<PAGE>

                                                                   EXHIBIT 10.12

                                                                  EXECUTION COPY

                                SECOND AMENDMENT

                  SECOND AMENDMENT, dated as of May 23, 2003 (this "Amendment"),
to the Credit Agreement, dated as of March 8, 2002 (as amended, the "Credit
Agreement"), among CALPINE CORPORATION, a Delaware corporation (the "Borrower"),
the various financial institutions as are or may become parties thereto (the
"Lenders"), THE BANK OF NOVA SCOTIA, as joint administrative agent and funding
agent (in such capacity, the "Agent") and CITICORP USA, INC., as joint
administrative agent.

                  WHEREAS pursuant to the Credit Agreement, the Lenders have
made extensions of credit to the Borrower; and

                  WHEREAS the Borrower has requested that certain provisions of
the Credit Agreement be modified in the manner provided for in this Amendment,
and the Lenders are willing to agree to such modifications as provided for in
this Amendment.

                  NOW, THEREFORE, the parties hereto hereby agree as follows:

                  1. Defined Terms. Capitalized terms used and not defined
herein shall have the meanings given to them in the Credit Agreement, as amended
hereby.

                  2. Amendments to Credit Agreement. The definitions of
"Revolving Loan Commitment Termination Date" and "Stated Maturity Date" in
Section 1.1 of the Credit Agreement and Section 2.7(a) of the Credit Agreement
are hereby amended by deleting the reference to "May 24, 2003" in such
definitions and such Section 2.7(a) and by substituting in lieu thereof in each
case "June 16, 2003".

                  3. Representations and Warranties. The Borrower hereby
represents and warrants to the Agent and the Lenders that, as of the date hereof
and after giving effect to the amendment contained herein:

                  (a) No Default or Event of Default has occurred and is
continuing.

                  (b) The execution, delivery and performance by the Borrower of
this Amendment has been duly authorized by all necessary corporate and other
action and does not and will not require any registration with, consent or
approval of, notice to or action by, any person in order to be effective and
enforceable. Each of this Amendment and the Credit Agreement as amended by this
Amendment constitutes the legal, valid and binding obligation of the Borrower,
enforceable against each in accordance with its terms, subject to applicable
bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium or
other laws affecting creditors' rights generally and subject to general
principles of equity, regardless of whether considered in a proceeding in equity
or at law.

                  (c) All representations and warranties of each Obligor set
forth in the Loan Documents as amended hereby are true and correct in all
material respects.

<PAGE>

                                                                               2

                  4. Covenants. The Borrower hereby agrees that during the
period commencing on the date hereof up to and including June 16, 2003 (the
"Extension Period"), the Borrower shall not take any action which could,
directly or indirectly, have a material adverse effect upon (i) the financial
condition, operations, assets (including power projects), business or prospects
of the Borrower and its Subsidiaries taken as a whole; or (ii) the ability of
the Borrower or any other Obligor to perform under any Loan Document. Without
prejudice to the foregoing, the Borrower shall ensure that, during the Extension
Period, (1) no Indebtedness is incurred, created, assumed or suffered to exist
by the Borrower or any of its Subsidiaries (except (A) Indebtedness under the
Loan Documents and the Loan Documents (as defined in the Existing Credit
Agreement), (B) unsecured Indebtedness incurred in the ordinary course of
business, other than Indebtedness of the type described in (1) clauses (a), (c)
or (f) of the definition of "Indebtedness" and (2) clauses (b) and (g) of the
definition of "Indebtedness" with respect to any Indebtedness described in
clause (1) above, (C) other unsecured Indebtedness or Non-Recourse Debt (as
defined in the Senior Note Indentures) incurred in the ordinary course of
business in connection with Indebtedness existing or contractually committed to
be made available as of the date hereof, and (D) Indebtedness outstanding on the
date hereof), and no guarantee, collateral or other credit support is provided,
and no Lien on the properties of the Borrower or any of its Subsidiaries is
created, incurred, assumed or granted, in each case in support of (x) any
Indebtedness (other than Indebtedness permitted above) or (y) any obligation
relating to any synthetic lease transaction of the Borrower or any Subsidiary of
the Borrower; (2) no amendment, modification or supplement is made to any
agreement or instrument evidencing any Indebtedness, other than amendments,
modifications or supplements entered into in the ordinary course of business in
respect of (A) the Credit Agreement or the Existing Credit Agreement, (B) any
agreement or instrument evidencing Non-Recourse Debt (as defined in the Senior
Note Indentures) of a Subsidiary of the Borrower, or (C) any agreement or
instrument evidencing Indebtedness other than Indebtedness of the type described
in (1) clauses (a), (c) or (f) of the definition of "Indebtedness" and (2)
clauses (b) and (g) of the definition of "Indebtedness" with respect to any
Indebtedness described in clause (1) above (the Indebtedness described in
clauses (B) and (C) being collectively referred to as "Excluded Indebtedness");
(3) no optional prepayment is made on, or purchase or optional redemption is
executed of, any Indebtedness other than Excluded Indebtedness (including,
without limitation, any buy-back or defeasance of any outstanding bonds,
puttable convertible bonds or other securities of the Borrower or any of its
Subsidiaries), it being understood and agreed that, during the Extension Period,
neither the Borrower or any of its Subsidiaries shall obtain or receive any such
Indebtedness (or instruments evidencing same) in consideration of the sale or
other transfer of any assets or properties thereof; (4) no Investment is made by
the Borrower or any of its Subsidiaries in any other Person (except (A)
Investments by the Borrower in the ordinary course of business in Subsidiaries
the equity in which has been pledged to the Lenders, and each of their
respective Subsidiaries, (B) Investments by the Borrower in other Persons
pursuant to contractual commitments existing as of the date hereof, and (C)
Investments by the Borrower in CES in support of transactions entered into by
CES in the ordinary course of CES's business, consistent with historical
practices); and (5) all transactions between any one or more of the Borrower and
its Affiliates entered into during the Extension Period are on terms that are
fair and reasonable and similar to those found in a comparable arm's length
transaction with a Person that is not an Affiliate of the Borrower.
Notwithstanding the foregoing, it is agreed that (x) the Borrower and its
Subsidiaries may effectuate the transactions referred to in Schedule I attached
to the letter from the Borrower to the Lenders dated May 20, 2003 and (y) none
of the

