Whither Cellulosic Ethanol?

Ethanol is often held up us a panacea to the world's transportation fuel woes. In theory its greenhouse neutral and renewable, and it has some heavyweight supporters in Richard Branson, Bill Gates, Paul Allen, Steve Case, John Doerr, and most vocal of all Vinod Khosla:

...he's obsessed by a crusade as grandiose as any he's ever pursued: ending America's dependence on foreign oil. "I think we have a replacement for oil today," he says. "It's cheaper, cleaner, it doesn't require a change of infrastructure, and it appeals to most of the lobbies. What is this platform? It's ethanol."

The current hype (largely stirred up by Khosla) is about cellulosic ethanol. This is the kind of ethanol that's produced from any part of a plant that you don't eat - straw, stalks, corn husks. All of that waste is rich in cellulose, which, in theory, can be converted into sugar, and then ethanol.

Kholsa talks about his vision for ethanol (cellulosic and otherwise) here: Biofuels: Think Outside The Barrel

Unfortunately it seems biochemists such as John Benemann are not so convinced as he explains at The Oil Drum:

I read the presentation of Vinod Khosla and most of the responses. I have some experience in this field, about 30 years of being in the ring of biofuels technology development, with first-row seats, so to speak, on the fights I was not in myself.

Re. lignocellulosic ethanol, I am, bluntly, a skeptic. See our abstract, copied below. This is R&D, not something ready for commercial ventures, at least not in any time, or with any risk ratio, a typical venture capitalist would accept. Perhaps Vinod Khosla is not a typical VC, though I have no basis for assuming that.

Much more important, this technology is not ready for policy decisions. It compares with, for one example only, the near-late-lamented Hydrogen Program of the Bush-Cheney Administration. Coming from the same source, talk about curing our addiction to Middle East oil by substituting for it an addiction to Middle America ethanol, has just as much credibility. I note that all long-term R&D (is there any other?) for hydrogen is being terminated next month by the Dept. of Energy.

Benemann continues ...

Bluntly, we should not put our trust and future in ethanol from biomass saving the day. No more than in to that prior canard that H2 would save the day after tomorrow (remember those GM ads so long ago, was it last year, saying that todays' toddlers would get their H2 cars for high school graduation?). And remember all the venture capital that went into those hydrogen companies?

And concludes:

Yes, biofuels are and will be very important, we are already doing some things, and need to do much more. Much work is required, in many areas, from anaerobic digestion to crop production, and including R&D on lignocellulosics to ethanol. Maybe we will get the proverbial breakthroughs. But multiple barriers must be overcome, and betting the farm on just this one ticket, on only ethanol from switchgrass and such, is foolish in the extreme. And that is, what I am afraid, the Bush-Cheneys are now attempting and the Gates-Khoslas accomplishing. This single rathole could easily consume most biofuels funding and, most likely, nothing real will be accomplished.

Oh well, I guess we won't be growing our own fuel in 2050 :(

Further reading:
Vinod Khosla Debunked: Ethanol is NOT the Answer
A Conversation with Vinod Khosla