Colorado Corn

But the Environmental Protection Agency in 2010 and this year had to "substantially reduce" requirements because of "limited production capacity," said Margo Oge, director of the EPA's office of air and radiation.

The targets set by Congress were 100 million gallons for 2010 and 250 million for 2011; EPA reduced them to 6.5 million gallon for both years.

Many government-supported cellulosic biorefineries have been stalled, in or delayed, including a project in Michigan's Upper Peninsula.

In March, President Barack Obama called for four new cellulosic ethanol refineries by 2013 as part of a strategy for cutting the nation's imported oil use by one third by 2025 from 2008 levels.

Rep. Lee Terry, R-Neb., questioned why more progress hasn't been made on cellulosic ethanol.

"In the last five years it doesn't seem like we've made a lot of progress," I would have expected mass production by now," he asked. "What's the hold up? What's the problem?"

At the same time, corn-based ethanol production and government subsidies have come under attack by some in Congress and others who argue that diverting so much corn into gas tanks raises food prices and feed prices for livestock.

Sens. Charles Grassley, R-Iowa, and Kent Conrad, D-N.D., introduced a bill Wednesday that "would reduce significantly tax incentives for ethanol," they said.

It would extend, through 2016, at descending levels, the volumetric ethanol excise tax credit. But it would extend, through 2016, the alternative fuel refueling property credit; the cellulosic producers' tax credit; and the special depreciation allowance for cellulosic biofuel plant property.

Ethanol now accounts for nearly 10 percent of all fuel used by vehicles. Most gasoline sold at pumps is E10 — a blend of 10 percent ethanol.

Bob Dinneen, president and CEO of the Renewable Fuels Association, told the committee that ethanol adds $54 billion to the U.S. economy, $12 billion in tax revenue and helps support more than 400,000 jobs. "Policymakers should be embracing — not shunning — ethanol's ability to add domestic fuel supplies and hold prices in check," he said.

Others have criticized a tariff that keeps most Brazilian ethanol out of the U.S. and other efforts to boost the amount of biofuels in gas tanks.

In February, the House voted 286-135 to block the EPA from spending any money to carry out a waiver to allow E15 to be sold at the nation's fueling stations.

The EPA has granted a waiver to allow a blend of 15 percent of ethanol to be sold for vehicles from the 2001 model year and newer. Automakers and others have filed suit to block the fuel use, saying it could harm engines.

Despite all of the efforts, the U.S. is almost totally dependent on oil. In 2009, 94 percent of all transportation energy came from oil, said U.S. Energy Information Administration deputy chief Howard Gruenspecht.

The agency has a very conservative outlook on the ramp up of plug-in electric vehicles and hybrids. By 2035, EIA predicts that hybrids will account for just 5 percent of all vehicles sold and plug-in hybrid electric and full electric vehicles will account for just 3 percent of all sales.

"Americans love their cars and we love to drive, so it only makes sense that we provide direction for the American people and move our country away from its heavy dependence on foreign source of oil," said Rep. Bobby Rush, D-Ill.

dshepardson@detnews.com