A Partial List of Approaches to Advanced Biofuels
Therecent ACS story, Race to the Pump, was linked here earlier in passing, but it deserves a longer look. The story features many of the most prominent scientists and investors in the advanced biofuels race, providing some interesting perspectives.
“Because the energy industry is so large, there is room for everybody to play, as long as you can meet the economics,” says Jay D. Keasling, a synthetic biologist at the University of California, Berkeley. “That is the great thing about this problem. Chemical technologies can be engineered to happen more quickly. It does take a long time to engineer the biology. But the beauty of biology is that it can work under dirtier conditions, and you can get the specific molecule you want under a range of conditions.”There is much more at the article above. As a quick executive summary, this ACS article is probably the best starting point for understanding where advanced biofuels currently stand, generally.
...“Chemical approaches offer plenty of advantages,” says Mark Mascal, a chemistry professor at UC Davis whose group is working on several biofuel projects. “Generally, if you have an inexpensive catalyst and a fast method, a chemical approach can be more cost-effective and doesn’t take a few days or a week the way most fermentation processes do,” he notes. “A consistent feedstock isn’t needed as is the case with microbes in sugar fermentation—you can use anything as long as it has sugar or cellulose in it.”
...Another primary chemical pathway to biofuels is pyrolysis. On this front, George W. Huber and his group at the University of Massachusetts, Amherst, have developed a continuous catalytic pyrolysis method that directly converts raw biomass such as wood chips into gasoline-range compounds. Huber is a former graduate student of Dumesic’s at Wisconsin and part of the team that developed some of Virent’s technology.
...A handful of companies are already zeroing in on commercial biofuels produced by microbes. For example, Gevo, based in Englewood, Colo., uses an engineered microbe to produce 2-methylpropanol, known in the industry as isobutanol, which can be used as a gasoline blend stock or dehydrated to isobutylene and then converted into octane, aromatics, and other gasoline ingredients. The technology is based on research by James C. Liao and coworkers at the University of California, Los Angeles.
...As biofuel technologies proliferate, start-ups and investors must decide which ones are technically and economically feasible on a commercial scale. Decision making typically has focused on how to convert the biomass, but it should be refocused on which raw material should be used, argues Bruce E. Dale, a chemical engineer at Michigan State University and a lead scientist at DOE’s Great Lakes Bioenergy Research Center, one of JBEI’s two sister centers.
...Another factor in decision making is the logistics of biomass availability, transport, and storage. To be commercially viable, a gasification plant would require up to about 15,000 tons of biomass per day, Dale says, whereas a fermentation facility would need about 5,000 tons per day and a pyrolysis facility would need about 2,000 tons per day. To win, companies must work out a long-term, reliable feedstock supply, as well as a partner who will take their fuel, Dale says.
...Khosla thinks that biofuels are one of the most interesting areas in the energy marketplace. That’s because, unlike electric cars, biofuels will be affordable most everywhere. Still, perhaps only half a dozen or so biofuel approaches will win, he said.
For example, biodiesel from palm oil might be a good idea, Khosla noted. But it may well disappoint investors because it’s just an incremental improvement and unlikely to come out on top. “Other people are trying to make magic work where it hasn’t worked before, such as using algae to make fuel,” he added. “I’ve looked at two dozen business plans, and I haven’t found one where the economics will work.”
Khosla instead has his bets on Gevo, LS9, and Amyris. That’s because all three companies have innovative biofuel technologies that they can also use to make high-margin chemical products, thereby reducing risk.
...UMass’s Huber thinks pyrolysis will be a big winner, with different technologies for making gasoline, diesel fuel, and jet fuel. Acid hydrolysis or enzymatic methods will be too expensive on a large scale, Huber believes. “The enzymes cost too much, and fermentation is very slow. If you use acids, then you have to pay to dispose of the acid or you have to try to recycle the acid.”
...“When the smoke clears, I think there will be a few technologies left standing,” Mascal agrees. “They will be the ones that can be done cheaply and in which feedstock supplies and their transportation aren’t an issue, capital and operating expenses aren’t prohibitive, and you get a product with a ready or emerging market. The more esoteric methods will be history in the literature.
“But scientists and engineers, or the federal government for that matter, don’t need to pick winners or losers,” Mascal continues. “The market does that itself, and science does that itself. We recognize when one method is much better than another; that’s a type of natural selection.”
“We spent decades getting petroleum-based fuels up to the volumes that we are producing now,” Keasling notes. “With new biofuel technologies, we can’t expect that to happen overnight. But in the next couple of years, we are going to see some of these advanced fuels on the market. From there it will continue to grow. But we’ve got to give it time.” _ACS
Professor James Clark of the University of York, is taking an interesting approach to extracting high value products from biomass. He is using super-critical CO2 to extract high value waxy products from the biomass, then proceeding to use microwave pyrolysis to produce pyrolysis gas, liquids, and solids.
We are approaching prime maple syrup time in North America, and it is good to remember all the different ways that nature has evolved to produce high energy chemicals -- including sugars. With the help of humans, nature is just getting started in the quest to ever higher energy crops.