UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM 8-K

                                 CURRENT REPORT

                       Pursuant to Section 13 or 15(d) of
                       the Securities Exchange Act of 1934

         Date of Report (Date of earliest event reported): May 28, 2005

                               CALPINE CORPORATION

             (Exact name of registrant as specified in its charter)

                                    Delaware
                 (State of Other Jurisdiction of Incorporation)

                        Commission file number: 001-12079

                  I.R.S. Employer Identification No. 77-0212977

                           50 West San Fernando Street
                           San Jose, California 95113
                            Telephone: (408) 995-5115
          (Address of principal executive offices and telephone number)

Check  the  appropriate  box  below  if the  Form  8-K  filing  is  intended  to
simultaneously  satisfy the filing obligation of the registrant under any of the
following provisions:

     [ ]  Written communications pursuant to Rule 425 under the Securities Act
          (17 CFR 230.425)

     [ ]  Soliciting material pursuant to Rule 14a-12 under the Exchange Act
          (17 CFR 240.14a-12)

     [ ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the
          Exchange Act (17 CFR 240.14d-2(b))

     [ ]  Pre-commencement communications pursuant to Rule 13e-4(c) under the
          Exchange Act (17 CFR 240.13e-4(c))




ITEM 1.01 -- ENTRY INTO A MATERIAL DEFINITIVE AGREEMENT

     On May 28, 2005, Calpine Corporation  ("Calpine") and its indirect,  wholly
owned  subsidiaries  Calpine UK Holdings  Limited (the  "Seller"),  and Quintana
Canada Holdings, LLC (the "Seller Guarantor",  and, collectively with the Seller
and  Calpine,  the "Seller  Parties"),  entered  into a share sale and  purchase
agreement (the "Agreement") with International Power PLC ("IPR"),  Mitsui & Co.,
Ltd.  ("Mitsui")  and  Normantrail  (UK  CO  3)  Limited  (the  "Purchaser"),  a
partnership  formed by IPR and Mitsui.  Pursuant to the terms of the  Agreement,
the Purchaser will acquire from the Seller (the "Acquisition") the entire issued
share capital of Saltend  Cogeneration  Company Limited  ("SCCL") and Calpine UK
Operations  Limited ("UK OpCo",  together with SCCL, the "Sale Group").  SCCL is
the owner of, and UK OpCo is the operator of, the Saltend Energy Centre,  a 1200
MW (nominal) natural gas-fired  cogeneration  facility located in Hull, England.
Calpine and the Seller  have  provided  certain  customary  warranties,  and the
Seller  Guarantor has  guaranteed  the payment by the Seller of  liabilities  in
respect  of all claims  under the  Agreement  other than  claims for breach of a
warranty.  The  obligations of the Purchaser are guaranteed as to 70% by IPR and
30% by Mitsui.

     The  total  amount  payable  by  the  Purchaser   under  the  Agreement  is
(pound)489,969,886,  comprising an amount  payable for the Sale Group shares and
an amount to repay intercompany loans made to SCCL by certain of its affiliates.
The purchase  price is subject to a net working  capital  adjustment at closing.
(pound)20,000,000  of the purchase price will be retained in escrow for one year
following  closing of the  Acquisition.  The Seller  will be entitled to receive
(pound)5,000,000  from the escrow every three  months,  subject to the Purchaser
making  any claims  under the  Agreement  in such  period,  which  claims may be
satisfied from amounts in escrow.

     The Acquisition is subject to certain conditions,  including (a) receipt of
(i) the approval of the European  Commission,  (ii) certain waivers and consents
of BP International  Limited ("BPI") under contracts relating to SCCL, including
the waiver by BPI or the expiration  without exercise by PBI of a right of first
refusal and BPI's agreement  regarding certain financing  arrangements that SCCL
will enter into at closing,  and (iii) audited financial statements for SCCL and
UK OpCo for the year ended December 31, 2004, and (b) conditions  requiring that
certain procedures be followed at closing, including the receipt of confirmation
from SCCL's  auditors  relating to a report  that is to be  delivered  to SCCL's
directors at closing,  to permit SCCL to provide  financial  assistance  for the
acquisition of its shares in compliance with UK Companies Law.

     The Agreement  may be terminated  (i) by the Seller or the Purchaser if the
conditions  precedent are not satisfied or waived by August 7, 2005, (ii) by the
Purchaser,  if there is a material  adverse  effect  relating  to the  business,
assets,  financial  or  trading  condition  of the Sale  Group  taken as a whole
("MAE"),  or if there is a breach of warranty  at signing or closing  that would
give rise to a MAE,  or (iii) by the Seller if there would be breach of warranty
at closing that the  Purchaser  estimates  would  result in a claim  against the
Seller or  Calpine in excess of  (pound)125,000  and such claim is not waived by
the Purchaser.  The Agreement will  automatically  terminate if closing does not
occur by August 30, 2005.

     The Agreement  contains certain  indemnities  given by the Seller including
with respect to certain  environmental  and tax matters.  The maximum  aggregate
liability of the Seller Parties for certain warranties  (relating,  for example,
to title to the shares,  and  capacity  and  authority to enter into and perform
their  obligations  under the  Agreement)  is equal to the purchase  price.  The
maximum aggregate liability of the Seller Parties for all other claims under the
Agreement   including   under  the   environmental   and  tax   indemnities   is
(pound)100,000,000. Included within this liability cap is a liability sub-cap of
(pound)35,000,000 applicable to claims under the environmental indemnity.

     Net  proceeds  from the sale will be used to redeem  the  outstanding  $360
million of 2-Year  Redeemable  Preferred  Shares and $260 million of  Redeemable
Preferred Shares due July 30, 2005, and as permitted by Calpine's  existing bond
indentures.



