Cutting Through the Coskata Cellulosic Ethanol Hype

I have a strong distaste for companies or individuals who overpromise and underdeliver. Changing World Technologies (CWT) and their thermal depolymerization (TDP) technology is probably the poster child for companies that promised lots and delivered little. The hype was that they had the "technological savvy" to "turn 600 million tons of turkey guts and other waste into 4 billion barrels of light Texas crude each year." Further, they were going to "make oil for $8 to $12 a barrel." (See TDP: The Next Big Thing).

Of course as time went by, the hype unraveled. But not before the hype resulted in CWT getting earmarks for building their plant (money that went down the drain as documented here) as well as a tax credit inserted by Missouri Congressman Roy Blunt to specifically benefit CWT. That money came out of the pockets of American taxpayers, and could have been better utilized. But it was hijacked by CWT and their overpromises.

These are the sorts of implications that cause me to be very skeptical of companies that make seemingly far-fetched claims. I don't want technologies receiving legal and tax benefits because of hollow boasts. This is also the reason I have been critical in my assessments of some of the cellulosic ethanol claims made by ethanol evangelists like Vinod Khosla.

Earlier this year a company called Coskata caught my attention after GM made a much-publicized investment. Coskata claims that their process "brings the first practical cellulosic opportunity to the market" and that they "will produce ethanol for under US $1.00 a gallon anywhere in the world." That is just the sort of hype we heard from CWT, and therefore was something that I was interested in investigating.

So I took a look at some of their published numbers, compared their costs per barrel of their pilot plant to several other technologies, and wrote a flippant article - Coskata: Dead Man Walking.

The article unleashed an unanticipated firestorm. Journalists started contacting me. The government contacted me. Investors contacted me. And Wes Bolsen, CMO & Vice President of Coskata contacted me. The first three all wanted to know whether Coskata was the real deal, because I seemed to be the first to conclude that the emperor had no clothes. Wes Bolsen contacted me to state emphatically that they were for real. And he reiterated that during a one-hour phone call in which I was able to quiz him about the process.

The experience taught me a few things. First, as I reach a larger audience than I did a couple of years ago, I have to be more careful about what I write and what I say. When someone at the Department of Energy, or some deep-pocketed investor is paying close attention to what I write, I should never be flippant. If I am going to state that a company is over-hyping their technology, I need to make sure that I have done a very thorough analysis. As I said in a follow-up essay, sometimes the dead man was falsely convicted.

My initial intent was to write just one short essay on Coskata, but there was so much fallout that I ended up spending an entire week following up. In my follow-up essays I did peel several layers of the onion (I got a much more detailed view of what they are doing), but I still don't think they can deliver on their promise of ethanol for less than $1/gallon. Why? In a nutshell, they are using two pieces of technology that are unproven in the service they have proposed. The technology has only been demonstrated at a small lab scale, and even then it was not all coupled together. On that basis they have made their claims of $1/gallon ethanol.

So what is the source of my skepticism around Coskata’s claims? Let’s look at two areas that I think are potential problem areas. I want to first look at their claims around the energy usage of the process, and then I want to look at the logistics to get a feel for the amount of biomass required to run a 100 million gallon a year plant. I am not going to offer up solutions to potential problems simply because I would require quite a bit more information to do so. But what I can do is flag various areas that a prospective investor/partner should investigate.

Energy Usage

The ethanol they produce is very dilute; only 3.5% or so according to Wes. This should take huge amounts of energy to purify. Coskata claims they have addressed the energy problem by using membrane technology. The claim is that it takes half the energy of distillation. This is somewhat hard to believe, as I would expect ethanol plants across the country to rush to adopt the technology. I am also unaware of any membrane separation technology that does a good job of concentrating up such dilute solutions of ethanol. The ones I know about may concentrate from 70% up to 90%. If you are starting at 3.5%, you are way outside of what these systems are normally designe for. And the technology isn't brand new. Here is a 2001 article talking up the benefits: Pervaporation comes to age.

Yet there have been numerous ethanol plants built since 2001. Why aren't they being built with membrane separation technology? Without going in and checking their claims, I can't say for a fact whether that claim of lower energy usage is valid. But there are question marks all around it. (Note: I don't dispute the technology, because I know that it works. But TDP also worked; just not as well as advertized. I would just make sure - if I were about to invest in Coskata - that I had a very close look at their claims around this area.)

Coskata also claims that they get "up to 7.7 times more energy than what is used in making the ethanol." In my conversation with Wes, I had asked if this was from Michael Wang. He said yes, which then put that claim into context for me. Michael Wang has created a model (the GREET model) that has been widely misused. The number above - 7.7 - will refer not to the energy that is used in the process but rather to the overall fossil energy used. This is the same way Brazilian sugarcane ethanol can claim an 8/1 energy return, despite the energy intensive process step of separating ethanol from water. This is a valid metric as long as the context is clear. But the context isn't usually made clear. (This is the same metric that has caused some to suggest that it is more energy efficient to produce ethanol than to produce gasoline).

Here is an illustration of the potential problems with this metric. Let's take an extreme example, as I think they are useful in illustrating concepts. Let's say that I have one million BTUs of biomass. But let's say I have a conversion process that is terribly inefficient. I use that biomass in an inefficient process to produce a trifling amount of liquid fuel: 100 BTUs. In the process, 999,900 BTUs - 99.99% of what we started with - are lost in the process because they are used to drive the process.

But let's say I have to input a small amount of fossil fuels; say in the form of electricity to run a pump. If I used 13 BTUs of fossil fuel to produce the 100 BTUs, then the energy return based on Wang's metric is 100/13, or 7.7. So, I could claim to have a high energy return despite the fact that almost all of the available BTUs are wasted. This is the 'opportunity cost' of those BTUs. Had we used the starting biomass to produce electricity, for instance, we would have had far more BTUs at the end of the process.

Now I am not suggesting that Coskata loses most of their BTUs in the process of making their ethanol. But without a real energy accounting - which the 7.7 number is not - it is difficult to determine whether this process makes better use of the available BTUs than a competing process. A proper energy accounting should take into account the overall BTUs consumed in the process, and not just the fossil fuel usage.


David Henson, President of Choren USA (another company involved in biomass gasification), once commented to me "You know, most people just don't understand that biomass isn't very energy dense." David was absolutely correct, but what does that mean? The lower the energy density of a substance, the closer it needs to be to the factory. Imagine hauling potatoes from New York to California in order to convert them into ethanol, and you get the picture. You would certainly burn more fuel transporting the potatoes than you could make from processing them into ethanol.

I believe this issue of low biomass density, which I have referred to as the logistics problem of cellulosic ethanol, is a killer for cellulosic ethanol. In fact, I recently calculated that to keep a medium-sized cellulosic ethanol plant running would consume the biomass equivalent of almost 900,000 mature Douglas firs every single year.

However, the Coskata process is not a cellulosic ethanol process. Gasification processes have distinct differences from cellulosic processes (I explained why here). The consequence is that a gasification process can have a higher yield because it converts lignin and hemicellulose in addition to cellulose. In Coskata's case, they promise 100 gallons (+) per ton. How much biomass then to run a 100 million gallon per year facility? A million tons per year. How much biomass is this? If we return to the Douglas fir example, it is the biomass equivalent of around 1.2 million mature Douglas firs per year.

That's still hard to wrap my head around, but I can put that in context from my current job. In our wood acetylation plant in the Netherlands, our nameplate capacity is 30,000 cubic meters of wood per year. A cubic meter weighs half a metric ton, so we run 15,000 metric tons per year through our plant (about 17,000 short tons). Coskata proposes to process about 60 times as much biomass through their 100 million gallon per year facility. That is the sort of logistical challenge that boggles my mind, when I try to scale up our process by a factor of 60. Further, that biomass has to be finely processed so it can be pushed through their gasifier (which can be very finicky if the biomass quality varies).

To put in the context of rail cars, the coal cars lined up outside of a coal-fired power plant are a familiar site. According to this, each car carries about 100 tons of coal. For a million tons of coal a year, you would have to have 1 million/(100 tons per car) = 10,000 cars per year coming into and leaving the plant. That's more than a car an hour, 24 hours a day, 365 days a year. And of course coal is quite a bit denser than biomass, so more cars would be required in the case of biomass.

I won't say that's impossible, but it is going to be a significant challenge. All I can say is Coskata better have hired some very good logistical experts. They are going to need them.

The Bottom Line

So what's the bottom line? Let's say you are an investor with a billion dollars burning a hole in your pocket. You need to know if Coskata is for real. Here is my free advice.

The plasma gasification piece and the membrane separation piece both need a very good technical vetting from someone who has signed a secrecy agreement and has access to the experimental data. A technology that works in the lab is one thing. But as you start to scale up, little problems turn into big problems (as was the case with TDP).

You need to know to what extent the gasifier works in conditions close to what Coskata is proposing. These plasma gasifiers are finicky, and normally used for waste disposal. Has the gasifier been tested extensively with a variable substrate like biomass? For how long? What were the results? What were the key challenges? How accurately were the energy inputs measured? In fact, I would probably want to park myself in their labs for a few days, and spend a lot of time talking to technicians. I would want to know - outside of the tours - what's really going on.

Second, I would really focus in on the logistics issue. I would want some serious details on how they are proposing to handle the logistics. How is the biomass going to come into the plant? Has a calculation been done on how far away something can be transported before it becomes break even on the energy? If it is waste biomass already coming into a point source, then it isn't as big an issue. But then I would ask if there is any location in the U.S. that is handling a million tons of waste biomass at a point source (which the gasification plant would be). I would want to see actual examples of someone handling this much biomass.

