
                                 Exhibit 10.13a

                        PINNACLE WEST CAPITAL CORPORATION


                           SUPPLEMENTAL EXCESS BENEFIT


                                 RETIREMENT PLAN

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                                TABLE OF CONTENTS

                                                                            Page
                                                                            ----
ARTICLE ONE - PREAMBLE......................................................  1
ARTICLE TWO - CONSTRUCTION..................................................  2
ARTICLE THREE - ELIGIBILITY AND PARTICIPATION...............................  2
ARTICLE FOUR - BENEFITS.....................................................  4
ARTICLE FIVE - PAYMENT OF BENEFITS..........................................  6
ARTICLE SIX - COORDINATION OF BENEFITS......................................  8
ARTICLE SEVEN - FUNDING.....................................................  9
ARTICLE EIGHT - ADMINISTRATION..............................................  9
ARTICLE NINE - AMENDMENT AND TERMINATION OF THE PLAN........................  9
ARTICLE TEN - ASSIGNMENT.................................................... 10
ARTICLE ELEVEN - WITHHOLDING................................................ 10
ARTICLE TWELVE - OTHER BENEFIT PLANS OF THE COMPANY......................... 10
ARTICLE THIRTEEN - MISCELLANEOUS............................................ 11
ARTICLE FOURTEEN - EFFECTIVE DATE........................................... 11

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                        PINNACLE WEST CAPITAL CORPORATION
                   SUPPLEMENTAL EXCESS BENEFIT RETIREMENT PLAN

                                   ARTICLE ONE

                                    PREAMBLE

     Effective  January  1,  1987,   PINNACLE  WEST  CAPITAL   CORPORATION  (the
"Company")  adopted the PINNACLE WEST CAPITAL  CORPORATION  SUPPLEMENTAL  EXCESS
BENEFIT  RETIREMENT  PLAN (the  "Plan")  for the  purpose  of paying  retirement
benefits to certain  employees  in excess of the  benefits  permitted to be paid
under the Pinnacle West Capital  Corporation  Retirement  Plan (the  "Retirement
Plan") by reason of Section 415 of the Internal  Revenue Code (the "Code").  The
Plan was  thereafter  amended  several  times to  provide  additional  benefits,
thereby  changing  the Plan from an "excess  benefit  plan"  under the  Employee
Retirement  Income Security Act of 1974, as amended (the "Act"),  to a "top hat"
plan under the Act.

     Effective  January 1, 1982,  ARIZONA PUBLIC SERVICE COMPANY ("APS") adopted
the ARIZONA PUBLIC SERVICE COMPANY  SUPPLEMENTAL  EXCESS BENEFIT RETIREMENT PLAN
(the "APS  Plan")  for the  purpose  of paying  retirement  benefits  to certain
employees  in excess of the  benefits  permitted  to be paid  under the  Arizona
Public Service Company Employees' Retirement Plan (the "APS Retirement Plan") by
reason of Section 415 of the Code. The Plan was thereafter amended several times
to  provide  additional  benefits,  thereby  changing  the Plan from an  "excess
benefit plan" under the Act to a "top hat" plan under the Act.

     By this amendment and restatement,  the Company and APS intend to merge the
APS Plan into this Plan and to make other technical changes.
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                                   ARTICLE TWO

                                  CONSTRUCTION

     Terms  capitalized in this Plan shall have the meaning given in Article Two
of the Retirement Plan,  governing  definitions and  construction,  except where
such terms are otherwise  defined in this Plan. If any provision of this Plan is
determined  to be  invalid  or  unenforceable  for  any  reason,  the  remaining
provisions  shall  continue in full force and effect.  All of the  provisions of
this Plan shall be construed and enforced  according to the laws of the State of
Arizona,  and shall be administered  according to the laws of such state, except
as otherwise  required by the Act, the Code or other applicable  federal law. It
is the intention of the Company that the Plan, as adopted by the Company,  shall
constitute  an  "unfunded  plan of deferred  compensation  for a select group of
management  and highly  compensated  employees"  within the  meaning of Sections
201(2)  and 301(3) of the Act.  Benefits  under this Plan shall be paid from the
Company's general assets,  and not from any trust fund or other segregated fund.
This  Plan  shall  be  construed  in a  manner  consistent  with  the  Company's
intention.

