70 Percent More Energy Required to Make Ethanol than Actually is in Ethanol: Cornell

• By Roger Segelken
  Cornell Chronicle, March 6, 2009
  Straight to the Source
  
  

CU scientist terms corn-based ethanol 'subsidized food burning'

Neither increases in government subsidies to corn-based ethanol fuel nor hikes in the price of petroleum can overcome what one Cornell agricultural scientist calls a fundamental input-yield problem: It takes more energy to make ethanol from grain than the combustion of ethanol produces.

At a time when ethanol-gasoline mixtures (gasohol) are touted as the American answer to fossil fuel shortages by corn producers, food processors and some lawmakers, Cornell's David Pimentel takes a longer range view.

"Abusing our precious croplands to grow corn for an energy-inefficient process that yields low-grade automobile fuel amounts to unsustainable, subsidized food burning," said the Cornell professor in the College of Agriculture and Life Sciences. Pimentel, who chaired a U.S. Department of Energy panel that investigated the energetics, economics and environmental aspects of ethanol production several years ago, subsequently conducted a detailed analysis of the corn-to-car fuel process. His findings will be published next month in the forthcoming Encyclopedia of Physical Sciences and Technology.

Among his findings:

* An acre of U.S. corn yields about 7,110 pounds of corn for processing into 328 gallons of ethanol. But planting, growing and harvesting that much corn requires about 140 gallons of fossil fuels and costs $347 per acre, according to Pimentel's analysis. Thus, even before corn is converted to ethanol, the feedstock costs $1.05 per gallon of ethanol.

* The energy economics get worse at the processing plants, where the grain is crushed and fermented. As many as three distillation steps are needed to separate the 8 percent ethanol from the 92 percent water. Additional treatment and energy are required to produce the 99.8 percent pure ethanol for mixing with gasoline.

* Adding up the energy costs of corn production and its conversion to ethanol, 131,000 Btu are needed to make 1 gallon of ethanol. One gallon of ethanol has an energy value of only 77,000 Btu. "Put another way," Pimentel said, "about 70 percent more energy is required to produce ethanol than the energy that actually is in ethanol. Every time you make 1 gallon of ethanol, there is a net energy loss of 54,000 Btu."

* Ethanol from corn costs about $1.74 per gallon to produce, compared with about 95 cents to produce a gallon of gasoline. "That helps explain why fossil fuels -- not ethanol -- are used to produce ethanol," Pimentel said. "The growers and processors can't afford to burn ethanol to make ethanol. U.S. drivers couldn't afford it either, if it weren't for government subsidies to artificially lower the price."

* Most economic analyses of corn-to-ethanol production overlook the costs of environmental damages, which Pimentel says should add another 23 cents per gallon. "Corn production in the U.S. erodes soil about 12 times faster than the soil can be reformed, and irrigating corn mines groundwater 25 percent faster than the natural recharge rate of ground water. The environmental system in which corn is being produced is being rapidly degraded. Corn should not be considered a renewable resource for ethanol energy production, especially when human food is being converted into ethanol," Pimentel said.

* The approximately $1 billion a year in current federal and state subsidies (mainly to large corporations) for ethanol production are not the only costs to consumers, the Cornell scientist observes. Subsidized corn results in higher prices for meat, milk and eggs because about 70 percent of corn grain is fed to livestock and poultry in the United States. Increasing ethanol production would further inflate corn prices, Pimentel said, noting: "In addition to paying tax dollars for ethanol subsidies, consumers would be paying significantly higher food prices in the marketplace."

Nickels and dimes aside, some drivers still would rather see their cars fueled by farms in the Midwest than by oil wells in the Middle East, Pimentel acknowledges, so he calculated the amount of corn needed to power an automobile:

* The average U.S. automobile, traveling 10,000 miles a year on pure ethanol (not a gasoline-ethanol mix), would need about 852 gallons of the corn-based fuel. This would take 11 acres to grow, based on net ethanol production. This is the same amount of cropland required to feed seven Americans.

* If all the automobiles in the United States were fueled with 100 percent ethanol, a total of about 97 percent of U.S. land area would be needed to grow the corn feedstock. Corn would cover nearly the total land area of the United States.

THE TRUTH ABOUT SUGAR CANE ETHANOL

Here in Puerto Rico we already have entrepreneurs, academics, engineers and assorted techno-geeks promoting the local production of sugar cane ethanol. In this country we have so many cars and trucks that we would have to blanket the whole island from one end to the other with sugar cane monocultures in order to make a meaningful dent in our petroleum imports. Read this information:

David Pimentel of Cornell University and Tad Patzek of the University of California at Berkeley have tallied up the environmental impact of ethanol production in Brazil, and they argue it’s not a pretty picture. It takes 393 kilograms of oil or its equivalent to produce a hectare of sugarcane, and it takes 12 to 14 kilograms of fresh sugarcane to produce a single liter of ethanol. Erosion is very high on sugar plantations, because farmers harvest almost the entire plant, leaving little behind to anchor the soil. According to Pimentel and Ptazek, Brazil sugarcane plantations lose 31 tons of soil from every hectare — 30 to 60 times more than the land can regenerate.

