Southern California Edison Co. closed on the purchase of the plant on March 12, after a full review and approval of project costs by both the California Public Utilities Commission and the Federal Energy Regulatory Commission.

The plant is scheduled to begin producing power by the summer of 2006.

The work force will peak at more than 600 workers during the summer months, said Gil Alexander, SCE spokesman.

The 1,054-megawatt power plant will be San Bernardino and Riverside counties' largest, serving about one million homes.

Electricity usage in the two-county area is increasing at approximately 4 percent a year, twice the rate of growth for other areas served by SCE.

The output of Mountainview will bring to approximately 6,000 megawatts the amount of generating capacity SCE owns and operates, including natural gas, nuclear, coal and hydro facilities.

During 2003, the peak power consumption by SCE customers was 20,163 megawatts, which occurred Sept. 5.

The Mountainview power plant will be a combined cycle plant, employing the most efficient, environmentally friendly power- generating technology available.

Instead of releasing into the atmosphere heat produced by the plant's combustion turbines, the thermal energy will be used to heat water and drive steam turbine generators.

The $600 million plant is about 15 percent complete.

In July 2003, SCE signed an option to acquire Mountainview Power Co., a subsidiary of Sequoia Generating.