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View Diary: Energize America - A Blueprint for U.S. Energy Security (Fourth Draft) (311 comments)

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  •  Livin' on Booze Power (none)

    On the theory that it is better to put EtOH in the tank than in the driver, I agree with you about the Ethanol issue. It is a great fuel - packs a lot of energy in a relatively small volume, burns clean, and can be made via several methods that use renewable energy. And it works in existing gasoline engines, or can be made to do so very easily. You can also use it to power gas turbines - it can repalce natural gas for the "peak power units".

    Anyway, in order of increasing "renewableness", here  are some ways to make EtOH:

    1. The "traditional" fermentation of crops, especially sugar can and corn. The problem is that the fertilizer to grow thse crops is made by making ammonia that is made from natual gas or coal (which are used to make the H2 used to react with N2 to make ammonia).

    2. Fermentation of crops grown with ammonia made via renewable means (such as wind turbine electricity used to make the H2 instead of coal or natural gas).

    3. Same as #2 but with renewable derived electricity in the ethanol plant, especially with regard to the ethanol distillation (heat pumps and vacuum distillation). These steps will squeeze the petroleum out of the ethanol made by fermenting crops.

    Note: Most modern bio-ethanol plants use every part of the crop - sell the CO2, the yeast residue from the fermentation, the oils in the food, and the proteins in the food.

    4. Ethanol via the Fischer-Tropsch method, involving the "frying" of the crop in the absense of air, with the resulting gasses treated and then fed to a high pressure reactor, where the CO and H2 in the "Syn-Gas" is reacted with the right catalyst at the right pressues and temperatures. The yield of EtOH is supposedly pretty good. (Google on Pearson + Ethanol + Biofuel + Ethxx): and

    1. Direct reaction of H2 (from renewable electricity sources (e.g. wind turbines) and water with CO2 to make CO + H2O (the water-shift reaction). After the CO2 and H2O is separated from the CO and H2, these gasses (which are a Syn-Gas mixture) are reacted to make EtOH via the F-T route.

    2. Direct reaction of H2 and CO2 to make Ethanol, with a bit of methane and CO as by products. The unreacted CO can be made into Methanol (MeOH) rather easily - commercially done, only with yucky coal right now.



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