Republicans and Democrats alike have long pushed federal subsidies for "cellulosic ethanol" -- an alternative biofuel to corn ethanol, whose problems are now widely known.

But a new federally funded study finds that one important type of cellulosic ethanol actually results in more near-term greenhouse-gas emissions than gasoline does.

The Associated Press reports:

Biofuels made from the leftovers of harvested corn plants are worse than gasoline for global warming in the short term, a study shows, challenging the Obama administration's conclusions that they are a much cleaner oil alternative and will help combat climate change.

A $500,000 study paid for by the federal government and released Sunday in the peer-reviewed journal Nature Climate Change concludes that biofuels made with corn residue release 7 percent more greenhouse gases in the early years compared with conventional gasoline.

This corn-residue ethanol is the hope of a couple of big projects by the biofuel industry, namely industry leader POET, and DuPont.

This study could undermine POET's and DuPont's ability to get federal subsidies for their corn-residue ethanol, the AP story explains:

Cellulosic biofuels that don't meet that threshold could be almost impossible to make and sell. Producers wouldn't earn the $1 per gallon subsidy they need to make these expensive fuels and still make a profit. Refiners would shun the fuels because they wouldn't meet their legal obligation to use minimum amounts of next-generation biofuels.

The best-laid plans of environmentalists, corporate lobbyists, and central planners often go awry.