Forget it! You hear a lot about the energy it takes to make ethanol. Is it more than you get from the ethanol produced, or is it less. Is the energy balance positive or is it negative. Enough! It doesn't matter. It's not energy we care about. What matters is (1) energy imported from dangerous places, and (2) greenhouse gases. Here' why neither matches the energy balance.
Suppose ethanol production used tons of coal and had a terrible energy balance. Since coal is not imported, ethanol would still reduce energy imports (oil) from dangerous places. Bad on energy, but good on energy independence.
Again suppose the heat for ethanol comes from coal, but less is used, so its energy balance is nicely positive. But the nitrogen fertilizer used for corn releases N2O, a potent greenhouse gas. Depending on how much coal and how much N2O, ethanol could be: Good on energy, and bad on greenhouse gas emission.
Energy balance is useless. It's not what we care about and it cannot be used to calculate what we care about which is only (1) Energy imports, and (2) Greenhouse gases. Tomorrow—the shocking saga of ethanol's gases. (from Chp. 3.3 Ethanol)
Friday, May 11, 2007
Ethanol energy balance?
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3 comments:
Bad on Greenhouse gases? The scientists fertilized the trees using 4 fertilizer treatments—one conventional, two organic (manure and alfalfa) and one integrated. The research team also measured emissions of nitrous oxide (N2O)—a potent greenhouse gas that is 300 times more effective at heating the atmosphere than carbon dioxide gas, the leading cause of global warming. The results showed that nitrous oxide emissions were similar among the four treatments. This is from,
http://www.stanford.edu/dept/news/pr/2006/pr-organics-030806.html
there is surplus corn being produced anyway and the farmers are being subsidized. Might as well use it for something. It probably is not a total solution by itself. Butanol production looks promising also. Butanol is produces using ANY vegetable fiber. How much of a corn plant is the corn kernel versus the whole plant. A much larger feedsock resource is available and butanol can be used with no modifications what so ever to current automobiles.
Algae based biodiesel is a much better answer. Algae produces 100 times more biodiesel than corn and replicates every 6 hours while corn takes a year. In addition, algae consumes large amounts of CO2 and does not displace food crops, nor does algae require fresh water. Leftover biomass can usually be used as a foodstock and fertilizer.
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