LONGMONT - Gov. Bill Ritter on Wednesday signed the Homegrown Renewable Power Act, a law that will credit homes and businesses for the energy they create through renewable energy sources they don't use and is recycled back to their utility power grids.

House Bill 1160 requires rural cooperative electric associations and some municipally owned utilities to credit members and customers for their unused electricity generated by solar, wind or geothermal systems.

Municipally owned utilities affected by the law are those with more than 5,000 customers, including Longmont, Loveland, Estes Park and Fort Collins. Residential customers can receive credit each month for up to 10 kilowatt-hours of excess power, and commercial, agricultural or industrial customers can receive credit for up to 25 kilowatt-hours.

Ritter signed the law that will take effect in August, at Steve Szabo's farm south of Longmont, where Szabo runs a photovoltaic solar system for his energy needs.

The bill was sponsored by state Rep. Judy Solano, D-Brighton; state Sen. Brandon Shaffer, D-Longmont; and state Sen. Jim Isgar, D-Hesperus, in southwest Colorado.