Finally, I would go over their $400 million capital estimate with a fine-toothed comb. I would ask for an example of any technology that has been piloted in the lab, and then had an accurate capital estimate done at a scale of tens of thousands of times larger than the lab scale. As I have said before, you have different problems at a pilot scale than you had at the lab scale, and the problems become even bigger at commercial scale. The capital estimate is already $400 million for a 100 million gallon per year plant - $61,000 per daily barrel. That puts it at a disadvantage to GTL or corn ethanol. Why wouldn't I expect that capital estimate to climb as they gain piloting experience? Why would I expect them to stick with biomass, when the logistics of gasifying (partially oxidizing) natural gas are trivial when contrasted with biomass logistics?


To conclude, let me state for the record that I want Coskata, and for that matter Choren, LS9, Range Fuels, Virent, Nanosolar - to be successful (defined as "produce energy in a sustainable manner"). The world needs solutions to our energy problems, and I applaud these companies for their efforts. I want my kids to grow up in a world with abundant energy. But I never let what I want cloud my judgment when I am trying to determine what is true. So, I still believe in scrutinizing their claims very closely, and stating for the record whether I believe their claims to be credible.

Thank you Robert. I was just wishing for an update on cellulosic ethanol technologies.

I think your point about transportation being a huge weakness for cellulosic is very important. Here is a graph from Cleveland's piece on Past Energy Transitions.

An eyeball estimate is that coal is 10 times as energy dense as wood by volume and 2 times as dense by weight. So possibly 20 times more truckloads to move the same energy? Now, what about uncompacted cellulose? twigs, branches, hay, grasses?

So the plants must be small, co located with the material and using a source that can be harvested easily year round.

And just to get a scale of the problem. Farmers use 5 billion gallons of diesel per year today. That is quite a few douglas firs.

First of all, thanks RR. And John, you beat me to it. IIRC, Miscanthus is 15 to 20 times less energy dense (by volume) than coal. So that would give you one train every 4 minutes at the 100MG/year ethanol plant! Maybe pyrolysis of biomass locally into bio-oil is worth looking at? (producing bio-oil, syngas and heat) And then ship the oil to more centralized bio-refineries?

There is some data on collection, storage and transportation of productive grasses. The Chariton Valley project collected switchgrass and after storage burned it in a power plant to see if it could displace coal. They discovered that they have to keep it dry (switchgrass is a powerful wick structure in a bale) and then at the plant they had to debale it and then grind it for the boilers, in the same way as one would grind it for any other processing. Their numbers, as I recall, were about $60 a ton for everything before the plant and $20 a ton for processing at the plant - there were some combustion issues as well that I can't fully remember this morning.

Thanks HO! So $80 per ton total? How does that compare to what power stations pay for coal? OK, just checked Google, and here in the UK, Scottish Power announced a 97% increase in coal costs from Feb '07 to Feb '08, ie from $68 per tonne to $134 per tonne.


So, $80 per ton for switch grass would be a bargain, no? Hmm, just realized that if energy density by mass is approx 2:1 then you need 2 tons of switchgrass for each ton of coal, ie $160 versus $134. OK, now we need to add in the carbon cost of coal. Yesterday CO2 was 18.4 EUR/tonne or $23.7/tonne. I'm finding a number of 2.4 tonnes CO2 per tonne of coal so CO2 cost is approx $56 per tonne.

OK, my calcs show for equivalent energy, switchgrass is more expensive than coal ($160 to $134). But if you add in CO2 costs, switchgrass is cheaper ($160 to $190). Assuming, naively I know, that switchgrass is CO2 neutral.

At the time the plant operator was paying closer to $20 a ton for the coal - and the plant did not factor in some of the combustion issues, or some of the costs in growing the grass, since EPA mandated that the field could only contain permitted species and thus it had to be treated with some weed killers to remove unwanted species. (This is from a paper that was given at Dubuque last year, and which I wrote about at the time .) Going back to check the reference I see I got some of the numbers wrong

Three test burns have been made, addressing such issues as boiler corrosion.

They harvest the grass after a killing frost, so that virtually all the nutrients have left the plant body which is harvested, and are left in the root bit which is left on site. The grass is bundled into special bales 3 x 4 x 8 ft, and hauled to storage. You can’t leave it in the field as it wicks water, and it must be stored on gravel in a barn (same reason). Bale integrity controls energy availability. The bales weigh 1,000 lb and when reground for combustion they prove to be abrasive, and moisture content helps with this (12% moisture at the boiler if kept well, which matches the harvested value). The third test burn used 25,000 tons of grass over the 90-day test period. It cost $61 per ton for haulage, and $26 per ton for re-processing the grass at the power plant into small fragments (< ¾ inch) that could be blown into the furnace. The plant was paying about $20 a ton for the coal, and in the above you will note that the farmer did not get paid for the grass. Like the coal, the grass had to be totally consumed by the fireball within 3 seconds of being fed into the boiler fireball.

They displaced 2% of the coal in these tests, and are now permitted to burn the switchgrass.

Torrefaction is definitely worth looking at for such fuels.  The torrefied product does not absorb water (most of the OH groups have been removed) and could be milled easily to powder.

So the plants must be small, co located with the material and using a source that can be harvested easily year round.

Or some plant which processes the biomass to a transportable form must be.

There are some candidates for transportable forms.  Torrefaction can be used to dry and densify biomass, make its properties more uniform and reduce the dry mass by about 30% while losing only about 10% of the energy; the product is better than coal in some ways because it is not hygroscopic.  Torrefied biomass can be gasified more easily than raw biomass because it is both dry and friable.  There is also fast pyrolysis to bio-oil.

Farmers use 5 billion gallons of diesel per year today.

At 140,000 BTU/gal, that's about 0.7 quads.

Herbacious biomass is about 15 million BTU per bone-dry ton.  If 70% of the energy can be produced as storable fuel, that's 10.5 million BTU/ton.  0.7 quads of fuel would require about 67 million tons of biomass.  The USA has a potential of about 300 million tons of crop wastes alone (straw, corn stover, etc.); we can power agricultural machinery from the farm, it's everything else that we need to worry about.

I didn't look at the details of Coskata's technology, but in general I am not so pessimistic about the feasibility of 2nd generation (= cellulosic) biomass conversion - even in the colder climate of Germany. This applies especially to of producing bio-gas using fermenters - a widespread and mature technology that farmers use to produce heat and / or electricity. With some more recent technologies (e.g. using extruders), that allegedly result in a positive EROEI, the applicability of the fermenters is enhanced to celullosic matter that could hardly be used before, e.g. wooden twigs.
About two years ago a study of the renowned Leipzig Institute for Energy assessed that this way on the long run this could supply the entire natural gas demand of Germany.
Electicity produced in these can already be fed into the national electricity network (and is paid by a feed in tariff) and feeding in the gas in to the national gas pipeline network probably will be possible from 2014.
At the time of the study biogas was still more expensive than natgas (I should look up the exact price tag), but with the present import prices it is certainly more than competitive.
According to this study (and others) using small, decentral fermenters feeding into the gas pipeline network avoids the need of transporting low-energy biomass over long distances. This is also an advantage over other more complex biofuel technologies developed by Choren or (with a somewhat less centralized approach) Lurgi.
Until recently biofuels as car fuel additive had a strong political support (possibly also due to agriculture lobbyism). But with increasing evidences of the ecological and technical limits of (1st generation) biofuel is now aiming lower. However I fear that due to our strong car lobby it will still take a while until there is a clear target to concentrate on developing the much more efficient electricity for transportation and conserve hydrocarbons for applications where they cannot be replaced.

As a former process development manager (my responsibilities included new plant start-ups as well as a pilot plant and semi-works), what gets to me about these companies is where is the pilot plant/scale-up work?

Perhaps we were conservative but we NEVER jumped into a new process or equipment without throughly running it through the pilot plant and then slowly scaling it up. These companies seem to take some bench work and simply want to go to commercial scale.


Hyping a product, buying a congressman, reaming the taxpayer... all as American as apple pie. You object? What are ya, some kinduva Commie?

If a cheap & easy way to produce fuel from ligno-cellulosic biomass is ever perfected - retrofitting some easily cultured prokaryote with a cellulase gene from some termite gut symbiont, for instance - then all forest, grassland & kelp ecosystems are doomed. Human population ramps up accordingly and the crash comes that much harder. Everyone enthralled with the "promise" of this technology is a fool.

But hey, then we'd end up with a nice covering of oil-like sludge all over the planet. Peak oil would be solved... and the planet would look just like Titan!

Imagine the unfortunate Titan native, staggering across the equatorial dune fields, clutching its throat while dying of thirst, crying "Methane... methane..." :)

My sentiments exactly. I applaud Robert for his work. The main difference I have with him (and he may just be being polite to the people he is communicating with) is that I DON'T want cellulosic technology to work. It reminds me of "Ice-nine" from that Kurt Vonegut novel Cat's Cradle:
"The author Vonnegut credits the invention of ice-nine to Irving Langmuir, who pioneered the study of thin films and interfaces. While working in the public relations office at General Electric, Vonnegut came across a story of how Langmuir, who won the 1932 Nobel Prize for his work at General Electric, was charged with the responsibility of entertaining the author H.G. Wells, who was visiting the company in the early 1930s. Langmuir is said to have come up with an idea about a form of solid water that was stable at room temperature in the hopes that Wells might be inspired to write a story about it. Apparently, Wells was not inspired and neither he nor Langmuir ever published anything about it. After Langmuir and Wells had died, Vonnegut decided to use the idea in his book Cat's Cradle.[1]"

In the book this lab technology gets out and all the oceans "freeze" effectively killing off most planetary life.

Cellulosic ethanol wouldn't be quite as dramatic, but the effects could be similar.

Robert, I have a couple of questions please:

1. Do you have any estimates for how many acres of Douglas Fir forests is represented by 900,000 mature trees every year? This shouldn't be given as a one-off estimate, as a single year's requirement needs to be multiplied by the number of years a forest needs to regrow to maturity for total area to sustain the plant over time.

2. Do you know if anybody has calculated the minerals contained in the biomass harvested, which represents nutrient loss from the soil, and made any suggestions for how to recoup that loss during plant processing and then reapplying those minerals to the areas harvested? This would be an essential step in any sustainable system and would impact the net energy of the system.

