The Lowdown on Miscanthus

Now that Blogger has determined that I am in fact a real person (see this note for an explanation), I am back in business. I notice the Barack Obama is now in favor of my proposal for allowing drilling and using that to fund alternative energy. Just glad I could help. Call me if you need an energy secretary who detests politics and doesn’t respond to direction very well. More on that proposal in a later post, but first there was some topical alternative energy news from a couple of days ago.

A new report from researchers at the University of Illinois suggests that using Miscanthus as a feedstock for cellulosic ethanol production would be far superior to switchgrass:

Miscanthus can meet U.S. biofuels goal using less land than corn or switchgrass

Using corn or switchgrass to produce enough ethanol to offset 20 percent of gasoline use – a current White House goal – would take 25 percent of current U.S. cropland out of food production, the researchers report. Getting the same amount of ethanol from Miscanthus would require only 9.3 percent of current agricultural acreage.

“What we’ve found with Miscanthus is that the amount of biomass generated each year would allow us to produce about 2 1/2 times the amount of ethanol we can produce per acre of corn,” said crop sciences professor Stephen P. Long, who led the study.

In trials across Illinois, switchgrass, a perennial grass which, like Miscanthus, requires fewer chemical and mechanical inputs than corn, produced only about as much ethanol feedstock per acre as corn, Long said.

One finding that I felt was significant:

“One of the criticisms of using any biomass as a biofuel source is it has been claimed that plants are not very efficient – about 0.1 percent efficiency of conversion of sunlight into biomass,” Long said. “What we show here is on average Miscanthus is in fact about 1 percent efficient, so about 1 percent of sunlight ends up as biomass.”

That’s pretty good solar capture for biomass. It is far short of the efficiency of solar cells, but you have a built in storage mechanism - the primary weakness of solar power.

So what’s the catch? Seems like there is always a catch, doesn’t it? The catch is that it is still highly energy intensive to turn this biomass into ethanol. You have energy inputs in growing and harvesting the biomass, getting it to the ethanol plant, converting the cellulose to sugars, fermenting the sugars to ethanol, and then purifying the highly dilute broth to fuel-grade ethanol. That is of course the conventional cellulosic route, and as I have argued before I do not believe this route will ever be commecially viable. The chemistry and physics are strongly aligned against you, which is why we have spent over 40 years failing to crack this nut. That doesn’t mean that companies won’t try to commercialize. They are trying. I just don’t think they will be commercially viable, any more than I think a company is going to cure the common cold in the next 3 years.

Biomass gasification is another story. While the capital costs are still very high, in the long run you may be able to justify growing something like Miscanthus for a gasification plant to produce ethanol, methanol, or diesel. First, though, there is a lot of available waste biomass that could be utilized. Use the waste that is currently rotting or just being burned, and then let’s debate whether or not to dedicate good cropland to growing fuel.

Visit to New Choren BTL Plant

Figure 1. Choren BTL Production Process. (Source: Choren)

Introduction

I had to dig way back in my Gmail archives to figure out how it was that I first interacted with Choren. I had written several articles on biomass gasification in 2006, and when I announced that I would be moving to Scotland in early 2007, I received an e-mail from Dr. David Henson at Choren. David, at that time in Business Development at Choren and now the President of Choren USA, said he had been reading the blog, and he extended an invitation to visit the biomass-to-liquids (BTL) plant that Choren was building in Freiberg, Germany.

While I tentatively planned to visit several times while I was living in Scotland, it wasn’t until I recently moved to the Netherlands that I was actually able to make the visit. So here is some background information on BTL, followed by the trip report from my visit on April 18th, 2008 (the day after German Chancellor Angela Merkel and Rob Routs from Shell visited for the inauguration of the facility).

BTL Background

I have written a number of articles on biomass gasification. However, let’s review. Biomass gasification takes biomass - ideally some sort of waste (and I understand that the term “waste” can be contentious) plant material - and partially burns the material with a controlled amount of oxygen to produce carbon monoxide and hydrogen (synthesis gas, or syngas). One of the often overlooked benefits of the thermochemical approach over fermentation is that it can be used to produce chemicals, synthetic natural gas, or electricity - and from a wide range of feedstocks. There are many different variations of how the gasification process is done, and I will delve into the specifics of what Choren is doing in the next section.

