Addendum to Memorandum of Agrement


         This Addendum is to the  Memorandum of Agreement  effective,  April 25,
1998 (hereafter  "Memorandum"),  between Arizona Public Service Company and Salt
River Project  Agricultural  Improvement  and Power District  (hereinafter  "the
parties").  By signing  this  Addendum to  Memorandum  of  Agreement  (hereafter
"Addendum")  the parties intend to change  certain  provisions in the Memorandum
and to bind  themselves  to certain  additional  obligations  in the event their
respective governing boards approve the Memorandum.

         By signing  this  Addendum  the  parties  intend to clarify a number of
provisions in the original Memorandum for the express purpose of eliminating any
interpretation   of  the  Memorandum  that  could  be  construed  as  permittimg
anticompetitive or unlawful conduct, or as being inconsistent with the policy of
the Arizona State Legislature and Arizona Corporation Commission,  that there be
competition in certain aspects of the electric  utility  business as provided by
law.


                                    RECITALS

These facts form the basis of this Addendum:

1. The parties entered into the Memorandum effective April 25, 1998;

2. At the time the Memorandum was executed the Arizona  Corporation  Commission,
within the scope of its jurisdiction, had declared that it is the policy of this
State  that there be  competition  in certain  aspects of the  electric  utility
business(1), and the Arizona State Legislature was considering a bill to declare
a similar statewide policy;

3. The Arizona Attorney  General has raised certain issues  involving  potential
anticompetitive effects from possible interpretations of certain language in the
Memorandum;

4. The parties do not intend the  Memorandum to limit  competition in any aspect
of the electric  utility  business in which the parties are authorized by law to
compete, or in which they choose to compete;

5.  The  parties  do not  intend  by the  incorporation  of any part of the 1955
Territorial  Agreement,  or the Power  Coordination  Agreement,  to continue the
allocation of  geographic  territories  or customer  classes with respect to any
aspect of the electric utility business subject to competition;

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(1) The terms  "electric  utility  business"  and  "electric  services" are used
interchangeably  in this  Addendum,  and are intended to mean all aspects of the
business of the parties.
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6. The parties do not intend by the words "operational  opportunities" of mutual
benefit to mean the pursuit of any opportunity that would be  anticompetitive or
unlawful  in any  aspect of the  electric  utility  business  that is subject to
competition, as of the date of the Memorandum and thereafter;

7. The parties  understand that their electric utility business  activities that
are not actively regulated are subject to state and federal antitrust law.


                               ADDENDUM AGREEMENT

Now, therefore, the parties agree as follows.

1. Amendment of Territorial Agreement(2).

         The parties hereby repudiate any aspect,  language or interpretation of
the 1955 Territorial Agreement that would permit any of the following:

         a. The allocation or division of customers or geographic territories as
between  the  parties  regarding  non-distribution  electric  services  that are
subject to competion;

         b. Any  collaborative  decision to fix, maintain or stabilize the price
of electric services subject to competition;

2. Amendment of the Power Coordination Agreement

         a. The parties agree that the Power Coordination Agreement shall not be
interpreted  or  performed  by the  parties  in  any  manner  inconsistent  with
paragraph 1;

         b. The parties agree that nothing in the Power  Coordination  Agreement
shall permit either to  discriminate  in access to  transmission or distribution
systems  against any  competitive  provider of  electric  services,  in a manner
prohibited by applicable federal and state statute or regulatory requirements.

3. Identification of future savings.

         a. The  parties  agree that  paragraph  3 of the  Memorandum  shall not
permit  them to jointly  

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(2) Paragraph  references in this Addendum refer to the same numbered paragraphs
in the  Memorandum,  except that the  sub-parts of  paragraph  1., 2. and 3. are
added by this Addendum.
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make any  determination  that  would fix,  maintain  or  stabilize  any price of
electric services subject to competition;

         b. The parties agree that  paragraph 3 of the  Memorandum  shall not be
interpreted or performed by the parties in a manner inconsistent with paragraphs
1. and 2. of this Addendum;

         c. The parties further agree that their senior executives shall not, in
any meetings to discuss joint business issues, enter into discussions concerning
the price or  allocation  of  territories  or customers of any electric  service
subject to competition.

5. State Political Issues

         a.- i. The parties  agree that nothing  contained in paragraphs a. - i.
will be  construed  by them to prevent  each from  advertising,  marketing,  and
promoting  itself by  comparison to the other in terms of price or efficiency in
connection  with  any  aspect  of  the  electric  utility  business  subject  to
competition;

         d. The parties  agree that nothing  contained in paragraph  5.d.  shall
require that APS disclose any stranded  cost or  regulatory  asset numbers which
are not otherwise publicly  available.  The parties further agree that paragraph
5.d. shall not require any  conformation of bills or billing format,  other than
the general  obligation  that APS disclose the fact that  regulatory  assets are
recovered as part of its distribution bill;

         f. The parties agree that each party will determine independently which
stranded  cost  calculation  and  recovery   methodology  to  present  to  their
respective  governing  authorities.  Such  calculation and recovery  methodology
shall be  determined  according to the  procedures  established  by State law or
Arizona  Corporation  Commission  Rule,  whichever  applies,  and  shall  be  in
accordance with federal and state antitrust law,  notwithstanding  any provision
in the Memorandum to the contrary.

6. Federal Political Issues

         a.-g. The parties agree that nothing contained in paragraphs a.-g. will
be construed by them to prevent each from  advertising,  marketing and promoting
itself by comparison to the other in connection  with any aspect of the electric
utility businesss that is subject to competition.

         d. The parties  agree that by paragraph  6.d. they do not intend to set
up  any  discriminatory   auditing  system,   entity  or  mechanism  to  resolve
transmission  system  constraints  that  is not in  compliance  with  applicable
federal and state regulatory or statutory requirements.

7. Transmission and Distribution Prices and Terms

         The parties  agree that  paragraph 7 obligates  them to allow access to
         their   respective   
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         electric power  transmission  and  distribution  facilities to all bona
         fide competitors, including, but not limited to each other, under rates
         and  terms  and  conditions  of  service  that  are  nondiscriminatory,
         cost-based,  just and  reasonable  and  comparable  to those charged by
         themselves for their own use in accordance with  applicable  regulatory
         or statutory "open access" rules.

10. Miscellaneous Provisions

d. No provision of the Memorandum,  the 1955  Territorial  Agreement or the 1955
Power Coordination Agreement, shall be binding on any party, successor,  assign,
subsidiary  or affiliate if a court of competent  jurisdiction  determines  in a
preliminary  order or final  judgment that the provision  violates any antitrust
law.


AGREED TO AS OF May 19, 1998


APS

ARIZONA PUBLIC SERVICE COMPANY


         By William J. Post
            ----------------------------
         William J. Post
         Chief Executive Officer

         Date 5/19/98
              ---------------------------



SRP

SALT RIVER PROJECT AGRICULTURAL
IMPROVEMENT AND POWER DISTRICT


         By Richard H. Silverman
            -----------------------------
         Richard H. Silverman
         General Manager

         Date 5/19/98
              ----------------------------
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