Thanks again. Like you, I like real numbers.

How about a "positive spin" on this. The NorthWest, and Canada have a Huge problem with pine-beetles. I've read where something like 2, or 3% of the pine up there are infected. It's too expensive to pay someone to go in and trim out the infected trees; but, it might be possible to get them excised if they can be made into bio-oil, or ethanol.

Just a thought.

Sure, if you can run all the road-building equipment, the chain saws, the skidders, the helicopters, the logging trucks and all the workers' transportation on your own ethanol, and still have enough left over to sell and make money.

Otherwise you're just wasting more oil to cut down trees and ship them far away in a wasteful fashion. They'd be better off rotting in place to help grow future trees.

As noted in my post below...

British Columbia already harvests the timber equivalent of 33,000,000 Douglas firs annually. This figure is less than 1% of the provincial resource base and a tiny fraction of the beetle-infested timber that surrounds the under-utilized infrastructure already in place.

The BC and Quebec governments are transitioning both the infrastructure and resource base away from traditional pulp-paper and construction industry support programs (i.e. US housing) to Bioenergy initiatives.

That said, Robert's Douglas fir analogy, albeit effective, is misleading.

Coskata Michigan is certainly not going to be harvesting Douglas fir but rather (in a perfect world) organically grown, nitrogenous fixing perennial Dedicated Energy Crops (DECs) such as hemp - a plant that maintains a higher biomass/btu ratio, higher biomass/acre ratio, not to mention an easier and more frequent harvesting profile.

That said, Robert's Douglas fir analogy, albeit effective, is misleading.

It is simply designed to give someone a feel for the amount of biomass required. If I said "a million hemp plants" that would have been completely meaningless to most people.

...a plant that maintains a higher biomass/btu ratio, higher biomass/acre ratio...


Fair enough.

My btu assertion is based on your ballpark usage of 12.5MMbtu/ton as opposed to the 15-17MMbtu/ton that a DEC would support.

And as for the latter assertion. You're looking at 10-30tons/acre for Douglas fir vs. 10-15tons/acre for a DEC.

But you and I both know that while the DEC acreage can be harvested annually, the same cannot be said for a stand of Douglas fir.

don't forget the beetles. They could be profitably converted into bio-diesel in a suitably engineered plant. Vinod Kholsa, are you listening?

My car runs on beetle juice.

As far as I am aware, hemp is neither a perennial nor nitrogen fixing.

Miscanthus rather, not hemp.

They'd be better off rotting in place to help grow future trees.

As someone who's had to deal with them, if you leave them as you are suggesting, they spread to other trees.

Thus the normal method is to remove the infested trees in the cold weather and 'process' the trees.

Do you have any estimates for how many acres of Douglas Fir forests is represented by 900,000 mature trees every year?

For a tree farm, 500 or so trees is a pretty good average. So, to run that plant would take an 1800 acre clear cut each year. If the maturity time for the tree is 20 years, you will clearcut an area of 36,000 acres around the plant. A section is 640 acres, which is 1 square mile. So you would need to remove the biomass from 56 square miles around the plant. This is one reason that I don't think the farmed biomass model will ever be viable for cellulosic ethanol.

If you have a source that is coming into a point source - such as biomass that is presently going to a landfill - then you might have a viable model. But it is going to be on a much smaller scale than a typical 50-100 million gallon per year ethanol plant. I just don't think there are those volumes of biomass coming into any point source.

Do you know if anybody has calculated the minerals contained in the biomass harvested, which represents nutrient loss from the soil, and made any suggestions for how to recoup that loss during plant processing and then reapplying those minerals to the areas harvested?

When I was in India back in March, they were returning the waste ash from burning bagasse back to the soil. Their model for sugarcane ethanol is pretty sustainable. But as I stated at ASPO when someone asked a similar question, some of those minerals may be in an oxidized, unusable state, and some trace minerals may be volatilized. So maybe it isn't sustainable long term, but what they are doing is far more sustainable than most biofuel schemes I have seen.

washington state, Oregon, Western Canada - What would you have there? 100,000 sq mi of forest? 200,000 sq mi? And, we're talking 56 sq mi? And, remember, you're not cutting 56 sq mi at a time. You're cutting about 3 sq mi. A decent-sized farm.

Anyhoo, it looks like you could do between 2,000, and 4,000 of these if it was "balls-to-the-walls, time. Of course, that's being silly; but, I could easily see a couple hundred. You could probably do that many if you were just taking out the diseased trees, and the three, or four trees immediately surrounding the dying one. Just a thought.

You're cutting about 3 sq mi. A decent-sized farm.

But the biofuel plant has to be smack dab in the middle of it. This gets into the biomass density and logistics problem. There is a lot of available biomass. It just isn't concentrated. Dead trees from the beetle kill are scattered over a large area. It won't be feasible to transport them very far to a plant before you eat your energy savings up.

I don't know. Would it? What can a log-hauling truck carry? 15 tons? (just guessing, haven't a clue.) If so, would that equate to a potential 1,000 gallons of ethanol? How much gasoline to get 20 miles? 6 gallons? 4 gallons for return trip? 10 gallons, Total? To carry 1,000. 1%? Double the distance, 2%? Throw in another 1% for chainsaws, mule, etc.

That probably wouldn't be the "showstopper." Labor? I don't know.

Pulling a few trees out here and there then moving on to a few more is time consuming. The felled timber can get hooked up in the standing trees. Extraction it is much harder too. Constantly resetting winches and clearing temporary roads for a few sticks is just not worth the bother in my opinion.

Douglas Fir to Ethanol per Rapier
1660 lbs dry matter per tree
500 trees per acre
830000 lbs dry matter per acre
20 years growing time
41500 lbs per year
20.75 tons dry per year

50 gallons per dry ton
1037.5 gallons per acre per year
$1.00 cost per gallon
$1,037.50 revenue per acre

50 million gallons per year
48193 acres per year

75.30 sq miles
7.64 miles radius
3.82 average miles trip
69.17 fresh tons
264.12 ton miles
0.30 cost per ton mile
79.24 cost per acre
8% hauling cost

"0.30 cost per ton mile"

How did you calculate that? A highway semi can carry 40 tons for $.50/mile, for about $.01/ton-mile. I realize trees are much less dense, but with lower weight wouldn't fuel consumption drop as well? Wouldn't a well organized farm optimize it's internal transport, with good roads, conveyors and electrification where appropriate, etc?

A truck doing 2 MPG with diesel at $3 would be already $1.50 per mile. So, not sure where you're getting your $0.50 per mile from.

But there are many other cost involved with hauling. You can use the model of Mississippi here: Look under "software" tab.

Sounds viable to me. One plant surrounded by 4 miles of biomass, providing 500 gallons of fuel per year for 200,000 people? So if we had about 1000 of these plants, we could totally eliminate our oil imports.

Oil imports cost more than half a trillion per year. In order for it to be viable in the business world, each plant would have to cost less than half a billion dollars. That again sounds feasible to me. But the cost of the plant would also have to include the cost of growing and harvesting the biomass, paying the workers, fueling the vehicles, etc. If total plant cost + 20 years of production and maintenance was kept below 500 million, then we could completely eliminate all foreign oil imports at no additional cost to us. With an added bonus of countless new jobs and a cost effective means of repatriating our offshored industry.

I just cant imagine how such a plant could cost more than 500 million. Maybe the first few might, but after it spreads out across the land, it should be very cheap to replicate the existing design.

1. It depends on what you mean by "mature." In old growth Pseudotsuga dominated mixed conifer forest there may only be about 10 to 20 mature (>80 cm dbh) Doug firs per hectare, and about the same number of equivalent sized trees of all other species combined. That along with maybe about 30 - 110 younger shade tolerant Doug firs per hectare. Of course, the numbers and sizes vary widely according to geographic location. Are you talking about the west slope of the Cascades or the southern Rockys? Such mature trees may be between 1 & 2 centuries old. Please remember that forest =/= tree farm.

2. Ash content of Doug fir may be as little as .2% in wood, or >3% in bark & needles. Half or more of this ash content may be inert silica, depending on edaphic conditions where grown. Do you really think that a commercial biofuels operation is going to return mineral ash to the ruined forest, after having clear cut it?

Good questions & good post Jason. Do you happen to know if the Langmuir thunderstorm research lab atop South Magdalena Peak in NM is named after the Irving Langmuir you mention?

I recently attended a conference here in Raleigh, NC that touted the southeast as "the Saudi Arabia of biomass." But out in the convention center hallways many realized that the elephant in the room was the sheer magnitude of the US energy consumption and while there are some promising developments, none of them (singly or perhaps in combination) will be able to replace and support the existing infrastructure for energy that we've put in place for today (from yesterday).

When CWT was in the news as the best thing since sliced bread, I was attempting dissuade people because the hype did not fit anything that I was taught as an engineer. More importantly, there did not seem to be anyone around who could come up with a cogent explanation that made all the energy and mass balances work.

We've developed a culture of "something for nothing" and that mentality is pervasive. You see it in campaigning for tax policy, environmental policy, fiscal policy,....

As Thom Friedman points out, you can jump off an 80 story building and for the first 79 floors imagine that you are flying and in control. It's only that sudden stop at the end.

If we ever get cellulosic ethanol ramped up, we are going to have to deal with competition of all kinds of users for biomass--electric utilities, homeowners, chemical industry, and cellulosic ethanol. Biomass may have to come from a greater distance, because of this issue.

There is already some concern about whether there will be excessive deforestation because of the use biomass for cellulosic ethanol. For example, Cellulosic biofuels endanger old-growth forests in the southern U.S.

Thanks for the link Gail.

Long live the Dogwood Alliance!

It's true that we can't jam pine trees into our existing oil pipelines, but we have to get off our current energy paradigm completely. I think you know this but you hesitate to make the leap.

If cellulosic ethanol is net energy positive, which USDA and others state it is, then it makes no sense to burn it in power stations, etc. The reference below for switchgrass shows a net energy gain of 60 GJ per hectare, about 600 gallons of ethanol per acre positive for a group of farms yielding 5.2-11.1 tons per hectare of crop. It was also shown that a gallon of ethanol replaces over 7 gallons of petroleum.

It's always better to convert biomass to ethanol in a net positive energy process than to simply burn it(for electricity).

From an economic viewpoint it depends on the costs of inputs and the price of ethanol. The way to insure that cellulosic ethanol can replace petroleum , which we all believe is a finite resource at a profit is to add a carbon tax to petroleum/gasoline.
A carbon tax will somewhat neutralize the unfair economic advantage that the huge hulking old technology/infrastructure has over new net energy positive biotechnologies.
We can all see that our energy infrastructure is hopeless; it is more economic to run it into the ground than to repair it or invest in it. We need to shift to a new processes.

Coskata's gasification technology has the advantage that it can take commingled trash and turn it into ethanol. I don't know if these processes are net energy positive, but if they are we should do them. The amount of US solid waste in paper is around 120 million tons(12 billion gallons of ethanol. Is it more valuable as recycled paper(in a 'paperless' society) than ethanol? We think of ourselves as a wasteful society but all our solid waste is tiny compared to our energy wastage. This (along with the fact that plastic is more expensive than oil) is why thermal polymerization of plastics isn't going ahead.

The USDA/DOE says we have over 300 million tons of forest resources(30 billion gallons), which because of a mix of feedstocks could be more amenible to Coskata's gasification than enzymes. IF the process is net energy positive AND somewhat carbon neutral we should do it(I suspect it uses quite a bit of natural gas to obtain the neccessary temperatures).

I feel that you are perpetuating many of the errors Robert discusses. The studies you cite are full of them. Yes, they come from government labs and departments, just like the USGS and EIA give us estimates of fossil fuel supplies.

I highly recommend looking at David Fridley's critiques. He also works at a government lab, but has a very different take on the feasibility of biomass at any significant scale to replace fossil fuels.

The first thing to do is get rid of any mention of money in the analyses. Do a biophysical accounting first. If that doesn't add up then no amount of fiscal accounting will either, unless massive subsidies are applied.

I assume you mean by citing the 7 to 1 petroleum replacement figure, I disagree. It is not an error but it requires some explanation.
The US consumes 40 billion gallons of diesel per year of which I think somebody said 5 billion gallons goes to agriculture. The US consumes 140 billion gallons of gasoline, so gasoline plus diesel =190 billion gallons per year.

If you produce 50 billion gallons(!) of ethanol per year you would increase the amount of diesel fuel by 7 billion gallons, but reduce the amount gasoline by 33 billion gallons(.66 (gge) of the 50 billion). You are saving 26 billion gallons of total amount or 13.6%(190-26/190).

Is it sustainable? NO!
Is it an improvement over petroleum fuel in terms of energy used--YES!

Can ethanol replace all petroleum at our present rate of consumption?
No. I never said that it could.
But I do think we have biomass resources large enough to make a significant dent in that.

I listened to your whole interview with Mr. Fridley, who mentioned that we use 100 quads of energy TOTAL, which is true but very misleading. But 40 quads of that is for petroleum and of that 30 quads(75%) actually goes for transportation fuels(diesel and gasoline and jet fuel). Right now we are getting about 22 mpg with gasoline cars and a much lower mileage with diesel trucks, jumbo jets, etc.

He mentioned that the 1.3 billion ton biomass project might produce 15 quads of energy(I'd say maybe 12 quads). I've seen projections that the annual renewable wood resource is 5-10 quads.

How much would fuel efficiency have to rise for supply to match current demand? 30 quads/12 quads=2.5. (a 55 mpg car?)

We could do it if radically improved fuel efficiency AND cut consumption.

He casually mentioned that the 15 quads was 20% of the total US annual biomass.

Pimental says that 7 billion kcals of sunlight shines on a hectare(2.5 acres,4 Btu per kcal)) per year in the growing season, therefore 330,000,000 agricultural acres under cultivation would receive something like 3700 quads of solar radiation. The solar efficency of photosynthsis is 2% so
that seems to check out, but for developed cropland only.

In fact we have 600 million acres of pastureland and 600 million acres of forest in addition to another 100 million acres of cropland not under cultivation. Adding these up we get a total of 1300 million acres of land receiving something like 15000 quads of sunlight over a growing season or 300 quads of biomass primary energy. It's not unlimited but it's also not tapped out.

Fridley's reals concern center around ecological and soil issues. I don't discount these factors( I'm not the 'worst person in the world'), but in an energy based discussion they are a bit extraneous.
He also believes that there is plenty of fossil fuel as I remember.
We are very far from absorbing all of the US biomass though were it not for fossil fuels we'd truly be out of gas.
The most important thing by far is to shrink our consumption to match renewable energy sources.

"Fridley's reals concern center around ecological and soil issues. I don't discount these factors( I'm not the 'worst person in the world'), but in an energy based discussion they are a bit extraneous."

I am going to argue that ecological and soil issues are NOT extraneous. Without fossil fuels we are going to be forced to rely more and more on the realities of ecological and soil issues. Abundant fossil fuels have both contributed to and masked our ecological debts. To go into even further ecological debt because we are about to reach a declining flow rate is the height of stupidity.

"He also believes that there is plenty of fossil fuel as I remember."

Not true. He is a believer in a near term peak in oil and other fossil fuels.

"We are very far from absorbing all of the US biomass..."

I agree with you here. The main question for me is "how" and at "what scale." You are right that we have to do a lot better in how we allocate the precious liquid fuels we have or might have with biomass.

No, it isn't "always better to convert biomass to ethanol," whether or not it's net energy positive.

Although it's a small fraction of total fuel used for generation, there is still considerable diesel burned for electricity, and if that can be displaced by burning bales of grass, then the computation changes.

It seems intuitively obvious that turning solid biomass into liquid fuel is a loser compared to switching some of the existing electricity production from liquid fuel to biomass. Of course that ignores the backup-power status of much of the diesel generation, but the point still stands, EROI wise. I have no quantitative model - sorry.

Ethanol is stored energy whereas grid electricity is continuous (aka waste).
You could burn the biomass in an intermitent hot air Stirling engine with an efficiency of about 10% with solid fuel.
The grid produces electricity at 30% efficiency.
The efficiency for producing ethanol from biomass is about 60% efficient.
For example generating grid electricity from ethanol with a 30% efficient generator would be .6 x .3 = .18 or 18% overall efficiency.

How do we use energy?
Out of 100 quads of energy 34 quads goes for transport, 40 quads
of primary goes to electricity of which 24 quads goes to baseload(coal and nukes--the cheapest fuels per kwh) and 16 quads(hydro and NG) goes to peaking load.
The rest goes to products like fertilizers, chemicals and space heating,etc.
Therefore of the primary energy we directly use only 33%(24/74) comes to us as a constant stream of electricity from the grid. The other 66% of the time we need storable energy for which we pay at least double.

Free Image Hosting at

Maybe this ugly quantitative model graph can show what I'm trying to demonstrate.
Above you can see that grid energy with the sharper slope produces more useable energy as primary energy use increases but also it also contains almost no 'inherent' energy(opportunity cost) whereas storable energy produces marginally less useable energy at high consumption but at lower consumption its 'inherent' value raises it 'utility'.

Given that 2/3 of all our energy is of the 'storage' type (and we are willing to pay extra for it per kwh) and that in the future we will be moving to lower energy consumption (and higher energy prices) I think it is likely that we will be moving to the left on the graph.

Another way of saying it would be that the less energy we use the more important storage becomes because we don't know when we will need it.

Burning ethanol (as a cheap fuel) continuously would be inherently wasteful of a limited and therefore scarce/pricey resource.

On the other hand I believe our University boiler uses 40% wood chips in their feed stock, and has for several decades.

It's always better to convert biomass to ethanol in a net positive energy process than to simply burn it(for electricity).

Why? You burn it to get heat. Otherwise, you use up a lot of energy to convert it to a liquid fuel ... then burn whatever's left over for heat (after transporting it). I don't see how that could ever win, especially if the waste heat from the power generation can also be used for building heat.

I shouldn't think analysis of this or any energy production system would require too much detail. The thermodynamics of the situation can be used to test the boundaries. Any time you start with a low density fuel and have to concentrate it, it requires work to do so. Even if you assume the most efficient (say Carnot maximum efficiency) for the concentration work (and it doesn't matter what technology you employ if you use that assumption) you should be able to calculate very quickly how much total energy is consumed reaching the desired concentration.

I have never understood why so many people believe in magic. There is a boundary condition in which the original concentration of available energy (exergy) is too low such that no reachable efficiency in the concentration process will allow a net gain in energy. I am still working on some calculations on this, but my guess right now is that no biological-based (photosynthesis) process will produce the quantities needed in the time needed at a net positive energy gain. Sorry.

Question Everything


IMO, so many people believe in magic because they cannot distinguish between magic and science (or science-based technological advances). For those who have not had rigorous training in science, the achievements based on science are just so much magic, because these people understand neither physics, nor chemistry, nor biology.

Also, people WANT to believe in magic, for much the same reasons as they want to believe in astrology. We want magic to solve our problems. We want answers and solutions for our problems. For most of the public, scientists do magic.

Indeed, any science you do not understand has a magical element in it.

"Magic, Science, and Religion" is a very interesting book by the late anthropologist Bronislaw Malinowski. He pointed out that primitive peoples do not have science, but they all have magic and religion which perform some of the same sociological functions as science in providing answers to why things are as they are.

Note: Relatively few economists have any background in science at all, though I can think of one exception--my old prof, Daniel McFadden, who was a physicist before he became an economist and eventually a Nobel Laureate in economics. Economists engage in magical thinking all the time, with their elaborate mathematical models that look scientific but actually are not.

I, too, was distressed to read the hype on CTW. However, if we could come up with small farm sized, proven to work, package units which use bio mass to produce fuel, they may prove to have a positive EROEI as a large quantity bio mass is available within less than a km. If the ATF restrictions on stills were eased, many of my students could run on moonshine to get to class.

The "waste" biomass produced on farms needs to go back into the soil in order to conserve soil texture, restore micronutrients, and sequester carbon in the form of refractile humic substances. Producing fuel - whether biodiesel or ethanol - from ligno-cellulosic biomass deprives the soil of these benefits while ensuring that the carbon ends up in the atmosphere in oxidized form, contributing to anthropogenic climate change. Biofuels are a bad idea at any scale.

Ummmmm.... not quite. Your "analysis" appears to place bio-fuels on the same level as fossil fuels regarding CO2 emissions. It is a simply proven fact that if an isolated system eg. earth, used only bio-mass-derived fuels for its energy purposes, the levels of CO2 in its atmosphere would remain constant, causing no GHG-based problems.

More "magic" and "religion" instead of science.

I agree that it is important to make sure that above ground carbon feeds below ground carbon to some extent, and that nutrients in the above ground parts need to be returned to the soil ecosystem.

However, plant ecosystems vary a great deal in the relationship between above ground productivity (e.g., biomass grown per year) and below ground metabolic rates (i.e., biomass consumed by soil organisms per year).

In general, where conditions are: 1) warm, 2) moist and 3) well aerated, any above ground productivity will be metabolized by soil organisms given the chance.

Where conditions are any combination of: 1) cold, 2) dry and 3) anaerobic, carbon produced above and below ground may not be decomposed as rapidly as it is produced.

Our best soils are in places where decomposition rates are somewhat below productivity rates, that is how soils with high organic contents form!

Theoretically, it could be possible to harvest above ground biomass in ways that do not lead to a loss of soil carbon given you are in an ecosystem where the mass balance is appropriate. The most difficult place to do this is in the tropics, hence all the excitement over biochar, since it appears to create a form of carbon that is highly resistant to decomposition.

Can you present any reference for a case where a plant adds carbon to its structure from any source other than from CO2 taken from the atmosphere?

The only circumstance I can think of is in aquatic ecosystems, but then the CO2 in the water is exchanged with the atmosphere.

Are you implying I said otherwise? You may be mis-reading me?

As I understand it, the soil itself needs carbon to keep it healthy.

The carbon provides structure and holds other nutrients in place. Actively putting biochar into the ground is far more effective than dead plant material, which leaves excess biomass to be harvested for energy. The nutrients in this biomass must not be destroyed and returned to the soil, of course, or there's going to be trouble. Biogas (fermentation) is pretty good at this. An artificial cow. Cow eats grass, we get the energy (food is energy too), return the shit to the soil. Cow or biogas digester, it's the same thing. There's no reason why this couldn't be produced sustainably, with most mobility powered by electric renewables (EV, PHEVS). It's the infinite growth thing, and the habit of waste, and not willing to make the sacrifices to change that habit, that's unsustainable.

Converting (ligno) cellulose into a liquid fuel suitable for our current cars seems certainly an onerous process and I agree that any charlatans making unrealistic claims so as to talk money of your pocket should be exposed.

But at least it should be stressed that one major advantage of using biomass is that plants keep making the stuff over and over again: it’s renewable.

The same cannot be said for oil and coal. Therefore it is unfair to paint the problems, such as for example the logistics of biomass, against the backdrop of the most advantageous fossil fuels, which you seem to do with your example of coal cars.
How would you put coal in your tank anyway?

And some others here want to make the point that biomass can never replace all crude oil needs. But is it therefore bad??? I would think that anyone concerned with the peak oil problem, would welcome alternatives that would diminish the slope on the right side of the curve.

"I would think that anyone concerned with the peak oil problem, would welcome alternatives that would diminish the slope on the right side of the curve."

Do you pull the bandaid off the wound slowly or do you yank it off? I say yank it off. The pain may be intense but it's over with quickly. Pulling the bandaid off slowly only prolongs the pain.

How would you put coal in your tank anyway?

The same way you put biomass in your tank. The coal example is simply a logistics illustration; it has nothing to do with whether burning coal is good, bad, or indifferent.

I would think that anyone concerned with the peak oil problem, would welcome alternatives that would diminish the slope on the right side of the curve.

The point of the post is to distinguish real alternatives from those that merely pretend to be. The essay isn't an indictment of Coskata; it is merely a reminder that there is value in being skeptical.

"The same way you put biomass in your tank." "it is merely a reminder that there is value in being skeptical."

Let's be skeptical about coal-to-liquids then too.

Oh, I have spent a lot of words on CTL as well. Here's a brief commentary that spells out my thoughts:

I also wrote of the dangers of all of these "XTL" options here:

That's also the essay in which I coined the term "XTL" to cover GTL, CTL, and BTL collectively.


Thanks for an interesting post.

How do the Coskata EROEI figures compare with direct gasification of woody biomass?

You will probably have been following Wayne Keith's coast to coast journey in a gasifier pick-up truck:

1.5 miles from a pound of wood seems quite respectable. Figures quoted were 12lbs wood replaces 1 gallon of gasoline (18mpg in Dakota pick-up?)

Wood is about 6500 BTU/lb

Whilst on-board gasification is very much for "Pioneers", with some development it could become more mainstream.


Fantastic Post Robert. My inclination is that there is a [exponential/linear] negative relationship between Energy Return on Investment for biomass to liquids as a function of distance from processing plant. Quantifying this relationship might be my next post/paper - thanks for the brain fodder...

Good post -- your conclusions pretty much jibe with everything Alice Friedemann raised in her very interesting article "Peak Soil: Why cellulosic ethanol, biofuels are unsustainable and a threat to America", that appeared on The Energy Bulletin web site in April of last year:

The Friedemann essay is an awesome read. Thanks for posting the link. Everyone interested in these issues should study this essay until its lessons sink in.

From your link: "To understand the concept of EROEI, imagine a magician doing a variation on the rabbit-out-of-a-hat trick. He strides onstage with a rabbit, puts it into a top hat, and then spends the next five minutes pulling 100 more rabbits out. That is a pretty good return on investment!"

This seems to be representative for the logic of this article: garbage in = garbage out.


I agree with the general sentiment that soil is a precious resource, which should be jealously guarded. However, I'm a bit skeptical of the conclusion that it's impossible to sustainably extract energy (in the form of biomass) from the landscape. Allow me to offer an historical example from my region.

The prairie soils of south-central and south-eastern Wisconsin are, in geological terms, relatively new. The entire area was covered with a glacier some 10-15,000 years ago; as it receded, it exposed deposits of sand, gravel, and clay which (although rich with minerals) were essentially devoid of any organic component. Today, the richest soils in this area are largely the product of a tallgrass prairie ecosystem which dominated the pre-settlement landscape for thousands of years. One of the key characteristics of this ecosystem was that it routinely burned - every year, or every several years - in a spectacular release of energy, leaving bare, blackened soil behind to accelerate the arrival of new growth in the spring. Indeed, in the absence of fire, the prairie in this rain-rich country could not survive, as it was quickly shaded out by encroaching shrubs and trees. Fire was integral to this marvelous machine of topsoil creation.

To my mind, our challenge is to figure out how to mimic this natural system while capturing for our own ends some, or most, of the energy which is "normally" released in an orgy of open-air combustion. I don't claim to know all the tricks for how this could be done, but I think that the lesson of the prairie that it can be done.

I'll be pondering this as I'm out helping with a prescribed burn this weekend. Watching a few hundred acres of good prairie erupt in flames gives one a visceral appreciation for the amount of energy contained in a single year's growth.

Great point, stclair. A systematic introduction of burned carbon onto the soil every year is something we should be doing now. We will Have To do this at some point. We Will run out of cheap, easily obtained phosphates at some point. Probably sooner than we think. Personally, I think seriousness of "peak oil" Pales in magnitude to the Danger inherent in "peak phosphates."

Where did/does that energy from fires go? Would our diverting that energy have any unintended consequences?

Operations that are dealing with similar logistics.

A list of 12 largest biodiesel (existing and proposed/funded/being built)

These appear to be operating:
7. Imperium Renewables plant in Grays Harbor, Washington, USA. Production capacity: 100 million gallons per year, opened on August 15, 2007, with raw product mostly oil derived from canola grown in USA and Canada.

8. Louis Dreyfus plant near Claypool, Indiana, USA. Production capacity: 250,000 gallons of biodiesel per day, which adds up to more than 80 million gallons per year.

This one being built describes the inputs. So the two above would use about 25-30% of the inputs or about 400,000-600,000 tons Canola for Grays Harbor.
Dominion Energy Services, LLC has broken ground for a $400-million integrated biodiesel and ethanol refinery in Innisfail, Alberta, Canada, it will consist of a combined 300 million gallon per year production facility (100 million gallon ethanol, a 100 million gallon canola crush facility and a 100 million gallon biodiesel) on commencement in the third quarter of 2008, and will use about 1 million tonnes of wheat and 900,000 tonnes of canola a year for raw residue.

A large ethanol plant
in california

The 60 million gallon per year Stockton facility is located at the Port of Stockton, with access to water, rail and road transportation. The facility will process 21 million bushels of corn per year, producing both ethanol and 500,000 tons of WDG annually for the use by local dairies for feed products.


Costs for regular biodiesel is 80-90% dependent upon the cost of the feedstock

EIA cost and energy analysis for soybean and yellow grease based biodiesel [2002, 2004-2006]

Gas 2.0 Clayton Cornell looks at 23 "myths" about biodiesel

Energy return (EROI) soybean biodiesel (2-3)

Some info on biodiesel from Robert Rapier [who just wrote this article questioning coskata)

Energy density and EROI estimates of different feedstocks

Used cooking oil EROI 34.7/37
Canola 1.39-3.62 (australia)
Palm oil 9

It has seemed to me for quite some time that "cellulosic" would need to be "local," in nature. Small plants at landfill locations, surrounded, perhaps, by a few miles square of switchgrass, miscanthus, or somesuch. From what little I've read it seems to me that maybe Bluefire might be on the right track.

One should be wary of hype, of course, but one, also, has to be wary of those saying, "it can't be done." It was Patzek, or Pimental, I think, that correctly stated a couple of years back that corn ethanol was a terrible idea because with the best available hybrids you could only get 123 bu/acre and 2.7 gal of ethanol/bu.

Of course, what happened was Dupont, and Monsanto kept slicing those genes, and, now, we're averaging 154 bu/acre (they say they'll be at 200 bu/acre in a decade) and up to 2.9 gal/bu. Add in a little fractionation, fluidized bed gassification, and cob harvesting while in the field, and suddenly it looks a whole lot different.

Anyhoo, we shall see fairly soon. In the meantime, good article RR. It's always good to be cautious with the retirement money.

Is there a specific corn variety grown for ethanol as opposed to yellow corn tortillas ?

What is its name ?

Jmygann, most tortillas are made with "White Sweet" Corn. Ethanol is made with yellow "Field" corn. Having said that, "some" commercial operations use "yellow sweet" corn for tortillas.

Monsanto, Dupont, etc are constantly creating new seeds. Some will give a higher oil yield. Some will give a higher starch yield. Some will jump up and "squirt corn juice" in your ear. I suspect you would have to email the seed companies (or, perhaps, just call your local seed dealer) to get this year's hot item.

waste and algae EROI ballpark expectation is 5-10 from [Michael Briggs, University of New Hampshire, Physics Department]

As I've noted in another thread, none of the vegetable-oil schemes can scale.  Waste-to-fuel (e.g. yellow grease) is great, but the supply is strictly limited.

I don't understand this whole thing about "Scale." Why can't we have several small solutions in leiu of of "One Grand Solution?"

BTW, I think I read where something like 7% of Californias semis could be operated off of "yellow grease." With Diesel selling for almost $1.00/gal above gasoline it seems like we'd want to use every conceivable, albeit "small" solution.

Why can't we have several small solutions in leiu of of "One Grand Solution?"

One of the problems is that the proponents of the small solutions often seem to have their eyes on the same (limited) feedstock.  Yellow grease is already in demand for things like livestock feed, so unless you have material that's going to a landfill you're adding demand (and impact) somewhere else.

The marginal cost is very important, because that's where the price is set (just look at what happened to oil prices when demand for the marginal barrel went over $140).  Even if you can find cheap fuel for 80%, the last 20% will drive the market price of shipping; running 7% on yellow grease isn't going to affect much.

If California wanted to make a much bigger impact on both fuel consumption and air pollution, it would push something like Bladerunner for shipping and electrify the tracks.  An electrified system could run through tunnels with relatively little ventilation, and could feed braking energy back into the system.  When you consider the amount of fuel burned just to climb mountains on I-5 between LA and points north, an electrified rail tunnel might pay for itself mighty fast.

It never hurts to remind everyone that ALL bio-X processes depend on plant photosynthesis for solar energy conversion at the start. About 1% efficient at converting solar energy to biomass. Long term, given issues of phosphorous and potash resources being GONE in 75 years, it seems much smarter for society to give up on the liquid-fueled SUV's and switch to solar-thermal-electric at 17% station efficiency, 16% after transmission (I know, but that 5%-of-product transmission loss only amounts to a 1%-of-solar-input loss. Work it out). It therefore obviously follows that a bio-X based energy system WILL use at LEAST 17 times more land area than a solar-themal-electric based energy system. (More when you factor in the winter down-time of bio-X based plant growth systems).

Just to start....

Good point Len, 17% efficiency of say CSP (concentrated solar thermal) to 1% for biomass. I also agree that society should switch to electrified transportation. But:
- CSP initial capital costs per acre are way higher than biomass
- annual biomass costs are probably higher than CSP annual costs
- liquid fuels fetch a higher price per kWh than electricity

Putting aside the $1-per-gallon-hype which RR has expertly deflated, I would like to ask him and others about the prospects of this technology to deliver product at say $5 per gallon....since that's where the market is headed medium term. (Say 5 years)

For personal transportation we seem to be headed in the direction of range-extended electric vehicles and thus liquid hydrocarbons could play a substantial role in our future for a very long time. And they don't need to be cheap to have a future. And they don't have to be super-abundant. But the renewable variety will, of course, always have to compete directly with remaining crude oil.

I have a positive bias towards biomass based liquid fuels, so you have been warned.

The criticisms of current entrepreneurial efforts are well taken. Biomass is low density. If/When it succeeds, it will drive a reorganization of society in which there is far less long distance trade in low value commodities, i.e. biomass. Because of the logistical issues that Robert raises, the eventual full production sized plants may well be smaller than current thinking imagines the proto-type plants to be. If one considers Fischer-Tropsch (FT) as an example, there is little need for further R&D. Yes, it is known to be uneconomic in a world that has petroleum to burn, but we all know that that will end some day. What is needed is a business model that conforms to the post peak business environment. That model is likely to be one in which processing plants are sized and sited so as to minimize transport costs of raw materials and waste ash. The demand for liquid fuel will be much less than today, because most travel and transport will be by rail, and rail will be electrified. A few of the elite will travel by air (needs liquid fuel) and farm machinery will still need liquid fuel.

What does it take, in the way of planning, to get from here to there?

Oh, and let's not lose sight of this. Conoco Phillips, and Tyson are teaming up to use this maligned avian offal technology (with improvements, I assume) to produce a whole bunch of "renewable diesel."

So, you never know.

Firstly, I'm not keen on the industrialisation of any technology that converts "waste flesh" into a saleable commodity, for what should be obvious reasons.

That aside though, how can one sustainably produce and sell the millions of fowl required to subsidise the flow of "waste" offal?

If meat consumption is not maintained without cheap energy, then the offal waste used as an input won't be available for the plant to use.

It's probably more energy efficient to have chickens dispersed throughout people's villages, with offal used as dog or pig food, or as fertilizer. Except then there's no industrialism/capitalism, so it's "broken" for many people.

geek, you're looking a looong way down the road. The kind of liquid-fuel volumes needed to run the farm equipment and fly the rich are a small fraction of the total current use, IMO. Conservation alone - driven by $10 gas, for starters - would be enough to guarantee sufficient stocks for essential use for who knows how many decades.

I'm all for alternatives, and for localizing production. Biomass used for home heating trumps transport fuel! The problem (and the reason you see so much kneejerk rejection of bio-EtOH here) is because of its popular implementation, which is all about defending the indefensible: BAU.

"Until you change the way money works, you've changed nothing." - Mike Ruppert, among others.

I think it is noteworthy that some wealthy individuals and corporations have foolishly declared cellulosic ethanol to be a winner; General Motors and Vinod Khosla being the prime examples. A parallel example is Google's support for geothermal despite lack of evidence.

My view is that if a concept can't get the bugs worked out within five or so years then the prospects are doubtful. Thus I would now question alcohol fuels in general (ie methanol, ethanol, butanol), pyrolysis and algal fuel. If there is no progress in a couple of years on wood gasification it may have to go the same way. To get a feel for gasification I've tried dry distilling of chopped straw in an airless retort and I can see the problems. Perhaps all hydrocarbon fuels, both fossil and renewable, are doomed.

All hydrocarbon liquid fuels are doomed only when the last major vehicle manufacturer stops making ICE vehicles and is making 100% EV's. One generation?

Interesting post Robert… I suspect Khosla came down on you pretty hard, especially after your Deadman piece.

At any rate, I’m not here to bash your prognosis on Coskata but rather intend to run a little thought experiment using your calculations.


You assert that Iogen’s demonstration yields of 70 gallons ETOH per ton of biomass in a 50MMg/y facility would require 714,286 tons of feedstock per year.

Using Coskata’s numbers of 114 gallons ETOH per ton of biomass, would you allow for the theoretical calculation of 50 million/114 = 438,596 tons of feedstock per year?

Hence, using your Douglas fir analogy, theoretically we would require 438,596 tons* 2000lbs/ton / (1660) or 582,645 trees per year, per Coskata plant.

That sure sounds like an awful lot of trees but maybe we should put that into perspective.

In 2007, the province of British Columbia harvested approx. 83 million cubic meters of timber (the majority of which –ironically– being Douglas fir).

Using ORNL conversion tables, there are 3.62 cubic meters to a cord or approx 1.2 dry tons (2400 pounds).

83 million cubic meters /3.62 * 2400 = 55,027,624,309 pounds or the biomass equivalent of 33,149,171 Douglas firs harvested annually. Right?

So in theory…

Just one province (BC), has a sustainable annual harvest of enough biomass to support 56 Coskata plants producing 50MMgy, for a total yield of 2.8 billion gallons ETOH a year. Similarly, and again using your calculations, this single province alone, could support 38 such facilities using Iogen’s demonstrated cellulosic production path, for a total of 1.9 billion gallons ETOH a year. Correct?

Note: that the 83 million cubic meter harvest referenced herein, is done so from less than 1% of BC’s provincial resource base. And that the amount of beetle-infected timber (in BC alone) is estimated to be 625 million cubic meters in 2008.

Interesting post Robert… I suspect Khosla came down on you pretty hard, especially after your Deadman piece.

No, I haven't spoken with Khosla in a while. Nobody came down on me, it was just that the article got so much attention I was a bit taken aback.

Just one province (BC), has a sustainable annual harvest of enough biomass

It's not about the amount of biomass. It is about the biomass density around the plant, and the relative proximity to the end marketplace of the fuel.

An obvious question is whether a plant can be made small enough to be portable? Like sawmills of old, a portable processing plant could potentially "follow" the saws.

It would be tough to make a portable gasifier, but I have looked into a portable torrefaction unit (EP mentions torrefaction above). I have not yet convinced myself that this isn't viable.

It would be tough to make a portable gasifier

You sure?

The University of Hawaii flash carbonizer looks to be about semi-trailer size.  The products are a combustible low-BTU gas and charcoal.  I'll bet that the charcoal could be gasified by a number of different means on a very small scale; gasogenes can be small enough to fit in a car trunk.

What's the minimum economic scale for a syngas-to-methanol plant?  Could one be built to fit on a bunch of semi-trailers and plumbed together at a job site?

I don't think the gasifier would be the problem. It's "what do you do with the gas?" If you could come up with an economical portable package - gasifier plus back end fuel plant - there would be a HUGE demand for it.


Poet: a 10MMgy syngas-methanol portable unit could be economically feasible, however, there are many externalities invloved as you know.

And although the higher order alcohols would be of greater value than methanol, I suspect that because it would be bio-methanol (derived from biomass) there could be a green premium attached or carbon trading angle to offset production costs.

Take note (as I'm sure Robert has) of the timely deployment of government and industry sponsored, environmentally-friendly chemistry clusters like Axelera

It's "what do you do with the gas?" If you could come up with an economical portable package - gasifier plus back end fuel plant - there would be a HUGE demand for it.

Okay.  What's the price at which such things become feasible?

Looking at this Linde Engineering report, the cost of synthesizing methanol from H2/CO2 is the smallest (I'm guessing that this is because no further feedstock treatment is required).  The cost figures are given in $ per metric ton, but given an alcohol density of 0.792 we can convert this to $/gallon:

$/MT $/gal
100 0.30
150 0.45
200 0.60
250 0.75
300 0.90
350 1.05
500 1.50

It looks like a cost up to $300/metric ton would be competitive right now, and $500/ton would be quite profitable at fuel prices of just last summer.  A 100 ton/day plant (about 12 million gallons/year) would be down there at the extreme left end of the graph (page 5).  Could something like Ze-gen turn wood into a properly balanced syngas at that rate in a unit that could be trucked to a job site?  It does look like the demand is just waiting for someone to put it all together.

I don't think you could ever justify producing syngas at the site and transporting it anywhere. Any mobile unit is going to have to produce a liquid, or gas that is easily condensed - at the site.

That's obvious to me too, but maybe I wasn't clear:

If a 100 ton/day methanol synthesis plant can produce MeOH from syngas at around $120/ton, could biomass from e.g. beetle-killed trees be harvested and gasified cheaply enough to add less than $380/ton to the product cost?  The syngas would never leave the (mobile) processing plant.

I don't know if this will help, but Burlington (Vermont) Electric operates a 50MW wood fired electric power plant that would seem to be somewhat to the scale Coskata would need. According to their web site, the peak capacity is 76 tons of wood chips an hour which works out to something over 600,000 tons a year if the plant were run full bore 24/7 -- which it isn't. Anyway their occasional lengthy, slow trains of wood chips are something of a nuisance, but nothing as dreadful as commuting in L.A. or San Diego or Washington, DC.

Here's a link to the web site. Perhaps you can glean some useful numbers.


Thanks for the link to the Burlington McNeil power plant.

76 tons of green wood chip per hour to fuel a 50MW plant puts a stake in the ground regarding the practical operating efficiency of a real wood fired power plant.

The green wood waste will be of very variable moisture content. A lot of heat energy is wasted in a conventional fluidised bed combuster to drive off this moisture.

The figure quoted is 2.5 tons per cord of green wood. This suggests that the green wood might be as much as 50% moisture content, compared to dry wood at 1.2 tons per cord.

The other useful figure quoted was the fuel input when the plant is running entirely on natural gas 550,000 cu ft per hour. With nat. gas being about 900 to 1000 BTU per cu ft you can estimate the overall efficiency of the plant boilers at around 31 to 34%% when running at the full 50MW output.

When running on green wood waste, the efficiency halves to about 16%. This is probably down to the thermal requirement of evaporating the moisture from the wood. Is 16% overall efficiency acceptable for converting wood waste into electricity?

The efficiency could be improved by using the heat in the exhausted steam to dry the wood fuel. Hot flue gases could also be used to dry and partially torrefy the wood chips, improving their overall energy density.

Could the overall plant efficiency be raised by gasification of the wood chips and running the syn gas into a combined cycle gas turbine, rather than the conventional steam boiler and turbine configuration at the Burlington plant.

Before we convert all of our wood waste into cellulosic ethanol, (very unlikely) perhaps we should review if there are any better conversion options available to us?


Reply posted to wrong comment.  Carry on.

Hi Robert,
Thanks very much for sharing your thoughts and identifying the hidden assumptions in this process.

Have you investigated the "Green Freedom" concept from LANL?

Essentially it makes transportation fuels from Nuclear Energy. Their break-even cost is around $4 per gallon.

I haven't seen anything since the Press Release in February this year.

Interesting link but little reference to net energy, only dollars. I envision a world circa 2050 when only movie stars and politicians can fly in planes using nuclear synthesised hydrocarbons. Everybody else has to take a steam train. For longer journeys there will be stops when passengers get out and chop wood for the boiler. Anybody caught digging coal will be punished but in any case the deepest mines will be exhausted.

"Green Freedom" is essentially H2CAR with a nuclear power supply and atmospheric carbon harvesting.

My dissection of H2CAR found very little to like. "Green Freedom" would be several times as expensive as running the nation on nukes to charge EVs.

in re. Green Freedom
on page 4 of the pdf:

"We have limited our studies to nuclear power because its capital costs are lower than wind and solar-electric power, ... "

I think that there are a lot of people, some of them here at TOD, who question this assertion about relative capital costs.

I have wondered for some time if there is a minimum size at which a solid biomass fueled steam powered powerplant would still be profitable. Could it be as small as one megawatt? 10 megawatts? 100 megawatts? What sort of expertise do the powerplant workers need to possess? The fewer ton/miles the fuel travels by truck the better. So where is the cross over point on truck ton/miles? 10 miles? 100 miles? 500 miles? What is the crossover point by rail? By barge?

I work in this area, about 25-30MW is the minimum size, any smaller and the capital cost kills you. Almost all wood transport (>95%??) is by truck in the U.S. The maximum transportable distance is probably between 50 and 100 miles, less as the price of diesel goes up. By the way the largest size possible is probably about 70-80 MW, any bigger and the wood requirements cannot be met in this transportable area in most locations in the south-east. One plant has been annouced at 100MW, lots of doubt if they will be able to get enough wood. Your operators would have to be experienced power plant personel, they will be running a fluidized bed boiler, a steam turbine, water treatment, etc.

What's the cost of transporting wood, say in ton-miles?

How much can a truck hold, and what MPG does it get?

RISI just completed a study on the impact of cellulosic ethanol on the U.S. south east wood supply. Cannot be linked to as it a protected document. Basic conclusion was that there is no way the projected cellulosic ethanol can be supplied as it would be totally unsustainable. They predict that there will be massive push back from the current users of this resource and that goals will have to be modified. Speaking as one of the current users I can assure everyone that the battle has begun and "easy" biomass (i.e. trees) will become a very hot political item.

This is from 2002
I don't think this went anywhere

To grow miscanthus, a producer needs to dig holes and plant sprigs of the grass one at a time to be successful. The crop will grow back on its own year after year for up to 30 years, but it's not big enough to be harvested the first few years its in the ground. Even with all these complications, University of Illinois researcher Steve Long says a farmer who's willing to make an investment in miscanthus can reap great rewards in the long run.

"You do need labor to put this into the ground, but then after that, this is considerably less labor than corn or soybeans, and on current figures, it is more profitable."

Those figures are more theory than reality at this point, because a market for miscanthus has yet to emerge. Dynegy is the only power company that buys miscanthus in this part of Illinois. And even dynegy won't be ready to harvest biomass crops on a large scale for another five years. But the energy company projects it could eventually pay 40 dollars per ton of dried… harvested miscanthus. That's pretty good money for the farmers. The reason dynegy will pay that much? While it doesn't burn as efficiently as coal… miscanthus emits far fewer pollutants. And while it emits greenhouse gases such as CO-2 while it's burning, it will recapture those gases when it grows. As energy companies are forced to meet more and more environmental requirements, Dynegy's Chris Williams says miscanthus becomes appealing:

"It's getting closer and closer to the cost of coal generation. And you look at that with the environmental benefits of the biomass, it really makes sense to do the research now to get it into production as soon as we can."

Dynegy is looking for farmers to grow miscanthus within a 50-mile radius of one of its central Illinois power plants. But the company doesn't know how many farmers it will be able to find. Even if enough farmers are interested, dynegy is still working out the specifics of harvesting, shipping, and burning grass effectively.

so the coal burning power company was thinking of something that would make them slightly greener
and then they didn't have to cut their emissions.

To grow miscanthus, a producer needs to dig holes and plant sprigs of the grass one at a time to be successful.

This sounds a lot like the process which is used by US Forest Service to plant trees. It is labor intensive, but lots of people really want to have trees in the forest, so the money is found, somehow. It might help if we could establish a 'Miscanthus Day', like Arbor Day ;-)

It is also similar to the way rice is planted in much of Asia. Remember the individual holes don't require a back hoe.

I have a strong distaste for companies or individuals who overpromise and underdeliver

OK - I'm starting my 9 unfinished posts in the queue today. One at a time.
Thx for the kick...;-)

Remember, though, that you didn't overpromise. You only underdelivered. :-)

Fascinating comments on a very relevant opinion piece about alternative fuels. One of your best.

As a blogger myself for the last 3.5 years (see BIOenergy BlogRing) I have been writing about biomass conversion processes, biomass feedstocks, biofuels, biopower, bioproducts, and biowaste. I would like to comment on your statement about logistics:

"I won't say that's impossible, but it is going to be a significant challenge. All I can say is Coskata better have hired some very good logistical experts. They are going to need them."

I have been working with a company that provides contracting services to some of the biggest biopower generators of the nation - the often maligned paper and pulp mills that, in addition to supplying their base products, made the switch from fossil fuels to biomass conversion for their boilers during the last energy crisis 30 years ago. As a result, they not only supply a majority of their own power, heat, and steam for their operations but they are the major contributor to renewable energy in the country. Combined with biofuel production, bioenergy produces as much renewable energy as hydro, wind, geothermal, and solar combined.

Our company produces about 16 million tons of woodchipped and hogged fuel for our 21 installations - more than a million tons per year at some installations - mostly in the Southeast U.S. We are poised to produce much more as the demand for woody biomass for biorefineries and biopower plants is being mandated by the national EISA renewable fuel standard (RFS) and state by state renewable portfolio standards (RPS) proliferate. We have a contract to provide woody biomass to the Range Fuels project in Soperton, GA. Coskata is relying on us for our expert logistics consultation on their plans for eventual deployment. We are working in BC (see below).

We are very focused on the sustainability issue which we see as a balance between environmental and economic concerns on the fulcrum of available biomass. This balance is horribly skewed right now because of the lack of choices at the pump. According to Robert Zubrin's book, Energy Victory, we have gone from spending the equivalent of 4.5% of our defense budget on oil imports during Carter to spending 120% of our defense budget on oil imports during 2008. Not economically sustainable - particularly considering that many of the nations receiving this transfer of wealth are not particularly sympathetic to our global diplomatic posture.

As a communicator, I see my job as trying to bridge the gaps between environmentalists, industrialists, academics, and policymakers so we can move forward on the production of clean, carbon-negative, alternative biofuels and biopower.

There is a good reason to wonder where this biomass for alternative fuel production is going to come from. We have excess biomass to draw upon as stated in the USDA Billion ton study. Furthermore, energy crops will provide a big part of the mix.

But the area I think has the most immediate environmental benefit is using biorefineries to help remedy current and future (thanks to global "weirding") environmental disasters. Here are five examples - 1) nonrecyclable municipal solid waste being diverted from landfills, 2) industrial waste (which is massively more abundant than MSW), 3) climate knockdown (hurricane Katrina reportedly damaged 5,000,000 acres of trees - by comparison Mt. St. Helens was 130,000 acres), 4) unstoppable beetle kill (not just in BC but also throughout Colorado and parts of the west), and 5) forest management trimmings to reduce the growth and impact of wildfires (which have been growing exponentially during the last 20 years). Forest thinnings, dead tree salvage, and restoration of forest growth should be a cornerstone of California's wildfire mitigation strategy ( ).

Comments in this column about the possibility of using British Columbia's beetle kill for biomass conversion is well founded. And we are working on it. We just signed a strategic alliance with Raven Biofuels to situate a thermochemical conversion site in Kamloops, BC to utilize mountain pine beetle kill as the primary feedstock to produce ethanol. (see ). It should be noted, however, that this feedstock, which should have a negative cost (tax incentives or tipping fee) because of its social liability as a source of ghg from decay, is among the most costly feedstock we have to deal with. It is up to policymakers to correctly incentivize access to these environmental liabilities to remedy ghg emissions. Growing public awareness of these issues is helping to draft appropriate legislation in the U.S. and Canada.

We need more biomass conversion deployments, not fewer. We are at a very, very nascent stage of development of most conversion technologies. As you mention logistics is key. Deployments in rural areas will have to be decentralized - we work to an ideal radius of 50 miles from each installation because beyond that hauling times prohibit more than two runs per day per vehicle.

Rural North America, through bioenergy installations, can play a major role at providing self-reliant solutions to energy generation - important to America but also exportable technology to help solve rural global problems. The paradigm shift will not succeed if it is not BOTH environmentally and economically sustainable.

We need a drop in growth of demand for fossil fuels. In view of the "Hot, Flat, and Crowded" future before us we also need decentralized alternatives customized to each location. Many of these should be based on biomass conversion technologies that utilize the non-fossil stored energy of the sun for feedstock.

Wonderful information, Scott. Thanks a lot. I've bookmarked your blog.

You mention GHG a couple of times -- how is the carbon return path significantly different for rotting wood or incinerating or converting it to Ethanol for combustion? Will the carbon be somehow sequestered in the biomass conversion case?

It could be, Paleocon, if you went with the fast pyrolysis route. You would end up with some biochar which would, then, be returned to the soil.

CCS would take ethanol from being roughly carbon neutral to carbon negative faster.

Archer Daniel Midland is going to sequestering 1 million tons of CO2 over 3 years from an ethanol plant in Decatur,Illinois starting next year.

Good question.

The best way to sequester fossil carbon is not drill or mine it out of the ground in the first place.

Like all renewable energy technologies (solar, wind, hydro, geothermal), the process is at worst carbon neutral (excluding the manufacture of the technology facilities). By replacing carbon-positive fossil fuels and electrical generation you help reduce the addition of new carbon into the atmosphere.

Bioenergy is unique because plants pull carbon out of the atmosphere to start with. Your conversion choices are :
1 - The clean combustion of biomass (with scrubbers) to create electricity that would be, at worst, carbon neutral. The carbon in the smoke could be sequestered using the same CSS that the fossil industry intends to use.
2 - Pyrolysis of biomass to generate heat with the carbon as a byproduct that can be sequestered as biochar for fertilizer (see also "terra preta")
3 - The gasification of biomass which captures the heat to cogenerate electricity while capturing the emissions as synthesis gas (H2 and CO). Syngas is not only a cleaner, carbon neutral combustible alternative to natural gas but can be used as a building block for catalysis (Range Fuels) or bioconversion to ethanol and other higher alcohols (INEOS and Coskata). The GHG emissions of the process are negligible and can be scrubbed in any event. It is estimated that 85% of the volume of MSW nonrecyclables can be reduced in this way.
4 - Enzymatic conversion of the biomass into fermentable sugars (to ethanol) and lignin for combustion or further processing into carbon sequestering bioplastics and other products. As mentioned before this method produces fewer gallons per ton of biomass but there is a need for bioproducts and green chemicals that might actually have higher value than ethanol.

Rotting wood wastes wood sugars and lignin - carbon emissions that could otherwise be converted into useful bioenergy and bioproducts. Rotting wood also suggests that new growth is unmanaged and there is evidence that forests killed by wildfires and bug infestations do not grow back as forests ( ).

IMO, by doubling the amount of carbon in the atmosphere we have, in essence, broken mother nature. Laissez faire doesn't work anymore -we need to manage our forests and forest restoration before the escaped carbon exacerbates the greenhouse gas phenomenon. I believe we can reduce wildfires if we preemptively thin forests and recapture released carbon from wildfires if we salvage and replant.

By the way, the new conversion technologies plan to utilize woody biomass (limbs, needles, twigs, and leaves) usually left by logging. We intend to leave 30% of this now valuable feedstock in the thinned forests to retain carbon balance in the soil.

Why wouldn't you just pile it up, and burn it? That's how, it's figured, the SA Indians created Terra Preta. Besides, that's what the loggers do now.

Rules about combusting anything varies across the country. I am simply saying that when harvesting for biomass, we will enforce a discipline to leave about 30% behind. Prescribed burns are healthy for forests so long as they don't get out of control. We will defer to the prevailing wisdom of the day.

What, unfortunately, is happening now in some federally managed forests is that BFPs (big __ piles) are left in place, dry out while emitting GHG, and run the risk of becoming kindling for wildfires. In today's mindset, that is a waste of energy resources and a danger for habitats and surrounding communities.

Rules about combusting anything varies across the country. I am simply saying that when harvesting for biomass, we will enforce a discipline to leave about 30% behind. Prescribed burns are healthy for forests so long as they don't get out of control. We will defer to the prevailing wisdom of the day.

What, unfortunately, is happening now in some federally managed forests is that BFPs (big __ piles) are left in place, dry out while emitting GHG, and run the risk of becoming kindling for wildfires. In today's mindset, that is a waste of energy resources and a danger for habitats and surrounding communities.

ThX Robert ! Your posts are always appreciated , highly so!

And I find it particularly important to try to lift the curtains on renewables b/c they are touted to become the salvation/replacement remedy for and when fossils dwindle.
Furthermore and as you point out, the media swallows and presents new renewable-lab-stunts with big, fat and bolded headline types like : "This or that will save us, and here is how ..... "-kind of journalism .... and the average reader even less skilled than the journalist is just simply left in the dark with this "Headline Truth" becoming part of his/her believe system. Scary.

Scalability and EROEI for renewables are everything : IT is the Yes-Do-it or No-forget-it trigger for them all. I have an itchy and growing feling that there are much more No-forget-it than Yes-Do-it's out there, that said we only need "a few" Yes-Do-it's to achieve a softer landing , no?

Robert your work is hard to put a pricetag on (obviously this one goes for all TOD contributers), and I reckon this kind of work is part of something greater than monies.
Your conclusion is "king", reality before guestimates and hopes.

key source of chipped wood that will be used to fire boilers at Robbins Community Power Plant, which will operate the power plant. The power plant needs 350,000 tons of wood chips annually

Lot's of focus on the biomass issue while the separation comments are ignored. The issue of energy savings by adoption of membranes versus conventional is real and demonstrated, albeit not for ethanol. A quick read is Spear, Mike; "Stretching separation choices", Chemical Processing, February 2006, pages 18-22. Distillation is an energy hog and requires far more than the second law demands.

I don't find the arguments that corn plants don't use membranes and therefore they don't work very compelling. Distillation scales very well and has little technical risk. Furthermore, in a dry mill plant, energy is recovered from the distillation for use in drying steps in the plant. Since the Coskata process will not have to dry the equivalent of DDGS, they will benefit more from the use of membranes. Even if membranes were available, a dry mill plant would have very little reason to be compelled to use them.

As for the commercial readiness of membranes, Vaperma is currently demonstrating membrane drying for use in ethanol manufacture. Replacing any current technology is tough and, except for the large energy requirements, distillation is robust, proven technology. At 3% concentration, distillation is not viable. This is a challenge for all biofuels made at low concentration, butanol included. It is one that membranes seem particularly suited to handle, too.