Once you have produced syngas, you can go a number of different directions. You can burn the syngas to produce combined heat and power (this has some cleanliness and efficiency advantages over directly burning the biomass), produce methanol, ethanol (Range Fuels, Coskata, Syntec), mixed alcohols (Standard Alcohol, Power Ecalene Fuels), or hydrocarbons like diesel via the Fischer-Tropsch process (FT). This latter approach is what Choren is doing. The diesel they are producing is not biodiesel, but “green diesel” as I have described in this essay (scroll down to the “renewable diesel” section).

To my knowledge no other company in the world is as far along as Choren is in producing diesel (and maybe any liquid fuel) from gasifying biomass. Whereas Range Fuels is currently building a plant (and the schedule for that is already slipping), and Coskata is building a much smaller demonstration plant, Choren has been piloting their technology since 1998, and their new plant is mechanically complete. (Yet Choren - funded largely by private investors - has been pretty low-key, issuing a fraction of the press releases of some of the other biofuel companies).

Choren’s Process

The Choren process (incidentally, Choren’s name comes from Carbon, hydrogen, oxygen, and renewable) starts off by feeding biomass into a low-temperature gasifier (about 500 degrees C). The purpose of this step is to remove volatile components that will form tars at higher temperatures. What remains in the gasifier is called char, and is fed into the high temperature gasifier.

Figure 2. Choren Gasification Process. (Source: Choren)

The volatile components are mixed with oxygen and steam and also fed into the high temperature gasifier where temperatures are around 1400 degrees C. Under these conditions, the volatile components are broken down into syngas. The char is first pulverized, and then blown into the bottom of the high-temperature gasifier. The gas that exits the high-temperature gasifier is cooled, generating steam in the process that is used for power generation. The gas is then further treated (filtered and scrubbed), and it is ready for the Fischer-Tropsch process. You can see an animation of the entire process here.

The gasification section of the plant has been in operation since 2004, proving the scale up of the design. Since 2005, the FT section of the plant has been under construction and is now mechanically complete.

I won’t go into detail on the FT process. That technology has been around for almost 100 years, and is best-known as the process by which Germany produced their fuel from coal in World War II. Shell - a world leader in FT technology - provided the FT for the Choren plant. If you are interested in learning more about Shell FT, you can read here about the 15 years of experience they have gained from their gas-to-liquids (GTL) plant in Bintulu, Malaysia. (In addition to providing the FT technology, Shell is also an investor in Choren).

The Plant Tour

It was difficult to find the place, and I got to brush up on my German a couple of times when I had to ask for directions. But finally we (I was with a colleague) found the place and met up with David. He started off with an introductory slide show in which he walked us through the process. One of the more interesting comments he made was that the potential production of their second generation product (dubbed SunDiesel®) is up to 3 times the production of first generation fuels. A third party analysis of various biofuels may be found here, at the Fachagentur fur Nachwachsenden Rohstoffe (FNR). This agency is essentially the German Renewable Energy Department. Detailed information on various BTL platforms can be found here.

Figure 3. Choren BTL Plant in Freiberg, Germany. (Source: Choren)

The new Choren plant, utilizes forest residue and waste wood and will take in 68,000 tons of biomass per year and produce 18 million liters of diesel and 45 MW of power. One thing David mentioned that too many in this business don’t seem to get is “You know, biomass just isn’t very energy dense.” Therein lies the source of a lot of people’s misconceptions about rapidly scaling up biomass to replace petroleum. The energy density is problematic to say that least - and this poses big logistical challenges.

