Corn Ethanol as Energy: The Case against US Production Subsidies
Pimentel, David, Harvard International Review
Corn grain is one of the major foods of the world. Grains in general provide about 80 percent of the world food calories. Today there is a per capita shortage of grains and other foods, exacerbating the serious global malnourishment problem. The World Health Organization reports that 3.7 billion people are malnourished today--nearly 60 percent of the world population. This is the largest number of malnourished ever in history. In addition to food shortages, there are shortages of cropland and freshwater as well as fossil fuel--particularly oil--shortages. The oil shortage in the United States has prompted politicians and others to propose the use of corn and other food crops as sources of fuel, especially for ethanol production. As a result, nearly 9 billion gallons of ethanol is produced in the United States, using about 33 percent of US corn grain. This 9 billion gallons of ethanol represents only 1.3 percent of total oil consumption in the United States. But the numbers are telling: if all US corn were to be converted into ethanol, it would provide the nation with only 4 percent of total oil consumption.
Given these facts, one asks, why is corn grain being converted into fuel while nearly 60 percent of the world population goes hungry? In particular why is US$6 to US$7 billion being spent to subsidize and encourage corn ethanol production? Unfortunately, the United States continues to produce corn ethanol because politicians find it politically useful, though the fuel is far from environmentally sustainable and a viable source for energy independence, as it uses up more energy to produce than it provides.
In the United States, ethanol from corn constitutes 99 percent of all biofuels. To produce corn ethanol, corn is finely ground and approximately 15 liters of water is added to 2.7 kg of ground corn. After fermentation, to obtain a liter of 95 percent ethanol from the mixture of 10 percent ethanol and 90 percent water, 1 liter of ethanol must be extracted from approximately 10 liters of the ethanol/water mixture. To be mixed with gasoline, the 95 percent ethanol must be further processed to remove more water, requiring additional fossil energy inputs to achieve 99.5 percent pure ethanol. Thus, 22 pounds of corn grain is required to produce 1 gallon of ethanol. To fill the fuel tank of a SUV vehicle with corn ethanol requires a total of 660 pounds of corn or food. This is enough corn to feed two people in a developing country for an entire year.
Furthermore, to produce corn ethanol, 46 percent more fossil energy is required to produce a liter of ethanol than than is yielded. Oil therefore must be imported to produce ethanol. As a result, the cost to produce 1 liter of corn ethanol is US$1.05 per liter or US$3.95 per gallon. The corn grain itself accounts for most of the economic and energy inputs to produce the ethanol. For example, it requires approximately 7,090 liters of fossil energy equivalents to produce 3,330 liters of ethanol.
Then US President George W. Bush proposed harvesting cellulosic biomass and converting it into ethanol, suggesting that the United States could produce 36 billion gallons of ethanol through this method by 2020. However, while he proposed producing 23 gallons of ethanol per ton of cellulosic biomass, this figure was more than optimistic: our studies shows that it requires 3.3 gallons of oil to produce 1 gallon of ethanol from cellulosic biomass. What Bush also neglected to report was that the total amount of biomass, including 100 percent of all agricultural crops, forest growth, and grass growth each year, totals 2 billion tons (Table 1). Therefore, in order to harvest 1.6 billion tons of cellulosic biomass each year, producers would have to harvest 80 percent of total biomass each year, a clearly unsustainable and infeasible enterprise.
Corn Ethanol Production Environmental Impacts
The environmental impacts of producing corn ethanol are enormous. …