                                  ARTICLE THREE

                          ELIGIBILITY AND PARTICIPATION

     Employees  of the  Company or its  Affiliates  who are  members of a select
group of management or highly compensated employees,  as determined by the Human
Resources Committee of the Board of Directors of the Company, in its discretion,
and from time to time,  shall be  eligible  to  participate  in the Plan if they
satisfy the eligibility requirements of Section 3(a) or Section 3(b).

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     (a)  Eligible  Employees  who are  officers of the Company or an  Affiliate
which is a participating employer under the Retirement Plan shall be entitled to
the benefits described in Section 4(a).

     (b)  Eligible  Employees  of  the  Company  or  an  Affiliate  which  is  a
participating  employer under the Retirement Plan who are not officers,  who are
designated for  participation by the Human Resources  Committee of the Company's
Board of Directors  and who are  participants  in the  Retirement  Plan shall be
entitled  to the  benefits  described  in  Section  4(b).  The  Human  Resources
Committee  may make its  designations  under  this  Section  3(b) by  individual
designation or by group designation.

     A participant shall commence participation in this Plan as of the first day
of the Plan Year in which he  becomes a  participant  pursuant  to this  ARTICLE
THREE or the first day of his employment  with the Company or an Affiliate which
is a participating  employer under the Retirement Plan, whichever is later. Such
participation  shall  continue  until  the  earlier  of the  date on  which  the
participant no longer satisfies the requirements for participation under Section
3(a) or Section 3(b) or the date on which the Human Resources  Committee informs
the  participant in writing that he is no longer eligible to participate in this
Plan.

     Notwithstanding  the foregoing,  if the status of a participant changes for
reasons other than  termination  of employment  with the Company or an Affiliate
which is a  participating  employer  under the  Retirement  Plan,  so that he no
longer is eligible to  participate in the Plan,  his  participation  in the Plan
shall  cease but his  benefit  under  this Plan as of the date of his  change of
status shall not be canceled or  distributed,  but shall be determined  upon his
termination of employment with the Company or an Affiliate.

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                                  ARTICLE FOUR

                                    BENEFITS

     (a) Subject to ARTICLE SEVEN,  a participant  who is eligible under Section
3(a) shall be entitled to a monthly  benefit equal to the lesser of (i) or (ii),
reduced by (iii), where

          (i) Equals three  percent (3%) of the  participant's  Average  Monthly
     Compensation  multiplied  by the  participant's  Years of  Service,  not to
     exceed  ten  (10)  Years  of  Service,   plus  two  percent   (2%)  of  the
     participant's Average Monthly Compensation  multiplied by the participant's
     Years of Service in excess of ten (10) Years of Service,

          (ii) Equals sixty percent (60%) of the  participant's  Average Monthly
     Compensation, and

          (iii)  Equals  the  amount  of  such  participant's   monthly  benefit
     determined  under the terms of the Retirement  Plan and payable in the form
     of  the  joint  and  survivor  annuity  described  in  Section  6.2  of the
     Retirement Plan.

     For purposes of this Section 4(a), Compensation shall be determined without
regard to the limitation  set forth in Section  401(a)(17) of the Code and shall
be increased by any cash payments made to the  participant  pursuant to bonus or
incentive  plans   maintained  by  the  Company  or  an  Affiliate  which  is  a
participating  employer under the Retirement Plan for employees generally and by
any amounts  deferred by the  participant  under any of the Company's or such an
Affiliate's  deferred  compensation plans for employees,  provided that bonus or
incentive  payments made in a form other than cash, bonus or incentive  payments
which  are not  "year-end"  bonus or  incentive  payments,  bonus  or  incentive
payments under  individual  agreements  between the Company or such an Affiliate
and a participant, and cash payments

