Politics, Business & Culture in the Americas

Does Ethanol Make Economic and Environmental Sense?

Does ethanol make environmental sense? Bruce Dale, Professor, Michigan State University, and David Pimental, Professor, Cornell University, duel over biofuels

Bruce Dale: YES!

Ethanol Will Reduce Our Dependence On Foreign Oil. Contrary to common criticism, ethanol will also help developing nations.

Ethanol offers a huge reduction in petroleum consumption per mile driven and it can significantly decrease greenhouse gas generation compared to gasoline. Ethanol derived from cellulosic materials can also be produced at low enough costs and in large enough volumes to seriously challenge petroleum’s dominance as a source of liquid transportation fuels.
A recent article in the journal Science provides data showing that, since very little petroleum is needed to produce ethanol, using ethanol as a fuel reduces petroleum consumed in proportion to the percentage of ethanol in the fuel mixture. Assuming a fuel efficient car getting about 50 miles per gallon of fuel and driving on E85 (a mixture of 85 percent ethanol and 15 percent gasoline), the overall petroleum consumed would be equivalent to about 250 miles per gallon. Higher percentage ethanol blends would get even more miles per gallon of petroleum consumed.  
It is important to distinguish between ethanol made from two different raw materials. Data show that corn ethanol can reduce greenhouse gases by about 18 percent. (The ethanol currently used in the U.S. is largely produced from corn.) In contrast, cellulosic ethanol made from the sugars contained in plant cell walls, can cut greenhouse gases by as much as 90 percent. An additional attraction of cellulosic ethanol is that it can be produced in much larger volumes from materials that are widely available. Tens of billions of tons of plant cell-wall materials, including grasses, crop residues, wood chips, and some wastes, are produced worldwide each year. Cellulosic ethanol could someday replace gasoline use entirely.
Both gasoline and ethanol are produced using fossil fuel energy carriers: petroleum, coal and natural gas. Some specialists have criticized ethanol as having a negative “net energy.” They calculate net energy as ethanol’s heating value minus the sum of the energy contents of the fossil energy required to make ethanol. Their net energy calculation treats one megajoule (MJ, a measure of energy content) of coal as equal to one MJ of natural gas which is also equal to one MJ of petroleum. A recent paper estimates a “net energy” for corn ethanol of -29 percent using this idea.
But this calculation of so-called “net energy” is based on a false premise. It assumes that all energy carriers are equally useful. They are not. We are willing to pay more than five times as much for a million MJ of petroleum than for a million MJ of coal. (A MJ of natural gas is worth about three times as much as a MJ of coal.) Coal’s energy content is simply not as valuable as petroleum’s energy content. Net energy analysis is akin to adding 10 U. S. dollars, 10 Mexican pesos and 10 Indian rupees to get 30 dollars. Different energy carriers cannot simply be added together and produce a meaningful result.
Perhaps worse, those critics never calculate gasoline’s net energy. If the net energy calculation is relevant (which I do not believe, but accept for the sake of discussion), then it is relevant for gasoline as well as ethanol. From the data in the Science paper, ethanol’s net energy is +25 percent while gasoline’s net energy is 18 percent. Gasoline has a worse net energy than ethanol.
More relevant to this debate is the issue of how much can be produced, and at what cost. The U. S. will produce about seven billion gallons of ethanol from corn this year, consuming less than 20 percent of our expected corn crop and much less than half of our corn exports. We can probably produce about 15 billion gallons of ethanol from corn (roughly 10 percent of our total gasoline consumption) before increasing corn prices cut off further expansion of the corn ethanol industry. At current prices of $4 per bushel, corn ethanol (even without subsidies) is competitive with gasoline from oil that over last winter soared to highs of $100 per barrel. About 16 bushels of corn are required to produce the ethanol equivalent to gasoline produced from one barrel of oil.
Currently, the ethanol production system in the U.S. receives a credit or subsidy of about 50 cents per gallon, but such subsidies should disappear if they are linked to oil prices, eventually decreasing to zero when the price of a barrel of crude is sufficiently high. But one byproduct of increasing ethanol use in the U.S. is that the resulting increase in corn prices has largely eliminated direct subsidies to corn producers. Meanwhile, it is important to note that oil is currently subsidized both by U.S. tax policy and indirectly through at least $50 billion a year in military spending required to protect access to Mideast oil.
Ethanol critics also raise the contentious “food vs. fuel” issue. But the cost of energy (transportation, packaging, refrigeration, etc.) affects the price of essentially everything that developed countries consume, while the cost of grain affects the cost of a few food items. Low-cost biofuels can in fact help keep a lid on food costs by reducing transportation costs.
How about poor countries? The U.S. is always challenged to stop subsidizing our agricultural production by exporting artificially cheap grain. If low grain prices are a great thing for the world’s poor, why do the governments of developing countries ask us to stop this practice? Because by making grain artificially inexpensive, we undermine rural economies and help keep poor people poor. If the value of agricultural products rises because of increased biofuel demand, more wealth will flow to rural areas around the world.
Brazil has benefited significantly from its decades-long program producing ethanol from cane sugar. Imagine the positive effects of redirecting even a fraction of the $8 billion-a-day world petroleum trade into the economies of developing nations for biofuel production. This would dwarf all foreign assistance programs and make debt forgiveness (a debt largely due to oil imports) unnecessary.  
The age of cheap oil is ending. Low-cost ethanol will be an important part of the emerging sustainable transportation system. Through appropriate technologies and policies, biofuels can provide economic growth, enhanced national security and real environmental improvements.  

