Amid a U.S. ethanol boom, new research offers another take on the long-debated question of whether corn grain ethanol provides more energy than its production consumes. A recent study that takes into account all the energy used in farming and processing corn to make ethanol concludes that there is a small energy gain, but that the gain from using soybeans to make diesel is far greater--and that biodiesel is less of a greenhouse-gas polluter, too.

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