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made  under  bonus or  incentive  plans  maintained  by the  Company  or such an
Affiliate  for  employees  generally  which  exceed the maximum  amount that the
Company's  President  or  Chief  Operating  Officer  determines,  in  his or her
discretion,  may be taken into  account  under this Plan shall not be taken into
account as Compensation for purposes of this Plan unless the Company's President
or Chief Operating Officer determines, in his or her discretion, that such bonus
or  incentive  payment  shall be taken into account as  Compensation  under this
Plan.  Eligible  bonuses and incentive  payments  shall be taken into account as
Compensation  in the year in which such amounts are paid rather than in the year
in which  they  are  earned,  provided  that the  Company's  President  or Chief
Operating  Officer  shall  have  the  authority  to  determine,  in  his  or her
discretion,  that such bonus or incentive payment shall be taken into account in
the year in which such amounts are earned  rather than in the year in which they
are paid. The Company's President or Chief Operating Officer shall have the sole
and absolute  discretion to determine  whether a bonus or incentive payment made
to a participant constitutes  Compensation for purposes of this Section 4(a) and
may  differentiate  among  individuals  in  establishing  the bonus or incentive
payments that may be taken into account under the Plan.

     (b)  Subject to ARTICLE  SIX and  ARTICLE  SEVEN,  any  participant  who is
designated for participation pursuant to Section 3(b) and who receives a benefit
under the Retirement Plan, or such participant's surviving spouse or beneficiary
in the event of the participant's  death, shall be entitled to a monthly benefit
payable in accordance  with this ARTICLE FOUR and with ARTICLE FIVE equal to (i)
reduced by (ii), where

          (i) Equals the amount of such  participant's or surviving  spouse's or
     beneficiary's  monthly benefit under the Retirement Plan computed under the
     provisions  of the  Retirement  Plan  but  without  regard  to  the  cap on
     Compensation in Section 2.1(n)

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     and  the  limitations  in  Section  5.10  of the  Retirement  Plan  and the
     provisions of Sections 401(a)(17) and 415 of the Code; and

          (ii) Equals the amount of such  participant's or surviving spouse's or
     beneficiary's  monthly  benefit  actually  payable  under  the terms of the
     Retirement Plan.

For purposes of this calculation,  Compensation  shall include any amount of the
participant's  regular  salary  that the  participant  elects to defer under any
deferred  compensation  plans for employees of the Company or an Affiliate which
is a  participating  employer  under the  Retirement  Plan and shall exclude all
bonus  or  incentive  payments  paid to the  participant.  The  Human  Resources
Committee   shall  have  the  sole  and  absolute   discretion  to  determine  a
participant's Compensation for purposes of this Section 4(b).

     Benefits  payable  under  this  Section  4(b)  shall be  payable  to a Plan
participant or his spouse or other beneficiary in the same manner and subject to
all the same options, conditions,  privileges and restrictions as are applicable
to the benefits payable to the Plan participant,  spouse or other beneficiary of
a Participant under the Retirement Plan, as though such benefits were payable as
a part of the benefits being paid under the Retirement Plan.

                                  ARTICLE FIVE

                               PAYMENT OF BENEFITS

     (a) A  participant  entitled to benefits  under  Section  4(a) may elect to
commence  receiving  unreduced  benefits  on or  after  the  date on  which  the
participant attains the age of sixty-five (65) years or attains the age of sixty
(60)  years and is  credited  with at least  twenty  (20)  Years of  Service.  A
participant may elect to commence  receiving benefits earlier if he has attained
at least the age of fifty-five (55) years and is credited with at least ten (10)
Years of Service,  provided that the  participant's  benefit shall be reduced by
three percent (3%) for each

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year (or part thereof) by which the  participant's  retirement  age precedes the
date on which he  would  have  attained  the age of  sixty  (60)  years if he is
credited  with at least  twenty  (20)  Years of  Service or the date on which he
would have attained the age of sixty-five  (65) years if credited with less than
twenty (20) Years of Service.

