The Rocky Mountain News reports that Xcel Energy Inc has voluntarily offered to shut down two coal-fired power plants to reduce emissions.  The company’s plans have been approved by state regulators, and the plants will close in 2010 and 2012. Xcel will build a 200-megawatt solar energy facility and add 850 megawatts of wind energy in order to replace the older coal-fired plants.  Several solar companies have expressed interest in bidding on the solar plant, including Abengoa Solar (ABG), BrightSourceEnergy and Ausra.