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Exhibit: 10.11.4

                                FIRST AMENDMENT
                        TO THE STOCK PURCHASE AGREEMENT

                                     AMONG

                GAS ENERGY, INC., GAS ENERGY COGENERATION INC.,
                         THE BROOKLYN UNION GAS COMPANY

                                      AND

              CALPINE EASTERN CORPORATION AND CALPINE CORPORATION

                             Dated August 22 1997;
                                   As Amended
                              on December 19, 1997


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FIRST AMENDMENT, dated December 19, 1997, among Gas Energy Inc., a New York
corporation ("GEI"), Gas Energy Cogeneration Inc., a Delaware corporation
("GECI," and together with GEI, the "Companies"), The Brooklyn Union Gas
Company, a New York corporation (the "Seller"), Calpine Eastern Corporation, a
Delaware corporation (the "Purchaser"), and Calpine Corporation, a Delaware
corporation (the "Guarantor"), to the Stock Purchase Agreement, dated August 22,
1997 (the "Original Agreement"), among the Companies, the Seller, the Purchaser
and the Guarantor.

      The Companies, the Seller, the Purchaser and the Guarantor entered into
the Original Agreement relating to the sale to the Purchaser of all of the
outstanding stock of each of the Companies.

      The parties desire to amend the Original Agreement in certain respects as
hereinafter set forth.


      Capitalized terms used herein and not otherwise defined herein shall have
the respective meanings set forth in the Original Agreement. References to "the
Agreement" or "this Agreement" contained in the Original Agreement and this
Amendment shall mean the Original Agreement as amended by this Amendment.

      In consideration of the mutual benefits to be derived from this Amendment
and of the agreements and promises contained herein and other good and valuable
consideration, the parties agree as follows:

      1.    Section 1.2(a) of the Original Agreement shall be deleted in its
entirety and replaced with the following:

            "(a)  The purchase price (the "Purchase Price") for the Shares shall
      be cash in the amount of $100,899,927 (of which $100,699,927 shall be
      consideration for the Shares and $200,000 shall be consideration for the
      put options set forth in Sections 3.9 and 3.10), subject to adjustment in
      accordance with paragraph (b) below, payable by wire transfer in
      immediately available funds, to one or more bank accounts of the Seller.
      Such bank accounts shall be designated by the Seller in writing not later
      than one business day prior to the Closing Date."


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      2.    The first sentence of Section 1.2(b)(i) of the Original Agreement
shall be deleted in its entirety and replaced with the following:

            "(b)  (i) No later than January 12, 1998, the Seller shall deliver
      to the Purchaser a statement (the "Net Working Capital Statement") setting
      forth the Net Working Capital of the Companies as of the Closing Date (the
      "Final Net Working Capital"), prepared by a Vice President of the Seller."

      3.    Schedules 2.2(f) and 2.2(k)-2 are hereby amended by adding thereto
the items set forth on Annexes A-1 and A-2, respectively.

      4.    Section 3.6(c) of the Original Agreement shall be deleted in its
entirety and replaced with the following:

            "(c)  Each of the Seller and the Purchaser hereby agree to reflect
      the allocation of the Aggregate Deemed Sale Price (as defined under
      applicable Treasury Regulations promulgated pursuant to the Code) of the
      assets of the Company as set forth in Schedule 3.6(c) hereto in all
      applicable tax returns filed by either of them, including the Section 338
      Forms. Neither the Seller nor the Purchaser shall take a position
      inconsistent with such allocation unless and to the extent required to do
      so pursuant to a determination (as defined in Section 1313(a) of the
      Code)."

      5.    Schedule 3.6(c), which is attached as Annex B to this Amendment,
shall be added as a Schedule to the Agreement.

      6.    Section 3.9(b) of the Original Agreement shall be deleted in its
entirety and replaced with the following:

            "(b)  It shall be a condition precedent to the Purchaser's right to
      exercise the Put Right that, on the date of exercise of the Put Right and
      on the Put Closing Date (as defined in paragraph (c)), (i) TEC then owns
      all of the assets it owns at the time of the Closing free and clear of all
      Claims (other than Claims which exist at the time of the Closing) and (ii)
      since the time of the Closing, TEC shall not have issued or made any
      commitment to issue any additional shares of capital stock."


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      7.    Section 3.9(e) of the Original Agreement shall be deleted in its
entirety and replaced with the following:

            "(e)  On the BFM Put Closing Date, the Purchaser shall provide a
      certificate of its Chief Financial Officer, in form and substance
      reasonably satisfactory to the Seller, stating that the information set
      forth in the Exercise Notice Certificate is true and correct as if
      provided on and as of the Put Closing Date. Contemporaneously with such
      provision and conveyance, the Seller shall deliver the adjusted BFM Put
      Price by wire transfer of immediately available funds to the Purchaser."