<PAGE>

                                                                               3

prohibitions contained in this Section 4 shall be applicable insofar as they
would otherwise constitute an encumbrance or restriction in violation of Section
3.5 of the Pre-2000 Indentures. The provisions of this Section 4 may be amended,
modified or waived, if such amendment, modification or waiver is in writing and
consented to by the Borrower and Lenders owed or holding at least 51% of the
aggregate Revolving Loan Commitments and Commitments under the Credit Agreement
and the Existing Credit Agreement, respectively (it being understood, however,
that no such amendment, modification or waiver shall amend, modify or waive the
provisions of the Credit Agreement unless such amendment, modification or waiver
satisfies the requirements of Section 11.1 of the Credit Agreement).

                  5. Conditions Precedent to Effectiveness. This Amendment shall
become effective as of the date hereof upon (i) the Agent having received
counterparts hereof duly executed and delivered by the Borrower, the Required
Lenders and each Revolving Lender and (ii) the Sixth Amendment, dated as of the
date hereof, to the Existing Credit Agreement becoming effective in accordance
with its terms.

                  6. No Other Amendments. Except as expressly amended hereby,
the provisions of the Credit Agreement are and shall remain in full force and
effect.

                  7. Expenses. The Borrower agrees to pay or reimburse the Agent
for its out-of-pocket expenses in connection with this Amendment, including the
reasonable fees, charges and disbursements of counsel to the Agent.

                  8. Governing Law; Counterparts. (a) This Amendment and the
rights and obligations of the parties hereto shall be governed by, and construed
and interpreted in accordance with, the laws of the State of New York.

                  (b) This Amendment may be executed by one or more of the
parties to this Amendment on any number of separate counterparts, and all of
said counterparts taken together shall be deemed to constitute one and the same
instrument. This Amendment may be delivered by facsimile transmission of the
relevant signature pages hereof.

<PAGE>

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

                                    CALPINE CORPORATION

                                    By   /s/ ROBERT D. KELLY
                                       -----------------------------------------
                                       Name: Robert D. Kelly
                                       Title: Chief Financial Officer

<PAGE>

                                    THE BANK OF NOVA SCOTIA, as Agent
                                    and Lender

                                    By   /s/ DENIS P. O'MEARA
                                       -----------------------------------------
                                       Name: Denis P. O'Meara
                                       Title: Managing Director

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    CREDIT SUISSE FIRST BOSTON

                                    By   /s/ JAMES P. MORAN
                                       -----------------------------------------
                                       Name: James P. Moran
                                       Title:  Director

                                    By   /s/ BRIAN T. CALDWELL
                                       -----------------------------------------
                                       Name: Brian T. Caldwell
                                       Title:  Director

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    BAYERISCHE LANDESBANK
                                    Cayman Islands Branch

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

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

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    BANK OF AMERICA, NA

                                    By   /s/ EILEEN C. HIGGINS
                                       ---------------------------
                                       Name: Eileen C. Higgins
                                       Title: Principal

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    ING CAPITAL LLC

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

                                    By   /s/ NICK BELLAMY
                                       -----------------------------------------
                                       Name: Nick Bellamy
                                       Title: Director

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    CITICORP USA, INC.

