Both the units of the plant have a power generation capacity of 485MW each. The Alamitos Unit 5 went offline on July 26, 2009 stated the state power grid manager. All the other units at the power plant were available for service except Unit 6.

The 1,997MW Alamitos plant comprises six units which include Units 1 and 2 with a generation capacity of 175MW each, Unit 3 with 332MW capacity, Unit 4 with 335MW capacity, Unit 5 with 485MW capacity and Unit 6 with 495MW of power generation capacity.

Unit 1, 2,3,4,5 and 6 began operations in 1956, 1957, 1961, 1962, 1964 and 1966 respectively. One MW of power generated from the plant can serve approximately 700 homes in California.

AES engages in the ownership and operation of power plants with a power generation capacity of 43,000MW in the Americas, Asia, Africa, Europe, and the Caribbean. It also markets energy commodities, and transmits and distributes power around the world.