A federal appeals court has ruled that the Environmental Protection Agency is overestimating the amount of fuel that can be produced from grasses, wood and other nonfood plants in an effort to promote a fledgling biofuels industry.

At issue is a 2007 renewable fuels law that requires a certain amount of those types of fuels, called cellulosic biofuels, to be mixed in with gasoline each year. Despite annual EPA projections that the industry would produce small amounts of the biofuels, none of that production materialized.

There have been high hopes in Washington that the cellulosic industry would take off as farmers, food manufacturers and others blamed the skyrocketing production of corn ethanol fuel for higher food prices. Those groups said the diversion of corn crops for fuel production raised prices for animal feed and eventually for consumers at the grocery store. Lawmakers hoped that nonfood sources like switchgrass or corn husks could be used instead, though the industry hadn't yet gotten off the ground.

The 2007 law mandated that billions of gallons of annual production of corn ethanol be mixed with gasoline, eventually transitioning those annual requirements to include more of the nonfood, cellulosic materials to produce the biofuels. As criticism of ethanol has increased, lawmakers and even Presidents George W. Bush and Barack Obama have talked of the cellulosic materials as the future of biofuels.