      8.    Section 3.10 of the Original Agreement shall be deleted in its
entirety and replaced with the following:

            "3.10. BFM Put Right. (a) Subject to the conditions set forth in
      paragraph (b), at any time in the period (the "BFM Put Exercise Period")
      between the Closing Date and the earlier of (i) the date which is 90 days
      after the Closing Date and (ii) the latest of (A) the date on which the
      transactions contemplated by the Makowski Stock Purchase Agreement (as
      defined below) are consummated, (B) the date on which the transactions
      contemplated by the GE Purchase Agreement (as defined below) are
      consummated, (C) the date on which the Purchaser receives from Northrup
      Grumman Corporation (formerly known as Grumman Aerospace Corporation)
      ("Grumman") the Grumman Consent (as defined below) and (D) the date on
      which the Grumman Amendments (as defined below) are executed, the
      Purchaser shall have the right (the "BFM Put Right") on one occasion, in
      its sole discretion, to require the Seller, or an affiliate of the Seller
      designated by the Seller, to purchase from the Purchaser all, but not less
      than all, of the Purchaser's right, title and interest in the shares of
      capital stock of Bethpage Fuel Management Inc. ("BFM"), currently owned by
      GEI (the "BFM Shares"), at a price of $5,813,230 (the "BFM Put Price"), as
      adjusted in accordance with the next succeeding sentence. The BFM Put
      Price shall be reduced by the amount of all payments from the Seller to
      any Indemnified Person (as defined in Section 5.3) pursuant to Section 5.1
      from the Closing Date to the BFM Put Closing Date, to the extent such
      payments arise from, are by 

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      reason of, or are in connection with, breaches of representations and
      warranties or covenants of the Seller herein relating to BFM. During the
      BFM Put Exercise Period, the Purchaser and the Guarantor shall use all
      commercially reasonable efforts to obtain from Grumman the Grumman Consent
      and the Grumman Amendments. Upon request by the Seller during the BFM Put
      Exercise Period, the Purchaser shall provide the Seller with a progress
      report or reports on its efforts to obtain the Grumman Consent and the
      Grumman Amendments. As used in this Agreement, (i) "Makowski Stock
      Purchase Agreement" shall mean the Stock Purchase Agreement by and between
      J. Makowski Company, Inc. and Purchaser, dated as of December 19, 1997,
      (ii) "GE Purchase Agreement" shall mean the Purchase Agreement by and
      between Purchaser, GE Power Funding Corporation and General Electric
      Company, dated as of December 19, 1997, (iii) "Grumman Consent" shall mean
      the consent of Grumman required pursuant to Section 17.9 of the Grumman
      Energy Purchase Agreement (as defined in Schedule 2.2(d)-1) for TBG Cogen
      Partners to contract for fuel supply and management with an entity other
      than the Seller or an affiliate thereof and (iv) "Grumman Amendments"
      shall mean amendments entered into after the Closing Date amending the
      Grumman Energy Purchase Agreement and the other agreements between TBG
      Cogen Partners and Grumman on terms and conditions satisfactory to the
      Purchaser in its sole discretion.

            (b)   It shall be a condition precedent to the Purchaser's right to
      exercise the BFM Put Right that, on the date of exercise of the BFM Put
      Right and on the BFM Put Closing Date, (i) all agreements to which BFM is
      a party which are listed on Schedule 2.2.(k)-1 (other than the BFM Credit
      Agreement (as defined in Schedule 2.2(c)-3)) (collectively, the "BFM
      Contracts") remain in full force and effect, without any amendment or
      supplement thereto, or waiver of rights thereunder, in each case from and
      after the Closing, and none of the BFM Contracts shall be subject to any
      Claims (other than Claims which exist at the time of the Closing), (ii)
      BFM is not then in default under any BFM Contract as a result of any act
      or omission of BFM or the Purchaser from and after the Closing Date and
      (iii) since the time of the Closing, BFM shall not have issued or made any
      commitment to issue any additional shares of capital stock.

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            (c)   If the Purchaser wishes to exercise the BFM Put Right, it
      shall give the Seller written notice thereof within the BFM Put Exercise
      Period (the "BFM Put Exercise Notice") together with a certificate of its
      Chief Financial Officer, in form and substance reasonably satisfactory to
      the Seller, (i) certifying the amounts, if any, which reduce the BFM Put
      Price under the second sentence of paragraph (a) and (ii) stating that the
      conditions set forth in paragraph (b) have been satisfied as of the date
      of such certificate (the "BFM Put Exercise Notice Certificate"). The
      purchase and sale of the BFM Shares shall be consummated within five
      business days following the receipt by Seller of the BFM Put Exercise
      Notice (the "BFM Put Closing Date").

