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I'm with you. It is definitely more "scam" than anything else. Everything I've read about using genetically modified organisms to produce fuel inevitably run into how to get the fuel out before the concentration kills the organism that produced it.

Technology like the Fischer-Tropsch method was proven viable using coal years ago. It isn't that big a step to use biomass. I'm watching companies like Range Fuels and research on plants like Miscanthus Giganteus. They have much more believable claims.

Inevitably, if it sounds too good to be true then it usually isn't true.

Much of the water use for ethanol production comes in the form of irrigation. For forests this is not an issue. For fermentation you use about 10 times as much water as you produce in fuel because yeast does not tolerate a very high alcohol content. Portions of this water can be reused in principle since it is not all evaporated upon distilation. Wet mashes are being used more an more for feedlots located adjacent to distilleries. That is water reused for other purposes.

In this case, only enough water to produce syngas is used and this is eventually encorporated into the fuel http://www.rangefuels.com/conversion_process. So, the water use is substantially less.
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OK, first we get past the blogodreck from some site that wants traffic, and look at the Range Fuels site.

This is funded by Kosla Ventures, which is Vinod Kosla's venture capital fund. That's a good sign; he has a decent track record as a VC. (He was one of the founders of Sun, but he later invested in Excite.) Anyway, they're not looking for money; they've got that.

People have been working on cellulostic ethanol for a while. It's not that hard to do; it's hard to do cost-effectively. Here's an overview of the known approaches. Range Fuels uses a heat-driven process, which of course takes energy to run, but is standard chemical engineering. There's other R&D underway to develop a bioengineered enzyme that will digest cellulose at commercially feasible rates. Such enzymes have been created, but they're too slow and making the enzymes costs too much. Work continues.

Anyway, this doesn't look like the big cellulostic ethanol breakthrough. But it's progress.

In this case, the residue is ash because the material is turned into a gas. This can still be used as a fertilizer but it is not the same as returning carbon to the soil:
http://www.rangefuels.com/conversion_process

Thanks, I didn't realize it was gasified, maybe I missed that in TFA. Yeap, I did: Range biofuels uses a more straightforward thermo-chemical process to gasify the cellulose and then convert it to ethanol.

In this case, the residue is ash because the material is turned into a gas. This can still be used as a fertilizer but it is not the same as returning carbon to the soil: http://www.rangefuels.com/conversion_process.
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They are actually going to gasification first: http://www.rangefuels.com/conversion_process. The enzymes are expensive (and proprietary) http://www.iogen.ca/cellulose_ethanol/what_is_etha nol/process.html. The extra heat used here probably make the whole thing less efficient, but it may still be less expensive. So far as I heard in May, the enzyme based method is not profitable yet.
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These guys are going for ethanol though they also get some methanol, propanol and butanol. Look at step 2b here: http://www.rangefuels.com/conversion_process
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Some of the stress on food prices might be reduced with this kind of plant: http://www.ajc.com/business/content/business/stori es/2007/07/03/0703bizrange.html. Their process works like this: http://www.rangefuels.com/conversion_process.
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One way to go directly to ethanol is to gassify and then make the ethanol from the gas. This is the method adopted for a new plant in Georgia that just got approval: http://www.ajc.com/business/content/business/stori es/2007/07/03/0703bizrange.html. Here is a scematic of their process: http://www.rangefuels.com/conversion_process. Their planned production is 100 million gal/year ethanol with methanol and butanol also produced. This is larger than most new larger fermentation plants. Forests don't grow all that fast so their estimate for what Georgia can sustainably produce is 2 billion gal/year, less than recent additions to farm belt fermentation capacity.
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