Colorado Governor Bill Ritter on Monday signed into law the Colorado Clean Air-Clean Jobs Act–legislation that requires Xcel Energy (NYSE: XEL) to cut nitrogen oxide emissions by up to 80% from several Front Range coal plants by the end of 2017, most likely sooner.

Xcel will work with the Colorado Department of Public Health and Environment to submit a plan to the Public Utilities Commission by Aug. 15, detailing how it will retire or retrofit 900 megawatts (MW) of coal-fired capacity. Xcel will give primary consideration to replacing or repowering those plants with natural gas, renewables, greater efficiencies and other cleaner energy sources.

“This law is a template for tomorrow that allows us to transform our energy portfolio, our economy and our environment by working strategically and collaboratively,” Gov. Ritter said. “By shifting our oldest and least efficient coal plants to cleaner, Colorado-produced natural gas, we send a strong message to the rest of the country that we absolutely can cut air pollution and protect public health while also creating jobs and protecting ratepayers.”

Governor Ritter was joined at the Capitol signing ceremony by members of a broad coalition that supported House Bill 1365, including Xcel Energy Chairman and CEO Dick Kelly, lawmakers, power producers and conservationists.