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                                                                     Exhibit 4.1

                               CALPINE CORPORATION

                             CONVERTIBLE ZERO-COUPON
                          DEBENTURES DUE APRIL 30, 2021


                          REGISTRATION RIGHTS AGREEMENT

                                                 April 30, 2001
Goldman, Sachs & Co.,
85 Broad Street
New York, New York 10004

Ladies and Gentlemen:

         Calpine Corporation, a Delaware corporation (the "Company"), proposes
to issue and sell to the Purchaser (as defined herein) upon the terms set forth
in the Purchase Agreement (as defined herein) its Convertible Zero-Coupon
Debentures due April 30, 2021 (the "Securities"). As an inducement to the
Purchaser to enter into the Purchase Agreement and in satisfaction of a
condition to the obligations of the Purchaser thereunder, the Company agrees
with the Purchaser for the benefit of Holders (as defined herein) from time to
time of the Registrable Securities (as defined herein) as follows:

         1.       Definitions.

         (a)      Capitalized terms used herein without definition shall have
the meanings ascribed to them in the Purchase Agreement. As used in this
Agreement, the following defined terms shall have the following meanings:

         "Act" or "Securities Act" means the United States Securities Act of
1933, as amended.

         "Affiliate" of any specified person means any other person which,
directly or indirectly, is in control of, is controlled by, or is under common
control with such specified person. For purposes of this definition, control of
a person means the power, direct or indirect, to direct or cause the direction
of the management and policies of such person whether by contract or otherwise;
and the terms "controlling" and "controlled" have meanings correlative to the
foregoing.

         "Closing Date" means the First Closing Date as defined in the Purchase
Agreement.

         "Commission" means the United States Securities and Exchange
Commission, or any other federal agency at the time administering the Exchange
Act or the Securities Act, whichever is the relevant statute for the particular
purpose.

         "Common Stock" means the Company's common stock, par value $.001 per
share.

         "DTC" means The Depository Trust Company.

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         "Effectiveness Period" has the meaning assigned thereto in Section
2(b)(i) hereof.

         "Effective Time" means the date on which the Commission declares the
Shelf Registration Statement effective or on which the Shelf Registration
Statement otherwise becomes effective.

         "Electing Holder" has the meaning assigned thereto in Section 3(a)(iii)
hereof.

         "Exchange Act" means the United States Securities Exchange Act of 1934,
as amended.

         "Holder" means, any person that is the record owner of Registrable
Securities (and includes any person that has a beneficial interest in any
Registrable Security in book-entry form).

         "Indenture" means the Indenture, dated as of April 30, 2001 between the
Company and Wilmington Trust Company, as amended and supplemented from time to
time in accordance with its terms.

         "Managing Underwriters" means the investment banker or investment
bankers and manager or managers that shall administer an underwritten offering,
if any, conducted pursuant to Section 7 hereof.

         "NASD Rules" means the Rules of the National Association of Securities
Dealers, Inc., as amended from time to time.

         "Notice and Questionnaire" means a Notice of Registration Statement and
Selling Securityholder Questionnaire in a form reasonably agreed to by the
Company and the Purchaser.

         The term "person" means an individual, partnership, corporation, trust
or unincorporated organization, or a government or agency or political
subdivision thereof.

         "Prospectus" means the prospectus (including, without limitation, any
preliminary prospectus, any final prospectus and any prospectus that discloses
information previously omitted from a prospectus filed as part of an effective
registration statement in reliance upon Rule 430A under the Act) included in the
Shelf Registration Statement, as amended or supplemented by any prospectus
supplement with respect to the terms of the offering of any portion of the
Registrable Securities covered by the Shelf Registration Statement and by all
other amendments and supplements to such prospectus, including all material
incorporated by reference in such prospectus and all documents filed after the
date of such prospectus by the Company under the Exchange Act and incorporated
by reference therein.

         "Purchase Agreement" means the purchase agreement, dated as of April
30, 2001, between the Purchaser and the Company relating to the Securities.

         "Purchaser" means Goldman, Sachs & Co.

         "Registrable Securities" means all or any portion of the Securities
issued from time to time under the Indenture in registered form and the shares
of Common Stock issuable upon conversion of such Securities, including any
Securities initially issued in bearer form and constituting the unsold allotment
of a distributor (within the meaning of Regulation S under the Securities Act)
of such Securities and later exchanged for Securities in registered form;

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provided, however, that a security ceases to be a Registrable Security when it
is no longer a Restricted Security.

         "Restricted Security" means any Security or share of Common Stock
issuable upon conversion thereof except any such Security or share of Common
Stock which (i) has been effectively registered under the Securities Act and
sold in a manner contemplated by the Shelf Registration Statement, (ii) has been
transferred in compliance with Rule 144 under the Securities Act (or any
successor provision thereto) or is transferable pursuant to paragraph (k) of
such Rule 144 (or any successor provision thereto), (iii) has been sold in
compliance with Regulation S under the Securities Act (or any successor thereto)
and does not constitute the unsold allotment of a distributor within the meaning
of Regulation S under the Securities Act, or (iv) has otherwise been transferred
and a new Security or share of Common Stock not subject to transfer restrictions
under the Securities Act has been delivered by or on behalf of the Company in
accordance with Section 2.6 of the Indenture.

         "Rules and Regulations" means the published rules and regulations of
the Commission promulgated under the Securities Act or the Exchange Act, as in
effect at any relevant time.

         "Shelf Registration" means a registration effected pursuant to Section
2 hereof.

         "Shelf Registration Statement" means a "shelf" registration statement
filed under the Securities Act providing for the registration of, and the sale
on a continuous or delayed basis by the Holders of, all of the Registrable
Securities pursuant to Rule 415 under the Securities Act and/or any similar rule
that may be adopted by the Commission, filed by the Company pursuant to the
provisions of Section 2 of this Agreement, including the Prospectus contained
therein, any amendments and supplements to such registration statement,
including post-effective amendments, and all exhibits and all material
incorporated by reference in such registration statement.

