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ethanol skeptics

Page history last edited by PBworks 11 years, 10 months ago

Ethanol Skeptics

 


 

Biofuels could actually produce more carbon — We all know that corn-based ethanol is inefficient and wasteful (unless you’re a corn farmer). Going a step further, this Environmental Science & Technology article suggests that ethanol’s production might actually release more carbon into the atmosphere than just using gasoline. And another article from the same publication points out the polluting side of harvesting sugarcane in Brazil, a more effective source of ethanol. (For those of you about to point out cellulosic ethanol as an answer, check out this piece from our own Contributor series, written by UC Berkeley professor Ted Patzek.

 

 

Net positive energy?

 

But the ethanol critics have shown that the industry calculations are bogus. David Pimentel, a professor of ecology at Cornell University who has been studying grain alcohol for 20 years, and Tad Patzek, an engineering professor at the University of California, Berkeley, co-wrote a recent report that estimates that making ethanol from corn requires 29 percent more fossil energy than the ethanol fuel itself actually contains.

 

The two scientists calculated all the fuel inputs for ethanol production—from the diesel fuel for the tractor planting the corn, to the fertilizer put in the field, to the energy needed at the processing plant—and found that ethanol is a net energy-loser. According to their calculations, ethanol contains about 76,000 BTUs per gallon, but producing that ethanol from corn takes about 98,000 BTUs. For comparison, a gallon of gasoline contains about 116,000 BTUs per gallon. But making that gallon of gas—from drilling the well, to transportation, through refining—requires around 22,000 BTUs.

 

In addition to their findings on corn, they determined that making ethanol from switch grass requires 50 percent more fossil energy than the ethanol yields, wood biomass 57 percent more, and sunflowers 118 percent more. The best yield comes from soybeans, but they, too, are a net loser, requiring 27 percent more fossil energy than the biodiesel fuel produced. In other words, more ethanol production will increase America's total energy consumption, not decrease it. (Pimentel has not taken money from the oil or refining industries. Patzek runs the UC Oil Consortium, which does research on oil and is funded by oil companies. His ethanol research is not funded by the oil or refining industries*.)

 

 

 

Energy independence?

 

First, 8 billion gallons of ethanol will do almost nothing to reduce our oil imports. Eight billion gallons may sound like a lot, until you realize that America burned more than 134 billion gallons of gasoline last year. By 2012, those 8 billion gallons might reduce America's overall oil consumption by 0.5 percent. Way back in 1997, the General Accounting Office concluded that "ethanol's potential for substituting for petroleum is so small that it is unlikely to significantly affect overall energy security." That's still true today.

 

Counter Arguments (back and forth)

 

Hosein Shapouri disagrees. An economist with the U.S. Department of Agriculture, he too has spent years studying the amount of energy needed to produce ethanol. His latest calculations, published in 2004, conclude that for each gallon of gasoline invested (or its equivalent in coal, electrical power, etc.), you get back the equivalent of 1.67 gallons of gasoline. That's up, he adds, from 1.36 gallons in 1996 and 1.24 gallons in 1991.

 

Shapouri charges that Pimentel's work is based on an outdated understanding of how the industry works. "He doesn't see technology," Shapouri says. "Corn production is becoming more efficient, and ethanol is, too."

 

Pimentel, on the other hand, charges Shapouri with overlooking important steps in the farm-to-ethanol process. "The reason the USDA comes up with positive returns and we do not," he says, "is that they omit about half of the inputs."

 

One "input" that Shapouri has overlooked, Pimentel says, is the energy used to make and maintain farm equipment. "Have you seen many farmers raising corn by hand?" he asks. Shapouri "draws the boundary too close to the gates of the ethanol plant," Patzek says. "His whole analysis accentuates the last element of the chain, which is ethanol production."

 

Patzek also says that Shapouri accidentally mixed up ethanol-production statistics for corn with different amount of moisture in it, so-called "wet" and "dry" corn. "That overestimates the yield by 15 percent," he says.

 

Shapouri, on the other hand, charges that Patzek and Pimentel should be basing their study on USDA's corn-growing data, rather than attempting to supplement the government statistics with figures from other sources. "We used a USDA corn survey and also a survey of ethanol plants," Shapouri told the National Corn Growers Association in 2004. "Our data are crystal clear."

 

Patzek, on the other hand, sees no reason not to try to improve on the USDA data. "They're not God," he says.

