SAN DIEGO, April 20, 2006 - Sempra Generation, a subsidiary of Sempra Energy (NYSE: SRE), and Riverstone Holdings, a New York-based energy private-equity firm, today announced that they have agreed to sell the jointly owned 632-megawatt (MW) Coleto Creek Power plant in Goliad County, Texas, to International Power plc (L:IPR; NYSE: IPR) for  $1.14 billion in cash.

        In July 2004, Sempra Generation and Riverstone Holdings formed the Topaz Power Group, with each firm acquiring 50-percent interest in Coleto Creek Power and nine other plants for $430 million.  

        “This agreement reflects the strong market value of coal-fired generation in Texas and is a credit to those within our asset management team who have operated and maintained Coleto Creek Power over the past two years,” said Michael R. Niggli, president of Sempra Generation. 

        “We have been extremely happy with the performance of these assets since our acquisition,” said Michael Hoffman, managing director of Riverstone Holdings.  “Coleto Creek Power has always been a top performer among coal plants largely due to the high quality group of employees and managers at the facility.”

        The completion of the Coleto Creek Power sale is subject to clearance by the U.S. Department of Justice under the Hart-Scott-Rodino Act and approval by the Public Utilities Commission of Texas.  The transaction is expected to be completed during the third quarter of 2006.

        The cash from the Coleto Creek Power transaction will be used to repay approximately $350 million in debt associated with the investment with the net cash proceeds split between Sempra Energy and Riverstone Holdings’ limited partners in Carlyle/Riverstone Global Energy & Power Fund II. 

        The sale of the Topaz Power Group’s remaining Texas assets is not part of the Coleto Creek Power transaction.

        Sempra Generation and Riverstone Holdings were advised by Goldman Sachs & Co. on the transaction.

        International Power plc is a leading independent electricity generating company with interests in 37 power stations in 18 countries around the world representing 16,642 MW (net) in operation and 1,729 MW (net) under construction.

        Sempra Generation operates and maintains a fleet of power plants serving the Western U.S. market and provides energy infrastructure for competitive markets. 

        Sempra Energy, based in San Diego, is a Fortune 500 energy services holding company with 2005 revenues of $11.7 billion.  The Sempra Energy companies’ 14,000 employees serve more than 29 million consumers in the United States, Europe, Canada, Mexico, South America and Asia.

        Riverstone Holdings LLC and The Carlyle Group are the co-general partners of Carlyle/Riverstone Global Energy and Power Fund(s).  Riverstone, a New York-based energy and power focused private equity firm founded in 2000, has $6 billion under management.  Riverstone conducts buyout and growth capital investments in the midstream, upstream, power, and oilfield service sectors of the energy industry.  To date, the firm has committed $1.3 billion to 16 investments across each of these four sectors, involving $15 billion of assets.  The Carlyle Group is a global private equity firm with $35 billion under management.  Carlyle invests in buyouts, venture capital, real estate and leveraged finance in North America, Europe and Asia.  Since 1987, the firm has invested $14.9 billion of equity in 439 transactions. 

###

This press release contains statements that are not historical fact and constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995.  When the company uses words like “believes,” “expects,” “anticipates,” “intends,” “plans,” “estimates,” “may,” “would,” “should” or similar expressions, or when the company discusses its strategy or plans, the company is making forward-looking statements.  Forward-looking statements are not guarantees of performance.  They involve risks, uncertainties and assumptions.  Future results may differ materially from those expressed in the forward-looking statements.  Forward-looking statements are necessarily based upon various assumptions involving judgments with respect to the future and other risks, including, among others: local, regional, national and international economic, competitive, political, legislative and regulatory conditions and developments; actions by the California Public Utilities Commission, the California State Legislature, the California Department of Water Resources, the Federal Energy Regulatory Commission and other regulatory bodies in the United States and other countries; capital markets conditions, inflation rates, interest rates and exchange rates; energy and trading markets, including the timing and extent of changes in commodity prices; the availability of natural gas; weather conditions and conservation efforts; war and terrorist attacks; business, regulatory, environmental, and legal decisions and requirements; the status of deregulation of retail natural gas and electricity delivery; the timing and success of business development efforts; the resolution of litigation; and other uncertainties, all of which are difficult to predict and many of which are beyond the control of the company.  These risks and uncertainties are further discussed in the company’s reports filed with the Securities and Exchange Commission that are available through the EDGAR system without charge at its Web site, www.sec.gov and on the company’s Web site, www.sempra.com.

Sempra Generation is not the same company as the utilities, SDG&E or SoCalGas, and is not regulated by the California Public Utilities Commission.