Wood Climbs from Supporting Role to Center Stage

Wood-to-ethanol projects approach feasibility
By Kris Bevill | September 12, 2011

In the classic children’s tale “The Giving Tree,” a lone tree willingly serves up all it has to offer to a growing boy in order to please him— providing first shade, food and shelter, then transportation, and, finally, a stump for the boy, who is now an old man, to rest his weary body on. While the moral of the story is up for interpretation, when taken in a literal sense the book highlights well the critical role trees play in providing resources to the human race. Trees have played a supporting role in the story of humankind since the dawn of time. As humans moved from cave to city, woody biomass has been a readily available resource to help advance society and expand technology. It seems a natural progression that as we seek renewable resources for alternative fuels, trees would be there once again for our benefit. But as it turns out, trees guard their precious C5 and C6 sugars, those necessary to produce cellulosic ethanol and biochemicals, with a nearly impenetrable system of natural defenses that has yet to be overcome by our best scientists. While significant advances have been made in solving this puzzle, there are some who say it is just too complicated to be completely conquered in the near future and perhaps wood is best left to be used for its many other purposes.

In May, timberland analysis firm Forisk Consulting LLC released a comprehensive study it conducted that concluded wood-based biofuels will not be commercially viable on a wide-spread basis for at least 10 more years. The technology to produce biofuels using wood products is extremely complex, the firm found, and while a few projects could produce biofuels commercially within the next decade, others will require up to 20 more years of development before they can be successful.

The study was conducted by examining 12 conversion pathways to produce liquid biofuels using gasification, hydrolysis and fermentation or pyrolysis methods and evaluating the proposed production methods of 36 renewable diesel and cellulosic ethanol projects under development. Among the cellulosic ethanol projects evaluated for the study were those being developed by Coskata Inc., Mascoma Corp./Frontier Renewable Resources LLC, Ineos New Planet Energy LLC, ZeaChem Inc., American Process Inc., and Range Fuels Inc. When compared to projects being developed to produce renewable diesel and/or jet fuel from wood sources, Forisk concluded that cellulosic ethanol projects face greater technical hurdles and will produce fewer gallons per dry ton of feedstock than renewable diesel. Therefore, it is more likely that wood will be used for renewable diesel production first. Of the production processes evaluated, gasification ranked first as the most promising technology, specifically those that employ microbes and catalytic, fast-pyrolysis processes.

In the time since Forisk’s study was released, the number of proposed and operating bioenergy projects using wood that it tracks has increased slightly—from 453 in May to 457 in late July—but the number of wood-using biofuels projects has decreased by one, down to 35. Brooks Mendell, principal investigator at Forisk, points out that the number of cellulosic ethanol projects targeting wood as a feedstock is already a small subset of the total number of proposed cellulosic ethanol projects in the U.S., and he thinks that number will get even smaller. Mendell says Forisk’s study results have been reinforced by investment firms that purchased the report to check their own analysis and while a few technology companies have contacted his firm to make the case that they are farther along than reported, Mendell doesn’t see any reason to update their status. “We have no proof that they can function at commercial scale,” he explains. “We would be the first to call a project and congratulate them when they build a commercial-scale facility and are able to run it at capacity for six to 12 months. That would be great.”


It’s true that no commercial-scale wood-based cellulosic facility is operating in the U.S., but several project developers insist that they are close to proving wood’s commercial viability as a biofuel feedstock. In Pennsylvania, Coskata is currently using woodchips to feed its demonstration-scale facility. Wes Bolsen, chief marketing officer and president of government affairs for Coskata, says Forisk did not contact his company prior to its study and likewise, Coskata has not been in contact with Forisk to dispute its study results, but he doubts it will take a decade to commercialize wood-to-ethanol. In January, Coskata received a conditional commitment for a $250 million USDA loan guarantee for its proposed 55 MMgy cellulosic facility in Boligee, Ala., and plans to be operating the facility in about 24 months. “Ten years versus two is quite a difference,” Bolsen says. “The USDA understands the technology and that it will return the taxpayers their money. It’s much closer than many people give it credit.”

