Re: OT - Biofuels, not so green


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Posted by David Sherman on Wednesday, May 14, 2008 at 19:40:56 :

In Reply to: Re: OT - Biofuels, not so green posted by M Fanoni on Wednesday, May 14, 2008 at 19:16:32 :

I'm all for trying the algae, but how can you say that we'd be "money ahead" if we had to provide artificial light? At that point, you're using electricity (a high-value form of energy) to produce a combustible fuel (a lower-value form). The efficiency of converting electricity into oil via light and algae is surely not very high. Efficiency doesn't matter when you're using free sunlight but if you have to make the light from electricity it ruins the whole equation.

Part of the problem with all the alternative-fuel discussions is we're going in two different directions. One direction says "We're running out of oil. What can we make to replace the oil as a motor fuel?" The other direction says "We're ruining the climate with CO2 emissions. How can we stop emitting CO2." Although those two concerns sound similar in that they both look for alternatives to burning oil, they tend to go in nearly-opposite directions after that. If CO2 is the issue, all the methods to reduce it require using considerably more energy overall than we currently do, because extra energy is needed to sequester the CO2, or make hydrogen out of water. If lack of petroleum is the issue, however, the only alternative that's truly realistic on a large scale is synthetic fuel made from coal. It's cost-competitive at around $50-$75/barrel from what I've read, and we still have plenty of coal. No biofuels come close to that if you account for all the energy inputs honestly. The only problem with Fischer-Tropsch oil is that although it's an alternative to oil, it's not an alternative to fossil fuels, so if you're concerned about CO2, it's not an option.

Personally, I'd like to see more organic wastes like municipal garbage, slaughterhouse waste, and some agricultural "waste" (though much of that is better used to build up the soil) used to make "biofuel" where it's convenient. Nevertheless, none of that will add up to more than a drop in the bucket in terms of what our country really needs for motor fuel. I'm real doubtful about "biofuels" too, mostly because I think the environmental impact of putting way more land under the plow, and the social impact worldwide of burning our food just isn't worth it for the sake of a reduction in CO2 that may be insignificant in terms of the climate. Besides, the current US policy towards "biofuels" might as well be called the "ADM subsidy". Nothing can be nearly as economical as fossil fuels for the simply reason that they already exist in combustible form, whereas anything else has to be manufactured by putting the energy into it today either from the sun or from some other energy source. With fossil fuels, the energy was "put in" a long time ago.

I also think that no matter what we do, we'll end up burning up all the oil and coal eventually and there won't be anything great to replace them. If we really had to make "biofuels" completely from biological sources, without any petroleum-derived mining, transportation, fertilizer, irrigation, etc., they'd be insanely expensive.

That's what's probably going to happen someday, maybe 100 years from now or maybe 1000. When it does, I don't think people will be very concerned any more about overpopulation or CO2 emissions. I don't know if the climate will be warmer or colder than it is now, but once all the oil and coal are burned up, "carbon taxes" and the like will be pointless. Without cheap transportation, people, food, merchandise, and armies won't travel very far. Yeah, we might all be flying around like the Jetsons or Buck Rogers in some sort of nuclear-powered cars, but I seriously doubt it. Humans will become just one more of a long line of species on the Earth that had a brief surge in population and then diminished to just a few groups here and there. If the human population stabilizes at the level of 300 years ago, they'll be doing well. I don't see any way to avoid it, though I won't be around to witness it either. Strangely, I just can't get too excited about it either way, although I do hope people won't totally strip every stick of vegetation off the Earth before they give up.



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