Colorado has increased its renewable energy standard to require large utilities to obtain 30% of their power from renewable sources by 2020. Governor Bill Ritter signed the legislation on March 22, noting that the new standard makes it the "best in the Rocky Mountain West" and one of the highest in the nation.

In 2004, the state became the first in the United States to have a voter-approved renewable energy standard, when a referendum was approved calling for 10% renewable power by 2015. In 2007, state legislation increased the requirement to 20% renewable energy by 2020, a target that the new legislation increased by another 50%.

As with the previous law, the new law credits electricity produced from solar energy, wind power, geothermal energy, biomass power (including power generated from non-toxic plants, animal wastes, and methane from landfills and wastewater treatment facilities), small hydropower, "recycled" electricity from waste heat, and fuel cells powered with hydrogen derived from eligible renewable energy resources. 

The new law requires utilities to supply at least 12% of their retail electric sales from such sources from 2011 to 2014, 20% from 2015 to 2019, and 30% for 2020 and thereafter. Those requirements apply to all providers of retail electric service in the state, with the exception of municipal utilities serving 40,000 customers or fewer. In-state power facilities receive extra credit towards the requirements.

The new law also sets specific requirements for distributed generation from eligible renewable energy resources. The law divides this into "retail distributed generation," which includes customer-located facilities connected to the customer's side of the meter, and sized to not exceed the customer's load by more than 20%, and "wholesale distributed generation," which includes systems of 30 megawatts of capacity or less that don't qualify as retail distributed generation.

The law requires investor-owned utilities to draw on distributed generation for at least 1% of their retail electric sales in 2011 and 2012, ratcheting up to 3% by 2020. At least half of the requirement must be met with retail distributed generation. According to the governor, that requirement will lead to at least 100,000 additional solar rooftops over the next decade.

Kevin Eber is a senior science writer at the National Renewable Energy Laboratory. In that capacity, he has promoted energy efficiency and renewable energy technologies for nearly 20 years.

Ernie Tucker is an NREL staff writer who has worked as a writer and editor in a variety of media, including newspapers, television and online content.

This article was first published in the U.S. Department of Energy's EERE Network News and was reprinted with permission.