Study: More Efficient Ways To Burn Ethanol

Some U.S. companies currently convert corn and other crops into ethanol, which is burned in cars. But a new study shows that it would be more energy-wise and better for the environment to burn biomass in boilers and make electricity — then use the electricity to power cars.

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American companies now produce billions of gallons of ethanol from grain. It's used to supplement gasoline and reduce the need for foreign oil. But a new study suggests that a much more efficient way to use plant material for transportation would be to burn it to generate electricity, and use that power to charge electric cars. NPR's Richard Harris reports.

RICHARD HARRIS: In principle, it sounds great to grow fuel instead of importing it. But many scientists are worried about what that would do to our environment if the technology swept the globe.

Professor ELLIOTT CAMPBELL (University of California Merced): We're concerned with how much land we dedicate to transportation, to biofuels, because we also need our land for conservation as well as for producing food.

HARRIS: So Elliott Campbell, at the University of California-Merced, set out with some colleagues to answer a simple question: What's the best way to use green plants to power cars? They compared the current practice of converting biomass to ethanol with simply burning plant material, any plant material, in a boiler to generate electricity. That could then be used to charge electric vehicle batteries.

Prof. CAMPBELL: If you have a limited amount of land you're working with, and you want to squeeze the most transportation off that limited amount of land, then the electricity route would make the most sense.

HARRIS: In fact, it's not even close, according to the analysis which Science Magazine has just published online. Making electricity for vehicles is 80 percent more efficient. That conclusion comes as no surprise to Dan Kammen at UC Berkley, who has studied this topic extensively.

Professor DAN KAMMEN (UC Berkley): There are real benefits of not making liquid fuel at all.

HARRIS: That process takes a lot of energy, and internal combustion engines are very inefficient when they burn the fuel. Electricity is a much better option, he says.

Prof. KAMMEN: If your car is running electricity, you use an electric motor to drive the wheels. And that's very efficient.

HARRIS: There's still the issue of cost, though. Right now, electric cars are unattractive because they're so expensive, and that wouldn't change even if they were powered by biomass electricity.

Richard Harris, NPR News.

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