While amber waves of corn might typify ethanol in the American mind, this is far from the earliest biofuel. Thousands of years old, yet often overlooked in current discussion, is traditional biofuel, such as fuelwood, still used in much of the world. The United Nations estimates that 2.4 billion people "rely on straw, dung, and other traditional biomass fuels to meet their energy needs" (4), a use it describes as "inefficient direct combustion" (2). Furthermore, this energy can lead to health problems, such as smoke inhalation, particularly often harming women (UN 20). The movement away from traditional biofuels, then, should be encouraged, provided they can be replaced with clean, contemporary energy.
Another important part of the biofuel picture is soy, used to make biodiesel. Indeed, biodiesel might prove to a more long-lived and efficient ethanol source than corn. A 2006 study finds "that corn-based ethanol provides a 12.4 percent reduction in GHG (compared with gasoline), and soy biodiesel provides a 40.5 percent reduction (compared with diesel)." (Tyner). Again, basic infrastructure, including engine types, will help determine the future of biodiesel.
An even more intriguing source of biodiesel is industrial, commercial, and consumer waste, such as animal manure and vegetable oil from restaurants. For instance, "with just a few modifications, any diesel vehicle can be converted to run on vegetable oil." This is particularly appealing, since "restaurants produce about 100 million gallons of waste oil each year, a tiny fraction of all the energy consumed in our cars" (Boyd). This elegant reuse of materials has a strong environmental appeal. However it is difficult or impossible to produce waste biodiesel on the kind of mass scale needed to supply more than a small part of our energy needs.
Perhaps the most underreported biofuel success is the tropical plant Jatropha, which, according to one source, can "produce a barrel of biofuel for about $43, compared to a barrel of sugarcane-based ethanol for $45, corn-based ethanol for $83, soy-based biodiesel for $122, and cellulosic-based ethanol for $305" (Boyd). Jatropha "can be cultivated on substandard land and help restore eroded areas, effectively generating clean energy while helping to reduce carbon dioxide emissions and revitalise local ecosystems" (UN 8). Mali is currently a center for experimentation with this innovative fuel. Again, local conditions and politics will determine just how much Jatropha will become a source of biofuels.
Go To Cellulose: Break It Down
List of Visuals
- Women in Malawi Gather Fuelwood
Photo by Anthony Njenga
World Agroforestry Centre