         "Trust Indenture Act" means the Trust Indenture Act of 1939, or any
successor thereto, and the rules, regulations and forms promulgated thereunder,
as the same shall be amended from time to time.

         The term "underwriter" means any underwriter of Registrable Securities
in connection with an offering thereof under a Shelf Registration Statement.

         (b)      Wherever there is a reference in this Agreement to a
percentage of the "principal amount" of Registrable Securities or to a
percentage of Registrable Securities, Common Stock shall be treated as
representing the principal amount of Securities which was surrendered for
conversion or exchange in order to receive such number of shares of Common
Stock.

         2.       Shelf Registration.

         (a)      The Company shall, no later than 90 calendar days following
the Closing Date, file with the Commission a Shelf Registration Statement
relating to the offer and sale of the Registrable Securities by the Holders from
time to time in accordance with the methods of distribution elected by such
Holders and set forth in such Shelf Registration Statement and, thereafter,
shall use its best efforts to cause such Shelf Registration Statement to be
declared effective under the Act no later than 180 calendar days following the
Closing Date; provided, however, that the Company may, upon written notice to
all Holders, postpone having the Shelf Registration Statement declared effective
for a reasonable period not to exceed 90 days if the

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Company possesses material non-public information, the disclosure of which would
have a material adverse effect on the Company and its subsidiaries taken as a
whole; provided, further, however, that no Holder shall be entitled to be named
as a selling securityholder in the Shelf Registration Statement or have its
Registrable Securities included therein or to use the Prospectus forming a part
thereof for resales of Registrable Securities unless such Holder is an Electing
Holder; provided, further, that the Company shall not be obligated to file a
Shelf Registration Statement unless and until it has received an opinion, dated
as of the date of the filing of such Shelf Registration Statement and from
counsel reasonably acceptable to the Company, as required by Item 601(b)(8) of
Regulation S-K; it being understood that Thelen, Reid and Priest LLP and
Skadden, Arps, Slate, Meagher & Flom LLP, are reasonably acceptable to the
Company.

         (b)      The Company shall use its best efforts:

                  (i) To keep the Shelf Registration Statement continuously
         effective in order to permit the Prospectus forming part thereof to be
         lawfully delivered by Holders until the earliest of (1) the sale of all
         Registrable Securities registered under the Shelf Registration
         Statement; (2) the expiration of the period referred to in Rule 144(k)
         of the Act (or any successor provision thereto) with respect to all
         Registrable Securities held by Persons that are not Affiliates of the
         Company; and (3) two years from the date (the "Effective Date") such
         Shelf Registration Statement is declared effective (such period being
         referred to herein as the "Effectiveness Period"); and

                  (ii) During the Effectiveness Period, promptly upon the
         request of any Holder of Registrable Securities that is not then an
         Electing Holder, to take any action reasonably necessary to enable such
         Holder to use the Prospectus forming a part thereof for resales of
         Registrable Securities, including, without limitation, any action
         necessary to identify such Holder as a selling securityholder in the
         Shelf Registration Statement; provided, however, that nothing in this
         subparagraph shall relieve such Holder of the obligation to return a
         completed and signed Notice and Questionnaire to the Company in
         accordance with Section 3(a)(ii) hereof.

Subject to the provisions of paragraph 2(c) below, the Company shall be deemed
not to have used its best efforts to keep the Shelf Registration Statement
effective during the Effectiveness Period if the Company voluntarily takes any
action that would result in Holders of Registrable Securities covered thereby
not being able to offer and sell any of such Registrable Securities during such
period, unless such action is required by applicable law and the Company
thereafter promptly complies with the requirements of paragraph 3(j) below.

         (c)      The Company may suspend the use of the Prospectus for a period
not to exceed 30 days in any 90-day period or an aggregate of 90 days in any
12-month period if the Board of Directors of the Company shall have determined
in good faith that because of valid business reasons (not including avoidance of
the Company's obligations hereunder), including the acquisition or divestiture
of assets, pending corporate developments and similar events, it is in the best
interests of the Company to suspend such use, and prior to suspending such use
the Company provides the Holders with written notice of such suspension, which
notice need not specify the nature of the event giving rise to such suspension.

         3.       Registration Procedures. In connection with the Shelf
Registration Statement, the following provisions shall apply:

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         (a)      (i)  Not less than 30 calendar days prior to the Effective
Time of the Shelf Registration Statement, the Company shall mail the Notice and
Questionnaire to the Holders of Registrable Securities. No Holder shall be
entitled to be named as a selling securityholder in the Shelf Registration
Statement or have its Registrable Securities included therein, and no Holder
shall be entitled to use the Prospectus forming a part thereof for resales of
Registrable Securities at any time, unless such Holder is an Electing Holder;
provided, however, Holders of Registrable Securities shall have at least 28
calendar days from the date on which the Notice and Questionnaire is first
mailed to such Holders to return a completed and signed Notice and Questionnaire
to the Company.

                  (ii) After the Effective Time of the Shelf Registration
         Statement and during the Effectiveness Period, the Company shall, upon
         the request of any Holder of Registrable Securities that is not then an
         Electing Holder, promptly send a Notice and Questionnaire to such
         Holder. The Company shall not be required to take any action to name
         such Holder as a selling securityholder in the Shelf Registration
         Statement or to enable such Holder to use the Prospectus forming a part
         thereof for resales of Registrable Securities until such Holder has
         returned a completed and signed Notice and Questionnaire to the
         Company.

                  (iii) The term "Electing Holder" shall mean any Holder of
         Registrable Securities that has returned a completed and signed Notice
         and Questionnaire to the Company in accordance with Section 3(a)(i) or
         3(a)(ii) hereof and has otherwise agreed to be bound by all the
         provisions of this Agreement applicable to such Holder.

