We are on a mission with respect to getting the message out as to why ethanol is so important. As you know, GM is fully committed to E85—it is the most significant near-term solution to oil and greenhouse gas emissions. Ethanol can offset 35% of future vehicle energy demand by 2030. Our focus is on next-generation biofuels, and we’ve made two investments—in Coskata and in Mascoma, in biothermal and biochemical technologies—representing what we see as the best in the commercial cellulosic ethanol future.

Making E85 a viable alternative fuel requires significant growth in stations. In pricing, it is important that we get the economics right for the consumer. Ethanol has its challenges, but we continue to believe that nothing else in the near term can make a difference in the issues we face.

— Beth Lowry

GM has become the global leader in flex-fuel vehicles, Lowry said, accounting for 3 million of the more than 7 million FFVs on the road worldwide. In Brazil, 100% of the cars GM produces are flex-fuel; the company is currently the only automaker there with an all flex-fuel lineup. In the US, GM will offer 15 FFV models in 2009, including the Chevy HHR—the company’s first four-cylinder flex-fuel offering.

At the Coskata briefing, Mary Beth Stanek, GM’s Director Energy and Environmental Policy & Commercialization, said that GM had started talks with Coskata in April 2007 as GM was recognizing that it needed to participate in the next generation of fuel, which includes, but is not limited to, cellulosic ethanol.

The largest single thing we can do immediately to change the equation is affordable, available E85—fuel from waste that not only competes with gasoline but beats it. We needed to jump the curve on that.

—Mary Beth Stanek

Pricing, especially given the lower energy density of ethanol that results in an increase in fuel consumption, is an issue that has to be tackled, Stanek said, and is one of the attractions for GM of Coskata, which foresees being able to produce ethanol for less than $1 per gallon. E85 needs to be priced fairly on an energy content basis—i.e., a lower price for E85 than gasoline.

Our cumulative learning since 2005 is that the fuel has to have stable pricing. Colorado has had a steady increase of E85 because they have held their price for months. The [overall] market is still uneven, we see pricing all over the place.

—Mary Beth Stanek

The Coskata process can combine a variety of gasification technologies with Coskata proprietary microorganisms and bioreactors. Click to enlarge.

Coskata. Coskata uses a three-stage hybrid biothermal process (gasification plus fermentation). Depending on the feedstock and with the cogeneration of bioelectricity or steam export, the Coskata process can result in up to a 96% reduction of CO₂ in the production of the fuel and is up to 7.7 times more energy positive compared to conventional gasoline, according to an evaluation by Argonne National Laboratory.

Coskata’s three-step syngas-to-ethanol continuous process uses:

1. Gasification. Carbon-based feedstock is converted into syngas using gasification. The Coskata process is not gasifier-specific. In its initial scale-up efforts, the company will use a Westinghouse plasma gasifier. (Earlier post.) Selection of the production gasifier may depend partially on the feedstock identified for a given plant. Coskata President and CEO Bill Roe said that the company has identified three or four key technology providers that fit different feedstock requirements.

   At the Coskata labs in Warrenville, the company creates a variety of syngas feeds simulating the results from different feedstocks by reforming a small amount of natural gas and mixing other gases with it to tune the mixture for different scenarios.

2. Fermentation. Coskata’s proprietary Clostridia anaerobic bacteria convert the resulting syngas into ethanol by consuming the carbon monoxide (CO) and hydrogen (H₂) in the gas stream. Although the current focus is on ethanol, Coskata plans to produce other fuels such as butanol, and has a butanol-producing strain in the lab.

   Butanol is going to be fabulous. It’s going to be a great range-extending type of fuel.

   —Mary Beth Stanek

3. Separation. Pervaporation technology separates and recovers the ethanol.

A comparison of different cellulosic ethanol processes. Click to enlarge. Source: Coskata

Coskata is targeting ethanol production for less than $1.00 per gallon.

Coskata originally licensed its technology and microbes from Oklahoma State University (the work of Dr. Ralph Tanner) and has subsequently optimized the microbes for the production of ethanol via strain management, assisted by a genomic analysis that helped identify optimal nutrients for the microbes. Coskata is now moving on to a phase of further optimization via mutagenesis—a process in which a mutagen is introduced to numerous cultures, and then Coskata screen for results.

To enable this process, Coskata developed a high-throughput screening technique for anaerobes that allows the company to run some 100,000 experiments per year. Although Coskata has yet to genetically engineer its microbes, that will occur in the future, said Roe.

With the feedstock flexibility enabled by the gasification approach—everything from energy crops through municipal solid waste—Coskata envisions numerous distributed plants in the 40-50 million gallon per year range that use local feedstocks and are contiguous or close to major urban centers, there by circumventing the needs for the same type of distribution infrastructure required by the petroleum industry.

Affordability is another big piece of this. The economics are driven by the feedstock, the efficiency of the process, and the overall energy footprint of the process as well. This is a big step change from the current world of ethanol.

—Bill Roe

Coskata currently is working with a number of different bioreactor designs, which it will implement in its Lighthouse commercial demonstration plant currently being built in Madison, Pennsylvania and due to come online in the first quarter of next year.

The Lighthouse plant is designed to be a minimum engineering scale that will support a linear scale-up to full commercial operation. It will feature an integrated processing system with the front-end biomass gasifier, and test the multiple commercial-scale bioreactor designs as well as multiple separations designs.

A key learning form the Lighthouse project will be the water cycle. Although the Coskata process is designed to use much less water than other processes, the company has not yet run a continuous fermentation and water recycling process for six months straight, Roe said.

Coskata is targeting a full commercial plant for the first quarter of 2011 (the Flagship plant). The Flagship plant will have a capacity of 50-100 million gallons per year, and use multiple gasifiers that process 1,500-3,000 dry tons of waste per day. Production cost of the ethanol will be less than $1.00 per gallon, and the CapEx for the plant will be on the order of $4-5 per gallon capacity (first plant economics).

The company plans a dual business approach: building and operating its own plants, as well as partnering with large corporations, including woody biomass players; sugar producers; municipal waste companies; steel mills with industrial waste gas; producers of new energy crops; and ag waste companies.

Our current commercialization plans have us starting two plants in 2011 and it scales from there. By 2015-ish, we expect to be enabling as many as 20 biorefineries per year to get to scale to get out with quantities that matter and that have an impact on transportation fuel utilization.

—Bill Roe

Green Car Congress attended the Coskata briefing at GM’s expense.