The contracts will be submitted to the California Public Utilities Commission for review and approval.
Pedro Pizarro, SCE's senior vice president of power procurement, said the contracts are needed, in part, to offset the impending shutdown of other aging power facilities.
"Many of our plants are 40 years old or older and getting near the end of their useful life," he said. "These plants will bring on more capacity and they will also be more efficient with lower environmental impacts than the older plants."
The 10-year contract with Blythe-based Blythe Energy would provide SCE with another 490 megawatts, via a new transmission link connecting a combined natural gas facility to the California Independent System Operator grid.
Competitive Power, based in the Coachella Valley, has also submitted a 10-year contract that would add 455 megawatts of energy. The power would come from "peaker" facilities that are capable of coming online within 10 minutes during times of extreme demand.
The Blythe plant, by contrast, would operate in intermediate mode throughout much of the year.
SCE's new generation initiative was started in 2005 in response to predicted future shortages of generation supply in the Southern California region of the electrical system overseen by the California Independent System Operator.
In November, Long Beach Generation LLC, a subsidiary of NRG Energy Inc., received a 10-year power-purchase agreement to provide 260 megawatts of new generating capacity to serve all customers on SCE's grid.
That contract involves refurbishing an older plant, which will be refitted with new emissions-control technology. The commission approved the contract with NRG late last month and the revamped plant could be online by August.