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Using more biofuels
Congress recently required refiners to replace 36 billion gallons of gasoline with biofuels by the year 2022. Currently the nation uses about 140 billion gallons of gas a year, with ethanol comprising about 9 billion gallons of that. Half of the 36 billion gallons are required to come from non-food crops like switch grass. Many want to see even higher rates of biofuels use.

They say displacing oil with domestically grown plants will offset over a million barrels of oil a day, and that's just under the current law. They also say biofuels emit far fewer greenhouse gasses than oil when the plant-growing process is taken into account.

But critics say biofuels are partly responsible for the surge in food prices, groundwater depletion and pollution, and pressure on topsoil. They also say it's perverse to put food in gas tanks when people are starving.

NEXT: Tapping the Strategic Petroleum Reserve

Last updated September 25 2008: 3:43 PM ET
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