Colorado’s chief energy supplier, Xcel Energy, announced today plans to build North America’s second largest photovoltaic solar power plant in Alamosa, Colorado. The 17-megawatt plant is to be completed by 2010 by builder SunPower, Inc.

Why is Excel Energy doing this? Colorado has a law that mandates Xcel get 20 percent of its electricity sales from renewables such as wind and solar by the end of 2010.

Xcel currently produces about 10 percent from solar, wind and other renewable resources. Colorado currently gets the vast majority of its power from coal fire plants.