Last Updated Jan 5, 2010 1:32 PM EST
But although the law "grandfathers" in at least 15 billion gallons of corn ethanol, it was designed to favor more advanced and environmentally friendly cellulosic ethanol (made from the stalks of plants) and encourage the production of gasoline and diesel fuel from biomass. This sits uneasily with Midwestern corn ethanol producers hard-hit by high corn prices, and their comments fill up many pages on the federal docket.
Environmentalists have no love for corn ethanol because they say it has an ultimately negative impact in terms of greenhouse gas emissions. For instance, a letter mass mailed to the EPA by Sierra Club supporters urged the feds to require corn ethanol producers to reduce emissions by 20 percent "and provide a clear end-date for grandfathered conventional ethanol. Biofuels that are not part of the solution must be phased out."
But ethanol subsidies are a tried-and-true way of delivering Midwestern votes. "Both parties got into a bidding war for the farm vote," says Frank O'Donnell of the Washington-based Clean Air Watch. "It started with the Republicans in 2005 and was ramped up by the Democrats in 2007."
The law ratchets up the amount of renewable fuels that can replace gasoline, but it also mandates that the program meet targets for reducing greenhouse gas emissions. And to do that required some tricky accounting. Part of the debate, environmentalists say, is whether you include indirect emissions (from, say, using farm machinery to plow up land) as part of the greenhouse calculations.
The government claims that its renewable fuel rule will replace 15 billion gallons of petroleum-based gasoline and diesel, and save 6.8 billion tons of carbon dioxide-equivalent greenhouse gas emissions in 2022. And it says that's comparable to taking 24 million vehicles off the road.
The EPA also took the rather novel approach of looking at greenhouse emissions of biofuels 100 years into the future, and thus ensuring a positive result. In the best case, using natural gas, corn ethanol can reduce emissions 39 percent, the draft lifecycle report says. Looking at just a 30-year horizon, corn ethanol can actually increase emissions five percent, the same study says.
"That's a silly accounting trick," O'Donnell said. "There's never been a rule that looks 100 years into the future, but corn ethanol looks better on that timeline."
The fact is that neither cellulosic ethanol nor gasoline from biomass (as greenhouse-positive as they may be) is yet ready for mass production, an inconvenient truth that the rulemaking process may not actually address.