California grid plans alternate source for lost nuclear capacity

* Two power plants to make up for shut nuclear plant

* Plants will push electricity through grid

NEW YORK, Sept 13 (Reuters) - The California Independent System Operator Corp (CAISO)said it will convert two power plants to compensate for electricity lost by the shut down of the San Onofre nuclear power plant in a bid to ensure enough power generation next summer.

Edison International's Southern California Edison (SCE)'s 2,150-megawatt San Onofre nuclear power station, or SONGS, has not produced electricity since Jan. 31 after a radiation leak was found in one of the two units.

It had supplied the state with some 8 percent of its power.

The grid operator will convert AES Corp 's Huntington Beach natural gas-fired units 3 and 4 into synchronous condensers, which act "somewhat like spinning flywheels, adjust to grid conditions by providing the voltage support, normally supplied by the nuclear plant", CAISO said in a statement.

The units had been taken out of retirement and restarted in May to offset power lost from San Onofre.

Those units would produce "megavars, instead of megawatts" and would "push megawatts through the grid, much like water pressure helps push water through a hose."

The units would have low environmental impact.

Since these units would not produce electricity, they do not require air emissions credits. As well, operating the units would not require cooling water from the ocean and would "comply with new once-through cooling restrictions," the grid operator said in the release.

Should the grid operator find it necessary, additional measures will be taken to supplement power generation.

The Nuclear Regulatory Commission said it will hold a public meeting on Oct. 9 to discuss the status of its oversight of the San Onofre plant in California.