                                                                    Exhibit 10.1

     This  Amendment  No.  5,  dated as of June 30,  2000,  to the  Amended  and
Restated Decommissioning Trust Agreement (PVNGS Unit 2), dated as of January 31,
1992,  as amended  by  Amendment  No. 1 thereto  dated as of  November  1, 1992,
Amendment  No. 2 thereto  dated as of November 1, 1994,  Amendment No. 3 thereto
dated as of June 20, 1996,  and Amendment No. 4 thereto dated as of December 16,
1996 (the  "Decommissioning  Trust  Agreement";  terms  used  herein as  therein
defined), is entered into between Arizona Public Service Company ("APS"),  State
Street  Bank and Trust  Company,  as  successor  to The First  National  Bank of
Boston,   as  Owner   Trustee  and  as  Lessor,   and  Mellon  Bank,   N.A.,  as
Decommissioning Trustee ("Decommissioning Trustee").

                                R E C I T A L S:

     WHEREAS, the parties hereto wish to amend the investment parameters for the
Decommissioning  Trust Fund and the Second  Fund  contained  in Exhibit B to the
Decommissioning Trust Agreement;

     NOW,  THEREFORE,  in  consideration  of the  premises and of other good and
valuable   consideration,   receipt   and   sufficiency   of  which  are  hereby
acknowledged, the parties hereto agree as follows:

                              A G R E E M E N T S:

     SECTION 1. Amendment.

     Paragraph (l) of Exhibit B to the Decommissioning Trust Agreement is hereby
deleted and is replaced in its entirety by the following:

     (l)  (x)  corporate  equity  securities,  including,  but not  limited  to,
          investment in units of common or collective  trust funds  investing in
          corporate  equity  securities;  including,  but not  limited  to,  the
          Decommissioning  Trustee's Nuclear  Decommissioning Trust Equity Index
          Fund (the "NDT Equity Index Fund") and (y) obligations not included in
          clauses (a) through (k) issued or guaranteed by a person controlled or
          supervised by and acting as an instrumentality of the United States of
          America  pursuant to  authority  granted by the Congress of the United
          States of America,  including Federal  Intermediate Credit Bank, Banks
          for Cooperatives, Federal Land Banks, Federal Home Loan Banks, Federal
          Home Loan  Mortgage  Corporation;  provided,  that no more than  fifty
          percent (50%) of the aggregate  assets of the Funds may be invested in
          securities  described in (x) and (y) of this  subparagraph  (l) during
          the period from June 27, 1996 through  December 31, 2003, no more than
          thirty  percent  (30%)  during the period from January 1, 2004 through
          December 31, 2006,  and no more than fifteen  percent (15%) during the
          period from  January 1, 2007 through  January 31,  2010;  and provided
          further that after January 31, 2010, no  investments  shall be made in
          such securities.
<PAGE>
     SECTION 2. Effectiveness.

     This Amendment No. 5 shall become  effective as of the date hereof upon the
execution and delivery of a counterpart  of this  Amendment No. 5 by each of the
parties hereto.

     SECTION 3. Miscellaneous

     (a)  Full Force and Effect.

     Except as expressly  provided herein, the  Decommissioning  Trust Agreement
shall  remain  unchanged  and in full force and effect.  Each  reference  in the
Decommissioning  Trust Agreement and in any exhibit or schedule thereto to "this
Agreement,"  "hereto,"  "hereof" and terms of similar  import shall be deemed to
refer to the Decommissioning Trust Agreement as amended hereby.

     (b)  Counterparts.

     This Amendment No. 5 may be executed in any number of counterparts,  all of
which taken together shall  constitute one and the same  instrument,  and any of
the  parties  hereto  may  execute  this  Amendment  No. 5 by  signing  any such
counterpart.

     (c)  Arizona Law.

     This Amendment No. 5 shall be construed in accordance  with and governed by
the law of the State of Arizona.

     IN WITNESS WHEREOF,  the parties hereto have caused this Amendment No. 5 to
the  Decommissioning  Trust Agreement to be duly executed as of the day and year
first above written.

                                        ARIZONA PUBLIC SERVICE COMPANY


                                        By Barbara M. Gomez
                                           -------------------------------------

                                        Title Treasurer
                                              ----------------------------------

                                      -2-
<PAGE>
                                        MELLON BANK N.A., as
                                        Decommissioning Trustee


                                        By Gerald T. McDermott
                                           -------------------------------------

                                        Title Vice President
                                              ----------------------------------


                                        STATE STREET BANK AND TRUST COMPANY,  as
                                        Owner  Trustee  under a Trust  Agreement
                                        with Security  Pacific  Capital  Leasing
                                        Corporation   and  as  Lessor   under  a
                                        Facility   Lease  with  Arizona   Public
                                        Service Company


                                        By John Correia
                                           -------------------------------------

                                        Title Assistant Vice President
                                              ----------------------------------


                                        STATE STREET BANK AND TRUST COMPANY,  as
                                        Owner  Trustee  under a Trust  Agreement
                                        with  Emerson  Finance Co. and as Lessor
                                        under  a  Facility  Lease  with  Arizona
                                        Public Service Company


                                        By John Correia
                                           -------------------------------------

                                        Title Assistant Vice President
                                              ----------------------------------


                                      -3-
<PAGE>
STATE OF ARIZONA         )
                         )  ss.
County of Maricopa       )

     The  foregoing  instrument  was  acknowledged  before  me  this  8th day of
December,  2000, by Barbara M. Gomez,  the Treasurer of ARIZONA  PUBLIC  SERVICE
COMPANY, an Arizona corporation, on behalf of said corporation.


                                        Suzanne W. Debes
                                        ----------------------------------------
                                        Notary Public

My commission expires:

June 20, 2003
----------------------



STATE OF PENNSYLVANIA               )
                                    ) ss.
County of Allegheny                 )

     The  foregoing  instrument  was  acknowledged  before  me this  14th day of
December,  2000, by Gerald T. McDermott, a Trust Officer of MELLON BANK, N.A., a
corporation having trust powers, as Decommissioning  Trustee,  on behalf of said
corporation.


                                        Leona Esken
                                        ----------------------------------------
                                        Notary Public

My commission expires:

11-18-02
----------------------

                                      -4-
<PAGE>
STATE OF MASSACHUSETTS              )
                                    )  ss.
County of Suffolk                   )

     The  foregoing  instrument  was  acknowledged  before  me  this  7th day of
December,  2000, by John Correia,  the Assistant  Vice President of STATE STREET
BANK AND TRUST COMPANY, a Massachusetts  trust company, in its capacity as Owner
Trustee  under  a  Trust   Agreement  with  Security   Pacific  Capital  Leasing
Corporation,  and as Lessor under a Facility  Lease with Arizona  Public Service
Company, on behalf of said association in such capacities.


                                        James M. Coolidge
                                        ----------------------------------------
                                        Notary Public

My commission expires:

June 19, 2003
----------------------



STATE OF MASSACHUSETTS              )
                                    )  ss.
County of Suffolk                   )

     The  foregoing  instrument  was  acknowledged  before  me  this  7th day of
December,  2000, by John Correia,  the Assistant  Vice President of STATE STREET
BANK AND TRUST COMPANY, a Massachusetts  trust company, in its capacity as Owner
Trustee under a Trust  Agreement with Emerson Finance Co., and as Lessor under a
Facility  Lease  with  Arizona  Public  Service  Company,   on  behalf  of  said
association in such capacities.


                                        James M. Coolidge
                                        ----------------------------------------
                                        Notary Public

My commission expires:

June 19, 2003
----------------------

                                      -5-

