Ethanol is seen as a “wonder drug” for the automobile companies.  They can continue to produce gas fueled automobiles and appear environmentally conscientious.  Of course it does require some modification of the engine to run with ethanol spiked gas.  Unfortunately, most ethanol is made from corn or other food stock like soybeans and is now causing food shortages.  GM has invested in two ethanol companies, Coskata and Mascoma.  Both use different methods to create ethanol without using food crops.

Coskata uses anaerobic microbes to create ethanol and only ethanol.  Rather than using the edible portion of corn, this process uses the stalks, cobs and other non edible corn parts.   Other plant based materials such as hay, straw and wood chips are used in Coskata’s ethanol production as well as such diverse materials like old tires and municipal waste. 

Coskata begins by “gasifying” the feed stock which is then routed to the microbe containing bio reactor which produces Ethanol and water.  The water is reused in the bio reactor.  Rather high tech and complicated. This process is also  fairly energy intensive.

Mascoma’s process also uses non edible plants or plant waste products such as wood waste, straw, hay, and paper pulp.   This process differs from Coskata’s process in several ways.  Initially, the material to be turned into ethanol goes through a mild treatment process and then has microbes added.  The microbes do all the work breaking down the material into sugar and turning the sugar into ethanol.  Very little energy is expended in this process.  Similar to Coskata’s method, Mascoma avoids the addition of enzymes that wind up breaking the sugar into multiple alcohols that then have to be separated.  Very little energy is expended to make the ethanol.

GM is also looking into developing a chain of E85 gas stations that would use the ethanol produced by Mascoma and Coskata.  The GM brand will not be seen on the stations.

The great thing about the ethanol produced by Mascoma and Coskata is that it only uses waste products and not food stock.  The ethanol created using their methods should not produce food shortages.  Unfortunately, ethanol doesn’t fuel cars unless it is mixed with at least some fossil fuel albeit a reduced amount.

Unfortunately, GM’s interest is not wholly altruistic.  GM would rather continue to produce traditional cars with slight modifications rather than look to truly innovative methods of creating alternative energy cars that don’t require gas at all.

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Entry was posted on Wednesday, May 7th, 2008 at 2:27 pm under Science and technology.

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