EXHIBIT 10.1.2.6

                                                                  EXECUTION COPY

                           FOURTH AMENDMENT AND WAIVER
                    TO AMENDED AND RESTATED CREDIT AGREEMENT

         This FOURTH AMENDMENT AND WAIVER, dated as of November 19, 2003 (this
"Amendment and Waiver"), to the Amended and Restated Credit Agreement, dated as
of July 16, 2003 (as the same may be amended, supplemented or otherwise modified
from time to time, the "Credit Agreement"), among CALPINE CORPORATION, a
Delaware corporation (together with its successors, the "Borrower"), the various
financial institutions as are or may become parties hereto (collectively, the
"Lenders"), various lead Arrangers (as defined below), and THE BANK OF NOVA
SCOTIA ("Scotia Capital"), as administrative agent and funding agent (in such
capacity, the "Agent").

                              W I T N E S S E T H:

         WHEREAS, the Borrower, the Lenders and the Agent have heretofore
entered into the Credit Agreement;

         WHEREAS, the Borrower, the Lenders and the Agent now desire to amend
the Credit Agreement in certain respects, as hereinafter provided; and

         WHEREAS, the Borrower has requested that the Agent and the Lenders
agree to waive any failure by the Borrower to comply with certain provisions of
the Credit Agreement, upon the terms and subject to the conditions set forth
herein;

         NOW, THEREFORE, in consideration of the premises and the mutual
agreements herein contained and for other good and valuable consideration, the
receipt of which is hereby acknowledged, the Borrower, the Lenders and the Agent
hereby agree as follows:

         SECTION 1. Defined Terms. Unless otherwise defined herein, capitalized
terms used herein shall have the meanings set forth in the Credit Agreement.

         SECTION 2. Amendment to Section 1.1 (Defined Terms). Section 1.1 of the
Credit Agreement is hereby amended by:

                  (a) deleting the definition of "Deeds of Trust" in its
         entirety and substituting in lieu thereof the following definition:

                  "Deeds of Trust" means, collectively, (i) in connection with
                  the Domestic Gas Reserves, the Existing Deeds of Trust, as
                  amended and restated by the Amended and Restated Mortgage,
                  Deed of Trust, Assignment, Security Agreement, Financing
                  Statement and Fixture Filing, dated as of July 16, 2003, and
                  each other mortgage, deed of trust or other real property
                  collateral security instrument with respect to the Domestic
                  Gas Reserves, from the Borrower to the Collateral Trustee (for
                  the benefit of, among others, the Lenders), dated as of July
                  16, 2003 and delivered pursuant to Article VI hereof, as
                  amended, supplemented, restated



                  or otherwise modified from time to time, (ii) in connection
                  with the Pledged Power Projects (other than the Fremont Energy
                  Center in Fremont, Ohio), each mortgage, deed of trust or
                  other real property collateral security instrument with
                  respect to a Pledged Power Project, from the Borrower to the
                  Collateral Trustee (for the benefit of, among others, the
                  Lenders), dated as of July 16, 2003 and delivered pursuant to
                  Article VI hereof, as amended, supplemented, restated or
                  otherwise modified from time to time and (iii) in connection
                  with the Pledged Power Project identified in the definition
                  thereof as the Fremont Energy Center in Fremont, Ohio, each
                  mortgage, deed of trust or other real property collateral
                  security instrument with respect to such Pledged Power
                  Project, from the Borrower to the Collateral Trustee (for the
                  benefit of, among others, the Lenders), dated as of November
                  18, 2003 and delivered pursuant to the Fourth Amendment, as
                  amended, supplemented, restated or otherwise modified from
                  time to time.

                  (b) deleting the word "and" before the Roman numeral "(vii)"
         in the definition of "Pledged Power Project" and by adding at the end
         of such definition the clause "; and (viii) as of November 18, 2003,
         the Fremont Energy Center in Fremont, Ohio";

                  (c) by inserting the following new definition in appropriate
         alphabetical order:

                  "Fourth Amendment" means the Fourth Amendment and Waiver to
                  the Amended and Restated Credit Agreement, dated as of
                  November 19, 2003, among the Borrower, the Lenders and the
                  Agent.

