01 February 2006

Biofuels (1)

For several years I've heard about the industrial process of converting crops into fuel. This is called biofuel, although from the first I've been highly skeptical of the technology. The reason is that agriculture is highly energy intensive, and after burning diesel fuel in order to grow crops such as maize [corn] or oilseed rape [saffola], the product has to be chemically processed into a chemical compatible with industrial applications. This processing, or "refining," of maize/oilseed into petroleum products likewise requires more energy inputs.

So what is the balance sheet? Are biofuel programs just a singularly perverse way of wasting tax dollars and petrol, in the name of pretending to be energy efficient?

At a lively comment thread on Daily Kos, an ardent supporter of biofuels offered a list of articles offering evidence. For your reading convenience, I'll list them here:

  1. "Estimating the Net Energy Balance of Corn Ethanol," by Shapouri, Duffield, & Graboski (1995); see also "The Energy Balance of Corn Ethanol: An Update" (PDF; 2002), same authors.
  2. "How Much Energy Does It Take to Make a Gallon of Ethanol?" Lorenz & Morris (1995)
  3. Others listed here

And as a counterpoint, here is David Pimentel's 1998 study on ethanol, "Energy & Dollar Costs of Ethanol Production with Corn" (PDF). Here's Prof. Pimentel's report:
The production of corn in the United States requires significant energy and dollar inputs. Indeed, growing corn is a major energy and dollar cost of producing ethanol ...For example, to produce an average of 120 bushels of corn per acre using conventional production technology requires more than 140 gallons of gasoline equivalents... The major energy inputs in U.S. corn production are oil, natural gas, and/or other high grade fuels. Fertilizer production and fuels for mechanization account for about two-thirds of these energy inputs for corn production...

Once corn is harvested, three additional energy expenditures contribute to the total costs in the conversion process. These include energy to transport the corn material to the ethanol plant, energy expended relating to capital equipment requirements for the plant, and energy expended in the plant operations for the fermentation and distillation processes...

The total energy input to produce one gallon of ethanol is 129,600 BTU. However, one gallon of ethanol has an energy value of only 76,000 BTU. Thus, a net energy loss of 53,600 BTU occurs for each gallon of ethanol produced. Put another way, about 71% more energy is required to produce a gallon of ethanol than the energy that is contained in a gallon of ethanol

If this is true, then the ethanol is not a competitor to gasoline and diesel; rather, the process of producing it, including such components as energy consumed in the production of agrichemicals, etc., is another demand for gasoline and diesel, or, weighted properly, coal, PNG, and hydroelectric. Additionally, ethanol is mainly used as a supplement to fuel; in several states it has been chosen as an oxidant to replace MTBE.

I could digress on ethanol versus MTBE, but I won't.

If my wife were writing this post, she would long ago have inveighed against inflicting a disastrous new scourge on the planet, in the form of tying up seven times as much land for supplying fuel, as is used now for supplying food. The amount of land required to sustain America's peculiar dietary habits, moreover, are vastly greater than those that for other national diets. That's because the US diet is dominated by meat. Beef requires about twenty pounds of grain per pound of food; so if a person replaces 11% (by weight) of her vegan diet with beef, she has doubled the land area required to feed her. Now, imagine if the US population has an energy "hiccough" when oil prices become prohibitive, then switches over to using its strong dollar to tie up the land of famine-stricken Africa for maize.

(Part 2)

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