We finally got to walk around the plant, and they have done a really nice job. Everything was brand new, and the design was well-thought out and well-engineered. This was not like a typical dirty, old refinery or ethanol plant I have walked through before: This plant was a Cadillac. Of course it’s a Cadillac yet to be driven, but it sure was a pretty picture. Here are some facts about the plant, courtesy of Choren:

Maximum production: 18 million litres of BTL p.a (= the annual requirement of about 15,000 cars)
Biomass requirement: About 65,000 tonnes of wood (dry matter) p.a.
Raw materials: Forest residue and waste timber
Supply is secure for several years
Investment: About €100 million
Technical details: 31.5 km pipelines, 57 km electrical cables,
5,000 fittings, 5,000 measuring signals,
60 pumps, 181 containers and reactors
45 MWth output
Partners: SHELL, Daimler and Volkwagon
Synthesis/hydrocracking partner: Shell

Of particular interest was the material handling piece, as this is a major cost factor in driving up the capital costs in a BTL plant. We traced out how the material comes into the plant, and how the flows of volatiles and char come off of the low-temperature gasifier. The one piece we didn’t really look at was the FT back end, but then again I have seen those before.

So, where do things stand, and what’s next? From the Choren site:

Over 150 suppliers and around 50 assembly companies, including many from the region, were involved in the building of the Beta plant. CHOREN designed and manufactured 180 main components itself. Over 600 companies had been involved in the development of the Carbo-V® technology. By April 2008 around 800,000 man-hours have been utilized in development and assembly, and the overall number of employees almost doubled.

In the coming months 113 sub-systems in 26 main operating units will be started up individually then in sequence. Around 1,200 steps will be needed for the commissioning of these systems, which in themselves consist of several sub-steps. A highly-complex process, which, not unusually for plants of this complexity, will take 8 to 12 months. CHOREN will receive valuable support for this from Shell.

What’s the Catch?

Capital costs for BTL are still pretty high. On the other hand, Choren’s costs were sunk at a much lower capital cost. Oil at $120/bbl should help them out quite a bit - provided they have a pretty good contract on their biomass. I have no doubt that they will be successful from a technical standpoint. They have a lot of experience on the gasification piece, having piloted it since the 90’s. Shell has many years of experience on the back-end FT piece. No doubt there will be some unexpected bumps as they commission the plant; after all it is a first of its kind and speaking from experience issues will come up. But they have a lot of engineers on staff, and I don’t think they will find any show-stoppers.

There are those who insist that using biomass for fuels can never be sustainable - so there are likely to be critics on that front. However, I disagree with this. There are a number of biomass sources that are true waste, and biomass can be grown sustainably. On the other hand, it can also be used to strip-mine the soil. Like most things, there are right ways and wrong ways to go about it. Biofuels have a part to play. But it would be foolish to try to completely replace petroleum with biofuels. That would require unsustainable practices. Incidentally, Choren has a life-cycle-analysis (LCA) on their process. Highlights can be seen here.

Short-term, I don’t know that this plant will be large enough to be profitable. I don’t think that’s the primary purpose; I think proving the technology for future plants is the purpose. In the longer-term, even though I am a fan of electrifying our transportation options, we will always have a demand for liquid fuel. Choren is trailblazing in an area that I believe will supply our liquid fuel in the future. The only question is, “How far off is that future?”

Additional Reading Material

Brochures and lectures for downloading may be found on Choren’s site here.

Cellulosic Ethanol is Dead

Cellulosic Ethanol is Dead! Long Live Biomass Gasification!

My thunder has been stolen. I have been kicking around a post in my head for the past couple of weeks. I just haven’t had time to get around to it, with the move and all. But this has been nagging away at me for a long time. My thinking goes something like this.

Cellulosic ethanol, and by that I mean cellulosic ethanol in the traditional mold of what Iogen has been working on for years - will never be commercially viable. How can I be so sure? For one, I have covered the logistical challenges here and here. These are not going away, and are serious barriers to commercialization. In brief, the cellulose content of biomass is accompanied by a lot of lignin, inorganics, etc. that won’t get converted in a standard fermentation process. But you still have to haul all of this biomass to the plant, convert the cellulose (and get a low concentration of ethanol for your efforts), and then get rid of a sopping wet mess of waste biomass. Sure, it can be burned - if you spend a lot of energy drying it first. Because of the very nature of the process, I don’t believe this challenge will be solved. (I know, I know. I just have to BELIEVE….)