         SECTION 3. Waiver of Section 8.2.3 (Liens). The Agent and the Required
Lenders hereby waive any violation of Section 8.2.3 of the Credit Agreement
occurring as a result of the granting by Calpine Gilroy of the Gilroy Plant Lien
and the Calpine Note Pledge (each as defined in the letter from the Borrower
attached hereto as Exhibit A, the "Gilroy Waiver Request Letter").

         SECTION 4. Waiver of Section 8.2.13 (Negative Pledges, Restrictive
Agreements, etc.). The Agent and the Required Lenders hereby waive any violation
of Section 8.2.13 of the Credit Agreement occurring as a result of the
undertaking by the Borrower and Calpine Gilroy of the Restrictive Covenants (as
defined in the Gilroy Waiver Request Letter).

         SECTION 5. Effectiveness. This Amendment and Waiver shall become
effective upon fulfillment of the following conditions precedent: (a) the
Borrower and each Guarantor shall have delivered to the Agent a duly executed
copy of this Amendment and Waiver; (b) the Agent shall have received duly
executed copies of this Amendment and Waiver from the Required Lenders; (c) the
Agent shall have received, on or before the date hereof, the Deed of Trust (as
defined above) for the Fremont Energy Center in Fremont, Ohio, executed and
delivered by the Borrower to the Collateral Trustee (for the benefit of, among
others, the Lenders), together with any additional supporting documentation as
shall be reasonably requested by the Agent, including (i) a certificate from the
Borrower's insurance advisor as to the sufficiency of the Borrower's insurance
program and compliance with the insurance requirements of the Loan Documents and
(ii) copies of all consents and approvals required in connection with the
execution and delivery by the Borrower of such Deed of Trust; (d) the Agent
shall have received



an opinion, dated the date hereof and addressed to the Agent and all Lenders,
from local counsel with respect to the Deed of Trust for the Fremont Energy
Center in Fremont, Ohio, in form and substance satisfactory to the Agent; (e)
the Agent shall have received evidence satisfactory to it that ownership of the
Fremont Energy Center in Fremont, Ohio (including, without limitation, all power
generation property and related equipment at such location) has been conveyed to
the Borrower by merger or otherwise; (f) the Agent shall have received such
other documents as the Agent shall have reasonably requested; and (g) no Default
or Event of Default shall have occurred and be continuing on the date hereof
after giving effect to this Amendment and Waiver.

         SECTION 6. Representations and Warranties. The Borrower hereby
represents and warrants that the representations and warranties contained in the
Credit Agreement and the Gilroy Waiver Request Letter will be, after giving
effect to this Amendment and Waiver, true and correct in all material respects,
as if made on and as of the date hereof, except for representations and
warranties which speak as of a certain date, which representations and
warranties shall be true and correct in all material respect as of such date.

         SECTION 7. Continuing Effect of Credit Agreement. This Amendment and
Waiver shall not constitute an amendment or waiver of any other provision of the
Credit Agreement or the Loan Documents not expressly referred to herein and
shall not be construed as a waiver or consent to any further or future action on
the part of the Borrower that would require a waiver or consent of the Agent
and/or the Lenders. Except as expressly amended or waived hereby, the provisions
of the Credit Agreement and the Loan Documents are and shall remain in full
force and effect. All references to the Credit Agreement in any other document,
instrument, agreement or writing shall hereafter be deemed to refer to the
Credit Agreement as amended hereby.

         SECTION 8. Counterparts. This Amendment and Waiver may be executed in
counterparts and all of the said counterparts taken together shall be deemed to
constitute one and the same instrument. Delivery of an executed signature page
of this Amendment and Waiver by facsimile transmission shall be effective as
delivery of a manually executed counterpart hereof.

