As you’ve almost certainly already heard by now, General Motors has announced a partnership with Coskata, Inc. to produce ethanol less expensively and without using food materials as feedstock for the process. This is exciting for a number of reasons. First of all, Coskata is close to completing a continuous demonstration stream at their laboratory. They also expect to have a pilot demonstration plant in place by the end of the year that will produce 40,000 gallons of ethanol. And later this year, they expect to announce the site for their first full-scale plant which will be capable of annual production of 100 million gallons of ethanol. The process also consumes less water resources (less than one gallon of water per gallon of ethanol produced) and delivers 7.7 units of energy per unit of energy used in the process.
The process relies on using anaerobic microbes that consume carbon monoxide and hydrogen and produce ethanol. Because the process uses specially bred strains of microbes, they produce ethanol exclusively, unlike other fermentation processes, which often produce a range of alcohols and which require further distillation. Furthermore, the flexibility of the Coskata process allows for other microbes to be used in the same process setup (or even a parallel setup). Other strains of microbes that produce other useful alcohols, including some used as precursors for plastic production, so that the same technology could be used in other applications to provide a petroleum replacement.