A recent report - brought to my attention by this story in Gristmill (and e-mailed to me by 4 different readers) - says the same thing (and stole my thunder!):

Crop-Based Biofuel Production under Acreage Constraints and Uncertainty

Here are some excerpts of comments by Tom Philpott at Gristmill:

A quiet consensus seems to be forming among people you’d think would know the facts on the ground: cellulosic ethanol, touted as five years away from viability for decades now, may never be viable.

Now we get a new study (PDF) from a trio of ag economists at Iowa State University. For the record, the authors are conventional ag scholars firmly entrenched within the corporate-dominated research world described so well by Nancy Scola in her recent “Monsanto U.” post.

So it’s surprising to see these mainstream economists deliver such a dismal forecast for cellulosic ethanol.

They start by calculating that without the latest round of goodies — i.e., the fat “Renewable Fuel Standard” of the 2007 Energy Act — cellulosic ethanol (and biodiesel, too) would have withered away. In that scenario, corn ethanol would keep ramping up from the current level of about 7 billion gallons, pushed by high oil prices and the $0.51/gallon tax credit that’s existed for years.

The authors seriously doubt the cellulosic target can even come close to being met. They reckon that the mandate can inspire “rational” farmers and investors to churn out 4.5 billion gallons of cellulosic ethanol by 2022 — but there’s a catch. In order to reach even that level, the government will have to significantly jack up the tax credit awarded to mixers — from the current 51 cents to $1.55.

Also some excerpts directly from the report:

Competition for land ensures that providing an incentive to just one crop will increase equilibrium prices of all. Also, at pre-EISA subsidy levels, neither biodiesel nor switchgrass ethanol is commercially viable in the long run. In order for switchgrass ethanol to be commercially viable, it must receive a differential subsidy over that awarded to corn-based ethanol.

Since switchgrass competes for the same acres as corn, and corn-based ethanol is less expensive to produce, corn-based ethanol will always have a comparative advantage over switchgrass ethanol in the absence of a differential subsidy.

Corn and soybeans compete for the same acreage, so when energy prices are such that corn-based ethanol is stimulated, then the price of soybeans must also increase if the farmer is to continue to allocate some land to soybeans.

We calculate the subsidies required to stimulate biofuel production to the levels required by the EISA RFS. We find that subsidy levels are needed in the range of $0.22 to $0.78 per gallon for corn ethanol, $1.97 to $2.90 per gallon for biodiesel, and $1.55 to $2.11 for cellulosic ethanol.

I can hear the ethanol and corn lobbyists scrambling for a response that involves a character assassination.

What Will Work

However, there are a couple of variations on this that I think will be viable. One is a gasification process. A number of people have taken to calling this process cellulosic ethanol, which to me is unfortunate and confusing. I have explained the differences in Cellulosic Ethanol versus Biomass Gasification. Long story short, cellulosic ethanol processes convert cellulose in a wet process. Biomass gasification converts all organic components in a thermal process. The yield for biomass gasification will be much higher, and the waste products much lower.

The other variation that I think will work is this project I have been working on for a while, but still haven’t been given the green light to talk about. Hopefully soon.

Coskata Hype

Several noteworthy energy stories in the past 24 hours, so a few quick posts.

First up is the Coskata news that has everyone talking:

GM Takes Stake in Small Biofuels Firm

Bill Roe, president and CEO of 18-month-old Coskata, said that at full production the company will be able to make ethanol for less than $1 a gallon. He said pump prices should dramatically reflect widespread production of the cheaper new ethanol by 2015 or 2016, when it expects to be building 20 to 25 fuel plants a year.

David Cole, chairman of the independent Center for Automotive Research, which receives a small part of its funding from auto companies, says GM’s move reinforces that U.S. carmakers are serious about developing alternative fuels. He calls the coming growth of cellulosic ethanol “a big deal.”

“Corn-based ethanol has never really been viable, it’s been driven by politics,” he said. “Once you’re into cellulosic or non-food biofuels, the resource base is very, very large and you’re talking about fuel at a buck a gallon. It changes the whole game.”