                                    By   /s/ ANTHONY MURPHY
                                       -----------------------------------------
                                       Name: Anthony Murphy
                                       Title: Managing Director

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    DEUTSCHE BANK TRUST COMPANY AMERICAS

                                    By   /s/ MARCUS M. TARKINGTON
                                       -----------------------------------------
                                       Name: Marcus M. Tarkington
                                       Title: Director

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    TORONTO DOMINION (TEXAS) INC.

                                    By   /s/ DEBORAH GRAVINESE
                                       -----------------------------------------
                                       Name: Deborah Gravinese
                                       Title: Managing Director

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    MERRILL LYNCH PRIME RATE PORTFOLIO
                                    By: Merrill Lynch Investment Managers, L.P.
                                        as Investment Advisor

                                        By   /s/ JAIMIN PATEL
                                           -------------------------------------
                                           Name: Jaimin Patel
                                           Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    MERRILL LYNCH GLOBAL INVESTMENT SERIES:
                                    INCOME STRATEGIES PORTFOLIO
                                    By: Merrill Lynch Investment Managers, L.P.
                                        as Investment Advisor

                                        By   /s/ JAIMIN PATEL
                                           -------------------------------------
                                           Name: Jaimin Patel
                                           Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    MERRILL LYNCH GLOBAL INVESTMENT SERIES:
                                    BANK LOAN INCOME PORTFOLIO
                                    By: Merrill Lynch Investment Managers, L.P.
                                        as Investment Advisor

                                        By   /s/ JAIMIN PATEL
                                           -------------------------------------
                                           Name: Jaimin Patel
                                           Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    MASTER SENIOR FLOATING RATE TRUST

                                    By   /s/ JAIMIN PATEL
                                       -----------------------------------------
                                       Name: Jaimin Patel
                                       Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    SENIOR HIGH INCOME PORTFOLIO, INC.

                                    By   /s/ JAIMIN PATEL
                                       -----------------------------------------
                                       Name: Jaimin Patel
                                       Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    LONGHORN CDO II, LTD.
                                    By:  Merrill Lynch Investment Managers, L.P.
                                         as Investment Advisor

                                    By   /s/ JAIMIN PATEL
                                       -----------------------------------------
                                       Name: Jaimin Patel
                                       Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    LONGHORN CDO (CAYMAN) LTD
                                    By:  Merrill Lynch Investment Managers, L.P.
                                         as Investment Advisor

                                    By   /s/ JAIMIN PATEL
                                       -----------------------------------------
                                       Name: Jaimin Patel
                                       Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    Longhorn CDO III, LTD.
                                    By:  Merrill Lynch Investment Managers, L.P.
                                         as Investment Advisor

                                    By   /s/ JAIMIN PATEL
                                       -----------------------------------------
                                       Name: Jaimin Patel
                                       Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    DEBT STRATEGIES FUND, INC.

                                    By   /s/ JAIMIN PATEL
                                       -----------------------------------------
                                       Name: Jaimin Patel
                                       Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    ENDURANCE CLO I, LTD.
                                    By:  ING Capital Advisors LLC,
                                         as Collateral Manager

                                    By   /s/ GORDON R. COOK
                                       -----------------------------------------
                                       Name: Gordon R. Cook
                                       Title: Managing Director

                                    ARCHIMEDES FUNDING III, LTD.
                                    By:  ING Capital Advisors LLC,
                                         as Collateral Manager

                                    By   /s/ GORDON R. COOK
                                       -----------------------------------------
                                       Name: Gordon R. Cook
                                       Title: Managing Director

                                    ARCHIMEDES FUNDING IV (CAYMAN), LTD.
                                    By:  ING Capital Advisors LLC,
                                         as Collateral Manager

                                    By   /s/ GORDON R. COOK
                                       -----------------------------------------
                                       Name: Gordon R. Cook
                                       Title: Managing Director

                                    BALANCED HIGH-YIELD FUND II, LTD.
                                    By:  ING Capital Advisors LLC,
                                         as Collateral Manager

                                    By   /s/ GORDON R. COOK
                                       -----------------------------------------
                                       Name: Gordon R. Cook
                                       Title: Managing Director

<PAGE>

                                    SEQUILS-ING I (HBDGM), LTD.
                                    By:  ING Capital Advisors LLC,
                                         as Collateral Manager