Sugar plantations are also very thirsty. To produce a single liter of ethanol in Brazil requires 7,000 liters of water. And as the water runs off sugar plantations, it carries with it some of the herbicides, pesticides, and fertilizers that are applied at high levels on the plants. Even after the cane is harvested, there’s still more wastewater to deal with: ethanol plants produce 10 liters of wastewater for every liter of ethanol they make.

The more fuel we get from sugar-fed microbes, the more land will need to be used to grow it. “As with any conversion technology, there is concern that land will be cleared to provide feedstocks,” says Jason Hill, economist at the University of Minnesota.

Aldrich thinks that water would be the environmental wild card in a synthetic-biology boom. “The impact of the large-scale conversion of land not currently under the plow into sugarcane fields has a potentially significant environmental cost with respect to freshwater resources,” says Aldrich.

SOURCE: http://www.e360.yale.edu/content/feature.msp?id=2106

Published on Tuesday, March 18, 2008 by the St. Louis Post-Dispatch

Corn Can’t Save Us

by David Pimentel

Dwindling foreign oil, rising prices at the gas pump and hype from politically well-connected U.S. agribusiness have combined to create a frenzied rush to convert food grains into ethanol fuel. The move is badly conceived and ill advised. Corporate spin and pork barrel legislation aside, here, by the numbers, are the scientific reasons why corn won’t provide our energy needs:

- First, using corn or any other biomass for ethanol requires huge regions of fertile land, plus massive amounts of water and sunlight to maximize crop production. All green plants in the United States - including all crops, forests and grasslands, combined - collect about 32 quads (32 x 1015 BTU) of sunlight energy per year. The American population today burns more than three times that amount of energy annually as fossil fuels. There isn’t even close to enough biomass in America to supply our biofuel needs.

- Second, biofuel enthusiasts - including agribusiness lobbyists and PR firms - suggest that ethanol produced from corn and cellulosic biomass such as grasses could replace much of the oil used in the United States.

But consider that 20 percent of the U.S. corn crop was converted into 5 billion gallons of ethanol in 2006, and that amount replaced only 1 percent of U.S. oil consumption. If the entire national corn crop were used to make ethanol, it would replace a mere 7 percent of U.S. oil consumption, far from making the United States independent of foreign oil.

- Third, ethanol production is energy intensive: Cornell University’s up-to-date analysis of the 14 energy inputs that go into corn production, plus the nine energy inputs invested in ethanol fermentation and distillation, confirms that more than 40 percent of the energy contained in one gallon of corn ethanol is expended to produce it. The energy expended to make ethanol comes mostly from oil and natural gas.

Some investigators conveniently omit several of these energy inputs required in corn production and processing, such as energy for farm labor, farm machinery, energy production of hybrid corn-seed, irrigation and processing equipment. Omitting energy inputs wrongly suggests that a corn-ethanol production system offers a more positive energy return. In reality, corn is an inefficient choice from an energy-cost and transport standpoint.

Cellulosic ethanol also is touted loudly as a replacement for corn ethanol. Unfortunately, cellulose biomass production requires major energy inputs to release minimal amounts of tightly bound starches and sugars needed to make fuel. About 70 percent more energy - coming, again, from precious oil and gas - is required to produce ethanol from cellulosic biomass than the energy contained in the ethanol produced. That makes cellulosic ethanol an even poorer performer than corn ethanol.

Also, the production of corn ethanol is highly subsidized: State and federal governments pay out more than $6 billion per year in subsidies, according to a 2006 report from the International Institute for Sustainable Development in Geneva, Switzerland. Calculated on a per-gallon basis, these subsidies are more than 60 times those for gasoline.

Moreover, the environmental impacts of corn ethanol production are serious and diverse. These include severe soil erosion of valuable food cropland, plus the heavy use of nitrogen fertilizers and pesticides that pollute rivers. Fermenting corn to make one gallon of ethanol produces 12 gallons of noxious sewage effluent. Making ethanol requires the use of fossil fuels, releasing large quantities of carbon dioxide into the atmosphere, adding to global warming.

- Finally, using food crops such as corn to produce ethanol raises major nutritional and ethical concerns. Nearly 60 percent of the people on Earth are malnourished according to the World Health Organization. Growing crops for fuel squanders land, water and energy vital for human food production.

The use of corn for ethanol has increased the price of U.S. beef, chicken, pork, eggs, breads, cereals and milk - a boon to agribusiness but a bane to consumers. Jacques Diouf, the director general of the U.N. Food & Agriculture Organization, reports that using 22 pounds of corn to produce one gallon of ethanol already is causing food shortages for the world’s poor.

One last set of statistics: The global population stands at 6.6 billion: A quarter-million mouths to feed are added daily. Energy experts report that the peak of oil production already has been reached. As cheap oil supplies decline, fuel prices will rise, causing food prices to climb, too, because maximum agricultural production requires the use of fossil fuels.

As global population soars to 8 billion or more toward mid-century and as we burn more grain as fuel, shortages and production costs could cause grain prices to skyrocket, taking food from the mouths of the world’s poorest people.

The science is clear: The use of corn and other biofuels to solve our energy problem is an ethically, economically and environmentally unworkable sham.

David Pimentel is a professor of entomology at the College of Agriculture and Life Sciences at Cornell University.