A growing number of biotechnology companies have been working to make cellulosic ethanol — long more costly than government-subsidized, corn-based ethanol — profitable.

Coskata’s three-step system — sending feedstock through gasification, a bioreactor and an ethanol recovery process — uses proprietary microorganisms and patented bioreactor designs that it is fine-tuning in its offices and laboratories in a Warrenville office park. It says the process is more energy-efficient than existing methods and will enable fuel to be made from a variety of non-food sources, even old tires.

The company says it can make more than 100 gallons of ethanol per ton of dry material, uses a third to a quarter the amount of fresh water for ethanol today and reduces greenhouse gas emissions by as much as 84 percent compared with conventional gasoline.

“We think that the Coskata process brings the first practical cellulosic opportunity to the market,” said GM’s Mark Maher, executive director of powertrain integration.

The first practical cellulosic opportunity? I thought that’s what Range Fuels was doing? Anyway, this story doesn’t mention it, but this is another Vinod Khosla backed venture. Is it legit? I have read through their web pages, and most of their technology has been done by others (like Range Fuels). If they can produce ethanol at high selectivity, that will be a breakthrough. But I will say again: Once you have syngas, I have no idea why you would put it in water and ferment it. Chemically convert it without the water, and avoid the wet purification step.

I will say that the process is over-hyped on their web page. They don’t even have a demonstration unit, and I can promise you the following statement from their Vision page is inaccurate:

Using its proprietary microorganisms and patented bioreactor designs, Coskata will produce ethanol for under US $1.00 a gallon anywhere in the world, from almost any input material.

Think about that. Anywhere in the world? My guess is that unless they found someone to pay a steep tipping fee to get them to take biomass, there is nowhere in the world that they will be able to make ethanol via gasification for under $1/gal.

I am not trying to be a naysayer - and I wish them all the luck in the world - but we heard all this before with TDP - and we know how that turned out. Often if you haven’t built a plant, you tend to underestimate your costs. My prediction is that this is what they will discover as they scale up. But even if they can produce ethanol from gasification at $2/gal, in the long run that will be pretty good.

Are they for real? Not enough information to say. Are there the classic signs of overhype? Definitely.

Cellulosic Ethanol vs. Biomass Gasification

Introduction

I have this neat new cellulose conversion process. I am looking for funding and working on a patent application. The invention is a personal cellulosic biomass reactor. In the first reaction step, the cellulose is partially converted to CO and H2 (syngas). In the second step, one could do many things with the syngas: produce methanol, ethanol, Fischer-Tropsch diesel, or combust it for heat or electricity. I chose the combustion for heat route, which occurs very rapidly following the 1st step. The combustion products are CO2 and water, but the CO2 that is released is equivalent to the CO2 that was taken up by the biomass while it was growing. It is therefore neutral with respect to Greenhouse Gas emissions. I am hoping to get some government subsidies, or possibly Silicon Valley startup money for my invention. You can see a picture of it below.

Personal Cellulose Reactor

And there you have an example of how technical terminology and buzzwords can be used to confuse people. This is currently happening with cellulosic ethanol, so I thought I would write this essay to talk about the differences between cellulosic ethanol and biomass gasification.

What is Cellulosic Ethanol?

A popular trend in the media lately – encouraged by various ethanol advocates – is to liberally apply the “cellulosic” label. It has become a buzzword. This is the same thing that has occurred in the field of nanotechnology. Since lots of research funding is available for nanotechnology, things like ultra-fine powders are now being called nanotechnology. This trend is being driven, in my opinion, by a bid for some of the money flowing to the nanotechnology sector.

This brings us to some of the recent claims of a big breakthrough in “cellulosic ethanol” technology. However, one of the “breakthroughs” – biomass gasification - has been around for decades, and the technology is quite different from what is commonly denoted as cellulosic ethanol. It is not completely clear to me why some advocates are so eager to blur the distinction. Perhaps the law is written such that there is a danger of not receiving ethanol subsidies if a combustion process is used. Perhaps they want to be the first to claim commercial success of “cellulosic ethanol.” Perhaps they just want to give the public and the government the impression that great strides are being made in cellulosic ethanol technology, thereby encouraging more money to flow in that direction.

While cellulosic ethanol has only recently gained buzzword status, the term has been around for decades. The historical definition of the term implies certain particular process steps. There is some variance from process to process, but the things that are common are that the cellulose in the plant material is broken down into simple sugars, and then the sugars are fermented into ethanol.

More money than ever before is being poured into cellulosic ethanol, but there are multiple hurdles that have proven difficult to overcome. For a good layperson’s overview of the process, I recommend the recent article in the Chicago Tribune: Beyond corn: Ethanol’s next generation. I think the article paints a balanced picture of the technology. In brief, there are three major hurdles that have proven challenging to resolve.

The first is that plants have evolved defense mechanisms to prevent the cellulose from being easily broken down. Cellulose is actually a polymer – a long chain of connected sugars, and it is intermingled with hemicellulose and lignin. Cellulose provides structural strength to the plant walls. If it was easily broken down, microorganisms could attack the plants and limit their structural stability. What this means is that the cellulose must first be broken down with steam or a strong acid into component sugars that can be fermented, and this adds to the production costs. It is primarily this step that differentiates cellulosic ethanol from grain or sugarcane ethanol.

The second challenge is common to all ethanol fermentation processes, but not to gasification processes. The ethanol that is produced in a fermentation process is highly diluted with water. In fact, the ethanol produced from fermenting grain typically makes up only 15-20% of the solution, with the remainder being mostly water. For cellulosic ethanol, the picture is much worse. The crude ethanol in this case is typically less than 5%, with the remainder being water. Separating water and ethanol is a very energy-intensive process. Even where the EROEI is highly favorable, as is the case with sugarcane ethanol, the distillation step takes up a substantial amount of energy. While the distillation energy in the case of sugarcane is provided by burning the bagasse, separating out that much water is still a major energy sink.

The final challenge for cellulosic ethanol is that it takes a significant amount of biomass to produce the ethanol. As the nearby biomass is consumed, trucks have to travel farther to bring biomass to the refinery. This adds to the energy inputs, and worsens EROEI. According to the previously referenced Chicago Tribune article:

Richard Hamilton, CEO of Ceres Inc., Hamilton termed this “the tyranny of distance,” a major cost issue for would-be producers of cellulosic ethanol. If a refinery needs tons of biomass to produce fuel, he said, “by the end of the year you’re driving your truck a long way to get that wheat or corn stover.”

Some proponents don’t appreciate that there are multiple challenges in bringing cellulosic ethanol to market, and that these challenges won’t be easily solved. When asked about how long it would be before the challenges are resolved, Hamilton added:

“Trying to predict technology trends is a fool’s game,” he said. “I wish I could put my finger on just one bottleneck. But it doesn’t work that way.”

I don’t want to paint too grim a picture of the future for cellulosic ethanol. It is possible that all the hurdles will be overcome. But I also don’t want to present an overly optimistic scenario in which multiple bottlenecks are merely hand-waved away, and successful resolution is presumed. The challenges are well-understood. There just isn’t a clear path at this point to solving them all, and a process with multiple challenges will face a lower probability of success.

What is Biomass Gasification?

Biomass gasification is different from cellulosic ethanol in at least two major respects. First of all, it is a combustion process, not a fermentation process. As a combustion process, it can be self-sustaining once the combustion is initiated. It does not require continual inputs of energy as is the case with a fermentation process. The products of biomass gasification are syngas and heat, if the reaction is operated in an oxygen-deficient mode, or CO2 and steam (and much more heat) in the case where sufficient oxygen is supplied. In the case of the former, the syngas can be further reacted to make a wide variety of compounds, including methanol, ethanol, or diesel (via the Fischer-Tropsch reaction). A biomass gasification process followed by conversion to a liquid fuel is commonly referred to as a biomass-to-liquids (BTL) process.

