AMENDATORY AGREEMENT NO. 4
                                       TO
               AGREEMENT FOR THE SALE AND PURCHASE OF NATURAL GAS
                                     between
                        CHUGACH ELECTRIC ASSOCIATION INC.
                                       AND
                              MARATHON OIL COMPANY
                            dated September 26, 1988


         WHEREAS,  Chugach Electric  Association,  Inc. ("Chugach") and Marathon
Oil Company ("Marathon"), entered into an Agreement for the Sale and Purchase of
Natural Gas ("Agreement") dated September 26, 1988;

         WHEREAS,  after having  operated under the Agreement,  the Parties have
determined that Section 7(c)4 of the Agreement does not  sufficiently add to the
smoothing of price increases to justify the effort required to use it;

         THEREFORE, the parties agree that:

         Section 7(c)4 of the Agreement is deleted

         In all other  respects,  the Agreement  remains in effect as heretofore
amended.

         IN WITNESS  WHEREOF,  Chugach and Marathon have caused this  Amendatory
Agreement No. 4 to be executed by their authorized representatives.


CHUGACH ELECTRIC ASSOCIATION, INC.              MARATHON OIL COMPANY


By:         /s/                                 By:     /s/
   -------------------------------                 -----------------------------
                                                Its Vice President, Natural Gas
Its: General Manager                                Marketing and Transportation
Date:  October 6, 1993                          Date: September 29, 1993