                                    By   /s/ GORDON R. COOK
                                       -----------------------------------------
                                       Name: Gordon R. Cook
                                       Title: Managing Director

                                    NEMEAN CLO, LTD.
                                    By:  ING Capital Advisors LLC,
                                         as Collateral Manager

                                    By   /s/ GORDON R. COOK
                                       -----------------------------------------
                                       Name: Gordon R. Cook
                                       Title: Managing Director

                                    ING-ORYX CLO, LTD.
                                    By:  ING Capital Advisors LLC,
                                         as Collateral Manager

                                    By   /s/ GORDON R. COOK
                                       -----------------------------------------
                                       Name: Gordon R. Cook
                                       Title: Managing Director

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    CITADEL JACKSON INVESTMENT FUND LTD.
                                    By:  Citadel Limited Partnership,
                                         its Portfolio Manager
                                    By:  GLB Partners, L.P., its General Partner
                                    By:  Citadel Investment Group, LLC,
                                         its General Partner

                                    By   /s/ BRAD COURI
                                       -----------------------------------------
                                       Name: Brad Couri
                                       Title: Senior Managing Director

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    CITADEL EQUITY FUND LTD.
                                    By:  Citadel Limited Partnership,
                                         its Portfolio Manager
                                    By:  GLB Partners, L.P., its General Partner
                                    By:  Citadel Investment Group, LLC,
                                         its General Partner

                                    By   /s/ BRAD COURI
                                       -----------------------------------------
                                       Name: Brad Couri
                                       Title: Senior Managing Director

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    AIMCO CDO SERIES 2000-A

                                    By   /s/ CHRIS GOERGEN
                                       -----------------------------------------
                                       Name: Chris Goergen
                                       Title: Authorized Signatory

                                    By   /s/ PATRICIA W. WILSON
                                       -----------------------------------------
                                       Name: Patricia W. Wilson
                                       Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    AIMCO CLO SERIES 2001-A

                                    By   /s/ CHRIS GOERGEN
                                       -----------------------------------------
                                       Name: Chris Goergen
                                       Title: Authorized Signatory

                                    By   /s/ PATRICIA W. WILSON
                                       -----------------------------------------
                                       Name: Patricia W. Wilson
                                       Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    HARCH CLO I LTD.

                                    By   /s/ MICHAEL E. LEWITT
                                       -----------------------------------------
                                       Name: Michael E. Lewitt
                                       Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    GALAXY CLO 1999-1, LTD.

                                    By   /s/ W. JEFFREY BAXTER
                                       -----------------------------------------
                                       Name: W. Jeffrey Baxter
                                       Title: Authorized Agent

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    SUNAMERICA LIFE INSURANCE COMPANY

                                    By   /s/ W. JEFFREY BAXTER
                                       -----------------------------------------
                                       Name: W. Jeffrey Baxter
                                       Title: Authorized Agent

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    KZH CNC LLC

                                    By   /s/ ROWENA SMITH
                                       -----------------------------------------
                                       Name: Rowena Smith
                                       Title: Authorized Agent

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    KZH PENDVIEW LLC

                                    By   /s/ ROWENA SMITH
                                       -----------------------------------------
                                       Name: Rowena Smith
                                       Title: Authorized Agent

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    KZH RIVERSIDE LLC

                                    By   /s/ ROWENA SMITH
                                       -----------------------------------------
                                       Name: Rowena Smith
                                       Title: Authorized Agent

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    KZH SOLEIL LLC

                                    By   /s/ ROWENA SMITH
                                       -----------------------------------------
                                       Name: Rowena Smith
                                       Title: Authorized Agent

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    KZH SOLEIL-2 LLC

                                    By   /s/ ROWENA SMITH
                                       -----------------------------------------
                                       Name: Rowena Smith
                                       Title: Authorized Agent

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    KZH WATERSIDE LLC

                                    By   /s/ ROWENA SMITH
                                       -----------------------------------------
                                       Name: Rowena Smith
                                       Title: Authorized Agent

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    LANDMARK CDO LIMITED
                                    By:  Aladdin Capital Management LLC,
                                         as Manager

                                    By   /s/ JOSEPH MORONEY
                                       -----------------------------------------
                                       Name: Joseph Moroney
                                       Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    LANDMARK II CDO LIMITED
                                    By:  Aladdin Capital Management LLC,
                                         as Manager

                                    By   /s/ JOSEPH MORONEY
                                       -----------------------------------------
                                       Name: Joseph Moroney
                                       Title: Authorized Signatory

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    INDOSUEZ CAPITAL FUNDING VI, LIMITED
                                    By:  Indosuez Capital as Collateral Manager