However, there is one other major factor that differentiates biomass gasification from cellulosic ethanol. Biomass consists of a number of different components, including cellulose, hemicellulose, and lignin. In the case of cellulosic ethanol, only the cellulose and hemicellulose are partially converted after being broken down to sugars. The lignin and other uncoverted carbon compounds end up as (wet) waste, suitable for burning as process fuel only if thoroughly dried. Conversion is limited to those components which can be broken down into the right kind of sugars and fermented.

Gasification, on the other hand, converts all of the carbon compounds. Lignin, a serious impediment and waste product in the case of cellulosic ethanol, is easily converted to syngas in a gasifier. The conversion of carbon compounds in a gasification process can be driven essentially to completion if desired, and the resulting inorganic mineral wastes can be returned to the soil.

Cellulosic Ethanol vs. Biomass Gasification

Gasification processes are of course not limited to biomass. In fact, biomass is currently the last feedstock of choice for economic reasons. It is much easier to transport natural gas and feed it on a continuous basis to a gasifier. In fact, most syngas in the U.S. today is made from natural gas. Coal is another option for gasification, and coal gasification is currently the dream of Montana Governor Brian Schweitzer.

While natural gas is easier to handle, and coal is cheaper, biomass is the only option capable of producing sustainable energy and mitigating greenhouse gas emissions. It is therefore the option that is most desirable, in my opinion. It is also a better option than most other “renewable” alternatives like corn ethanol or cellulosic ethanol. The conversion is much higher for gasification, and the energy return will undoubtedly be better because the product won’t need to be removed from an aqueous solution.

Compared to cellulosic ethanol, there are few technical challenges to solve with biomass gasification. The problems with biomass gasification aren’t technical, they are economic. According to the EIA’s Annual Energy Outlook 2006, capital costs are $15,000-20,000 per installed barrel for a conventional oil refinery, $20,000-$30,000 for an ethanol plant, around $40,000 for gas-to-liquids (GTL), around $60,000 for coal-to-liquids, and around $120,000-$140,000 for biomass-to-liquids.

Capital Costs of Fuel Facilities
Source: EIA Annual Energy Outlook 2006

The reasons for this should be obvious – it is much more difficult to handle biomass than to handle natural gas, for instance. Until we are willing (or forced) to pay a penalty for using fossil fuels, or are willing to pay a premium for renewable energy, biomass gasification is going to be passed over in favor of lower capital options. In the long-term, though, biomass gasification has staying power as an option for using biomass as a transportation fuel.

Vinod Khosla and Kergy

What actually prompted my interest in writing this essay were the media reports of Vinod Khosla’s latest alternative energy venture. This has been hailed as a breakthrough in cellulosic ethanol. While some may consider this a subtle distinction, I think it is very important that people understand the difference. It may make sense to preferentially fund gasification options over cellulosic ethanol options, but this will be more difficult if the public doesn’t understand the difference.

A recent entry in Venture Beat brought Mr. Khosla’s new venture to my attention. The company is called Kergy, and details were discussed in a recent story in Wired written by Vinod Khosla. Mr. Khosla explains:

In the corner of an unmarked warehouse tucked away in an industrial neighborhood north of Denver, a new company called Kergy has what is, to my knowledge, the first anaerobic thermal conversion machine (which explains why Khosla Ventures is a seed investor). It’s a 6- by 4-foot contraption that stands about 8 feet high. It looks vaguely like a souped-up potbellied stove. But it runs cleanly enough to operate indoors.

Kergy’s machine is special because it makes cellulosic ethanol through anaerobic thermal conversion rather than through fermentation or acid hydrolysis. It does not need organisms or enzymes to do its work. Biomass is heated in an oxygen-free environment to produce carbon monoxide and hydrogen. Once that happens, “the world is your oyster,” says Bud Klepper, the engineer who invented this device. The carbon monoxide and hydrogen are then reconstituted into various alcohols – like ethanol. Better still, fermentation and acid hydrol¬ysis can take days to occur, but thermal conversion breaks down organic matter and converts it to ethanol in minutes.

And here’s the really exciting part: Because all organic matter contains carbon, Klepper can make ethanol out of cellulose or any form of organic matter. This means the usual suspects such as corn, switchgrass, sugarcane, and miscanthus but also any waste product such as wood chips, paper pulp, cow manure, and even human waste. Municipal sewage has been tested already, as has hog manure. “We could double the ethanol output of the Mead facility,” Klepper says. It’s a big leap forward on the biohol trajectory, and it is right in front of us.

