FROM ONE OF MY COLLEAGUES AT U.T., A LOOK AT NON-CORN-BASED ETHANOL:

Biomass can also be derived from residue left behind after forest products have been harvested or from the elements of corn left in the field to rot after the grain has been harvested. Cellulosic ethanol comes from the part of the corn plant not used for food.

So, in addition to corn grain-based ethanol, Tennessee has an array of potential new energy sources from biomass – cellulosic ethanol. This expands ethanol’s potential availability well beyond corn grain, which greatly expands our alternative fuel options – and in no way competes with any utilization of corn.

A unit of corn ethanol, made from grain, yields about 40 percent more energy than it takes to produce that unit, according to the National Renewable Energy Laboratory.

A unit of cellulosic ethanol yields more than 500 percent of the energy that goes into producing it. In contrast, gasoline made from petroleum returns 20 percent less energy than it takes to produce it.

That’s why cellulosic ethanol is the future of energy.

Since cellulosic ethanol can already be made in the lab, the next challenge is to make it at the commercial scale.

The only political downside is that this isn’t likely to win the kind of enthusiastic support from corn farmers that corn-based ethanol enjoys. But it seems to me that ethanol from waste biomass is a lot better than ethanol that’s made from . . . food.

UPDATE: The prospect of making fuel from waste biomass inspires reader Brian Cubbison to utter a single magic word: “Kudzu.”

Watch out, Saudis!