 

Competition with FOOD sources

 

One concern is that sugarcane cultivation will displace other crops, thus causing food shortages. However, these concerns seem to be groundless. Despite having the world's largest sugarcane crop, the 45,000 km² Brazil currently devotes to sugarcane production amount to only about one-half of one percent of its total land area of some 8.5 million km². In addition, the country has more unused potential cropland than any other nation. Some commentators, like George Monbiot, fear that the marketplace will convert crops to fuel for the rich, while the poor starve and biofuels cause environmental problems. It is unclear how this would be different from the current situation, as most food crops are grown and exported to richer nations, and neglects the very real environmental problems that the burning of fossil fuels causes. The cultivation of sugarcane for energy production is only likely to increase as fossil fuels become increasingly scarce and more expensive.

 

 

 

 

 

By products

 

But the most important dispute involves how to account for the fact that fuel isn't the only product to come from an ethanol plant. The leftovers from the fermentation process form dry distillers grain, which can be used in food production. Because dry distillers grain represents nearly 34 percent of the plant's output, Shapouri says that 34 percent of the total energy cost should be credited to it. That leaves only 66 percent to be charged against the ethanol.

 

Pimentel agrees that a credit is appropriate but argues that because soybean meal can be used for many of the same purposes, the appropriate adjustment is for the amount of energy needed to grow and produce soybean meal – vastly smaller than the amount needed for growing corn and making dry distillers grain.

 

An additional problem is that corn is an environmentally unfriendly crop. It contributes more to soil erosion than do other crops, says Pimentel, and pesticides and the nitrates from nitrogen fertilizer contaminate creeks, rivers and even the Gulf of Mexico.

 

These problems can be reduced by using other crops for ethanol, such as grass or wood, or by making biodiesel from soybean oil or sunflower oil. But grass and wood are difficult to process, and oilseed crops have relatively low yields compared with corn. Pimentel did his energy calculations with all four and found that only soybeans fare better than corn (because they don't need nitrogen fertilizer to grow). But even they require 1.27 times as much energy to produce as they give back in biodiesel, he says.

 

A fifth alternative, sugar cane, might be slightly better, he adds, but it too depletes soils and increases erosion.

 

 

 

 

 

 

 

Logistics problems

 

Adding more ethanol will also increase the complexity of America's refining infrastructure, which is already straining to meet demand, thus raising pump prices. Ethanol must be blended with gasoline. But ethanol absorbs water. Gasoline doesn't. Therefore, ethanol cannot be shipped by regular petroleum pipelines. Instead, it must be segregated from other motor fuels and shipped by truck, rail car, or barge. Those shipping methods are far more expensive than pipelines.

 

 

Increased refining costs

 

There's another problem: Ethanol, when mixed with gasoline, causes the mixture to evaporate very quickly. That forces refiners to dramatically alter their gasoline to compensate for the ethanol. (Throughout the year, refiners adjust the vapor pressure of their fuel to compensate for the change in air temperature. In summer, you want gasoline to evaporate slowly. In winter, you want it to evaporate quickly.) In a report released last month, the GAO underscored the evaporative problems posed by ethanol, saying that compensating for ethanol forces refiners to remove certain liquids from their gasoline: "Removing these components and reprocessing them or diverting them to other products increases the cost of making ethanol-blended gasoline."

 

In addition to the transportation and volatility issues, ethanol will add yet more blends of gasoline to the retail market. Last year, American refiners produced 45 different types of gasoline. Each type of gasoline needs specific tanks and pipes. Adding ethanol to the 45 blends we already have means we will be "making more blends for more markets. That complexity means more costs," says David Pursell, a partner at Pickering Energy Partners, a Houston brokerage.

 

 

Less powerful energy source

 

There's a final point to be raised about ethanol: It contains only about two-thirds as much energy as gasoline. Thus, when it gets blended with regular gasoline, it lowers the heat content of the fuel. So, while a gallon of ethanol-blended gas may cost the same as regular gasoline, it won't take you as far.

 

 

Better alternatives

 

What frustrates critics is that there are sensible ways to reduce our motor-fuel use and bolster renewable energy—they just don't help the corn lobby. Patzek points out that if we channeled the billions spent on ethanol into fuel-efficient cars and solar cells, "That would give us so much more bang for the buck that it's a no-brainer."

 

 

Sources:

http://slate.com/id/2122961/

http://feinstein.senate.gov/05speeches/ethanol-oped.htm

 

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