *24.1    Power of Attorney of Officers and Directors of Calpine
          Corporation (as set forth on the signature pages of this
          Registration Statement)
 *25.1    Statement of Eligibility of Trustee
</TABLE>

- -------------------------
 *  Filed herewith.

 +  To be filed.

(a) Incorporated by reference to Calpine Corporation's Registration Statement on
    Form S-3 (Registration No. 333-40652) filed with the SEC on June 30, 2000.

(b) Incorporated by reference to Calpine Corporation's Annual Report on Form
    10-K for the year ended December 31, 2000, filed with the SEC on March 15,
    2001.

(c) Incorporated by reference to Calpine Corporation's Quarterly Report on Form
    10-Q for the quarter ended March 31, 2001, filed with the SEC on May 15,
    2001.

(d) Incorporated by reference to Calpine Corporation's Registration Statement on
    Form S-1 (Registration No. 333-07497).

(e) Incorporated by reference to Calpine's Registration Statement on Form 8-A
    filed with the SEC on June 18, 1997 and amended by the Corporation's
    Registration Statement on Form 8-A/A filed with the SEC on June 24, 1997
    (File No. 001-12079).
