If one takes into account all energy inputs more than 140% more energy (mostly high value oil and natural gas) is needed to produce a gallon of corn ethanol than is in the ethanol itself. There are various environmental impacts of corn ethanol, including severe soil erosion of valuable cropland, and heavy use of nitrogen fertilizer and pesticides that pollute rivers. Because significant amounts of fossil fuel energy are used in ethanol production, large quantities of carbon dioxide are produced and released into the atmosphere, and during the fermentation process about 25% of the carbon from the sugars and starches is released as carbon dioxide . Besides this, growing the crops takes large amounts of water which in some parts of the US is already becoming an issue that will likely worsen in the soon future.
And that doesn't even touch on the ethical problems it causes because ground that's used for biofuel crops is ground that's not available for food production. (The type of corn used in biofuels is not the same that is used to feed humans.) Some of the richest countries, among them the United States, Brazil, Canada and several European Union states, have large and expanding food-for-fuel industries. The poorer countries, among them Egypt and Venezuela, have been highly critical of biofuels because the crops used to make them take food off the table.
I was puzzled by this biofuel discussion because it wasn't news to me. Okay, I couldn't have quoted the exact numbers or details, but I knew the general sentiment. Neither did I have the impression this was news to commenters on my blog when it was casually mentioned in a previous post. I am not usually following these things too closely, I mean, I have a job and spend most of my time reading papers anyway. So, I think it must have been my younger brother, who is a mechanical engineer, explaining me that, which leaves me wondering how widely known these facts were.
To state the most important fact again and really clearly: Growing 'biofuel' does not make your country more independent of oil and gas resources, because you need more of these resources to grow it than you eventually gain. The only thing it does is a psychologically interesting 'greenization' of energy. You could as well use an oil-powered turbine to pump water up a hill, then let it run down again and call that clean energy from water-power. The energy you gain back is of course less than you invested, but since it's now an 'alternative' energy it deserves governmental subsidies. (I think they've actually been doing that somewhere in Switzerland, but can't recall the details, anybody has a reference?) It's not an investment that makes sense in any way.
I probably would have forgotten about the biofuel, hadn't I read some time later that the German ministry for environment wakes up when hearing biofuel might drive up food prices and utters confused statements ("muss auf den Prüfstand"), before calming down and proclaiming one would hold onto what the plan says. Meanwhile Sean from Cosmic Variance states that Energy Doesn't Grow on Trees and is pleased that "People seem to be gradually catching on to the fact that biofuels are an especially wasteful and dirty energy storage system." Talking to my friends, they confirm my sense that little of that was surprising.
So I tried to find out how 'new' actually is that news. Here's the story. Since the early eighties, there have been dozens of studies showing that ethanol production from corn and other crops is not an economically and ecologically sensible option. It is expensive and under quite general circumstances takes more energy than one gains from it. Two articles by the U.S. Department of Energy (USDOE) dealing with ethanol production using corn for liquid fuels from biomass reported a negative energy return [2,3]. These reports were reviewed by 26 expert U.S. scientists independent of the USDOE; their findings concluded that the conversion of corn into ethanol energy was negative and these findings were unanimously approved. Since then other investigations have confirmed these earlier findings.
In 2002 and 2004 there were reports from the US Department of Agriculture [4,5] in which it was claimed biofuels could have a net energy return (34% in 2002, 67% in 2004). These studies however were based on wrong assumptions that neglected needed energy sources, and the conclusions not appropriate. This has has been documented in further research articles. For an excellent review, see .
Now this makes me wonder how can it be possible that this knowledge has been so consequently disregarded? Sure, there's big money in the game, there's lots of people trying to make profit, but how can we life with a system in which scientific studies are just ignored? And now that the problems are catching up with us, and we're possibly seeing the first signs of a global food crisis, I read
"Food-summit draft rejects biofuels control
The final declaration of United Nations food summit will not call for controls on biofuels even though almost every delegate at conference agrees that turning crops into fuel has had some role in raising food prices to crisis point. A draft declaration making the rounds at the UN's Food and Agriculture Organization (FAO), the sponsor of the three-day summit which ends Thursday night, calls only for more study on the effect of biofuels on food security. "
Why this bothers me: The world economy is a very powerful system that has without any doubt done an incredibly well job increasing wealth, improving the infrastructure and the lives of billions of people. But not in all cases does this pursuit of micro-interests lead to a desirable outcome on the macro-level, especially not when long time and/or distance scales are involved. To put it bluntly: what do I care what happens in a decade somewhere in Africa? Its for this reason that we have political systems that ought to implement these aspects. Unfortunately, our political systems are far too slow and inefficient for this task, especially on a global level.
 Pimentel D, Patzek T (2005) Ethanol Production using corn, switchgrass, and wood and biodiesel production using soybean and sunflower. Natural Resources and Research 14(1): 65-76.
 ERAB (1980) Gasohol. Energy Research Advisory Board, U.S. Department of Energy, Washington, DC.
 ERAB (1981) Biomass Energy. Energy Research Advisory Board, U.S. Department of Energy, Washington, DC.
 Shapouri H, Duffield JA, Wang M (2002) The Energy Balance of Corn Ethanol: An Update. USDA, Office of Energy Policy and New Uses, Agricultural Economics. Report No. 813. 14 p.
 Shapouri H, Duffield J, McAloon A, Wang M (2004) The 2001 Net Energy Balance of Corn-Ethanol (Preliminary). US Department of Agriculture, Washington, DC.