                                    By   /s/ JACK C. HENRY
                                       -----------------------------------------
                                       Name: Jack C. Henry
                                       Title: Principal

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    AMMC CDO I, LIMITED
                                    By:  American Money Management Corp.,
                                         as Collateral Manager

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

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    AMMC CDO II, LIMITED
                                    By:  American Money Management Corp.,
                                         as Collateral Manager

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

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    EAST WEST BANK

                                    By   /s/ NANCY A. MOORE
                                       -----------------------------------------
                                       Name: Nancy A. Moore
                                       Title: Senior Vice President

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    JUPITER FUNDING TRUST

                                    By   /s/ ANN E. MORRIS
                                       -----------------------------------------
                                       Name: Ann E. Morris
                                       Title: Authorized Agent

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    RIVIERA FUNDING LLC

                                    By   /s/ ANN E. MORRIS
                                       -----------------------------------------
                                       Name: Ann E. Morris
                                       Title: Asst. Vice President

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    SRF TRADING, INC.

                                    By   /s/ ANN E. MORRIS
                                       -----------------------------------------
                                       Name: Ann E. Morris
                                       Title: Asst. Vice President

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    STANWICH LOAN FUNDING LLC

                                    By   /s/ ANN E. MORRIS
                                       -----------------------------------------
                                       Name: Ann E. Morris
                                       Title: Asst. Vice President

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    WINGED FOOT FUNDING TRUST

                                    By   /s/ ANN E. MORRIS
                                       -----------------------------------------
                                       Name: Ann E. Morris
                                       Title: Asst. Vice President

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    SRF 2000, INC.

                                    By   /s/ ANN E. MORRIS
                                       -----------------------------------------
                                       Name: Ann E. Morris
                                       Title: Asst. Vice President

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    STEIN ROE FLOATING RATE
                                    LIMITED LIABILITY COMPANY
                                    By:  Columbia Management Advisors, Inc.
                                         (f/k/a Stein Roe & Farnham
                                         Incorporated), As Advisor

                                    By   /s/ JAMES R. FELLOWS
                                       -----------------------------------------
                                       Name: James R. Fellows
                                       Title: Sr. Vice President & Portfolio
                                              Manager

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    LIBERTY FLOATING RATE
                                    ADVANTAGE FUND
                                    By:  Columbia Management Advisors, Inc.
                                         (f/k/a Stein Roe & Farnham
                                         Incorporated), As Advisor

                                    By   /s/ JAMES R. FELLOWS
                                       -----------------------------------------
                                       Name: James R. Fellows
                                       Title: Sr. Vice President & Portfolio
                                              Manager

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    STEIN ROE & FARNHAM CLO I LTD.
                                    By:  Columbia Management Advisors, Inc.
                                         (f/k/a Stein Roe & Farnham
                                         Incorporated), As Advisor

                                    By   /s/ JAMES R. FELLOWS
                                       -----------------------------------------
                                       Name: James R. Fellows
                                       Title: Sr. Vice President & Portfolio
                                              Manager

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    AURUM CLO 2002-1 LTD.
                                    By:  Columbia Management Advisors, Inc.
                                         (f/k/a Stein Roe & Farnham
                                         Incorporated), As Advisor

                                    By   /s/ JAMES R. FELLOWS
                                       -----------------------------------------
                                       Name: James R. Fellows
                                       Title: Sr. Vice President & Portfolio
                                              Manager

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    GALLATIN FUNDING I LTD.
                                    By:  Bear Stearns Asset Management Inc.
                                         as its Collateral Manager

                                    By   /s/ JUSTIN DRISCOLL
                                       -----------------------------------------
                                       Name: Justin Driscoll
                                       Title: Managing Director

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    GRAYSTON CLO 2001-01 LTD.
                                    By:  Bear Stearns Asset Management Inc.
                                         as its Collateral Manager

                                    By   /s/ JUSTIN DRISCOLL
                                       -----------------------------------------
                                       Name: Justin Driscoll
                                       Title: Managing Director

<PAGE>

                                    Signature page to the Second Amendment,
                                    dated as of May 23, 2003, to the Credit
                                    Agreement, dated as of March 8, 2002, as
                                    amended, among Calpine Corporation, the
                                    various financial institutions as are or may
                                    become parties thereto, The Bank of Nova
                                    Scotia and Citicorp USA, Inc., as joint
                                    administrative agents.

                                    SAGAMORE HILL HUB FUND
                                    By:  Sagamore Hill Capital

                                    By   /s/ LEON ZALTZMAN
                                       -----------------------------------------
                                       Name: Leon Zaltzman
                                       Title: