R-Squared Energy Blog: Guest Post on Cellulosic Ethanol
Thursday, August 24, 2006
Guest Post on Cellulosic Ethanol
The following is a guest post by Don Augenstein and John Benemann.
They have many years of expertise in biomass conversion. This essay
is in response to Vinod Khosla's recent posting on ethanol. In my
opinion, it is an excellent essay. First is the introduction by Don
This post presents a perspective on ethanol from lignocellulose by my
friend and co-worker, John Benemann. We have worked on, and been
immersed in, biofuels and analyses of fuels from biomass processes
for over 3 decades. We are to substantial degrees biotechnologists,
as well as chemical engineers and have successful processes going
today (methane from wastes. You can google Don Augenstein). We have
worked long and hard on biofuels for entities including Exxon (long
ago), the Electric Power Research Institute, and others. Our
carefully considered view, for which we will be happy to provide
abundant evidence is that severe barriers remain to ethanol from
lignocellulose. The barriers look as daunting as they did 30 years
ago. Ethanol from lignocellulose may indeed come to pass. But the
odds against are so dismal that a hydrocarbon fueled 200 mile per
gallon passenger automobile would be more likely to be developed.
We have been tied up with project work and were not able to
participate in the interesting, and extensive Oil Drum discussion
regarding Vinod Khosla's views on ethanol from lignocellulose. As you
can tell from our paper (abstract at the end of the essay) to the
solid waste people (which remains rather obscure, to a limited
audience), we think that there is desperate need for more airing of
the reasons for skepticism and warning the energy community of the
obvious barriers. We are astonished and stupefied that the hype has
gone as far as it has.
Better late than never. I present John Benemann's statement below.
Dr. John Benemann on Cellulosic Ethanol
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.
Of course, the issue is not whether Vinod Khosla is making a wise
investment, one that will make him even richer and his investors too,
or the opposite is true, or even what the Bush-Cheney administration
dictates that our reality will be. The issue is, does the technology
work now, can it be made to work in short order, or can we predict
when and if it will work with any assurance?
One thing I notice from this entire discussion is an absence of any
arguments based on technology. I am among other things a
biotechnologist, and very familiar with the associated chemical
engineering issues. I would have expected at least some mention of
past and recent experiences, of problems, such as needs for extensive
feedstock pretreatment or problems with fermentations, about current
R&D focus, at least a few citations to the web. Nothing. Neither from
Vinod Khosla nor the 360 odd Oil Drum respondents.
The only information presented is that Vinod Khosla has invested in
three different technologies. Well, a fair enough investment
strategy, but even with a one out of three chance, this is a long
shot, even in the long term, by which I mean over 10 plus years,
beyond which there are no crystal balls.
I strongly support R&D in this field. Money would be better spent on
that than on just one commercial plant. Or even a pilot plant. And,
let me hasten to add, that it is perfectly possible to make ethanol
from lignocellulosic biomass, it's just extraordinarily inefficient,
with EROEI easily determined to be about 1:5. The Soviets had some
wood-to-ethanol plants running during WWII, and kept them going
afterwards, with at least one going on until the Soviet Union
collapsed. Not a pretty technology, without even looking at the
energy balance (cheap coal or then-cheap Soviet natural gas to
expensive state subsidized ethanol, an economic model now adopted for
corn ethanol in the US.)
And we, in the U.S., even made butanol from seaweed harvested off San
Diego during WWI, in a major industrial enterprise that was set up in
a few months, a perfect example of necessity as the mother of
invention, and showing how fast we can do something when we need to,
for our survival. But extrapolating from making explosives for war to
transportation fuels for civilians driving SUVs is more than a bit of
a reality stretch. I like the analogy of this being the difference
between going to the Moon and Mars, another Bush-Cheney vision, I
must note. Of course, we still haven't figured out why to go to the
Moon, aside from the feel-good factor.
Bottom line, making ethanol from lignocellulosics is a technical
issue, actually many separate technical issues: can we really make 60
or 80 or 100 gallons of ethanol per ton of biomass, can we really
ferment pentoses outside the laboratory, will we have a positive
energy balance and not run this on fossil fuel as we do corn ethanol?
And, coming to the details, can we really use commercial enzymes, or
the same fermentation vessels that are used in the corn ethanol
business, or do we need to go to very, very expensive contained
fermentations. And at the end, do we get a high enough ethanol
content in the fermentation beer (above 10%) to have a reasonable
distillation cost? And, finally, can we put it all together, starting
with the necessary pretreatment of lignocellulose (and what kind at
what cost?). Actually, some applications for particular, minor,
biomass waste resources, could make ethanol now at food processing
plants, breweries and such, but this is not what Bush-Cheney or
Gates-Khosla are promoting, to bring up another "venture" investor's
Not that Vinod Khosla lacks information - his semi-public
presentations on the topic earlier this year (I saw one of the power
point presentations) provide some technology background, which,
perhaps not too surprisingly, was almost exactly what was presented
just before (or even on) January 31st in the briefing papers for
White House, to support the "oil addiction" talk in the State of the
Union speech. Another great example of sales of good sounding policy
first, supporting facts to be provided later, a well used modus
operandi. And now the Bush-Cheney administration has reshaped the
federal government funding priorities for biomass R&D, to support
their ethanol from lignocellulosics visions.
However, these visions of tens of billions of gallons ethanol per
year from biomass must, by all reasonable analysis, be considered a
distant possibility not an imminent accomplishment, as is being
portrayed. That is the bottom line.
Of course, reasonable researchers will argue about where exactly we
are and when and how can we could get there. As one close colleague
told me, all the technical problems I talk about (see attached
abstract) are actually viewed as "opportunities" by the R&D
community. I agree, but there is now the belief that with current
high ethanol prices, we have the means to this end at hand. After
all, if for the past 25 years we were almost there, according to the
National Renewable Energy Laboratory and others working on this. It
stands to reason that with ethanol prices two or three times that
high we must now be in clover. Right?
Well that is the rub of it. Wrong. We aren't any more "there" or in
clover than before. Yes, we can shave down some of the assumed costs
to reach such low, low costs, but the assumptions are still there,
only slightly closer to reality. Need I point out that there is only
one pilot plant operating, Iogen in Canada, at a quarter of initially
announced capacity? That is all we really can, and actually need, say
about the commercial status of this technolgoy.
Thus jumping on this bandwagon and joining in the suspension of
disbelief, which seems to pervade public discourse, outside some
participants of this esteemed Peak Oil blog, is premature.
There is more to this argument, however, than just the issue of
whether there is real technology (real could be defined, loosely and
very charitably as less than $10/gallon of ethanol, or about a
$100/mmBtu liquid fuel). The most important question is: what is a
better way to use our billion plus ton per year potential biomass
resource (and I stress potential, also not real, maybe one or two
hundred million tons are real): conversion to ethanol or use for
other purposes? Would it not be better to use surplus and waste wood,
crop residues, or energy crops (another whole subject) to heat our
homes, using wood pellets or even gasification to make heating oils?
And if we really want ethanol from crops, and I would favor some,
10%, to 20%, of our use if ethanol is economically or energetically
feasible, would it not be better to grow high starch crops (requiring
lower fertilizer inputs than corn)? Then we can make ethanol the way
we know how, while using part of the crop residues for the process
heat, rather than coal or natural gas. That should be an improvement
what we are doing now, the corn to ethanol fiasco.
Well Vinod Khosla is probably correct, as I read him, that there is
nothing that can be done about the world as we find it, and the
function and reward of capital is to serve the system as is, not as
it should be. And when I ask, do we want to drive our SUVs or freeze
in our homes, that is rhetorical, as I do realize that the question
is becoming irrelevant, the "we" will include only those who can do
both, and they won't really care, any more than any other ruling
class has, about those that can't heat their houses or drive their
And a final question, should we, including our venture capitalists,
foist on to other countries, let me give India as an example I know
of personally, our simultaneously myopic energy policy and visionary
technology focus? The answers to this and the prior questions are
apparent, they hardly need to be answered, but they are not being
So I sincerely wish Vinod Khosla all the success in his enterprises.