            (d)   In order to confirm the information set forth in the BFM Put
      Exercise Notice Certificate, between the date of the receipt of the BFM
      Put Exercise Notice by Seller and the BFM Put Closing Date, the Purchaser
      shall permit, and shall cause BFM to permit, the Seller and its agents and
      representatives to have access to the Purchaser and BFM, and each of their
      respective officers, auditors, books and records, upon reasonable notice
      and during normal business hours. All information so furnished to the
      Seller shall be held in strict confidence by the Seller.

            (e)   On the BFM Put Closing Date, the Purchaser shall provide a
      certificate of its Chief Financial Officer, in form and substance
      reasonably satisfactory to the Seller, stating that the information set
      forth in the BFM Put Exercise Notice Certificate is true and correct as if
      provided on and as of the BFM Put Closing Date. Contemporaneously with
      such provision and conveyance, the Seller shall deliver the adjusted BFM
      Put Price by wire transfer of immediately available funds to the
      Purchaser."

      9.    The following Section 3.11 shall be added after Section 3.10 of the
Agreement:


            "3.11 Amendment of TBG Balancing Agreement. The Purchaser hereby
      acknowledges, and confirms its agreement with, the amended gas
      transportation arrangements for TBG Cogen Partners as set forth in Exhibit
      D hereto."

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      10.   Exhibit D, which is attached as Annex C to this Amendment, shall be
added as an Exhibit to the Agreement.


      11.   Section 4.1(c) of the Original Agreement shall be deleted in its
entirety and replaced with the following:

                  "(c) Consents and Waivers. The Purchaser shall have received
            copies of all duly executed and delivered waivers and consents
            contemplated by Section 2.2(d) and Schedule 2.2(d)-1 (except the
            Grumman Consent), all in form and substance reasonably satisfactory
            to the Purchaser. Any applicable waiting period under the HSR Act
            relating to the transactions contemplated hereby shall have expired
            or been duly terminated."


      12.   Section 4.1(i) and (j) of the Original Agreement shall be deleted in
their entirety and replaced with the following:


      "(i)  [Intentionally omitted].


      (j)   [Intentionally omitted]."


      13.   Section 4.2(c) of the Original Agreement shall be deleted in its
entirety and replaced with the following:

            "(c)  Consents and Waivers. The Seller shall have received copies of
      all duly executed and delivered waivers and consents contemplated by
      Section 2.2(d) and Schedule 2.2(d)-1 (except the Grumman Consent), all in
      form and substance reasonably satisfactory to the Purchaser. Any
      applicable waiting period under the HSR Act relating to the transactions
      contemplated hereby shall have expired or been duly terminated."


      14.   Section 4.2(h) and (i) of the Original Agreement shall be deleted in
their entirety and replaced with the following:


      "(h)  [Intentionally omitted].


      (i)   [Intentionally omitted]."


      15.   Section 6.2 of the Original Agreement shall be deleted in its
entirety and replaced with the following:

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            "6.2. Aggregate Liability. The aggregate liability of the Seller
      under Article V or for any claim for any breach or violation of any
      provision of this Agreement shall not exceed (i) the Purchase Price (as
      adjusted pursuant to Section 1.2) minus (ii) the sum of the Put Price, if
      any, and the BFM Put Price, if any, paid by the Seller or the Seller's
      designee upon the exercise of the Put Right or the BFM Put Right."

      16.   The second to last sentence of Section 6.7 is hereby amended by
adding a reference to "3.11" immediately after the reference to "3.10" therein
and before the reference to "5.2" therein.

      17.   Except as provided herein, all provisions of the Agreement remain
unmodified and in full force and effect.


      18.   This Amendment may be executed in any number of counterparts, and
each such counterpart hereof shall be deemed to be an original instrument, but
all such counterparts together shall constitute but one agreement.

      19.   THIS AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH
THE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD TO CONFLICT OF LAWS
PRINCIPLES.


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               IN WITNESS WHEREOF, each of the parties has caused this Agreement
to be duly executed and delivered as of the day and year first above written.

                                          GAS ENERGY INC.


                                          By:__________________________________
                                               Name:
                                               Title:

                                          GAS ENERGY COGENERATION INC.


                                          By:__________________________________
                                               Name:
                                               Title:

                                          THE BROOKLYN UNION GAS COMPANY


                                          By:__________________________________
                                               Name:
                                               Title:

                                          CALPINE EASTERN CORPORATION


                                          By:___________________________________
                                               Name:
                                               Title:

                                          CALPINE CORPORATION


                                          By:___________________________________
                                               Name:
                                               Title: