Substituting ethanol for petroleum – what could be wrong with that? A lot, it turns out, including a cynical “stealth tax” on drivers.

A few days ago the Environmental Protection Agency announced that soon gasoline can be made from 85 percent petroleum and 15 percent ethanol, up from a current limit of 10 percent ethanol. Such a move to replace imported petroleum with home-grown ethanol sounds great — until you examine the details.

Ethanol is the king of subsidies. Ethanol from genetically engineered dwarf trees or tall grasses holds tremendous promise as a cost-effective, greenhouse-neutral fuel. But for today, nearly all ethanol sold in the United States is made from corn. Domestically produced corn-based ethanol is subsidized via federal payments to grain farmers, by refinery tax exemptions for fuel containing domestic ethanol, and by tariff barriers intended to prevent Brazilian sugar-based ethanol from entering the country. Annual federal subsidies to corn ethanol cost around $5 billion. Are the benefits worth that?

Corn ethanol may not save petroleum. There’s a dispute, but some research suggests corn-based ethanol is a net loser in energy terms — more petroleum goes into production of the corn than the energy value in the ethanol. Indisputably, raising corn to burn as ethanol depletes topsoil. Topsoil may be a more important resource than petroleum, given there are vast reserves of oil and alternatives being developed, while with current science, topsoil is irreplaceable. We’ve got to deplete topsoil to eat. We don’t need to deplete topsoil for fuel: topsoil should be allocated to its highest use, food production.

Corn ethanol may not be good for the environment. If ethanol occurred by magic, then replacing fossil fuel with corn ethanol would reduce greenhouse gas emissions. But ethanol calculations should take into account the greenhouse gases associated with corn production, especially carbon released by changes in land use. Last year, the EPA concluded that corn ethanol production would be worse overall for the environment than petroleum refining http://www.epa.gov/otaq/renewablefuels/420f09024.htm. The ethanol lobby howled, and the EPA “reworked” its ethanol data to reach the desired PC outcome. In politics, “sound science” is whatever supports your predetermined conclusions.