Move over, corn--last week saw the groundbreaking of the U.S.'s first commercial cellulosic ethanol plant, which will use wood scraps to produce the fossil fuel alternative. Range Fuels' plant, located in Georgia, is expected to produce 20 million gallons of ethanol per year by 2009, every drop of which will be made from leftover wood waste.
Wood is a feedstock there should be no shortage of, since the area's surrounding timber industry disposes of about a quarter of each tree processed. The conversion to fuel involves mixing waste products--not only wood but leaves, bark, and pine cones--with steam, chemically transforming them into a gas known as "syngas." Syngas can then be refined into a liquid and made into ethanol and methanol. The complexity and expense of this refinement process are great in comparison to other biofuels (see figure), and until now these factors have limited cellulosic ethanol to the laboratory. Therefore, many are closely watching Range Fuels as a test of whether such plants can be commercially successful in the U.S.
Cost Ranges for Ethanol and Gasoline Production, 2006
Reproduced from WorldWatch, 2006. Biofuels for Transportation
Recycled, cheap and renewable
Alongside forestry waste, agricultural and municipal wastes are potential candidates for recycling into biofuels. But even when the feedstock isn't otherwise-waste like wood chips, cellulosic ethanol production is more environmentally friendly than production of corn ethanol, the primary biofuel in the U.S. today. This is because unlike corn ethanol, which is made by fermenting just the plant's sugars, cellulosic ethanol is made from the whole plant, a greater productivity that could potentially double ethanol production per acre of corn.
Cellulosic ethanol can be produced from cheap and renewable feedstocks, including wheat straw, corn stover, and grass. And unlike corn, crops such as switchgrass can be grown on degraded lands not suitable for food production, which could potentially defuse the escalating competition between food supply and biofuel production in countries around the world.
Reducing emissions and gasoline dependence
Cellulosic ethanol requires less fossil fuel energy for processing, which means it contains more net energy than corn-based ethanol and also produces less greenhouse gases. The energy required to generate one gallon of corn-based ethanol is equal to about 60-75 percent of the energy produced; by contrast, fuel produced at the new Georgia plant is predicted to consume only about 10 percent of its total. As a result, cellulosic ethanol will have 65-110 percent lower greenhouse gas emissions than gasoline.
Eventually, Range Fuels plans to produce 100 million gallons of ethanol annually at the Georgia plant--which is merely a drop in the barrel for a nation that consumes 388.6 million gallons of gasoline every day. However, Range Fuels estimates that in Georgia alone, enough waste wood is available to make two billion gallons of ethanol a year, or about 1.5 percent of the U.S. annual gasoline demand, and other cellulosic ethanol plants are in the works across the U.S. With the momentum in favor of cellulosic ethanol, the future looks bright.
RELATED LINKS
NY Times: "Fuel Without the Fossil" (11/9/07)
Worldwatch: 'Biofuels for Transportation'
BBC News: Forests cleared in Indonesia for palm oil biofuel production
EarthTrends
Monthly Update: Global Biofuel Trends
Data: Biogas and liquid biomass consumption by country
Top photo by papalars on Flickr
