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At the end of the day, is producing/using ethanol greener? (http://www.economist.com/science/displaystory.cfm?story_id=9861379)

http://www.cleanmpg.com/photos/data/501/Corn_to_Propane.jpgThe Economist - September 27, 2007

SOMETIMES you do things simply because you know how to. People have known how to make ethanol since the dawn of civilisation, if not before. Take some sugary liquid. Add yeast. Wait. They have also known for a thousand years how to get that ethanol out of the formerly sugary liquid and into a more or less pure form. You heat it up, catch the vapour that emanates, and cool that vapour down until it liquefies.

The result burns. And when Henry Ford was experimenting with car engines a century ago, he tried ethanol out as a fuel. But he rejected it—and for good reason. The amount of heat you get from burning a litre of ethanol is a third less than that from a litre of petrol. What is more, it absorbs water from the atmosphere. Unless it is mixed with some other fuel, such as petrol, the result is corrosion that can wreck an engine's seals in a couple of years. So why is ethanol suddenly back in fashion? That is the question many biotechnologists in America have recently asked themselves.
...http://www.economist.com/science/displaystory.cfm?story_id=9861379

Thank you c0da!

While very interesting, this "green" attitude misses an important question -- can the ecosystem lock up this carbon as quickly as we release it? That's really the problem we face right now. We are releasing massive amounts of hydrocarbons into the environment and it can't sequester them again fast enough to restore a "normal" balance. How is switching to a designer fuel going to help unless we also figure out a way to clean out the hydrocarbons and reuse them??

My point is, I don't think this is possible. We'll sidestep the supply issues, yes, but not the environmental damage.

While very interesting, this "green" attitude misses an important question -- can the ecosystem lock up this carbon as quickly as we release it? That's really the problem we face right now. We are releasing massive amounts of hydrocarbons into the environment and it can't sequester them again fast enough to restore a "normal" balance. How is switching to a designer fuel going to help unless we also figure out a way to clean out the hydrocarbons and reuse them??

My point is, I don't think this is possible. We'll sidestep the supply issues, yes, but not the environmental damage.

Apart from any other practical and political concerns with ethanol (of which I have a number), I do think it is a good step as regards CO2 balance. FOssil fuels have been reduced and sequestered away for millions of years and now we are burning them far too quickly - more quickly than the planet can re-absorb the CO2. But if we start from plant material, there is an inherent balance in the new cycle. Or at least much closer to a balanced system, after energy involved in processing is taken into account.

Same goes with biodiesel, or other biomass synfuels.

You heat it up, catch the vapour that emanates, and cool that vapour down until it liquefies.

The result burns. And when Henry Ford was experimenting with car engines a century ago, he tried ethanol out as a fuel. But he rejected it—and for good reason. The amount of heat you get from burning a litre of ethanol is a third less than that from a litre of petrol. What is more, it absorbs water from the atmosphere.

A nit to pick with the intro to the article. When you do this distillation, you tend to get get 95% ethanol/5% water (a positive azeotropic mixture). Repeated distillations will not get you higher than 95%, and the 95% mix does not absorb futher water on contact with the atmosphere. If you extract this mix with an immiscible solvent that absorbs water (e.g., benzene), you can remove that 5% water and end up with 100% ethanol (contaminated with traces of benzene, so this should never be ingested). Now if you expose 100% ethanol to atmosphere, yes it will absorb water vapor and gradually become 95%.

It's just a nit, but when a science writer makes such a basic mistake in the intro one worries about the rest of the article.

there are some benefits in using E100 (Octane rating of 115 I think) as you can extremely downsize the engine (like motorcycle size like 600 cc) 3- cylinders with a turbocharger. Since Ethanol allows the engine to burn at much lower temperatures it can stand more compression, therefor increasing the ICE efficiency beyond the 20% number. Also don't forget that downsizing paired up with a plug in battery and getting E100 through the efficent methods possible at least one can skip the importing process!

http://www.greencarcongress.com/2007/10/turbo-charged-d.html#more

Ethanol is a ****ed poor excuse for avoiding fuel-efficient vehicles.

Harry