         SECTION 9. Governing Law. THIS AMENDMENT AND WAIVER SHALL BE GOVERNED
BY AND CONSTRUED IN ACCORDANCE WITH THE INTERNAL LAWS OF THE STATE OF NEW YORK.

         SECTION 10. Expenses. The Borrower agrees to pay or reimburse the Agent
for all of its out-of-pocket costs and expenses incurred in connection with the
preparation, negotiation and execution of this Amendment and Waiver, including
the fees and disbursements of counsel to the Agent.



         IN WITNESS WHEREOF, the parties hereto have caused this Amendment and
Waiver to be duly executed by their respective officers thereunto duly
authorized as of the day and year first above written.

                                    CALPINE CORPORATION

                                    By: /s/ MICHAEL THOMAS
                                        ----------------------------------
                                       Name:
                                       Title:

The undersigned Guarantors hereby consent and agree to the foregoing Fourth
Amendment and Waiver and agree that their Guarantee as set forth in the Security
Agreement remains in full force and effect:

QUINTANA MINERALS (USA), INC.

By: /s/ MICHAEL THOMAS
- ------------------------------------
Name:
Title:

JOQ CANADA, INC.

By: /s/ MICHAEL THOMAS
- ------------------------------------
Name:
Title:

QUINTANA CANADA HOLDINGS, LLC

By: /s/ MICHAEL THOMAS
- ------------------------------------
Name:
Title:



                                             THE BANK OF NOVA SCOTIA,
                                             as Agent

                                             By: /s/ PAUL V. FARRELL
                                                 ------------------------------
                                                 Name: Paul V. Farrell
                                                 Title: Managing Director



                                             BAYERISCHE LANDESBANK, CAYMAN
                                             ISLANDS BRANCH

                                             By: /s/ OLIVER HILDENBRAND
                                                 ------------------------------
                                                 Name: Oliver Hildenbrand
                                                 Title: Vice President

                                             By: /s/ JAMES H. BOYLE
                                                 ------------------------------
                                                 Name: James H. Boyle
                                                 Title: Vice President



                                             ING CAPITAL LLC

                                             By: /s/ ERWIN THOMET
                                                --------------------------------
                                                Erwin Thomet
                                                Managing Director

                                             By: /s/ G. DOMINICK BELLAMY, JR.
                                                 -------------------------------
                                                 G. Dominick Bellamy,
                                                 Jr. Director



                                             UNION BANK OF CALIFORNIA, N.A.

                                             By: /s/ KAREN ELLIOTT
                                                 -------------------------------
                                                 Name: Karen Elliott
                                                 Title: Assistant Vice President



                                             CREDIT LYONNAIS NEW YORK BRANCH

                                             By: /s/ MARTIN C. LIVINGSTON
                                                 -------------------------------
                                                 Name: Martin C. Livingston
                                                 Title: Vice President



                                    This FOURTH AMENDMENT AND WAIVER, dated as
                                    of November [__], 2003 (this "Amendment and
                                    Waiver"), to the Amended and Restated Credit
                                    Agreement, dated as of July 16, 2003 (as the
                                    same may be amended, supplemented or
                                    otherwise modified from time to time, the
                                    "Credit Agreement"), among CALPINE
                                    CORPORATION, a Delaware corporation
                                    (together with its successors, the
                                    "Borrower"), the various financial
                                    institutions as are or may become parties
                                    hereto (collectively, the "Lenders"),
                                    various lead Arrangers (as defined below),
                                    and THE BANK OF NOVA SCOTIA ("Scotia
                                    Capital"), as administrative agent and
                                    funding agent (in such capacity, the
                                    "Agent").

                                    AURUM CLO 2002-I LTD.