Bolsen admits that wood is a “somewhat difficult” feedstock to extract sugars from, and says that is why he agrees with Forisk’s findings that gasification is the best technology for wood-based biofuel production. “When you gasify it, you utilize the entire feedstock—the lignin, the cellulose and the hemicellulose,” he says. “Gasifying wood biomass is a fantastic front-end wood process. That’s what the core of our technology is. What we’re adding is a back-end syngas fermentation that makes the platform technology very viable. I don’t think anyone should worry about wood biomass being the downfall. I think, in fact, we’ll embrace wood biomass as an early leader in biofuel production.”

ZeaChem CEO Jim Imbler doesn’t wholly agree that gasification is the best process for producing biofuels and chemicals from wood, but he does believe that wood-based biofuels will soon be commercially viable. ZeaChem is in the midst of constructing its demonstration-scale facility in Oregon and will begin producing chemicals by the end of the year. Cellulosic ethanol production is expected to commence early next year. ZeaChem’s hybrid biochemical-thermochemical approach will utilize a bacteria that occurs naturally in termites and converts mixed sugars to acetic acid in high-temperature, harsh environments. This is what enables ZeaChem to break down difficult wood products, he says, adding, “If you can make wood work, it works out pretty well.”

Both Imbler and Bolsen claim their technologies are capable of producing high yields. Coskata is already churning out 100 gallons of ethanol per dry ton of feedstock at its demo plant, according to Bolsen. ZeaChem is projecting to produce 135 gallons of product per dry ton. To compare, Mendell says Forisk’s analysis shows diesel and jet fuel processes using wood can produce up to 60 gallons per dry ton.

In addition to the project developers, several other end-users and suppliers, as well as the federal government, appear to have confidence in wood as a biofuel feedstock. The U.S. DOE has invested in ZeaChem’s demonstration-scale plant, the USDA awarded a Biomass Crop Assistance Program to develop hybrid poplar supplies for the facility, and the company has been busy in recent months announcing offtake and feedstock supply agreements. Agreements are nice, but Mendell says they mean very little until the process is proven. “Until the technologies prove that they’re actually going to be consuming wood at a significant level on an ongoing basis, all feedstock programs basically have minimal implications,” he says. “The same is true for offtake agreements. Until they prove the ability to produce at significant volumes over time, they have no implication on the market.” Many people in the timber sector will be “thrilled” when these projects finally become viable, he says, but supply agreements for a plant are not enough to cause concern that ethanol plants will become competition for wood resources any time soon.

Fair enough, says Imbler, who says the mature technology already used in the timber industry makes its members less likely to respond enthusiastically to new ideas. “The forestry world doesn’t change that fast,” he says. “This will be a transformative change. But it’s up to us to prove it. When people figure out how to make it work, it’ll be big.”

Trend Setter

While the U.S may not have an example of commercial-scale, wood-to-ethanol production, Norway does. In Sarpsborg, about an hour outside of Oslo in southeast Norway, Borregaard operates a biorefinery that currently produces 5 MMgy of wood-based ethanol. In fact, the company has been producing lignocellulosic ethanol since 1938. Borregaard favors the use of enzymes to produce ethanol from wood because it enables the company to utilize more of the feedstock’s potential, says Klaus Neumann, vice president of business development. “Our approach is to fractionate the biomass and work with what you get there because we see a lot of value in that,” he says.

Fermenting sugars from wood to produce ethanol was a big business throughout Scandinavia and parts of Russia for many years, according to Neumann, but was pushed out due to regulatory issues and the rise of cheap oil. Borregaard still operates the Sarpsborg facility profitably, but the company’s current view toward wood-based biofuels production is that it can hardly be done economically if ethanol is the only revenue stream. “In Scandinavia, it would be quite hard to be profitable only producing ethanol from woody biomass,” he says. “One idea is to diversify and make a lot of products out of the same type of biomass. We have developed a lot of interesting new applications with the lignin coming out of the process as a performance chemical. We don’t really look at the lignin as a fuel, but in order to have the maximum value addition of the raw material, we try to convert as much as possible off the fractions, both from the lignin and the fiber, into commercial products.” Borregaard’s process converts more than 90 percent of the incoming biomass into various products, including lignin, vanillin, carbon dioxide and biofuels.