In back of Kergy’s warehouse, workers are busy putting the finishing touches on a beautified and expanded version of his original thermal convertor. The new one is made out of lustrous red I-beams, shiny metal tanks and coils, bright blue metallic joints, and a porous metal-grating floor. The whole thing is 14 feet high, 40 feet long, and 25 feet wide and is capable of producing 15,000 gallons of ethanol a day. And the machine can be scaled for far more capacity.

I knew this technology has been around for a while, so I looked up Klepper’s patents. After reading through the claims, it wasn’t at all clear to me what differentiated Klepper’s version from the patents that came before. Sometimes it boils down to very subtle differences in the claims, so I wrote to Mr. Khosla asking for some information:

Hi Vinod,

Just finished reading the Wired essay. Of course I disagree with several of the things you wrote, but that isn’t the purpose of this e-mail. What I am particularly interested in are the claims on “anaerobic thermal conversion.” Some people have been calling this cellulosic ethanol, but that’s really a misnomer because it is a completely different process. It is actually biomass gasification to produce syngas, a technology that has been around for at least 30 years. So it certainly isn’t “the first anaerobic thermal conversion machine.” Lots of people have done this, just not commercially. The technology for turning the resulting syngas into methanol, ethanol, or even diesel (via the Fischer-Tropsch reaction) has also been around for many years.

As I am sure you know, the reason this hasn’t been done commercially before is the high capital costs per barrel of product. But I just did a patent search, and saw that Klepper has been issued a patent on the process. It just isn’t clear to me what distinguishes his patent from those that came before. Do you know? I am not trying to downplay the invention; differences in patents are often very subtle. But I am trying to determine how his patent differs from all of the other biomass gasification patents.

I will say that I believe you are on the right track with biomass gasification. I have never had any concerns about this technology, and I believe that this is clearly the future. I just don’t know if it will be commercially viable without subsidies or mandates, because it is much easier (and far less costly) to do the same process with natural gas (GTL). But it is certainly more efficient to gasify biomass than it is to ferment it. I think you will find that it would be far more efficient to turn the syngas into diesel, but you might lose out on the subsidies. I guess if the government accepts this process as cellulosic ethanol, then maybe they would accept that product as biodiesel (which would qualify for the subsidies).

Sincerely,

Robert Rapier

He responded, but on the topic of Kergy he wrote “I am not interested in public disclosure of what we are doing at Kergy at this stage. Hope you understand.” Of course I wasn’t asking for proprietary information; I just wanted to know what distinguished this patent from previous gasification patents.

Again, my purpose here is certainly not to denigrate those involved with Kergy. In fact, if an opportunity hadn’t come up recently at work (see the note at the end), I would seriously consider working for them. Mr. Khosla and I have discussed this, and I was contacted over the weekend by one of their Senior VPs. I think what they are doing is definitely a step in the right direction, and I think it would be fun to be a part of it.

I just want people to understand that this is not brand new technology, so they shouldn’t think that the cellulosic ethanol problem has suddenly been resolved with a breakthrough. Biomass gasification certainly works, but it worked 20 years ago. It is just a capital-intensive process that has the problem of competing against lower cost (but unsustainable) gasification options.

Personal Note

I recently accepted an offer to take up a management position within my company in Aberdeen, Scotland. I will be responsible for 10-15 engineers in our Europe and Africa business unit. Most of the work will involve exploration and production projects in the North Sea, but the best draw of all is that my family and I love Scotland.

My report date is February 1, 2007, and I will be pressed for time between now and then. Therefore, my posting will be sporadic over the next few months. Hopefully, after I get settled in over there, I can start contributing again on a regular basis. I have lived in Europe before, and I am slowly archiving the essays on our previous trips at Traveling in Europe. I plan to keep this updated as we travel around Europe. I will continue to maintain the same Gmail address, so feel free to contact me there with questions or comments.