Rebuttal:
Two senior authors of the Science 2006 article mentioned by Dr. Dale as support for his view have already reversed themselves. That should be the most effective rebuttal of all. They now concede that ethanol production is undesirable from both an energy and an environmental perspective. As I have argued, that makes sense. Corn ethanol production requires significant amounts of imported oil, plus large quantities of imported natural gas, to produce vital nitrogen fertilizer. And an additional 600,000 gallons of water are required per acre for corn.
The dismal future for cellulosic ethanol should already be clear. Switchgrass and wood sawdust contain only one-half to one-fifth the starches and sugars of corn grain. Not one drop of ethanol has been produced using cellulosic biomass with a net positive energy return. Studies confirm that 70 percent more fossil energy is required to produce a gallon of ethanol from switchgrass cellulose than the energy produced in the ethanol. For this reason, not one single commercial plant in the world has been built to produce cellulosic ethanol. Filling the tank of an SUV requires the equivalent of 660 pounds of corn. The strain on supplies has already escalated shortages of corn needed for livestock and for the production of other foods like bread and eggs from 10 percent to 20 percent. If this keeps up, we can project prices of $5 per gallon of gas and $3.50 per dozen eggs. —DP

David Pimentel NO!
Ethanol Wastes More Energy Than It Produces. Production of ethanol is a drain on resources and pollutes the environment.

