Fuels blended with ethanol and hybrid vehicles are two potential ways to alleviate the United States's dependence on imported fossil fuels, improve tail-pipe emissions and reduce greenhouse gasses. Ethanol-blended fuel and hybrid vehicles differ in terms of their overall impact on the environment and in their impact on the lives of poor people worldwide.
Benefits of Ethanol
In the United States, ethanol that is used for fuel is derived from corn through fermentation and is a renewable resource, unlike oil or other fossil fuels. Ethanol burns more cleanly than fossil fuels, because ethanol contains an oxygen atom, and ethanol contributes less to greenhouse gases. In addition, all vehicles can run on a 90:10 ethanol mix, and any ethanol burned reduces demand for gasoline.
Benefits of Hybrids
Hybrid vehicles, which combine gas-powered engines and electric motors, also reduce gasoline consumption and greenhouse gas emissions. Hybrid vehicles use rechargeable battery packs to power the electric motor, with recharging taking place during normal operation of the vehicle from regenerative braking and spare gas-powered energy. Hybrids can currently get up to 50 miles per gallon, substantially more than normal vehicles.
Downsides of Ethanol
Production of ethanol from corn is an energy intensive process---studies have shown that it takes more energy to grow the corn and process it into ethanol than the ethanol contains. In addition, ethanol cannot be transported in normal pipelines because it absorbs water; it must be shipped by barge, rail car or truck instead. Finally, wholesale diversion of corn to production of ethanol may distort the world grain markets, increasing the price of grain in developing countries and making people there worse off.
Downsides of Hybrids
One of the biggest environmental problems with hybrid vehicles is the disposal/potential recycling of the battery pack once it has reached the end of its useful life. Hybrid batteries are currently based on nickel metal hydride technology. Nickel, while not as toxic as the lead in lead-acid batteries, is still a heavy metal. Lithium ion batteries are more environmentally friendly, but they are also more expensive and the technology is not as advanced as yet.
References
- Sierra Club: Ask Mr. Green,Prius Versus Hummer: A Nickel for Your Thoughts
- "Slate"; Corn Dog: The ethanol subsidy is worse than you can imagine; Robert Bryce; July 19, 2005
- "Technology Review"; Ethanol's Forecast: Rain and floods in the corn-growing Midwest could drive up the costs of producing the biofuel; Kevin Bullis; June 12, 2008
- U.S. Department of Energy: 2010 Most and Least Fuel Efficient Vehicles
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