         (b)      The Company shall furnish to the Purchaser, prior to the
Effective Time, a copy of the Shelf Registration Statement initially filed with
the Commission, and shall furnish to such Purchaser, prior to the filing thereof
with the Commission, copies of each amendment thereto and each amendment or
supplement, if any, to the Prospectus included therein, and shall use its best
efforts to reflect in each such document, at the Effective Time or when so filed
with the Commission, as the case may be, such comments as such Purchaser and its
counsel (which shall be Skadden, Arps, Slate, Meagher & Flom LLP) reasonably may
propose.

         (c)      The Company shall promptly take such action as may be
necessary so that (i) each of the Shelf Registration Statement and any amendment
thereto and the Prospectus forming part thereof and any amendment or supplement
thereto (and each report or other document incorporated therein by reference in
each case) complies in all material respects with the Securities Act and the
Exchange Act and the respective rules and regulations thereunder, (ii) each of
the Shelf Registration Statement and any amendment thereto does not, when it
becomes effective, contain an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading and (iii) each of the Prospectus forming part
of the Shelf Registration Statement, and any amendment or supplement to such
Prospectus, does not at any time during the Effectiveness Period include an
untrue statement of a material fact or omit to state a material fact necessary
in order to make the statements therein, in the light of the circumstances under
which they were made, not misleading.

         (d)       The Company shall promptly advise each Electing Holder, and
shall confirm such advice in writing if so requested by any such Holder:

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                            (i)      when a Shelf Registration Statement and any
                  amendment thereto has been filed with the Commission and when
                  a Shelf Registration Statement or any post-effective amendment
                  thereto has become effective;

                            (ii)     of the issuance by the Commission of any
                  stop order suspending the effectiveness of the Shelf
                  Registration Statement or the initiation of any proceedings
                  for such purpose;

                            (iii)    of the receipt by the Company of any
                  notification with respect to the suspension of the
                  qualification of the securities included in the Shelf
                  Registration Statement for sale in any jurisdiction or the
                  initiation of any proceeding for such purpose; and

                            (iv) of the happening, during the Effectiveness
                  Period, of any event or the existence of any state of facts
                  that requires the making of any changes in the Shelf
                  Registration Statement or the Prospectus included therein so
                  that, as of such date, such Shelf Registration Statement and
                  Prospectus do not contain an untrue statement of a material
                  fact and do not omit to state a material fact required to be
                  stated therein or necessary to make the statements therein (in
                  the case of the Prospectus, in light of the circumstances
                  under which they were made) not misleading (which advice shall
                  be accompanied by an instruction to such Holders to suspend
                  the use of the Prospectus until the requisite changes have
                  been made).

         (e)      The Company shall use its best efforts to prevent the
issuance, and if issued to obtain the withdrawal, of any order suspending the
effectiveness of the Shelf Registration Statement at the earliest possible time.

         (f)      The Company shall furnish to each Electing Holder, without
charge, at least one copy of the Shelf Registration Statement and all
post-effective amendments thereto, including financial statements and schedules,
and, if such Holder so requests in writing, all reports, other documents and
exhibits that are filed with or incorporated by reference in the Shelf
Registration Statement.

         (g)      The Company shall, during the Effectiveness Period, deliver to
each Electing Holder, without charge, as many copies of the Prospectus
(including each preliminary Prospectus) included in the Shelf Registration
Statement and any amendment or supplement thereto as such Electing Holder may
reasonably request; and the Company consents (except during the continuance of
any event described in Section 3(d)(v) above) to the use, in accordance with the
terms of this Agreement, of the Prospectus and any amendment or supplement
thereto by each of the Electing Holders in connection with the offering and sale
of the Registrable Securities covered by the Prospectus and any amendment or
supplement thereto during the Effectiveness Period.

         (h)      Prior to any offering of Registrable Securities pursuant to
the Shelf Registration Statement, the Company shall (i) register or qualify or
cooperate with the Electing Holders and their counsel (which shall be Skadden,
Arps, Slate, Meagher & Flom LLP) in connection with the registration or
qualification of such Registrable Securities for offer and sale under the
securities or "blue sky" laws of such jurisdictions within the United States as
any Electing Holder may reasonably request in writing, and (ii) keep such
registrations or qualifications in effect and comply with such laws so as to
permit the continuance of offers and sales in such jurisdictions for so long as
may be necessary to enable any Electing Holder or underwriter, if any, to

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complete its distribution of Registrable Securities pursuant to the Shelf
Registration Statement, and (iii) take any and all other actions necessary or
advisable to enable the offer and sale in such jurisdictions of such Registrable
Securities; provided, however, that in no event shall the Company be obligated
to (A) qualify as a foreign corporation or as a dealer in securities in any
jurisdiction where it is not there so qualified or (B) take any action which
would subject it to the general service of process or taxation in any
jurisdiction where it is not as of the date hereof so subject.

         (i)      Unless any Registrable Securities shall be in book-entry only
form, the Company shall cooperate with the Electing Holders to facilitate the
timely preparation and delivery of certificates representing Registrable
Securities to be sold pursuant to the Shelf Registration Statement, which
certificates, if so required by any securities exchange upon which any
Registrable Securities are listed, shall be penned, lithographed or engraved, or
produced by any combination of such methods, on steel engraved borders, and
which certificates shall be free of any restrictive legends and in such
permitted denominations and registered in such names as Electing Holders may
request in connection with the sale of Registrable Securities pursuant to the
Shelf Registration Statement.

