On September 22, 2010, U.S. Senators Jeff Bingaman (D-NM) and Sam Brownback (R-KS) released a bill establishing a national renewable energy standard (RES). The Renewable Energy Promotion Act of 2010 will require that at least 15 percent of the nation's electricity is supplied by renewable sources by 2021. If enacted, the bill will for the first time create a national market for renewable energy credits. Qualifying renewable resources will include wind, solar, biomass, tidal, new hydropower, and landfill gas.