GM Announces Biofuel Partnership with Coskata: Cheap, Green Ethanol?


At noon today, General Motors announced an undisclosed equity share in Coskata, Inc., a renewable energy company with the means to produce low-cost ethanol from virtually any carbon-containing feedstock including biomass, municipal solid waste—even used car tires. GM believes Coskata has the premier technology for rapidly implementing ethanol production technology worldwide. Click here for a video of the announcement.

GM already has a vested interested in ethanol, with 2.5 million FlexFuel model vehicles already on the road (15 models planned for 2009), and plans to make half their fleet ethanol-ready by 2012. The partnership is a win-win situation as Bill Roe, President and CEO of Coskata puts it: “GM is enabling Coskata to produce the next generation of biofuels – without using a food source – making it economically viable and commercially available.”

GM will test Coskata’s ethanol at the Milford Proving Grounds by late 2008, followed by completion of a 40,000 gallon per year commercial demonstration facility by the end of the year. A larger, 100 million gallon per year facility is currently being sited for construction in the U.S.

Coskata claims it can produce ethanol for under $1.00 per gallon from almost any carbon-containing feedstock, while reducing greenhouse gas emission by 84% compared to gasoline, using only 1 gallon of water for each gallon ethanol produced, and returning 7.7 times as much energy as is used in the production process.

How is this possible? The numbers, which verge on the fantastic, come straight from well-to-wheels analysis by Argonne National Laboratories and seem to be the product of a unique combination of innovative engineering, proprietary microorganisms, and patented reactor designs.

And here’s the punchline: Coskata will use gasification technology to turn carbon-containing materials into carbon monoxide and hydrogen, which can then be converted into ethanol by their highly-specialized microorganisms.

Gasification is a different process for achieving the same endpoint, but works on a wider variety of materials and uses unconventional microbial pathways. Instead of producing sugar (as in other cellulosic-ethanol production methods), carbon-based materials undergo partial combustion to produce carbon monoxide and hydrogen, a gaseous mixture known as synthesis gas (or syngas for short). I was assured during a series of short interviews that not only did Argonne’s analysis take into account the energy required for gasification, but also produced no harmful emissions since the gas is filtered through a scrubber before further processing.

So what kind of organism is willing to eat carbon monoxide and hydrogen and produce ethanol? On January 4th, I had the good fortune to tour the Coskata biofuel pilot plant and world headquarters, which is part business office, ethanol production facility, and microbiology R&D lab. Located just outside Chicago, the unassuming building houses 25,000 square feet of the most technologically advanced equipment available, including one of only a handful of specialized Time-of-Flight Mass Spectrometers used in the U.S. This fancy machinery allows researchers to rapidly evaluate new microbial strains, part of the neverending quest for improved efficiency, or the next breakthrough in alcohol fuels (biobutanol, anyone?). Combining genetic manipulation with real-time analytic equipment gives scientists a way to see how each change affects an organism—it’s like evolution at 1,000 miles per hour.

But Coskata’s bugs are pretty good already: they can convert any ratio of carbon monoxide and hydrogen into ethanol, a striking feat if you think about it. Few understand this better than Dr. Dick Tobey, VP of R&D and Engineering at Coskata biofuels. He confirmed for me that, yes, these are unique and highly developed organisms, with thirteen catalytic sites that preferentially attack CO or H2 (syngas), but can function on either gas pure. Discerning readers will note that pure hydrogen cannot be converted to CH3OH (ethanol) without an additional carbon input. The microbe’s trick? Pull extra carbon and oxygen from the water (H2O) bath in which it resides. As if that wasn’t good enough, Coskata’s organisms produce only ethanol, which mitigates contamination issues and increases overall yield.

Coskata’s other key technology is a proprietary bioreactor system. Their patented organisms live in a colony called a ‘biofilm’, which coats the surface of a thin, semi-permeable membrane likened to Gortex. Each membrane is about the width of a human hair and shaped like a straw, which allows syngas to flow freely through the hollow interior. The hair-thin straws are clumped together into several inch-thick tubes, and are housed in a large, water-filled cylinder. Water can’t flow into the straw, and syngas can’t flow out unless it interacts with part of the biofilm. This design is extremely effective because it prevents dilution of syngas and increases bacterial surface area. Bacteria don’t have to work to ‘find’ syngas, as they would if they were floating in an unstructured mixture.

Most importantly, a system of modular bioreactor tubes is almost infinitely scalable. Coskata’s larger 40,000 gallon facility will simply be an expanded version of their several-gallon per day pilot plant. To discuss more about how the process works I’ll leave you to fellow GO Media Writer Philip Proefrock. He’ll also be covering the front end of this system, gasification technology.

The new partnership between Coskata Biofuels and General Motors is worth taking seriously as it may have broad implications for the future of transportation. GM will continue to produce FlexFuel vehicles in significant numbers and, if Coskata’s promise holds out, we may be seeing a cheap, renewable and non-corn based source of ethanol within the next few years.

For another cellulosic-ethanol related announcement, see later post: Cellulosic Ethanol Sugar Diverted to Algae Biodiesel Production


In a past life, Clayton was a professional blogger and editor of Gas 2.0, Important Media’s blog covering the future of sustainable transportation. He was also the Managing Editor for GO Media, the predecessor to Important Media.