Last Updated Feb 10, 2009 5:49 PM EST
Professor David Pimental is a leading critic of corn-based ethanol
, claiming that to power just one automobile for a year requires 11 acres of farmland--enough space to feed a family of seven for that same 12 months. He also claims that corn ethanol is energy negative, producing fuel at a net loss.
Pimentel has his critics (it all depends on how you measure the energy going into production) but most scientists agree that the real promise lies with the cellulosic form of ethanol, produced from the stalks and stems of plants.
Cellulosic ethanol is still in the experimental stage, but its use as a motor fuel got a big boost this week from General Motors
and Sandia National Laboratories
, which released a new report
entitled "Growing Green Energy: The 90 Billion Gallons Study."
According to Bob Carling
, director of Sandia's Transportation Energy Center
, investing in the infrastructure to produce 90 billion gallons of cellulosic ethanol (the energy equivalent of 60 billion gallons of gasoline, a third of estimated annual U.S. use by 2030) would not require sacrificing any land currently used to produce food crops.
Carling also said the cost would be approximately the same as investing in new oil development. And, he added that, although ethanol is too corrosive for current pipelines, we have the rail car capacity to move it around the country.
General Motors' Lawrence Burns, vice president for research and development, is best known for his championing of hydrogen and fuel cells at the big automaker, but they got barely a mention as he talked about being "excited" at the possibilities presented by biofuels. "Domestically based non-food biofuels may be the best way to offset our supplies of imported oil. It's the right thing for our nation right now, and the most promising opportunity to do something quickly."
GM has already built 3.5 million flexible-fuel vehicles; Burns says half the company's production will be able to burn E85 ethanol by 2012.
Burns and Carling admit that their report assumes a certain amount of progress in producing cellulosic ethanol commercially. Today, cellulosic processes remain largely experimental.
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