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Green GM

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A year ago, General Motors launched the Chevy Volt, a battery-powered concept car that has generated a huge amount of interest with the car-buying public. Amidst growing speculation that GM are having problems with the Volt’s battery technology, to the extent that they are steering potential customers towards their hybrid models, the car giant unveiled two more ‘alternative’ fuel vehicles at this year’s North American International Auto Show. No batteries here: the Hummer HX (pictured above) and the Saab 9-4X both run on ethanol.

Alongside the new concept cars, GM Chairman and CEO Rick Wagoner announced a partnership with Coskata Inc, an Illinois startup company with breakthrough technology which affordably and efficiently makes ethanol from practically any renewable source, including garbage, old tires and plant waste. Using patented microorganisms and bioreactor designs, the Coskata process can produce ethanol for less than $1 a gallon, about half of today’s cost of producing gasoline. For every unit of energy used, 7.7 units of ethanol energy are produced, compared to conventional corn-derived ethanol which provides 1.3 times the energy input. Less than one gallon of water is used for each gallon of ethanol, a third that of other processes.

The GM-Coskata partnership coincides with last month’s Energy Independence and Security Act, which calls for a huge increase in the use of biofuels, from 7.5 billion gallons in 2012 to 36 billion gallons in 2022. Amid growing concerns over the effect on food prices caused by diverting food crops to bio-fuels, the search is on for viable alternative bioenergy crops. A joint study involving the US Department of Agriculture and Midwest farmers has identified the potential of switchgrass, a native North American perennial grass (Panicum virgatum) which can deliver more than five times more energy than it takes to grow it. Sounds good; a native plant, must be good for biodiversity and the environment generally as well as for energy. Sadly not; the impressive efficiency figures demand that the switchgrass is planted in dense monocultures, fed with artificial fertilisers and optimised with genetic ‘tweaking’. It will also require a lot of land. Even though switchgrass and its cousins grow happily on marginal land, an estimated 3.1 million to 21.3 million hectares of existing US agricultural land is projected to be converted to perennial grasses for bioenergy, the majority coming from the reallocation of existing cropland, with land currently enrolled in the Conservation Reserve Program and pastures coming second and third.

It’s clear that American technologists are working hard to justify President Bush’s long-term mantra that technology can solve all our problems. The major worry is that there are so many new technologies and initiatives competing for investment, not all of which will succeed and with no guarantee that they won’t cause more problems than they solve. Against a background of imminent recession in the US economy, will all this effort actually pay off in time?

GM-Coskata announcement

Coskata “Next Generation Ethanol”

“Net energy of cellulosic ethanol from switchgrass”


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