If you drive down PCH in Huntington Beach you will pass the only power plant in Orange County. Located at Newland and PCH, across the street from the beach.
The natural gas plant is owned by AES a leading global power company with 132 plants in 32 countries with $17 billion in revenue. It is currently listed at #150 on the Fortune 500 (pdf).
In California, it operates 2 other natural gas plants in Los Alamitos and Redondo Beach. As well as 5 wind stations. Although, the largest section of its portfolio are coal powered plants located elsewhere in the USA.
The plant in Huntington Beach was purchased from Southern California Edison in 1998 and has been in operation since 1958. It uses conventional GM steam turbines among others.
In 2001, the company petitioned to upgrade and then turn on gas burners 3 and 4 (additional source), which would bring the capacity up to 904 MW. They were successful and, in 2002, the city valued the plant at $325 million.