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.
Energy in, energy out
Farming and processing corn grain to make ethanol yields about 25 percent more energy–in ethanol and coproducts such as animal feed–than it consumes. In contrast, biodiesel and coproducts yield 93 percent more energy.
Producing and burning ethanol results in 12 percent less greenhouse-gas emission than producing and burning gasoline. Producing and burning biodiesel from soybeans offers a 41 percent reduction compared with regular diesel.