         (j)      Upon the occurrence of any fact or event contemplated by
paragraph 3(d)(v) above, the Company shall promptly prepare a post-effective
amendment to any Shelf Registration Statement or an amendment or supplement to
the related Prospectus or file any other required document so that, as
thereafter delivered to purchasers of the Registrable Securities included
therein, the Prospectus will not include an untrue statement of a material fact
or omit to state any material fact necessary to make the statements therein, in
the light of the circumstances under which they were made, not misleading. If
the Company notifies the Electing Holders of the occurrence of any event
contemplated by paragraph 3(d)(v) above, the Electing Holder shall suspend the
use of the Prospectus until the requisite changes to the Prospectus have been
made.

         (k)      Not later than the Effective Time of the Shelf Registration
Statement, the Company shall provide a CUSIP number for the Registrable
Securities that are debt securities under such Shelf Registration Statement.

         (l)      The Company shall use its best efforts to comply with all
applicable Rules and Regulations, and to make generally available to its
securityholders (or otherwise provide in accordance with Section 11(a) of the
Securities Act) as soon as practicable after the effective date (as defined in
Rule 158(c) under the Securities Act) of the Shelf Registration Statement, an
earning statement of the Company and its subsidiaries complying with Section
11(a) of the Securities Act and the rules and regulations of the Commission
thereunder (including, at the option of the Company, Rule 158), but in no event
later than 45 days after the end of a 12-month period (or 90 days, if, such
period is a fiscal year) beginning with the first month of the Company's first
fiscal quarter commencing after the effective date of the Registration
Statement, which statement shall cover such 12-month period.

         (m)      The Company shall cause the Indenture to be qualified under
the Trust Indenture Act in a timely manner and containing such changes, if any,
as shall be necessary for such qualification. In the event that any such
amendment or modification referred to in this Section 3(m) involves the
appointment of a new trustee under the Indenture, the Company shall appoint a
new trustee thereunder pursuant to the applicable provisions of the Indenture.

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         (n) The Company may require each Electing Holder as a condition to the
registration of such Electing Holder's Securities under the Registration
Statement to furnish to the Company such information regarding the Electing
Holder and the distribution of such Securities as the Company may from time to
time reasonably require for inclusion in such Shelf Registration Statement. Each
Holder who offers and sells Registrable Securities by means of the Shelf
Registration Statement shall do so in accordance with the terms thereof and the
requirements of the Securities Act.

         (o)      In the event of an underwritten offering conducted pursuant to
Section 6 hereof, the Company shall, if requested, promptly include or
incorporate in a Prospectus supplement or post-effective amendment to the Shelf
Registration Statement such information as the Managing Underwriters reasonably
agree should be included therein and to which the Company does not reasonably
object and shall make all required filings of such Prospectus supplement or
post-effective amendment as soon as practicable after it is notified of the
matters to be included or incorporated in such Prospectus supplement or
post-effective amendment.

         (p)      The Company shall enter into such customary agreements
(including an underwriting agreement in customary form in the event of an
underwritten offering conducted pursuant to Section 6 hereof) and take all other
appropriate action in order to expedite and facilitate the registration and
disposition of the Registrable Securities, and in connection therewith, if an
underwriting agreement is entered into, cause the same to contain
indemnification provisions and procedures substantially identical to those set
forth in Section 5 hereof (or such other customary provisions and procedures
acceptable to the Managing Underwriters, if any) with respect to all parties to
be indemnified pursuant to Section 5 hereof.

         (q)      The Company shall:

                  (i)(A) make reasonably available for inspection by Electing
         Holders, any underwriter participating in any disposition pursuant to
         the Shelf Registration Statement, and any attorney, accountant or other
         agent retained by such Holders or any such underwriter all relevant
         financial and other records, pertinent corporate documents and
         properties of the Company and its subsidiaries, and (B) cause the
         Company's officers, directors and employees to supply all information
         reasonably requested by such Holders or any such underwriter, attorney,
         accountant or agent in connection with the Shelf Registration
         Statement, in each case, as is customary for similar due diligence
         examinations; provided, however, that all records, information and
         documents that are designated in writing by the Company, in good faith,
         as confidential shall be kept confidential by such Holders and any such
         underwriter, attorney, accountant or agent, unless such disclosure is
         made in connection with a court proceeding or required by law, or such
         records, information or documents become available to the public
         generally or through a third party without an accompanying obligation
         of confidentiality; and provided further that, the foregoing inspection
         and information gathering shall be coordinated on behalf of the
         Electing Holders and the other parties entitled thereto by one counsel
         designated by and on behalf of Electing Holders and other parties,
         which shall be Skadden, Arps, Slate, Meagher & Flom LLP;

                  (ii) in connection with any underwritten offering conducted
         pursuant to Section 6 hereof, make such representations and warranties
         to the Holders participating in such underwritten offering and to the
         Managing Underwriters, in form, substance and scope as are customarily
         made by the Company to underwriters in primary underwritten

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         offerings of equity and convertible debt securities and covering
         matters including, but not limited to, those set forth in the Purchase
         Agreement;

                  (iii) in connection with any underwritten offering conducted
         pursuant to Section 6 hereof, obtain opinions of counsel to the Company
         (which counsel and opinions (in form, scope and substance) shall be
         reasonably satisfactory to the Managing Underwriters, if any) addressed
         to each Holder participating in such underwritten offering and the
         underwriters, covering such matters as are customarily covered in
         opinions requested in primary underwritten offerings of equity and
         convertible debt securities and such other matters as may be reasonably
         requested by such Holders and underwriters (it being agreed that the
         matters to be covered by such opinions shall include, without
         limitation, as of the date of the opinion and as of the Effective Time
         of the Shelf Registration Statement or most recent post-effective
         amendment thereto, as the case may be, the absence from the Shelf
         Registration Statement, including the documents incorporated by
         reference therein, of an untrue statement of a material fact or the
         omission of a material fact required to be stated therein or necessary
         to make the statements therein not misleading, and the absence from the
         Prospectus, including the documents incorporated by reference therein,
         of an untrue statement of a material fact or the omission of a material
         fact required to be stated therein or necessary to make the statements
         therein not misleading, in light of the circumstances under which they
         were made);

