The Sustainable Energy Myth Called Ethanol
By EV World
"We have too many people for the resources that are available to us," began Cornell professor Dr. David Pimentel, confronting the 800 pound gorilla in the room that few are willing to acknowledge when the topic turns to energy and the environment.
This is classic Pimentel, a willingness to say -- and write -- bluntly about often unspoken truth, frequently in the face of strong opposition, especially when it comes to the high stakes game of agriculture and energy. While it may be politically correct to endorse the use of agricultural commodities -- usually corn -- to produce ethanol in America, Pimentel argues that it is economically and environmentally unsound.
"In case you didn't know it, we have 6.5 billion people on Earth today, and we add a quarter of a million… a quarter of a million daily to our problem. And the World Health Organization reports that we have 3.7 billion people who are malnourished today. This is the largest number ever in the history of the Earth…
"And we in the United States have an abundance of food types and our main problem is we eat too much. Two thousand, two hundred pounds of food per person per year, and we should be eating about a third that quantity."
He pointed out to the audience at the 2006 Sustainable Energy Forum conference on Peak Oil and the Environment that 99 percent of all that food comes from the land and only 1 percent from the oceans, lakes, rivers and streams.
"And that 1 percent is decreasing yearly."
From his perspective the issue is the relatively inefficiency of plant photosynthesis that, on average, collect just one tenth of one percent of available solar energy. This contrasts with crystalline silicon photovoltaic panels that are two hundred times more efficient at converting photos to useable energy, in the case of PV around 20 percent.
"I am an agriculturist and I wish that biodiesel and ethanol… were going to save us, because it would be a benefit to agriculture… but I am a scientist first and an agriculturalist second."
Pimentel is convinced, based on his research that when all fourteen types of energy inputs are included in the production of biofuels -- especially ethanol from corn -- that there is a net energy loss, not a gain, however modest, as others contend. He sees ethanol production as "relatively energy intensive."
"It takes about 2,500 kilocalories of energy to produce roughly one liter of ethanol." He noted that energy is also needed to generate the stream required for the fermentation and distillation processes. He told the conference that if bioengineering could get yeast to take the fermentation process up to 90 percent that we'd have an economically viable renewable energy system, though he still has reservations because of the energy it takes to get to the 99.5 percent pure alcohol required to blend with gasoline.
Pimentel takes issue with his pro-ethanol colleagues on the grounds that they selectively omit the energy cost that goes into manufacturing the farm implements and processing equipment needed to make fuel-grade ethanol.
"The energy that goes into hybrid corn is omitted. Irrigation is omitted. Now only 15 percent of the corn is irrigated, but that 15 percent is a significant input in corn production. And the environmental impacts are omitted."
He charges that if he too included an energy credit for the distiller's dry grain that is left over from the ethanol process, that he could come up with a net energy benefit. He calculates that it takes 25,000 kilocalories to produce one gallon of ethanol with an energy equivalent of 19,400 kilocalories.
"Which means we have a minus energy return of 29 percent. It takes roughly 30 percent more energy to produce a gallon of ethanol than we actually get out in the ethanol fuel itself."
He told the audience that according to Energy Department figures, the industry produced 3.4 billion gallons of ethanol in the U.S. last year and that is "a lot of ethanol, but what they didn't include is the energy it took to produce that ethanol."
He points out that even assuming the 3.4 billion gallons is a net energy gain, it still represents less than one percent of the gasoline consumed on a daily basis in America.
"If we used 100 percent of U.S. corn grain and converted it into ethanol using DoE's optimistic numbers, it would provide us with less than 7 percent of our total vehicle fuel use. Is this making us oil independent?" he asked.
But the necessary energy inputs required to make ethanol is just part of the problem, Pimentel charges.
"It takes 1,700 gallons of water to produce one gallon of ethanol. Another way to look at that, a corn crop per acre during the growing season of just three months utilizes 500,000 gallons…. This is why agriculture uses 80 percent of all the water we pump."
On top of this is the nitrate pollution caused by the use of nitrogen fertilizer on corn, vast quantities of which leak into the water table or eventually flow into the Gulf of Mexico creating an enormous aquatic "dead zone" at the mouth of the Mississippi River.
"Corn causes more soil erosion than any other crop grown in the nation," he asserted. "Soil is being lost ten times faster than the soil formation rate. And if you harvest the (corn waste) stover, as some have suggested, that would increase soil erosion ten-fold. And instead of ten to fifteen tons of soil lost per hectare per year, this would mean we would be running a hundred to a hundred-and-fifty tons per hectare…"
Add to this the $3 billion a year in ethanol tax subsidies, which also impacts the cost of beef, pork and poultry. He charges that the beneficiaries of these subsidies are the large agribusiness corporations who earn $7 a bushel in direct tax benefits. This would double, he contends, if you include the environmental costs. Worse yet, when all the farmer's costs are factored in, the small, independent family farm is getting the equivalent of just 2 cents per bushel of corn.
"I am not for subsidies, but I would like to see the farmers get a larger share of this."
For Pimentel, no amount of biofuel exploitation is going to solve America's -- and much of the World's -- energy problems. He pointed to a graph demonstrating that U.S. residents are using twice the amount of fossil fuel energy as is produced by the sun falling on U.S. territory."
Pimentel is just a pessimistic about wood waste and switch grass, neither of which he contends are positive energy producers when compared to oil and gas.
He concluded by saying that he has been very careful about what he included in his numbers to arrive at his conclusion that biofuels simply aren't the panacea many are hoping they are.
You can listen to Dr. Pimentel's entire 18:42 minute presentation by using either of the two MP3 players in the right-hand column or by downloading to your computer hard drive for playback on your favorite MP3 device. EV World thanks the Sustainable Energy Forum for granting use permission to audio record this important event.