Mow Your Gas: The Ethanol of the Future
Landscaping and yard care of the future will mean turning your grass into gas.
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The newest ethanol technologies, often lumped under the name cellulosic ethanol, can make that thought a reality.
According to statistics from the Environmental Protection Agency, Office of Transportation and Air Quality, in 2006, corn based ethanol accounted for well over ninety percent of ethanol production in the United States. Distilling ethanol from corn follows some basic procedures common to all alcohol production. Corn is milled into starch, and enzymes are added to convert corn starch to sugar. Adding yeast to the mixture promotes its fermentation into an alcohol called ethanol.
All plants, including grass clipping, contain starch. They also contain other materials such as lignin, the fibrous part of the plant. The challenge facing ethanol producers is to separate those materials efficiently in order to convert any part of a plant, not just the seed, into ethanol. Researchers have adopted two different approaches for accomplishing that task, hydrolysis, a chemical process which breaks down plants into their constituent parts, and combustion, a thermal process that turns plants into liquids or gasses.
In February 2007, the United States Department of Energy (DOE) awarded funding to six different biomass technology companies to begin construction of commercial cellulosic ethanol demonstration plants.
Four of the companies will use hydrolysis and fermentation. Each will use a different combination feedstocks, including grass clippings. POET, a company in Sioux Falls, SD will use a hydrolysis technology to convert corn cobs into ethanol. The technology compliments their already established corn based ethanol business.
Two of the companies will use a thermal gasification process. Range Fuels of Broomfield, CO., provides an interactive diagram explaining their gasification technology. Their plant will use wood biomass as its stock.
These demonstration plants are indented to determine how well the technologies scale up for mass production of ethanol. They can also be studied for how well the technology scales down, making it a profitable home based business for enterprising individuals.
How much gas you can grow in you back yard depends partly on technology and partly on the type of grass your grow. Researchers at Auburn University, for example, studied switchgrass, not your ordinary yard grass. Their study concluded that "Test plots of switchgrass at Auburn University have produced up to 15 tons of dry biomass per acre, and five-year yields average 11.5 tons, enough to make 1,150 gallons of ethanol per acre each year."
Since the average driver uses less than one thousand gallons of gas per year, the numbers suggest that small scale ethanol distillers might soon stand next to every back yard barbecue in the United States.
© 2007 Patricia A. Michaels