WASHINGTON -- Along with automakers, the Bush administration wants to end debate over whether ethanol made from corn yields more energy than does the fuel used to produce it.

The Energy Department's verdict: It does.

A new department brochure says that 740,000 British thermal units of fossil energy are consumed to make and deliver ethanol that contains 1 million Btu of energy. The latest version of the brochure, issued last month, is part of a broad department defense of ethanol.

The department cites an analysis by the Argonne National Laboratory, which identifies a big positive energy balance for corn ethanol. The calculation includes the natural gas, petroleum products, electricity and coal used to grow corn, distill it into alcohol and deliver ethanol. It does not count solar energy in the corn.

The analysis "has laid to rest some long-held misunderstandings about ethanol," the department says. Critics who call ethanol an energy loser don't account for the improving efficiency of ethanol plants or other benefits, the department adds.

When scientists perfect methods for making ethanol from plant debris — so-called cellulosic ethanol — the energy equation will look even better, the department says.

Critic unbowed

"Every argument they make is bogus," says Tad Patzek, one of the leading critics of ethanol, of the administration's defense. Patzek, a professor of chemical engineering at the University of California at Berkeley, vows to keep fighting ethanol.

Even if the administration's optimistic assumptions are granted, Patzek says, ethanol at best breaks even. That is, the energy derived from ethanol would be no greater than the energy used to make it, he says.

The technology to produce cellulosic ethanol is far from proven, Patzek adds. And it would threaten tropical ecosystems where plants would be harvested for ethanol.

Automakers build hundreds of thousands of vehicles each year that can run on E85. Those manufacturers — especially the Detroit 3 — want to see the debate ended in ethanol's favor. E85 consists of 85 percent ethanol and 15 percent gasoline.

Beth Lowery, General Motors' vice president of environment and energy, says she knows of at least a dozen major studies of the energy balance of ethanol. Nine of them find ethanol to be an energy winner, she says. The Argonne study is the most important, she adds.

The disagreements among the studies reflect researchers' assumptions, Lowery says. Some analysts who declare ethanol an energy loser count the energy used to make trucks that haul corn, she says.

They also don't account for the value of ethanol byproducts, such as cattle feed that remains after the fuel is made, she adds. And ethanol critics rarely consider the amount of energy needed to deliver a gallon of gasoline to a service station, Lowery says.

Other hurdles

Ethanol faces other big obstacles. The fuel requires heavy government tax breaks to be economically competitive with gasoline. Fewer than 900 of the nation's 170,000 filling stations sell E85.

Ethanol got a big boost this year when President Bush, a former oil man, touted it as a way to break the nation's "addiction to oil."

The Union of Concerned Scientists, an environmental group, says ethanol made from corn offers limited environmental benefits and limited potential for large-scale replacement of petroleum. But it is a key to the transition to cellulosic ethanol, the group says.

Michael ****, the Argonne analyst whose research model calculated ethanol's positive energy balance, believes the debate is overblown.

**** says about two-thirds of the energy used to make electricity is lost before the current reaches consumers.