Neumann points out that woody biomass is a more affordable feedstock in the U.S. and in other parts of the world, like Southeast Asia, but the concept of diversifying revenue streams to produce products other than just ethanol is one that is already being embraced by wood-to-ethanol producers here. ZeaChem touts its technological ability to produce a variety of valuable biobased chemicals and Coskata, though not as vocal about it, has a platform that will also produce chemicals. Bolsen says diversified revenue streams play an important role in Coskata’s business strategy, but for now, it is publicly focused on ethanol. “As a young company, you have to focus on what you believe is the best ready-now, commercially viable technology,” he says, adding that, for now, that’s cellulosic ethanol.

Mendell agrees that projects using wood as a feedstock to produce biochemicals as well as ethanol have a leg up on commercialization potential over single-stream production models. It makes sense economically and there are fewer technical hurdles that need to be overcome in order to produce chemicals as opposed to ethanol, he says. “If you’re going to pursue this really hard-to-get technology, you have to do things that work along the way to pay your bills,” he says. “That’s what these firms are doing when they’re producing chemicals, which seems like a good cash-generating strategy. Diversifying away from transportation fuels seems like a really smart move on all measures.”

Biofuels industry observers such as Forisk are also noting a trend toward diversifying away from wood as a sole feedstock. ZeaChem and Coskata both say they can, and probably will, use more feedstocks than just wood. Borregaard has also recently begun construction of a pilot-scale facility in Sarpsborg to demonstrate a new process to produce ethanol and chemicals from other feedstocks. The process, dubbed BALI for its ability to process bagasse and lignin into performance chemicals, is extremely efficient in breaking down C5 and C6 sugars and allows flexibility in the pretreatment phase, according to Neumann. “We can actually select how to break down the fibers and how to work up the different types of sugars,” he says. The technology is expected to allow Borregaard to enter markets other than biofuels in locations around the world through partnerships with other biofuel or biochemical producers. “If we can put together a concept where they would become a biofuel producer and we would produce specialty chemicals from the remainder of the biomass, that’s one way we think it will be quite possible to commercialize those types of technologies,” he says. Borregaard’s BALI pilot plant is scheduled to become operational in the second quarter of next year and will process up to 1 dry ton of various feedstocks per day.

Borregaard would like to partner with biofuel or biochemical producers to establish commercial plants using its BALI process because, according to Neumann, while his company has lengthy experience as a biorefiner, its specialty lies in producing chemicals from biomass. “That’s the area where we feel we have competency and we would like to expand the market, and where we see the opportunities,” he says. “Also, in developing new biorefinery concepts where we try to sell multiple products, I think it will add a lot to the speed if you can do that together with other companies who have expertise in complimentary areas—maybe technology, or feedstock or even marketing for those products.” The U.S. is an ideal area to launch this new concept due to its emphasis on technology development as well as policies that promote the production of cellulosic biofuels and interest in biochemicals, he says.

Biofuels producers may see the benefit of using wood to produce liquid fuels and chemicals, but Mendell says that, for now, the U.S. forestry industry will be content to watch the development of wood-based biofuels from the sidelines, and instead focus on the use of wood to produce energy. “That’s smart for the forestry industry,” he says. “Today 71 percent of the wood-fired electricity produced in the country is within the forest products industry. Many of these projects represent extensions of what they already know how to do. I suspect that's one reason why even in the case of electricity projects or these liquid-fuel projects there's been less emphasis on wood. Projects are learning it's a little more complicated than saying you're going to use forest residues that have been left untouched out in the woods. It's a more complicated story than that."

Author: Kris Bevill
Associate Editor, Ethanol Producer Magazine
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