                  (iv) in connection with any underwritten offering conducted
         pursuant to Section 6 hereof, obtain "cold comfort" letters and updates
         thereof from the independent public accountants of the Company (and, if
         necessary, from the independent public accountants of any subsidiary of
         the Company or of any business acquired by the Company for which
         financial statements and financial data are, or are required to be,
         included in the Shelf Registration Statement), addressed to each Holder
         participating in such underwritten offering (if such Holder has
         provided such letter, representations or documentation, if any,
         required for such cold comfort letter to be so addressed as
         contemplated, and only if permitted, by Statement of Auditing Standards
         No. 72) and the underwriters, in customary form and covering matters of
         the type customarily covered in "cold comfort" letters in connection
         with primary underwritten offerings;

                  (v) in connection with any underwritten offering conducted
         pursuant to Section 6 hereof, deliver all customary documents and
         certificates as may be reasonably requested by any Holders
         participating in such underwritten offering and the Managing
         Underwriters, if any, including, without limitation, certificates to
         evidence compliance with Section 3(j) hereof and with any conditions
         contained in the underwriting agreement or other agreements entered
         into by the Company.

         (r)      The Company will use its best efforts to cause the Common
Stock issuable upon conversion of the Securities to be listed on the New York
Stock Exchange or other stock exchange or trading system on which the Common
Stock primarily trades on or prior to the Effective Time of the Shelf
Registration Statement hereunder.

         (s)      In the event that any broker-dealer registered under the
Exchange Act shall be an "affiliate" (as defined in Rule 2720(b)(1) of the NASD
Rules (or any successor provision thereto)) of the Company or has a "conflict of
interest" (as defined in Rule 2720(b)(7) of the NASD Rules (or any successor
provision thereto)) and such broker-dealer shall underwrite, participate as a
member of an underwriting syndicate or selling group or assist in the
distribution

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(within the meaning of the NASD Rules) of any Registrable Securities covered by
the Shelf Registration Statement, whether as a Holder of such Registrable
Securities or as an underwriter, a placement or sales agent or a broker or
dealer in respect thereof, or otherwise, the Company shall assist such
broker-dealer in complying with the requirements of the NASD Rules, including,
without limitation, by (A) if such Rules, including Rule 2720, shall so require,
engaging a "qualified independent underwriter" (as defined in Rule 2720(b)(15)
of the NASD Rules (or any successor provision thereto)) to participate in the
preparation of the registration statement relating to such Registrable
Securities, to exercise usual standards of due diligence in respect thereto and
to recommend the public offering price of such Registrable Securities, (B)
indemnifying such qualified independent underwriter to the extent of the
indemnification of underwriters provided in Section 5 hereof, and (C) providing
such information to such broker-dealer as may be required in order for such
broker-dealer to comply with the requirements of the NASD Rules.

         (t)      The Company shall use its best efforts to take all other steps
necessary to effect the registration, offering and sale of the Registrable
Securities covered by the Shelf Registration Statement contemplated hereby.

         4.       Registration Expenses. Except as otherwise provided in Section
3, the Company shall bear all fees and expenses incurred in connection with the
performance of its obligations under Sections 2 and 3 hereof and shall reimburse
the Electing Holders for the reasonable fees and disbursements of a single
counsel, which shall be Skadden, Arps, Slate, Meagher & Flom LLP, to act as
counsel therefore in connection therewith. Each Electing Holder shall pay all
underwriting discounts and commissions and transfer taxes, if any, relating to
the sale or disposition of such Electing Holder's Registrable Securities
pursuant to the Shelf Registration Statement.

         5.       Indemnification and Contribution.

         (a)      Indemnification by the Company. Upon the registration of the
Registrable Securities pursuant to Section 2 hereof, the Company shall indemnify
and hold harmless each Electing Holder and each underwriter, selling agent or
other securities professional, if any, which facilitates the disposition of
Registrable Securities, and each of their respective officers and directors and
each person who controls such Electing Holder, underwriter, selling agent or
other securities professional within the meaning of Section 15 of the Securities
Act or Section 20 of the Exchange Act (each such person being sometimes referred
to as an "Indemnified Person") against any losses, claims, damages or
liabilities, joint or several, to which such Indemnified Person may become
subject under the Securities Act or otherwise, insofar as such losses, claims,
damages or liabilities (or actions in respect thereof) arise out of or are based
upon an untrue statement or alleged untrue statement of a material fact
contained in the Shelf Registration Statement under which such Registrable
Securities are registered under the Securities Act, or any amendment or
supplement thereto, or arise out of or are based upon the omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, or arise out of or are
based on an untrue statement or alleged untrue statement of a material fact
contained in the Prospectus contained therein or any Prospectus furnished by the
Company to any Indemnified Person, or any amendment or supplement thereto, or
arise out of or are based upon the omission or alleged omission to state therein
a material fact required to be stated therein or necessary to make the
statements therein not misleading, in light of the circumstances under which
they were made, and the Company hereby agrees to reimburse such Indemnified
Person for any legal or

                                       10
<PAGE>   11
other expenses reasonably incurred by them in connection with investigating or
defending any such action or claim as such expenses are incurred; provided,
however, that the Company shall not be liable to any such Indemnified Person in
any such case to the extent that any such loss, claim, damage or liability
arises out of or is based upon an untrue statement or alleged untrue statement
or omission or alleged omission made in such Shelf Registration Statement or
Prospectus, or amendment or supplement, in reliance upon and in conformity with
written information furnished to the Company by or on behalf of any Holder
specifically for inclusion therein.