I hope they work for him and his investors, and for all of us.
However, I am not enthusiastic about the free enterprise tail
enabling -- or even able to enable -- this preordained policy dog to
wag. 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? Anyone into
financial forensics? But that is not our problem.
OK, as I said, reasonable people can argue the merits of this case,
but these merits, particularly the technical nitty gritty, have not
been argued to the extent necessary in this forum, neither by Vinod
Khosla nor the many who responded to this blog. I hope to add to
knowledge, in a minor way, by pointing this out, and some of the
technical issues, and suggesting that ethanol from lignocellulosics
is not something we should count on, any more than most of the other
1970s ideas and technologies being re-floated (biodiesel from algae
being a personal favorite of mine).
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.
Another victory for the fossil-nuclear energy companies?
John R. Benemann, Ph.D.
Institute for Environmental Management, Inc.
3434 Tice Creek Dr. No.1
Walnut Creek, CA 94595
(925) 939 5864
Abstract of Cellulosic Ethanol Paper
The following abstract is to be presented August 29th at the
Conference on Biofuels and Bioenergy: Challenges and Opportunities,
Univ. British Columbia, Vancouver, Canada (see www.task39.org).
ETHANOL FROM LIGNOCELLULOSIC BIOMASS - A TECHNO-ECONOMIC ASSESSMENT
John R. Benemann1*,Don C. Augenstein1, Don J. Wilhelm2 and Dale R. Simbeck2
1Institute for Environmental Management, Inc. 4277 Pomona Ave., Palo
Alto, CA 94306 *Presenter and contact, [EMAIL PROTECTED]
2SFA Pacific, Inc, 444 Castro St., Suite 720, Mountain View, CA 94041
Proposed lignocellulosic-to-ethanol processes envision a
pre-treatment step, to liberate cellulose and hemicelluloses from
lignin, followed by a hydrolysis step, to convert the carbohydrates
to simpler sugars, and then a yeast or bacterial fermentation step,
to yield ethanol, followed by ethanol recovery (distillation,
drying). Some steps might be combined, such as in acid hydrolysis
(combining pre-treatment and saccharification) or in a simultaneous
saccharification-fermentation process. After five decades of
intensive R&D, currently only a single pilot plant (Iogen Corp. in
Canada) is operating, reportedly producing about one million liters
of ethanol per year, though well below its planned capacity.
An independent analysis identified many problems with the currently
proposed processes, including the relatively high costs of biomass
delivered to commercial-scale plants (which would need to be 200
million liters per year output, or greater, for economics of scale),
the problems with pretreatment, the low rates and yields of sugars
from enzymatic cellulose hydrolysis, the resulting low sugar and
ethanol concentrations, and the overall high energy consumption of
the overall process. In addition to not tolerating high ethanol
concentrations, genetically engineered organisms developed for
combined hexose-pentose fermentations are subject to contamination,
which will require prohibitively expensive containment systems.
Even ignoring, as most studies do, such major problems, and using
available corn stover and enzymatic hydrolysis, the currently favored
biomass resource and process, our techno-economic analysis estimated
a cost of ethanol twice as high as that of ethanol from corn. Forest
residues and wastes, biomass crops, and municipal wastes are even
less promising. The conclusions of this assessment are that none of
the existing processes are ready for commercial applications in any
foreseeable time frame and that continuing fundamental and applied
R&D is required. Some opportunities may exist for near-term
applications of cellulose conversion technologies to some specific,
modest-scale, agricultural wastes.
Biofuel mailing list
Biofuel at Journey to Forever:
Search the combined Biofuel and Biofuels-biz list archives (50,000 messages):