The sustainable living
/ renewable energy
branch of Environmentalism
has long listed ethanol as one of the many viable alternatives to fossil fuel
, the others list members typically being wind
, and perhaps biomass
The purpose of this write-up is not to re-hash the debate over whether there is at the moment a viable alternative to fossil fuel. The point is to make you aware that based on recent science, environmentalists should no longer consider ethanol to be a viable alternative.
Surprised? I was. Read on.
This write-up is based on peer reviewed research
by a scientist who is manifestly "pro-Environment". He is not, so far as I can tell, funded by or supportive of the fossil fuel industry or any other parties that might have an anti-Environmentalist axe to grind
The most recent research I've found was published in the Sept., 2001 issue of the prestigious, peer reviewed Encyclopedia of Physical Sciences and Technology. The study is by David Pimentel, a Professor Emeritus at the College of Agriculture and Life Sciences at Cornell University in Ithaca, NY, USA. I haven't found the study itself on the Internet, and the Encyclopedia itself costs over $3000 a copy, but you can read the press release for the study at http://www.news.cornell.edu/releases/Aug01/corn-basedethanol.hrs.html.
Ethanol fuel from corn faulted as 'unsustainable subsidized food burning' in analysis by Cornell scientist
The essential finding, from the press release:
Neither increases in government subsidies to corn-based ethanol fuel nor hikes in the price of petroleum can overcome...a fundamental input-yield problem: It takes more energy to make ethanol from grain than the combustion of ethanol produces.
For those of you who think ethanol would be desirable even if it isn't economical, remember that the argument here isn't that it's more expensive than fossil fuels, it's that ethanol is not economically viable on its own terms. It would require a net investment of energy from non-ethanol sources to produce ethanol. Using a gas-ethanol mix only dilutes the problem; the net energy contribution of ethanol to the mix is still negative.
And even if we solved the input-yield problem, the press release continues:
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.
You can read an earlier, peer reviewed study by Pimentel (BioScience
-- Vol. 44, No. 8, September 1994) with essentially the same conclusions, thanks to the cheerful folks
(page down to the section titled "Ethanol"). This study, called Renewable Energy: Economic and Environmental Issues
, while optimistic about many other renewable energy approaches, calmly and dispassionately dismantles the myth of ethanol (emphasis added):
The total...energy expended to produce 1 liter of ethanol from corn is 10,200 kcal, but note that 1 liter of ethanol has an energy value of only 5130 kcal. Thus, there is an energy imbalance causing a net energy loss.
These current ethanol techniques, which a recent U.S. energy bill just blessed
with massive support, are not even close
to having a positive net energy yield. Pimentel goes on to evaluate various ways ethanol can be made at a lower energy cost, including a promising, but still experimental, membrane technology that reduces the energy input cost from 10,200 to 6,200 kcal. Nevertheless, "the energy budget remains negative".
Even if the energy budget problem were to be solved, according to Pimentel, there are other fundamental problems with ethanol, including the environmental costs of intensive corn farming, the non-nutritive components of the sewage produced by the fermentation and refining processes, and the tailpipe emissions from burning ethanol in conventional combustion engines. He concludes: "Ethanol produced from corn clearly is not a renewable energy source. Its production adds to the depletion of agricultural resources and raises ethical questions at a time when food supplies must increase to meet the basic needs of the rapidly growing world population."
Is Pimentel Alone in His Conclusions?
Pimentel is citing not just his own research, but others as well, read the study for the list. He is published in peer reviewed journals, meaning his peers may or may not agree with him, but they agree that his research is scientific.
And some well-known lobbying groups with impeccable environmental credentials have quietly supported his view. There are many examples; if you have time to spare, search the Congressional Record or the science section of a major newspaper. For now, just one example from the Web: On April 8, 2002, Environmental Defense wrote to the National Highway Traffic Safety Administration, a major US government regulatory body,
"...a fleet (of dual-fuel cars) is of no value without a broader business case for economically viable non-petroleum fuels. In spite of massive subsidies, to the domestic ethanol industry in particular, such a business case is nowhere close to being established."
The ethanol industry has, of course, responded to Pimentel's early studies. For example, the American Coalition for Ethanol
(ACE), conveniently at http://www.ethanol.org/
, cites a 1995 U.S. Department of Agriculture
) study available at http://www.ers.usda.gov/publications/aer721/AER721.PDF
. This study finds a net positive energy balance by making more optimistic assumptions about farming techniques, discounting the energy costs to build capital equipment and plants, etc. This study is also peer reviewed, so it's hard to evaluate these conflicting assumptions, but I can say that the Agriculture Department study is underwhelming: it finds an energy balance of 1.24, meaning you'd have to burn the energy equivalent of 4 liters of ethanol to produce 5 liters of ethanol. I'm guessing that Pimentel is aware of this USDA study, and has every incentive to give ethanol the benefit of the doubt. Yet Pimentel still concluded in 2001 that the net energy balance is negative.
Corn-based Ethanol is Probably a Bust
When scientists disagree about how much benefit a new technology promises, that's one thing. When scientists can't agree if a technology with a known track record
even has a benefit or not, it is safe to conclude that technology is not ready for prime time
At this point let me insert my standard disclaimer with regards to technology: sure, it's possible that future research could solve all these ethanol problems: the next generation of refining technology could solve the energy budget problem and produce less sewage; combustion engines and emissions controls designed specifically for ethanol or gas/ethanol could ameliorate or even solve the tailpipe problem; revolutionary new agriculture techniques could one day generate high, sustainable yields on less land, or we might find a way to make ethanol from "waste" biomass instead of growing corn.
...Or, the Taelons might arrive and solve all our energy problems! The universe is a big place; Taelons aren't that much less likely than all these other solutions emerging in time for ethanol to save the planet.
But to say that the current approach, growing corn for ethanol, is one of those prêt à porter technologies held back only by inertia, addiction to fossil fuels, or evil big business, is just not true. Probably, the only reason ethanol-containing fuel is currently available in a very small scale in the U.S. at anything like a reasonable price is because cheaper fossil fuels are used to harvest, refine, and dilute the ethanol, and massive subsidies for ethanol production (on top of the traditional subsidies for corn production) hide the true cost of the process. Indeed, I would argue that corn ethanol is mostly propaganda pushed by immense agri-business concerns such as Archer Daniels Midland (ADM) who benefit financially as well as by appearing to be Green.
Under any current or foreseeable technology, corn ethanol is probably a bust.