NRG said two solar facilities in south-central California reached commercial production, delivering 40 megawatts of electricity to utility providers Southern California Edison and Pacific Gas & Electric.
The company said the two projects combined would generate enough electricity to meet the annual demands of nearly 11,800 households in the region.
A 2008 state law requires retail energy providers to use renewable energy to meet 33 percent of consumer demand by 2020.
NRG said Friday the two latest solar installments are part of a wider 11-array effort spread out over three states in the southwestern United States. The company in May said it was selling renewable energy to PG&E from its Alpine solar generating facility in southern California.
Last year, the company marked the first 100 MW of electricity generated from its mega 290 MW Aqua Caliente solar project in Arizona.