Cellulosic ethanol falls short
For two years, now, the EPA has given fuel blenders a waiver from using the cellulosic ethanol mandated by the Energy Independence and Security Act of 2007. That’s because, except for small amounts from experimental plants, there isn’t any.
This week a report for the National Academy of Sciences predicts that the mandate for using 16 billion gallons of cellulosic ethanol by 2022 will likely fail. Among the reasons: short of a big breakthrough, it will cost more to make than corn-based ethanol. And there’s a big gap between the prices farmers want for feedstocks like corn stover or switchgrass, and how much plants will pay.
"We have more than 200 corn ethanol plants producing more than 14 billion gallons of ethanol today. It took 30 years to get there. We have 11 years to reach even higher numbers for cellulosic biofuels," said Wally Tyner, a Purdue University agricultural economist who co-chaired the committee that made the report. "We would need a build rate three times that of corn ethanol.”
The 2007 energy law’s renewable fuel standard doesn’t give investors much confidence, Tyner told Agriculture.com, since EPA’s power to grant waivers adds uncertainty.
“Overlay on top of that, the current financial crisis,” and investment in cellulosic ethanol likely will remain inadequate to meet the 2022 deadline, Tyner said.
Congress requested the report, Renewable Fuel Standard: Potential Economic and Environmental Effects of U.S.Biofuel Policy. The 650-page report cites hundreds of scholarly papers on the subject, all reviewed by peers of experts.
“Here’s what we know and here’s what we don’t know,” said Tyner.
Some, including the Environmental Working Group, have used the report to attack biofuels.
"This report highlights the severe damage to the environment from corn-based ethanol," said Sheila Karpf, EWG's legislative and policy analyst. "It underscores just how misguided and U.S. biofuels policy has become. It catalogs the environmentally damaging aspects of corn-based ethanol and also casts serious doubt on the future viability of so-called 'advanced' biofuels made from other sources."
Tyner called that statement “cleverly worded.”
The EWG statement lumps together the report’s findings that corn ethanol can pose environmental disadvantages—although much depends on where and how the corn is grown. But the doubts about the viability of advanced biofuels like cellulosic ethanol are more economic than environmental.
Anyone who digs deeper into the report will see that there are really three sources of ethanol:
The first, ethanol made from corn starch, has questionable environmental effects due to indirect land use changes. The theory behind indirect land use is based on the fact that if forests or savannahs are cleared anywhere in the world to grow corn to make up for ethanol demand, cutting the forests or plowing the grasses puts more carbon dioxide into the atmosphere than is saved from using ethanol.
The effects of indirect land use have turned out to be much smaller than environmentalists first proposed. The EPA has found that corn ethanol meets the required 20% reduction in greenhouse gases over gasoline in order to be part of the renewable fuel standard mandate.
Tyner has calculated indirect land use for the California Air Resources Board.
“I’m the first person to tell you that it’s uncertain, but that doesn’t mean it’s zero,” he says.
A second source of biomass for cellulosic ethanol is corn stover, wheat straw and forest residue, Tyner said.
That does have clear environmental benefits from reducing greenhouse gas emissions, Tyner said.
“There are unquestionable greenhouse gas gain from residues,” he said.
A third source for ethanol, dedicated crops like switchgrass, is less certain, he said. They will likely capture carbon in the soil and residue, but there could be land use changes as pastures for livestock are converted to feedstocks for cellulosic ethanol production.
Even the National Academies press release on the report doesn’t make the distinction between crop and forest residues and dedicated energy crops, Tyner said.
“That summary of something that complex was unfortunate,” he said.
Tyner isn’t taking sides between the interest groups that are pulling out the parts of the report they agree with.
“The way I look at this. Our job is to lay out [the facts] as best we can,” he said.
Nor does the report say the nation shouldn’t pursue its policy of ramping up biofuel production. Cellulosic ethanol production likely will require subsidies, since oil prices will have to be above $120 a barrel for the new biofuel to be competitive.
“We have not tried to say don’t do cellulosic biofuels,” Tyner said. “We’re saying understand what it’s going to take.”