Biofuels are broadly defined as fuels derived from plants or plant material. They are often thought better than fossil fuels, because as plants grow, they remove carbon dioxide from the air. When we burn them, we return carbon dioxide to the air, but the net effect can be close to zero.
Some biofuels, like firewood, are burned directly. Wood pellets are usually derived from debris that is left over during forest harvest, though they are occasionally produced from whole logs. Still another form of biofuel is ethanol, which is made by fermenting plants or plant wastes to produce liquid fuel. Ethanol has been criticized because it’s energy-intensive to create and, when made out of crops like corn, can cause food prices to rise.
In instituting policies to reduce carbon dioxide emissions, the European Union gives credit to those who generate electricity with wood pellets. This has created a growing production of wood pellets in the U.S., where they are shipped to Europe.
Wood pellet production has two unfortunate consequences: we don’t know whether pellets are derived from wood or wood wastes, and, if from wood, we don’t know if U.S. harvests are sustainable. When forests are cut faster than they can grow, carbon dioxide is released to the atmosphere, even with the use of biofuels. Adding to this is the fuel needed to ship the wood pellets abroad.
Biofuels will undoubtedly be an important part of our transition away from fossil fuels, but wood pellet production needs to be examined closely to assess its potential advantages.
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Photo, taken on July 26, 2012, courtesy of U.S. Department of Agriculture via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio. Support for Earth Wise comes from the Cary Institute of Ecosystem Studies in Millbrook, NY.