     Benefits  payable to a  participant  under Section 4(a) shall be payable in
the form of a fifty  percent  (50%)  joint and  survivor  annuity,  which  shall
provide a monthly  payment to the  participant  for his life equal to the amount
determined under Section 4(a) and upon his death, shall provide monthly payments
to the participant's spouse for life equal to fifty percent (50%) of the monthly
payment being received by the participant at the time of his death.

     If a  participant  entitled to benefits  under  Section  4(a) dies prior to
commencing  benefits,  the participant's  spouse shall be entitled to a survivor
annuity equal to fifty percent (50%) of the monthly benefit that the participant
would have  received  had he  terminated  employment  on the day before he died,
survived to the age on which he would  first be  eligible  to commence  benefits
under this Section 5(a),  elected to retire and commence benefits under the Plan
at that time and then died.

     (b)  Benefits  payable to a  participant  under  Section  4(b) shall become
payable  when a  participant  (or his spouse or  beneficiary)  begins to receive
payments under the Retirement Plan, and shall be subject to the same adjustments
and shall be payable by the  Company in the same  manner and at the same time as
the Plan  participant's  (or his spouse's or  beneficiary's)  benefits under the
Retirement  Plan are paid, as though such benefits were  otherwise  payable as a
part of the benefits  being paid under the Retirement  Plan,  subject to ARTICLE
SIX. An election or mode of payment under the Retirement  Plan shall  constitute
an election of a similar mode of payment under this Plan.

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                                   ARTICLE SIX

                            COORDINATION OF BENEFITS

     If an employee who was  participating  in a retirement plan sponsored by an
Affiliate, which is not a participating employer in the Retirement Plan, becomes
an employee of the Company or a participating Affiliate and a participant in the
Plan under Section 4(b) and such employee's accrued benefit under the retirement
plan  maintained by the Affiliate  formerly  employing him is transferred to the
Retirement  Plan,  upon  termination  of employment,  the  employee's  benefits,
calculated  in accordance  with Section  4(b),  will be payable in full from the
Plan in accordance  with Section  5(b). If an employee who was a participant  in
the retirement plan of an Affiliate,  which is not a  participating  employer in
the  Retirement  Plan,  becomes an employee  of the  Company or a  participating
Affiliate and a participant in this Plan, and such  employee's  accrued  benefit
under the retirement  plan  maintained by his former employer is not transferred
to the Retirement Plan, upon termination of employment, the employee's benefits,
calculated  in accordance  with Section  4(b),  will be payable from the Plan in
accordance with Section 5(b) to the extent such benefits are attributable to the
pension  benefits  payable  to that  employee  under the  Retirement  Plan.  The
benefits  calculated  pursuant  to  Section  4(b) that are  attributable  to the
pension  benefits  payable to the employee under the  Retirement  Plan are those
benefits  that bear the same ratio to the total  benefits  due to the  employee,
calculated pursuant to Section 4(b), as the benefit payable to the employee from
the Retirement  Plan bears to the total  benefits  payable to the employee under
both the  Retirement  Plan and the retirement  plan  maintained by the Affiliate
formerly employing that employee.

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                                  ARTICLE SEVEN

                                     FUNDING

     Benefits  under this Plan shall be payable  from the general  assets of the
Company and shall not be segregated  in a trust fund or otherwise  funded in any
manner prior to the time of payment.  No Plan participant  shall have any vested
rights hereunder nor any right hereunder to any specific assets of the Company.

                                  ARTICLE EIGHT

                                 ADMINISTRATION

     The  Plan  will  be  administered  by  the  Administrative  Committee  that
administers the Retirement Plan. Except as otherwise  expressly provided in this
Plan,   the   Administrative   Committee   shall   have  the  same   powers  and
responsibilities  as it has under Sections 10.4 and 12.2 of the Retirement Plan.
Claims for benefits  under the Plan shall be  determined in the manner set forth
in Article Eleven of the Retirement Plan.

