by Andrew Herndon , Bloomberg | May 24, 2012

California has expanded a program that forces utilities to buy solar electricity generated by homeowners and businesses.

Formerly, "net metering," as the practice is known, was subject to a cap equivalent to 5 percent of “aggregate customer peak demand,” according to a statement from the California Public Utilities Commission.

Today’s ruling by the commission, reached in a 5-0 vote, changes the way the cap is calculated and as a result doubles the amount of eligible solar power, the commission said.

The prior net metering cap in California would have been met after about 2.4 gigawatts of installations, and today’s decision raises it to about 5 gigawatts, said REC Solar Legislative Director Ben Higgins.