         (b)      Indemnification by the Holders and any Agents and
Underwriters. Each Electing Holder agrees, as a consequence of the inclusion of
any of such Holder's Registrable Securities in such Shelf Registration
Statement, and each underwriter, selling agent or other securities professional,
if any, which facilitates the disposition of Registrable Securities shall agree,
as a consequence of facilitating such disposition of Registrable Securities,
severally and not jointly, to (i) indemnify and hold harmless the Company, its
directors, officers who sign any Shelf Registration Statement and each person,
if any, who controls the Company within the meaning of either Section 15 of the
Securities Act or Section 20 of the Exchange Act, against any losses, claims,
damages or liabilities to which the Company or such other persons may become
subject, under the Securities Act or otherwise, insofar as such losses, claims,
damages or liabilities (or actions in respect thereof) arise out of or are based
upon an untrue statement or alleged untrue statement of a material fact
contained in such Shelf Registration Statement or Prospectus, or any amendment
or supplement, or arise out of or are based upon the omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, in each case to the
extent, but only to the extent, that such untrue statement or alleged untrue
statement or omission or alleged omission was made in reliance upon and in
conformity with written information furnished to the Company by or on behalf of
such Holder, underwriter, selling agent or other securities professional
specifically for inclusion therein, and (ii) reimburse the Company for any legal
or other expenses reasonably incurred by the Company in connection with
investigating or defending any such action or claim as such expenses are
incurred.

         (c)      Notices of Claims, Etc. Promptly after receipt by an
indemnified party under subsection (a) or (b) above of notice of the
commencement of any action, such indemnified party shall, if a claim in respect
thereof is to be made against an indemnifying party under this Section 5, notify
such indemnifying party in writing of the commencement thereof; but the omission
so to notify the indemnifying party shall not relieve it from any liability
which it may have to any indemnified party otherwise than under this Section 5.
In case any such action shall be brought against any indemnified party and it
shall notify an indemnifying party of the commencement thereof, such
indemnifying party shall be entitled to participate therein and, to the extent
that it shall wish, jointly with any other indemnifying party similarly
notified, to assume the defense thereof, with counsel satisfactory to such
indemnified party (who shall not, except with the consent of the indemnified
party, be counsel to the indemnifying party), and, after notice from the
indemnifying party to such indemnified party of its election so to assume the
defense thereof, such indemnifying party shall not be liable to such indemnified
party under this Section 5 for any legal expenses of other counsel or any other
expenses, in each case subsequently incurred by such indemnified party, in
connection with the defense thereof other than reasonable costs of
investigation. No indemnifying party shall, without the prior written consent of
the indemnified party, effect the settlement or compromise of, or consent to the
entry of any judgment with respect to, any pending or threatened action or claim
in respect of which indemnification or contribution may be sought hereunder
(whether or not the indemnified party is

                                       11
<PAGE>   12
an actual or potential party to such action or claim) unless such settlement,
compromise or judgment (i) includes an unconditional release of such indemnified
party from all liability arising out of such action or claim and (ii) does not
include a statement as to, or an admission of, fault, culpability or a failure
to act, by or on behalf of any indemnified party.

         (d)      Contribution. If the indemnification provided for in this
Section 5 is unavailable to or insufficient to hold harmless an indemnified
party under subsection (a) or (b) above in respect of any losses, claims,
damages or liabilities (or actions in respect thereof) referred to therein, then
each indemnifying party shall contribute to the amount paid or payable by such
indemnified party as a result of such losses, claims, damages or liabilities (or
actions in respect thereof) in such proportion as is appropriate to reflect the
relative fault of the indemnifying party and the indemnified party in connection
with the statements or omissions which resulted in such losses, claims, damages
or liabilities (or actions in respect thereof), as well as any other relevant
equitable considerations. The relative fault of such indemnifying party and
indemnified party shall be determined by reference to, among other things,
whether the untrue or alleged untrue statement of a material fact or omission or
alleged omission to state a material fact relates to information supplied by
such indemnifying party or by such indemnified party, and the parties' relative
intent, knowledge, access to information and opportunity to correct or prevent
such statement or omission. The parties hereto agree that it would not be just
and equitable if contribution pursuant to this Section 5(d) were determined by
pro rata allocation (even if the Electing Holders or any underwriters, selling
agents or other securities professionals or all of them were treated as one
entity for such purpose) or by any other method of allocation which does not
take account of the equitable considerations referred to in this Section 5(d).
The amount paid or payable by an indemnified party as a result of the losses,
claims, damages or liabilities (or actions in respect thereof) referred to above
shall be deemed to include any legal or other fees or expenses reasonably
incurred by such indemnified party in connection with investigating or defending
any such action or claim which is the subject of this subsection (d). No person
guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of
the Securities Act) shall be entitled to contribution from any person who was
not guilty of such fraudulent misrepresentation. The obligations of the Electing
Holders and any underwriters, selling agents or other securities professionals
in this Section 5(d) to contribute shall be several in proportion to the
percentage of principal amount of Registrable Securities registered or
underwritten, as the case may be, by them and not joint. For purposes of this
paragraph (d), each person, if any, who controls such indemnified party within
the meaning of the Securities Act or the Exchange Act shall have the same rights
to contribution as such indemnified party and each person, if any, who controls
the Company within the meaning of the Securities Act or the Exchange Act shall
have the same rights to contribution as the Company.

         (e)      Notwithstanding any other provision of this Section 5, in no
event will any (i) Electing Holder be required to undertake liability to any
person under this Section 5 for any amounts in excess of the dollar amount of
the proceeds to be received by such Holder from the sale of such Holder's
Registrable Securities (after deducting any fees, discounts and commissions
applicable thereto) pursuant to any Shelf Registration Statement under which
such Registrable Securities are to be registered under the Securities Act and
(ii) underwriter, selling agent or other securities professional be required to
undertake liability to any person hereunder for any amounts in excess of the
discount, commission or other compensation payable to such underwriter, selling
agent or other securities professional with respect to the Registrable
Securities underwritten by it and distributed to the public.