ITEM 2.05 -- COSTS ASSOCIATED WITH EXIT OR DISPOSAL ACTIVITIES

     We  incorporate  by  reference  in this Item 2.05 our response to Item 1.01
above.  In  connection  with the  Acquisition  we  estimate  that we will  incur
approximately  $9 million  of  various  transaction  fees  including  investment
banking,  legal  and tax  consulting  costs.  In  addition,  as a result  of the
Acquisition,  we expect to record non-cash losses of  approximately  $74 million
due to the close-outs of a net  investment  hedge and a series of commodity cash
flow hedges.

     We estimate that we will incur charges of approximately $24 million related
to the  redemption  of the two existing  series of Redeemable  Preferred  Shares
consisting  of a  pre-payment  penalty and  write-off  of  unamortized  deferred
financing  costs.  Of this amount  approximately  $13 million will be a non-cash
charge.

     The expected  closing date of the Acquisition is July 26, 2005,  subject to
satisfaction of the conditions as described in Item 1.01 above.



ITEM 9.01 -- FINANCIAL STATEMENTS AND EXHIBITS


(a) Financial Statements of Businesses Acquired.


Not Applicable


(b) Pro Forma Financial Information.


Not Applicable


(c) Exhibits.


99.1 Press Release dated May 31, 2005.





                                   SIGNATURES



Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned hereunto duly authorized.

                               CALPINE CORPORATION


                          By: /s/ Charles B. Clark, Jr.
                              ------------------------------------
                              Charles B. Clark, Jr.
                              Senior Vice President, Controller and
                              Chief Accounting Officer


Date: June 3, 2005


                                  EXHIBIT INDEX

Exhibit Number             Exhibit
- --------------             -------

99.1                       Press Release dated May 31, 2005.




EXHIBIT 99.1


NEWS RELEASE                                            CONTACTS: (408) 995-5115
                                   Media Relations:  Katherine Potter, Ext. 1168
                                    Investor Relations:  Karen Bunton, Ext. 1121


                Calpine to Sell Saltend Energy Centre Generating
                     Proceeds of Approximately $925 Million

     (SAN JOSE,  Calif.) /PR  Newswire - First Call/ May 31, 2005 - A subsidiary
of Calpine Corporation [NYSE:CPN], has agreed to sell its 1,200-megawatt Saltend
Energy Centre for a total purchase price of (pound)490 million, or approximately
$US906  million,   plus   adjustments   for  working  capital   expected  to  be
approximately  $US19  million -  generating  total  expected  gross  proceeds to
Calpine  of  approximately  $US925  million.  Saltend  is a  natural  gas-fired,
cogeneration power plant located in Hull, England.

     Calpine  is  selling  the  Saltend  power  plant to a  partnership  between
International Power plc and Mitsui & Co., Ltd. Calpine currently anticipates the
sale to close on or about July 26, 2005, pending  regulatory  approval and other
conditions of closing.

     Calpine Chief  Financial  Officer Bob Kelly stated,  "Calpine  continues to
focus on optimizing  the value of our core North American power plant assets and
strengthening  our balance sheet.  We acquired the Saltend power plant in August
2001 for $810 million.  This transaction is an excellent opportunity for Calpine
to capture significant value for our Saltend investment."

     Net  proceeds  from the sale of the Saltend  Energy  Centre will be used to
redeem two existing series of Redeemable Preferred Shares for approximately $620
million, and as permitted by Calpine's existing bond indentures.

     Credit Suisse First Boston acted as Calpine's  advisor for the sale. Credit
Suisse First Boston,  which is regulated in the United  Kingdom by the Financial
Services  Authority,  is acting only for  Calpine and no one else in  connection
with  this  matter  and will not  regard  any other  person as its  client or be
responsible  to anyone  other  than to Calpine  for  providing  the  protections
afforded to clients of Credit  Suisse  First  Boston,  nor for giving  advice in
relation to this or any other matter referred to in this announcement.

     Calpine  Corporation  is  a  North  American  power  company  dedicated  to
providing electric power to customers from clean,  efficient,  natural gas-fired
and geothermal  power plants.  The company  generates power at plants it owns or
leases in 21 states in the United States,  three  provinces in Canada and in the
United Kingdom.  The company is included in the S&P 500.  Calpine was founded in
1984 and is publicly traded on the New York Stock Exchange under the symbol CPN.
For more information, visit .

     This  news  release  discusses  certain  matters  that  may  be  considered
"forward-looking" statements within the meaning of Section 27A of the Securities
Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934,
as  amended,  including  statements  regarding  the  intent,  belief or  current
expectations  of  Calpine   Corporation  ("the  Company")  and  its  management.
Prospective investors are cautioned that any such forward-looking statements are
not  guarantees  of  future  performance  and  involve  a number  of  risks  and
uncertainties  that could  materially  affect  actual  results  such as, but not
limited to, (i) the timing and extent of  deregulation of energy markets and the
rules and regulations adopted on a transitional basis with respect thereto; (ii)
the timing and extent of changes in  commodity  prices for energy,  particularly
natural gas and electricity; (iii) unscheduled outages of operating plants; (iv)
a competitor's  development of lower cost generating gas-fired power plants; (v)
risks  associated  with  marketing  and selling  power from power  plants in the
newly-competitive  energy market;  (vi) other risks identified from time-to-time
in the  Company's  reports  and  registration  statements  filed  with  the SEC,
including the risk factors  identified in its Annual Report on Form 10-K for the
year ended  December 31, 2004 and in its  Quarterly  Report on Form 10-Q for the
quarter ended March 31, 2005,  which can also be found on the Company's  website
at  www.calpine.com.  All  information  set forth in this news  release is as of
today's date, and the Company undertakes no duty to update this information.