Corn lobby's tall tale of a gas substitute

America is swooning over ethanol, the renewable fuel which, in the US, is derived from corn. President Bush predicts ethanol will replace gasoline. Congress has mandated nearly doubling its production. But so far, ethanol is more politics than promise.

Over the next five years, $5.7 billion in federal tax credits will support the ethanol market - a boon to Midwest corn growers who are certainly no hayseeds when it comes to lobbying members of Congress.

But just what do US taxpayers get in return for these silo-sized subsidies? A renewable biofuel that reduces greenhouse-gas emissions, yes, and a safe substitute for dangerous gasoline additives. Overall, though, the net energy gain from corn-based ethanol is modest, and there are serious issues to consider in making it widely available at America's gas stations. Currently, it accounts for just 3 percent of the nation's fuel.

Supporters of corn-based ethanol promote it as one way to cure America's fossil-fuel addiction. That's an exaggeration as high as an elephant's eye. The libertarian Cato Institute says it takes the equivalent of seven barrels of oil to produce eight barrels of corn-derived ethanol. Argonne National Laboratory, which studies ethanol for the Department of Energy, is more generous: for each unit of energy to grow, process, and transport corn ethanol, it yields 1.35 units of energy.

True, this high-octane fuel gives engines a kick, but it gets significantly lower miles per gallon, necessitating more frequent fill-ups. Ethanol's also more expensive than gasoline, and, as a blend, contributes to its high price.

Other downsides: Corn ethanol does reduce atmosphere-warming carbon emissions, but environmental organizations such as the Sierra Club say it actually is worse than gasoline in making smog. Meanwhile, builders of the nearly 200 ethanol manufacturing facilities under construction or planned are being tempted to power their facilities with coal. That's because it's less expensive than their current choice, natural gas. Coal power would wipe out or reduce the greenhouse gains of ethanol.

However, there is a better way. Fly on down to Rio for a look at the world's leader in sugar-cane ethanol. Brazil's widely consumed ethanol is almost eight times more fossil energy efficient to produce than the US corn-based stuff. Its ethanol manufacturing is powered not by fossil fuels, but by cane-stalk residue. The downside is huge acreage demand (no small consideration if the US greatly ramps up production).

The sugar cane that grows so easily in the tropics may not be America's answer, but common agriculture and forestry products that contain highly energy-efficient cellulose could be. Prairie switch grass touted by President Bush is just one of many possibilities, although years away.

Yet the US continues to focus almost exclusively on domestic corn ethanol, for instance shutting out imports through high tariffs. This keeps US ethanol prices high and protects the industry from competition with more energy efficient varieties. Arizona Republican Congressman John Shadegg is rightly bucking the US ethanol lobby by proposing a temporary suspension of these tariffs.

Ethanol holds promise for the US, but not unless corn-based politicaldistortions are distilled out of it.