THE TRUTH ABOUT SUGAR CANE ETHANOL

Here in Puerto Rico we already have entrepreneurs, academics, engineers and assorted techno-geeks promoting the local production of sugar cane ethanol. In this country we have so many cars and trucks that we would have to blanket the whole island from one end to the other with sugar cane monocultures in order to make a meaningful dent in our petroleum imports. Read this information:

David Pimentel of Cornell University and Tad Patzek of the University of California at Berkeley have tallied up the environmental impact of ethanol production in Brazil, and they argue it’s not a pretty picture. It takes 393 kilograms of oil or its equivalent to produce a hectare of sugarcane, and it takes 12 to 14 kilograms of fresh sugarcane to produce a single liter of ethanol. Erosion is very high on sugar plantations, because farmers harvest almost the entire plant, leaving little behind to anchor the soil. According to Pimentel and Ptazek, Brazil sugarcane plantations lose 31 tons of soil from every hectare — 30 to 60 times more than the land can regenerate.

Sugar plantations are also very thirsty. To produce a single liter of ethanol in Brazil requires 7,000 liters of water. And as the water runs off sugar plantations, it carries with it some of the herbicides, pesticides, and fertilizers that are applied at high levels on the plants. Even after the cane is harvested, there’s still more wastewater to deal with: ethanol plants produce 10 liters of wastewater for every liter of ethanol they make.

The more fuel we get from sugar-fed microbes, the more land will need to be used to grow it. “As with any conversion technology, there is concern that land will be cleared to provide feedstocks,” says Jason Hill, economist at the University of Minnesota.

Aldrich thinks that water would be the environmental wild card in a synthetic-biology boom. “The impact of the large-scale conversion of land not currently under the plow into sugarcane fields has a potentially significant environmental cost with respect to freshwater resources,” says Aldrich.

SOURCE: http://www.e360.yale.edu/content/feature.msp?id=2106