By John Trotti

We know about air quality issues and the joined-at-the-hip relationship of energy and water, but what, you ask, does dirt have to do with energy?

Nothing.

That is until some enlightened souls decided the way to save the planet was to provide incentives to convert biomass into ethanol, thus reducing our dependence on fossil fuel. Not a bad idea on the face of it, particularly if you’re talking about converting organic wastes whose handling costs have been absorbed by existing waste management activities.

But enter the US Department of Agriculture with buckets full of tax dollars for its agribusiness buddies under the guise of saving the planet, and I’ve got some serious concerns.

The benefits? There are none. I mean zero/zip with the possible exception of the pocketbooks of the agribusiness folks. Instead of increasing our energy resources, the corn-huckstering business is an energy sink, not only in terms of Btus-out versus Btus-in, but in a whole host of energy-related markers, most of which have to do with economic dislocations.

In their study on the energy input/yield ratios from various biomass feedstocks (corn, switchgrass, and wood for ethanol; soybean and sunflower plants for biodiesel) David Pimentel, professor of ecology and agriculture at Cornell, and Tad W. Patzek, professor of civil and environmental engineering at Berkeley, concluded there was “... no energy benefit for using plant biomass for liquid fuel.” [The report is published in Natural Resources Research (Vol. 14:1, 65-76)].

Comparing energy output with energy input for ethanol production, the study found that: corn requires 29%, switchgrass 45%, and wood biomass 57% more fossil energy than the fuel produced; while for biodiesel production, soybean plants require 27% and sunflower plants 118% more fossil energy than their biodiesel derivative.

While something in the neighborhood of 20% of the nation’s corn crop was used to produce ethanol in 2006, corn-based ethanol supplanted less than 4% of the gasoline supply (less than 3% of the energy contribution).

Okay, so energy’s sort of a bust … how does the environment fare?

Greenhouse gases—Conventional wisdom holds that the carbon dioxide absorbed by the corn should balance the carbon dioxide released from ethanol’s conversion to work. Nice idea, except that fossil fuels come into play in virtually every step of the production cycle. Moreover, the nitrogen found in fertilizers often yields nitrous oxide, which as a greenhouse gas is 300 times more potent than carbon dioxide.

Water use—It takes roughly 4 gallons of water to produce 1 gallon of ethanol, a number that grows dramatically where irrigation is required. The water impact is compounded by its degradation by soil erosion and fertilizer and pesticide use.

Fertilizer use—Nitrogen fertilizer use is associated with increased global warming gasses and its runoff causes “dead” areas in the sea. Nitrogen fertilizer is made from natural gas, which is in declining supply in the US.

Soil erosion—The vast majority of US cropland—estimates point to around 90%—is losing soil amounting to more than tenfold the sustainable rate. A case in point is the state of Iowa, whose topsoil loss is 30 times the rate of its formation. In the 150 years since plows first broke the plains, Iowa has lost half its topsoil, and the rate of loss shows no sign of slackening.

Even as we struggle with finding sustainable means of increasing energy resources to meet increasing worldwide demands, I think we all hold some level of confidence that science, ingenuity, and investment will rise to the challenge. Ditto the maintenance of our precious air and water resources.

But dirt is another matter. Unlike air and water, topsoil is not a renewable. When it’s gone, in human terms it’s really gone. When you consider that only one-seventh of the Earth’s surface is landmass, that of this, perhaps 60% is presently arable, and that lousy stewardship on our part is carving swathes from this at an accelerating rate, you’ll see that the bottom line really is the dirt beneath our feet, and that senseless, politically motivated, feel-good practices cannot be tolerated.

Some suggested reading:

Congressional Research Service Report for Congress, “Ethanol and Biofuels: Agriculture, Infrastructure and Market Restraints Related to Expanded Production” [http://collinpeterson.house.gov/PDF/ethanol.pdf]

Supply Impacts of an MTBE Ban, US Energy Information Agency;

Refining 101: Summer Gasoline, Robert Rapier on TheOilDrum.com.

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DE - November/December 2007