                                       12
<PAGE>   13
         (f)      The obligations of the Company under this Section 5 shall be
in addition to any liability which the Company may otherwise have to any
Indemnified Person and the obligations of any Indemnified Person under this
Section 5 shall be in addition to any liability which such Indemnified Person
may otherwise have to the Company. The remedies provided in this Section 5 are
not exclusive and shall not limit any rights or remedies which may otherwise be
available to an indemnified party at law or in equity.

         6.       Underwritten Offering. Any Holder of Registrable Securities
who desires to do so may sell Registrable Securities (in whole or in part) in an
underwritten offering; provided that (i) the Electing Holders of at least
33-1/3% in aggregate principal amount of the Registrable Securities then covered
by the Shelf Registration Statement shall request such an offering in a written
notice delivered to the Company and (ii) at least such aggregate principal
amount of such Registrable Securities shall be included in such offering; and
provided further that the Company shall not be obligated to cooperate with more
than one underwritten offering during the Effectiveness Period. Upon receipt of
such a request, the Company shall provide all Holders of Registrable Securities
written notice of the request, which notice shall inform such Holders that they
have the opportunity to participate in the offering. In any such underwritten
offering, the investment banker or bankers and manager or managers that will
administer the offering will be selected by, and the underwriting arrangements
with respect thereto (including the size of the offering) will be approved by,
the Company; provided, however, that such investment bankers and managers and
underwriting arrangements must be reasonably satisfactory to the holders of a
majority of the Registrable Securities to be included in such offering. No
Holder may participate in any underwritten offering contemplated hereby unless
(a) such Holder agrees to sell such Holder's Registrable Securities to be
included in the underwritten offering in accordance with any approved
underwriting arrangements, (b) such Holder completes and executes all reasonable
questionnaires, powers of attorney, indemnities, underwriting agreements,
lock-up letters and other documents required under the terms of such approved
underwriting arrangements, and (c) if such Holder is not then an Electing
Holder, such Holder returns a completed and signed Notice and Questionnaire to
the Company in accordance with Section 3(a)(2) hereof within a reasonable amount
of time before such underwritten offering. The Holders participating in any
underwritten offering shall be responsible for any underwriting discounts and
commissions and fees and, subject to Section 4 hereof, expenses of their own
counsel. The Company shall pay all expenses customarily borne by issuers,
including but not limited to filing fees, the fees and disbursements of its
counsel and independent public accountants and any printing expenses incurred in
connection with such underwritten offering. Notwithstanding the foregoing or the
provisions of Section 3(n) hereof, upon receipt of a request from the Managing
Underwriter or a representative of holders of a majority of the Registrable
Securities to be included in an underwritten offering to prepare and file an
amendment or supplement to the Shelf Registration Statement and Prospectus in
connection with an underwritten offering, the Company may delay the filing of
any such amendment or supplement for up to 90 days if the Board of Directors of
the Company shall have determined in good faith that the Company has a bona fide
business reason for such delay.

         7.       Liquidated Damages.

         (a)      Pursuant to Section 2(a) hereof, the Company may, upon written
notice to all the Holders, postpone having the Shelf Registration Statement
declared effective for a reasonable period not to exceed 90 days if the Company
possesses material non-public information, the disclosure of which would have a
material adverse effect on the Company and its subsidiaries taken as a whole.
Notwithstanding any such postponement, if (i) on or prior to the 90th day

                                       13
<PAGE>   14
following the Closing Date, a Shelf Registration Statement has not been filed
with the Commission or (ii) on or prior to the 180th day following the Closing
Date, such Shelf Registration Statement is not declared effective by the
Commission (each, a "Registration Default"), the Company shall be required to
pay liquidated damages ("Liquidated Damages"), from and including the day
following such Registration Default until, but excluding the day on which, such
Shelf Registration Statement is either so filed or so filed and subsequently
declared effective, as applicable, at a rate per annum equal to an additional
one-quarter of one percent (0.25%) of the principal amount of Registrable
Securities, to and including the 90th day following such Registration Default
and one-half of one percent (0.5%) thereof from and after the 91st day following
such Registration Default.

         (b)      In the event that the Shelf Registration Statement ceases to
be effective (or the Holders of Registrable Securities are otherwise prevented
or restricted by the Company from effecting sales pursuant thereto) (an
"Effective Failure") for more than 45 days, whether or not consecutive, in any
90-day period, or 90 days, whether or not consecutive, during any 12-month
period, then the Company shall pay Liquidated Damages at a rate per annum equal
to an additional one-half of one percent (0.5%) from the 46th day of the
applicable 90-day period or the 91st day of the applicable 12-month period, as
the case may be, that such Shelf Registration Statement ceases to be effective
(or the Holders of Registrable Securities are otherwise prevented or restricted
by the Company from effecting sales pursuant thereto) to but excluding the
earlier of (i) the date on which the Shelf Registration Statement again becomes
effective or the Holders of Registrable Securities are again able to make sales
under the Shelf Registration Statement or (2) the date on which the
Effectiveness Period expires. For the purpose of determining an Effective
Failure, days on which the Company has been obligated to pay Liquidated Damages
in accordance with the foregoing in respect of a prior Effective Failure within
the applicable 90-day or 12-month period, as the case may be, shall not be
included.

         (c)      In the event the Company fails to file a post-effective
amendment to the Shelf Registration Statement, or the post-effective amendment
is not declared effective, within the periods required by Section 3, the Company
shall pay Liquidated Damages at a rate per annum equal to an additional one-half
of one percent (0.5%) from and including the date of such Registration Default
until such time as such Registration Default is cured.

