What Makes the Best Biodiesel?
Biodiesel is a form of fuel used to replace petroleum-based gasolines to power automobiles and other gas-powered devices. There is some debate about biodiesel because of the implications involved with sourcing it from corn and soybean crops, mainly regarding increased prices for the consumer for these common food items and the fact that they are carbon-positive sources. On the horizon, promising new alternative sources for biofuels are being investigated that may prove to be more practical than these traditional sources.
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History
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Funding for biofuel research first occurred in the late 1970s as a response to the steep rise in oil prices accompanying the Middle East oil crisis. Interest in biofuels backed down with gas prices in the early 1980s and '90s, but in 2005, when gas prices rocketed to almost five dollars a gallon, biodiesel popularity soared along with it.
Misconceptions
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When demand for biodiesel burgeoned, more and more of the traditional sources for the fuel--corn and soybeans--were diverted from the food industry into the fuel industry. The associated rise in the cost of soy and corn items like tortillas and soy milk was a direct, undesirable and highly publicized result. This led to a notion that biodiesel was not the right choice to replace gasoline because it was an unsustainable resource.
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Identification
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The use of corn and soy as the predominant source for biodiesel has also been criticized because they are carbon-positive sources. Carbon-positive means that more carbon is released to grow them and convert them into biofuels than is saved by using them instead of fossil fuels. Carbon is the primary greenhouse gas that scientists say is causing global warming.
Considerations
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In one study, prairie grass was shown to be a more efficient producer of biofuels than corn or soybeans, with the added advantage of being able to thrive in poorer soils. In research supported by the National Science Foundation and led by David Tillman, an ecologist at the University of Minnesota, it was shown that a mixture of native perennial grasses and flowering plants provided more usable energy per acre than corn or soybeans.
"Biofuels made from high-diversity mixtures of prairie plants can reduce global warming by removing carbon dioxide from the atmosphere. Even when grown on infertile soils, they can provide a substantial portion of global energy needs and leave fertile land for food production," Tillman said.
Benefits
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If the prairie lands don't pan out as the solution to our biodiesel needs, some believe the answer lies in the deep blue sea. Marine algae are known as the most efficient organisms for converting sunlight into natural biomass. The algae's energy potential comes from its production of lipid oils, or fat molecules. The lipids are turned into liquid in a relatively simple chemical process, and then in a few more simple steps you have biodisel from algae.
"Algae yields five to 10 times more bioenergy molecules per area, per time, than any terrestrial plant," said Greg Mitchell, a bioligist at the Scripps Institution at the Unversity of San Diego. "Nothing else comes close."
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