                                  ARTICLE NINE

                      AMENDMENT AND TERMINATION OF THE PLAN

     The  Plan  may  be   amended  in  whole  or  in  part,   prospectively   or
retroactively,  by  action  of the  Company's  Board  of  Directors,  and may be
terminated at any time by action of the Board of Directors;  provided,  however,
that no such amendment or termination  shall reduce any amount payable hereunder
to the extent such amount accrued prior to the date of amendment or termination.
All amendments shall be in writing, approved by the Company's Board of Directors
and executed by a duly authorized officer of the Company.

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                                   ARTICLE TEN

                                   ASSIGNMENT

     No Plan  participant or beneficiary  of a Plan  participant  shall have any
right to assign, pledge, hypothecate, anticipate or any way create a lien on any
amounts  payable  hereunder.  No amounts  payable  hereunder shall be subject to
assignment  or  transfer or  otherwise  be  alienable,  either by  voluntary  or
involuntary act, or by operation of law, or be subject to attachment, execution,
garnishment,  sequestration or other seizure under any legal, equitable or other
process,  or be liable in any way for the debts or defaults of Plan participants
and their  beneficiaries.  Notwithstanding  the  foregoing,  assignments  of the
benefits  provided under this Plan shall be permitted for purposes of satisfying
family  support  obligations if such  assignments  are pursuant to a court order
which satisfies the requirements for a "qualified  domestic  relations order" as
defined in Section 206(d)(3) of the Act.

                                 ARTICLE ELEVEN

                                   WITHHOLDING

     Any taxes  required to be withheld from  payments to the Plan  participants
hereunder shall be deducted and withheld by the Company.

                                 ARTICLE TWELVE

                       OTHER BENEFIT PLANS OF THE COMPANY

     Nothing  contained in this Plan shall prevent a Plan  participant  prior to
his death, or his spouse or other  beneficiary  after his death, from receiving,
in addition to any payments  provided for under this Plan, any payments provided
for under the  Retirement  Plan or under The Pinnacle  West Capital  Corporation
Savings Plan, or which would otherwise be payable or  distributable  to him, his
surviving spouse or beneficiary under any plan or policy of

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the Company or otherwise.  Nothing in this Plan shall be construed as preventing
the Company or any of its subsidiaries  from establishing any other or different
plans providing for current or deferred compensation for employees.

                                ARTICLE THIRTEEN

                                  MISCELLANEOUS

     Nothing  contained  in this  Plan  shall  be  construed  as a  contract  of
employment between the Company and an employee, or as a right of any employee to
be continued in the  employment of the Company,  or as a limitation of the right
of the Company to discharge any of its employees, with or without cause.

     All of the  provisions  of this Plan shall be binding  upon all persons who
shall  be  entitled  to  any  benefit   hereunder,   their  heirs  and  personal
representatives.

                                ARTICLE FOURTEEN

                                 EFFECTIVE DATE

     The Plan,  as amended and  restated,  shall be  effective  as of January 1,
2000. From and after such date, all benefits accrued under the APS Plan shall be
payable under and in accordance with the terms of this Plan.

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     IN WITNESS  WHEREOF,  the Company and APS have  caused this  Pinnacle  West
Capital Corporation  Supplemental Excess Benefit Retirement Plan, as amended and
restated herein, to be executed by their duly authorized  officers this 7 day of
December, 1999.

                                        PINNACE WEST CAPITAL CORPORATION


                                        By Armando Flores
                                           -------------------------------------
                                        Its EVP Corp Bus Svcs
                                           -------------------------------------
Attest:

By Faye Widenmann
   -------------------------------------
Its Secretary
   -------------------------------------

                                        ARIZONA PUBLIC SERVICE COMPANY

                                        By Jack Davis
                                           -------------------------------------
                                        Its President
                                           -------------------------------------
Attest:

By Faye Widenmann
   -------------------------------------
Its Secretary
   -------------------------------------

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