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Summer 2007               Fueling Our Future

Cellulosic Ethanol
Ranking: Yellow

Great at emissions reduction, but powerful agri-corporations could keep the focus on not-so-great corn ethanol.  For more immediate climate benefits, biodiesel is a better bet. 

What is it?:
Like corn ethanol, cellulosic ethanol is made by fermenting the sugars in plant matter. It is chemically identical to corn ethanol, but is derived from biomass—i.e. plant waste matter, like paper pulp and corn stalks—or fast-growing plants, like switchgrass. Whereas corn ethanol uses only the seed of the plant, cellulosic ethanol can be processed from the entire plan.


  • Cellulosic ethanol produced from plant waste (like corn stalks) and industrial waste (like paper pulp), uses matter that would otherwise be composted, burned, or landfilled. The US Departments of Energy and Agriculture estimate that forest and agricultural waste could provide 1 billion tons of biomass for cellulosic ethanol production each year, or enough to displace 30 percent or more of the nation’s current fuel usage.
  • Cellulosic ethanol takes far less energy to produce than corn, in part because a by-product of cellulosic breakdown (lignin), can be used as an energy source, and in part because it can be made from agricultural waste and crops that take less energy to grow than corn.
  • Because it is less energy-intensive to grow, cellulosic ethanol produces less greenhouse gases; Argonne National Lab estimates that ethanol from cellulosic biomass results in an 87 percent emissions reduction over gasoline. This benefit only improves when cellulosic ethanol is made from waste.
  • University of Minnesota scientists argue that cellulosic feedstocks could provide ecosystem benefits, because farmers could grow native grasses and plants that would benefit wildlife and soil, and reduce water use. Because such feedstocks could grow on less-fertile land, they would compete less for food land than corn ethanol. 
  • The National Resources Defense Council predicts that as cellulosic ethanol production becomes more efficient, the amount of ethanol made from each acre of biomass could more than double; however, this assumption is based on a heavy use of genetically modified plants.
  • As with other biofuels, an emphasis on converting acres of food into feedstock for fuels runs the risk of raising food prices in the US and abroad; any large-scale attempt to make cellulosic ethanol must focus on waste and native plants that can grow in infertile and desertified land.
  • Development is still in the research phase. Many fear that agribusiness giants like Archer Daniels Midland (ADM), which currently controls 40 percent of the corn ethanol market, will stand in the way of any real movement for cellulosic ethanol. The current corn ethanol infrastructure can’t switch over, because making ethanol from cellulosic feedstock requires a different process than making it from corn.
Current status:
Cellulosic ethanol is still in the research phase. Michael McElroy, professor of environmental studies at Harvard, wrote in Harvard Magazine that the benefits of cellulosic ethanol, “assuming they exist, surely lie a decade or more in the future.”

In his 2006 State of the Union address, President Bush set a goal of making cellulosic ethanol production cost-competitive by 2012, but the government continues to offer subsidies to growers and producers of corn ethanol. Doug Koplow of the International Institute for Sustainable Development estimates that total government support for corn ethanol comes to between $820 million and $1.4 billion per year.

There are currently only about 31 pilot and demonstration cellulosic plants either functioning or being built around the world, with 80 corn ethanol plants being added in 2007 alone to the hundreds that exist in the US.

“Changing course from corn ethanol as the ‘it’ fuel of the day to cellulosic is going to require a drastic shift in gears on the part of our politicians—a challenge if they’re easily swayed by the powerful corn lobby,” notes Alisa Gravitz, Green America’s executive director.

Should You Make the Switch?:
It’s not possible yet. Corn ethanol is the only type of ethanol that is currently available on the market—and it’s a terrible alternative to gasoline in terms of environmental impact and global warming mitigation.

If we do move forward with cellulosic ethanol, we need to first move away from corn ethanol and then ensure that we manufacture cellulosic ethanol from waste, not crops—and that we don’t use farm or forest land.

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plug-in electric hybridbiodieselgas-electric hybridcellulosic ethanolnatural gasultra-low-sulfur dieselhydrogen fuel cellsE85 corn ethanol

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