                                    By: Columbia Management Advisors, Inc.,
                                        As Investment Manager

                                    By: /s/ KATHLEEN A ZARN
                                       -------------------------------
                                       Name: Kathleen A. Zarn
                                       Title: Senior Vice President



                                    This FOURTH AMENDMENT AND WAIVER, dated as
                                    of November [__], 2003 (this "Amendment and
                                    Waiver"), to the Amended and Restated Credit
                                    Agreement, dated as of July 16, 2003 (as the
                                    same may be amended, supplemented or
                                    otherwise modified from time to time, the
                                    "Credit Agreement"), among CALPINE
                                    CORPORATION, a Delaware corporation
                                    (together with its successors, the
                                    "Borrower"), the various financial
                                    institutions as are or may become parties
                                    hereto (collectively, the "Lenders"),
                                    various lead Arrangers (as defined below),
                                    and THE BANK OF NOVA SCOTIA ("Scotia
                                    Capital"), as administrative agent and
                                    funding agent (in such capacity, the
                                    "Agent").

                                    STEIN ROE & FARNHAM CLO I LTD.

                                    By: Columbia Management Advisors, Inc.,
                                        As Portfolio Manager

                                    By: /s/ KATHLEEN A ZARN
                                        ---------------------------------------
                                        Name: Kathleen A. Zarn
                                        Title: Senior Vice President



                                        AMMC CDO I, LTD.

                                           BY: AMERICAN MONEY MANAGEMENT CORP.,
                                               AS COLLATERAL MANAGER

                                        By: /s/ DAVID P. MEYER
                                            ----------------------------------
                                            Name: David P. Meyer
                                            Title: Vice President



                                        AMMC CDO II, LTD.

                                          BY: AMERICAN MONEY MANAGEMENT CORP.,
                                              AS COLLATERAL MANAGER

                                        By: /s/ DAVID P. MEYER
                                            ----------------------------------
                                            Name: David P. Meyer
                                            Title: Vice President



                                    GALLATIN FUNDING I LTD.

                                    BY: BEAR STEARNS ASSET MANAGEMENT INC.
                                        AS ITS COLLATERAL MANAGER

                                    By: /s/ JONATHAN BERG
                                        ---------------------------------------
                                        Name: Jonathan Berg
                                        Title: Vice President



                                    ARES III CLO LTD.

                                    By: ARES CLO Management LLC,
                                        Investment Manager

                                    By: /s/ DAVID A. SACHS
                                        ------------------------------------
                                        Name: David A. Sachs
                                        Title: Vice President



                                    ARES IV CLO LTD.

                                    By: Ares CLO Management IV, L.P.,
                                        Investment Manager

                                    By: Ares CLO GP IV, LLC,
                                        Its Managing Member

                                    By: /s/ DAVID A. SACHS
                                        ------------------------------------
                                        Name: David A. Sachs
                                        Title: Vice President



                                    ARES V CLO LTD.

                                    By: Ares CLO Management V, L.P.,
                                        Investment Manager

                                    By: Ares CLO GP V, LLC,
                                        Its Managing Member

                                    By: /s/ DAVID A. SACHS
                                        ----------------------------------
                                        Name: David A. Sachs
                                        Title: Vice President



                                    ARES VI CLO LTD.

                                    By: Ares CLO Management VI, L.P.,
                                        Investment Manager

                                    By: Ares CLO GP VI, LLC,
                                        Its Managing Member

                                    By: /s/ DAVID A. SACHS
                                        ----------------------------------
                                        Name: David A. Sachs
                                        Title: Vice President



                                    ARES VII CLO LTD.

                                    By: Ares CLO Management VII, L.P.,
                                        Investment Manager

                                    By: Ares CLO GP VII, LLC,
                                        Its General Partner

                                    By: /s/ DAVID A. SACHS
                                        ------------------------------------
                                        Name: David A. Sachs
                                        Title: Vice President



                                    ARES VIII CLO LTD.

                                    By: Ares CLO Management VIII, L.P.,
                                        Investment Manager

                                    By: Ares CLO GP VIII, LLC,
                                        Its General Partner

                                    By: /s/ DAVID A. SACHS
                                        ------------------------------------
                                        Name: David A. Sachs
                                        Title: Vice President