Xcel Energy, the main utility for the Denver metro area and biggest in Colorado, sells natural gas to 1.4 million households in the state. It sells even more natural gas to commercial and industrial customers, and it generates 37% of the electricity it sells from burning natural gas. Hansen hasn't heard opposition from Xcel Energy about the bill, he said. The company hasn't publicly declared a stance. It's looking at the standards and considering what it could mean for the state's emissions reduction goals, keeping an eye on customer costs, said Michelle Aguayo, a spokeswoman for Xcel Energy in Colorado "We are committed to evaluating the most cost-effective options," she said. "These projects present unique opportunities for us, and we'll continue to explore them." Xcel already buys some renewable natural gas from a methane capture project at a Waste Management landfill east of the metro area.