In Bigger Pictures the selective use of factoids to support advocacy was noted and questioned since doing so misleads people and often results in mistaken views or bad policies. More.

Corn doesn’t grow like a weed. Modern corn farming involves heavy inputs of nitrogen fertilizer (made with natural gas), applications of herbicides and other chemicals (made mostly from oil), heavy machinery (which runs on diesel) and transportation (diesel again). Converting the corn into fuel requires still more energy. The ratio of how much energy is used to make ethanol versus how much it delivers is known as the energy balance, and calculating it is surprisingly complex.

The National Renewable Energy Laboratory states that, “Today, 1 Btu of fossil energy consumed in producing and delivering corn ethanol results in 1.3 Btu of usable energy in your fuel tank.” Even that modest payback may be overstated. Skeptics cite the research of Cornell University professor David Pimentel, who estimates that it takes approximately 1.3 gal. of oil to produce a single gallon of ethanol.

All of the costs are noted but not all of the benefits. As the price of maize grain rises due to demand for ethanol production so do other commodities. Corn stover - the leaves, stems and cobs - was once considered to be all but worthless. Some could be used as animal fodder, but only if there was no need to harvest and transport it since those costs would exceed the value of the stover. Not any more, even though the costs of transport have never been higher.

This is even more true for the byproducts of ethanol fermentation. The easily fermentable starches are gone, converted to ethanol, but the rest of the grain is intact. It has a higher percentage of protein than unfermented grain since none of it was taken out by the process, and so is worth even more than raw grain. Protein is always more expensive and valuable than starch.

Further down the chain, after the fermenters and the livestock have had a go at the grain and stover, most of the material is still there in the form of manure. It is also a valuable commodity which can be used to start the cycle again, replacing inputs that are otherwise purchased and sometimes (not always) made from fossil fuels.

Each step in this cycle can be more efficient, increasing yields at each step while reducing costs. The article understated just how complex the energy balance calculations are since it failed to consider the dynamics of an evolving technology. As a consequence an absurd conclusion was reached.

It would take 450 pounds of corn to yield enough ethanol to fill the tank of an SUV. Producing enough ethanol to replace America’s imported oil alone would require putting nearly 900 million acres under cultivation—or roughly 95 percent of the active farmland in the country. Once we’ve turned our farms into filling stations, where will the food come from?

It's a sure bet that it won't always take 450 pounds of corn to yield enough ethanol to fill the tank of an SUV. Even without alternative methods such as gasification that can produce ethanol from cellulose and many other carbon compounds (tires!) the yields are sure to rise while costs fall. As land becomes more scarce methods will improve. Inputs will be used more efficiently and crop yields will rise as the industry adapts to the requirements of an ethanol market. For example: fuel and fertilizers can be produced on site from manure and other ag wastes, leaving a durable carbon soil amendment that can reduce the need for more fertilizer while sequestering carbon in the soil.

That doesn't mean that ethanol is smart. There are much better uses for that biomass, and much better energy sources for transportation. But the arguments need to be sound in order to make good decisions. Not that they ever are, or that we ever make good decisions. Politics is never smart and does not value good arguments.

Never mind.