A group of state leaders chaired by Iowa Governor Chet Culver is calling on Congress to adopt new national standards for renewable energy. The Governors’ Wind Energy Coalition wants Congress to mandate ten-percent of America’s electricity be renewable by 2012. Iowa Senator Chuck Grassley says that’s aiming a little high.

Senator Grassley says he’s supported what are referred to as renewable portfolio standards in the past, but not necessarily at that percentage or by that year. Grassley, a Republican, says wind energy is growing in popularity, but the mandate the governors are calling for is too high.

“Probably not ten-percent by 2012,” Grassley says, “I don’t think that that’s possible but I surely think 15% by 2020 is possible.” Culver is among 29 governors who signed a letter to President Obama, requesting the renewable energy mandate. Reports say Iowa already gets up to 20% of its electricity from the wind.