:: Alternative Energy
:: Biofuels
| Biofuels are, in short, fuels made from anything that can be grown. As long as we can grow more plants and harvest them to make fuel, biofuels come from renewable resources. With America's agricultural capacity, and the ease with which the current energy and transportation systems in the United States could be converted, biofuels seem like a promising solution to the oil problem. However, resources once devoted to producing food are now being diverted to producing fuel, leading to concern that the rise of biofuels is contributing to the global rise in food prices. |
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The environmental theory behind the use of biofuels is that they exist on a short-term carbon cycle. Plants take in CO2 from the atmosphere to grow, then their carbon structures are burned to release energy. By burning the organic matter, carbon is released back into the atmosphere. This carbon is then absorbed by other plants, closing the loop. Petroleum based fuels pull carbon out of the ground and release it into the atmosphere, making more of a line. Biofuels can be divided into three types: - Ethanol--Fuels derived from plant sugars - Biodiesel and Vegetable Oil--Fuels composed of fats and oils - Biomass--Unprocessed plants The future of biofuels depends largely on new technology. Research in how to produce cellulosic ethanol (ethanol from waste biomass, i.e.: cornstalks) shows promise to separate the food and fuel markets. Another development in the production of biodiesel is extracting oil from algae. Algae produces a high amount of energy in the form of oil per energy input so if large-scale algae farms can be created without covering too many lakes and wetlands, it is a promising source of fuel. Ethanol Ethanol, or ethyl alcohol, is made by fermenting plant sugars and distilling the alcohol. Normally, ethanol intended for use as fuel is produced from corn, wheat and barley. Ethanol is frequently blended with petroleum-based gasoline to lower emissions and increase engine performance. Vehicles manufactured since 1970 should have no problem with a 10% ethanol blend (E10). Recently, car manufacturers have been producing “flexfuel” vehicles, which they market as guaranteed to handle up to 85% ethanol fuel blends (E85). The increased use of ethanol is thought to have contributed to a worldwide increase in food prices. An alternative to food-based ethanol is cellulosic ethanol, a process still in development that would extract sugars from organic matter (i.e.: corn stalks, wood processing waste, switchgrasss). Cellulosic ethanol has been produced in labs, but nobody has yet figured out how to mass-produce it in a cost effective manner. Biodiesel is derived not from the sugars in plants, but from the oils. In fact, diesel engines were first invented to run on peanut and other plant oils that were abundant before the discovery of petroleum. Biodiesel is produced by reacting vegetable oil with an alcohol (usually methanol) and a catalyst. This process lowers the viscosity of pure vegetable oil to that of petro-diesel. A similar reaction can make biodiesel from the animal fats leftover from meat processing. Especially in Europe, biodiesel is now being used as an additive to regular diesel in order to meet environmental standards. Like ethanol, the amount of biodiesel in a fuel blend is noted by the letter B then the percent of the fuel that is in the mix, so pure biodiesel is B100 and a 10% mix is B10. Waste Vegetable Oil is what runs our bus. Pure vegetable oil is purchased by restaurants to fry things like french fries in. After they use it, it usually goes in a dumpster behind the restaurant where, with permission from the owner, it may be collected for free. Using waste vegetable oil as fuel is one way to recycle the grease (other uses for waste vegetable oil include dog food and cosmetics). In order to use WVO as a fuel, the bits of food must be filtered out, then the oil is heated (usually by the coolant in the engine) in order to be less viscous. WVO conversion kits are available to convert the fuel systems of diesel engines to run WVO. As the use of biodiesel and WVO conversions on diesel cars, trucks and busses become more popular, restaurants have started selling their waste vegetable oil; what was once a waste product is now a commodity. In some parts of the country, cities, companies or cooperatives have contracts with local businesses to collect their waste grease and use it to produce fuel. Filtered vegetable oil can be used as the feedstock for biodiesel as well as a fuel on its own. The last form of biofuel is biomass. Biomass is any type of plant matter that is used to make electricity, heat or to power a machine. Putting a log on a fire is a form of using biomass as fuel. This can be done on a larger scale by burning farm waste to make electricity. Biomass is not a likely solution for transportation, as the energy-per-unit-volume of most plants is too low to be practical. | |