Corn ethanol production is energy inefficient and expensive. In 2007 alone the U.S. sank more than $6 billion in subsidies to support the production of corn ethanol. It is also represents an environmental hazard, threatens nutritional balance by raising the cost of key food staples—the price of milk, meat and eggs has increased between 10 percent and 20 percent in 2007—and, finally, poses genuine ethical concerns.
While diminishing oil supplies, along with high prices, have accelerated projects to convert grains and other biomass into ethanol fuel, it is important to take a longer perspective. Ethanol production, whether based on corn or on biomass such as plants and grasses, requires large areas of fertile soil and huge quantities of water—both of which obviously represent a reduction in the amount of those often-scarce resources needed for the world’s growing food supply needs.
Many enthusiasts suggest ethanol produced from corn grain or grasses could replace much of the oil used in the U.S. But consider this: the six billion gallons of ethanol produced from 20 percent of the U.S. corn crop in 2007 replaced only one percent of U.S. oil consumption last year. If the entire corn crop were used, it would replace a mere seven percent of oil consumption—a percentage that would do little towards making the U.S. independent of foreign oil.
Up-to-date analyses of all the energy inputs that typically go into corn production, and fermentation and distillation operations, confirm that in order to produce a gallon of corn ethanol you need 60 percent more fossil energy that what you actually get from that gallon.1 To put this into perspective, a gallon of gasoline requires only 10 percent more fossil energy.
Ethanol advocates argue that the corn ethanol production provides a positive energy return, but they base their conclusions on research that ignores several key energy inputs required for production and processing, such as the use of farm machinery and the energy required for irrigation and production of hybrid corn-seed.
Some researchers skeptical about the energy value of the byproducts (such as distiller grain) from making corn ethanol claim that ethanol produced from sugarcane is a slightly better resource. However, for each gallon of oil invested in ethanol from sugarcane we get a mere 1.1 gallon of ethanol. Moreover, if we combined all the ethanol produced annually in Brazil with the corn ethanol produced in the U.S., it would still supply only two percent of total U.S. oil consumption.
Others argue that ethanol produced from cellulosic biomass is a better energy source than corn ethanol. In fact, cellulosic biomass contains less than one-third the amount of the starches and sugars of corn grain, and major fossil energy inputs are required to release the tightly held starches and sugars for fermentation. As a result, approximately 70 percent more fossil energy is used to produce ethanol from cellulosic biomass than the energy it produces.
In the U.S., corn ethanol is a highly subsidized industry. According to a 2006 report by the Geneva-based International Institute for Sustainable Development, Biofuels—at What Cost? Government Support for Ethanol and Biodiesel in the United States, the subsidies for a gallon of ethanol represent more than 60 times the subsidies for a gallon of gasoline. The current subsidy per gallon of gasoline is about three cents.
The environmental impacts of corn ethanol are also worrying. They include severe soil erosion of valuable cropland and the heavy use of nitrogen fertilizer and pesticides that pollute rivers.
The significant amounts of fossil fuel energy used in ethanol production release large quantities of carbon dioxide into the atmosphere. Then, during the fermentation process, about 25 percent of the carbon from the sugars and starches is released as carbon dioxide into the atmosphere. These two major releases of carbon dioxide significantly contribute to global warming. The production of corn ethanol causes twice the problem for global warming that gasoline causes.
Another issue which few advocates discuss is that each gallon of ethanol needs 1,700 gallons of water (mostly to grow the corn) and releases 12 gallons of noxious sewage effluent from the fermentation process into the environment.
Using food crops such as corn to produce ethanol also raises major nutritional and ethical concerns. Nearly 60 percent of the world population is currently malnourished according to the World Health Organization (2005), so diverting crops for fuel production squanders land, water and energy resources that are otherwise vital for feeding the hungry.
For example, the current production of corn ethanol in the U.S. requires 1.5 million acres of valuable crop land plus 900 billion gallons of water needed for production and conversion processes. In addition, 80 percent of U.S. corn is used in livestock production. With more than 20 percent being used for ethanol production, livestock has a shortage of corn and this has led to increased prices of U.S. beef, chicken, pork, eggs, breads, cereals, and milk.2
Ethanol production has decreased crop yields in some crucial places and has meant a shift away from farming for human consumption toward crops for biofuels and cattle feed. It takes about 22 pounds of corn to produce one gallon of ethanol. A 30-gallon SUV tank would require 660 pounds of corn to fill it with ethanol. Is that a trade-off we are prepared to accept? 

Rebuttal: Dr. Pimentel’s critique of ethanol has so many errors that they cannot all be refuted in my allotted 250 words. But here are some important facts. Higher food prices are primarily driven by rising energy costs (fertilizing, growing, harvesting, transporting, processing, and refrigerating food), not by corn prices. Cellulosic materials for ethanol are produced on marginal lands not suitable for food production or from wastes such as bagasse, a sugar cane processing residue. Water is used, purified and reused by plants in the biosphere; otherwise we would have run out of water long ago. “Energy return” and “net energy” are irrelevant; what matters is ethanol produced per unit of petroleum consumed, and that figure is over 20 to one in favor of ethanol. Brazil and the U. S. produced about 12 billion gallons of ethanol last year, enough to displace about 5 percent of total U.S. petroleum consumption. Carbon dioxide produced in the ethanol fermentation came from the atmosphere in the first place; therefore it cannot contribute to net global warming. Malnourishment affects around 15 percent of the world population, not 60 percent and is caused by poverty and war, not by grain prices. Last but not least, the U.S. exported about 2 billion bushels of corn last year, approximately our long-term average. There is no “corn shortage.” In short, ethanol is one of very few alternatives for ending our petroleum dependence. It’s time to move forward with ethanol. I invite you to visit www.everythingbiomass.org for a fuller rebuttal. —BD


Tags: biofuel, cellulosic, coal, corn, corn ethanol, corn grain, energy inputs, Environment, Ethanol, food staples, foreign oil, fossil fuel energy, fuel, gasoline, grasses, greenhouse gases, Int, natural gas, oil, oil supplies, petroleum, petroleum consumption
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