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 17, 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 8.01 -- OTHER EVENTS

     On May 17, 2005, the Registrant  issued the press release  attached hereto
as Exhibit 99.1.



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 17, 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: May 17, 2005






EXHIBIT 99.1.


NEWS RELEASE                                            CONTACTS: (408) 995-5115
                                   Media Relations:  Katherine Potter, Ext. 1168
                                    Investor Relations:  Rick Barraza, Ext. 1125


      Calpine Evaluating Strategic Alternatives for its Natural Gas Assets

     (SAN  JOSE,  Calif.)  /PR  Newswire  - First  Call/ May 17,  2005 - Calpine
Corporation  [NYSE:CPN] is currently evaluating  strategic  alternatives for its
U.S.  natural  gas  assets,  including  the  potential  sale of all or a portion
thereof.

     Calpine's  natural gas assets are primarily located in the Sacramento Basin
of California,  south Texas and the Gulf of Mexico, with additional  significant
activity in Colorado,  New Mexico and Utah. As of December 31, 2004, the company
had 389 billion  cubic feet  equivalent  of net proved gas  reserves.  Calpine's
natural  gas  land  interests   currently  include  386,674  net  developed  and
undeveloped  acres.  The company's  assets  currently  produce  approximately 90
million cubic feet equivalent per day from 607 net wells.

     Net  proceeds  from any sale of the  natural  gas  assets  would be used in
accordance with Calpine's existing bond indentures.

     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 listed on the S&P 500. The company was founded in
1984 and is publicly traded on the New York Stock Exchange under the symbol CPN.
For more information, visit www.calpine.com.

     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.