Thursday, May 25, 2006
Corn-ethanol
Given the recent high price of gasoline, one of the proposed replacements is ethanol derived from corn. The problem with this idea is that it may take almost as much fossil fuel to make the stuff. Today in the New York Times, Michael Pollan, author of The Omnivore's dilemma: A Natural History of Four Meals, has an op-ed piece arguing against corn-based ethanol. Future Pundit also has a recent posting with links to economic and thermodynamic analyses of ethanol production. Currently, the federal government offers a tax break of 54 cents for every gallon of ethanol produced and levies a tariff of 54 cents a gallon on imported ethanol. We also subsidize the farming of corn, which takes a lot of fertilizer, pesticides and tractors, all of which use fossil fuels of some sort. Depending on how you do the estimate, it may even take more than a gallon of fossil fuel to produce one gallon of ethanol from corn. Ethanol could make sense if it is derived from a crop that is more efficient like switch grass or sugar cane. But with the strength of the corn lobby, those other options may never get a chance. Maybe it's time that we stop subsidizing the growth of all that corn. We produce way more than we can eat and high fructose corn syrup may be part of why we're getting fat and diabetic.
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3 comments:
Ethanol as a fuel, aside from having dubious value on thermodynamic and economic grounds, also poses an ethical question, in my view. It is this: Quite a few people in the world are going hungry, yet we have a surplus of food -- and we're going to burn some of that food so we can drive our cars down the highway at 75 mph? Is that right?
Using corn-derived ethanol for fuel is in many ways a good idea, but, even setting aside the very real practical limitations on its production that Carson has highlighted, it seems rather self-indulgent to use this resource just because we don't know how to limit our energy use.
Thanks for the comment. I didn't think anyone was still reading.
Carson
This strikes at a core question about the goal of creating a "hydrogen economy". There is a clear need for a portable fuel with higher energy density than battery technologies can currently achieve. However, generating hydrogen requires energy. Currently, hydrogen is produced by cracking hydrocarbons, but as fossil fuels are exhausted, this source will disappear.
The earth may be full of "used" hydrogen in water, but to make it useful it needs to be put in a higher energy state - and that is not free. If we are producing our own fuel (be it hydrogen or hydrocarbons), it could be very nearly greenhouse-gas neutral regardless of the fuel. So why go after a "hydrogen" economy? Instead retain our current hydrocarbon infrastructures and produce hydrocarbons from -for example- CO2 and H2O (plus a large amount of energy).
Synthesis of fuel will require prodigious amounts of energy regardless of the type of fuel. I would contend that though Iran's claim to be pursuing nuclear power is suspect, looking forward 50 years they probably would be wise to invest in developing a nuclear energy infrastructure.
PS – Conservation is necessary, but it is not a long term solution to our modern societies’ energy needs.
PPS - Keep on writing Carson. The lurkers are always watching.
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