         (d)      Any amounts to be paid as Liquidated Damages pursuant to
paragraphs (a), (b) or (c) of this Section 7 shall be paid semi-annually in
arrears, with the first semi-annual payment due on the first Interest Payment
Date (as defined in the Indenture), as applicable, following the date of such
Registration Default. Such Liquidated Damages will accrue (1) in respect of the
Securities at the rates set forth in paragraphs (a), (b) or (c) of this Section
7, as applicable, on the principal amount of the Securities and (2) in respect
of the Common Stock issued upon conversion of the Securities, at the rates set
forth in paragraphs (a), (b) or (c) of this Section 7, as applicable, applied to
the Conversion Price (as defined in the Indenture) at that time.

         (e)      Except as provided in Section 8(b) hereof, the Liquidated
Damages as set forth in this Section 7 shall be the exclusive monetary remedy
available to the Holders of Registrable Securities for such Registration Default
or Effective Failure. In no event shall the Company be required to pay
Liquidated Damages in excess of the applicable maximum amount of one-half of one
percent (0.5%) per annum set forth above, regardless of whether one or multiple
Registration Defaults exist.

         8.       Miscellaneous.

                                       14
<PAGE>   15
         (a)      Other Registration Rights. The Company may grant registration
rights that would permit any Person that is a third party the right to
piggy-back on any Shelf Registration Statement, provided that if the Managing
Underwriter of any underwritten offering conducted pursuant to Section 6 hereof
notifies the Company and the Electing Holders that the total amount of
securities which the Electing Holders and the holders of such piggy-back rights
intend to include in any Shelf Registration Statement is so large as to
materially threaten the success of such offering (including the price at which
such securities can be sold), then the amount, number or kind of securities to
be offered for the account of holders of such piggy-back rights will be reduced
to the extent necessary to reduce the total amount of securities to be included
in such offering to the amount, number and kind recommended by the Managing
Underwriter prior to any reduction in the amount of Registrable Securities to be
included in such Shelf Registration Statement.

         (b)      Specific Performance. The parties hereto acknowledge that
there would be no adequate remedy at law if the Company fails to perform any of
its obligations hereunder and that the Purchaser and the Holders from time to
time may be irreparably harmed by any such failure, and accordingly agree that
the Purchaser and such Holders, in addition to any other remedy to which they
may be entitled at law or in equity and without limiting the remedies available
to the Electing Holders under Section 7 hereof, shall be entitled to compel
specific performance of the obligations of the Company under this Registration
Rights Agreement in accordance with the terms and conditions of this
Registration Rights Agreement, in any court of the United States or any State
thereof having jurisdiction.

         (c)      Amendments and Waivers. This Agreement, including this Section
8(c), may be amended, and waivers or consents to departures from the provisions
hereof may be given, only by a written instrument duly executed by the Company
and the holders of a majority in aggregate principal amount of Registrable
Securities then outstanding. Each Holder of Registrable Securities outstanding
at the time of any such amendment, waiver or consent or thereafter shall be
bound by any amendment, waiver or consent effected pursuant to this Section
8(c), whether or not any notice, writing or marking indicating such amendment,
waiver or consent appears on the Registrable Securities or is delivered to such
Holder.

         (d)      Notices. All notices and other communications provided for or
permitted hereunder shall be given as provided in the Indenture.

         (e)      Parties in Interest. The parties to this Agreement intend that
all Holders of Registrable Securities shall be entitled to receive the benefits
of this Agreement and that any Electing Holder shall be bound by the terms and
provisions of this Agreement by reason of such election with respect to the
Registrable Securities which are included in a Shelf Registration Statement. All
the terms and provisions of this Agreement shall be binding upon, shall inure to
the benefit of and shall be enforceable by the respective successors and assigns
of the parties hereto and any Holder from time to time of the Registrable
Securities to the aforesaid extent. In the event that any transferee of any
Holder of Registrable Securities shall acquire Registrable Securities, in any
manner, whether by gift, bequest, purchase, operation of law or otherwise, such
transferee shall, without any further writing or action of any kind, be entitled
to receive the benefits of and, if an Electing Holder, be conclusively deemed to
have agreed to be bound by and to perform all of the terms and provisions of
this Agreement to the aforesaid extent.

         (f)      Counterparts. This Agreement may be executed in any number of
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be

                                       15
<PAGE>   16
deemed to be an original and all of which taken together shall constitute one
and the same agreement.

         (g)      Headings. The headings in this agreement are for convenience
of reference only and shall not limit or otherwise affect the meaning hereof.

         (h)      GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

         (i)      Severability. In the event that any one or more of the
provisions contained herein, or the application thereof in any circumstances, is
held invalid, illegal or unenforceable in any respect for any reason, the
validity, legality and enforceability of any such provision in every other
respect and of the remaining provisions hereof shall not be in any way impaired
or affected thereby, it being intended that all of the rights and privileges of
the parties hereto shall be enforceable to the fullest extent permitted by law.

         (j)      Survival. The respective indemnities, agreements,
representations, warranties and other provisions set forth in this Agreement or
made pursuant hereto shall remain in full force and effect, regardless of any
investigation (or any statement as to the results thereof) made by or on behalf
of any Electing Holder, any director, officer or partner of such Holder, any
agent or underwriter, any director, officer or partner of such agent or
underwriter, or any controlling person of any of the foregoing, and shall
survive the transfer and registration of the Registrable Securities of such
Holder.

                                       16
<PAGE>   17
         Please confirm that the foregoing correctly sets forth the agreement
between the Company and you.

                                           Very truly yours,

                                           Calpine Corporation


                                           By: /s/ Ann B. Curtis
                                               --------------------------------
                                               Name:  Ann B. Curtis
                                               Title: Executive Vice President,
                                                      Chief Financial Officer
                                                      and Secretary

Accepted as of the date hereof:
Goldman, Sachs & Co.


By: /s/ Goldman Sachs & Co.
    -----------------------------------
    Name:  Goldman Sachs & Co.
    Title:


                                       17