Colorado Springs Utilities and three other utility companies operating in Colorado are seeking new sources of renewable natural gas as part of ongoing statewide efforts to reduce greenhouse gas emissions.

Colorado Springs Utilities, Atmos Energy Corporation, Black Hills Energy and Xcel Energy-Colorado on Monday issued a joint request for information seeking future developers of renewable natural gas.

"This is the beginning of what's going to be a long-term project for all utilities in the state ... to provide renewable natural gas for our systems," Tom Henley, senior community program manager at Black Hills Energy, said by phone Monday.