quimica - chemistry Sugaras fuel for electric cars?

Who could resent the attention being showered on electric cars? Stylish and clean, they’re the darling of the renewable-energy crowd, which is hailing the scheduled rollout of several e-powered models next year as a major blow against global warming.

Well, Eduardo Leao, for one.

He’s executive director of Brazil’s largest sugar-industry association, called UNICA, and he insists that cane-based ethanol produced in massive quantities by his members is a better alternative fuel for the environment than electricity. He also is adamant that Brazilian sugar-based ethanol is a greener and more socially beneficial fuel than the corn-based ethanol commonly used in the United States, an assertion backed, with some qualifications, by many environmentalists.

All of which only adds to the ire of Leao and his members at being largely shut out of U.S. markets by a 54-cent-a-gallon tariff that is levied on Brazilian ethanol imports. He says the duty makes the fuel uneconomical for U.S. consumers except when oil prices spike.

“Electric cars will be an alternative but an expensive one that leaves questions about where all that electricity will come from,” Leao said. “Most U.S. electric power is generated with fossil fuels, which means, at the end of the day, you may not be reducing carbon emissions.”

The Brazilian sugar industry’s complaint – which was relayed in person by Brazilian President Luiz Inacio Lula da Silva to President Obama at a regional summit in April – points up one of the trickier aspects of U.S. renewable-energy policy that aims to reduce foreign oil imports, cut greenhouse gas emissions and promote the development of a domestic biofuel industry.

The U.S. government is trying to ensure a growing domestic market by mandating that an increasing percentage of fuel at the pump is ethanol and keeping most of Brazil’s lower-cost ethanol out.

But the trade-off forsakes short-term environmental benefits that ethanol made from sugar cane might provide.

Sugar-based ethanol as produced by Brazil is not without its critics. Some environmentalists such as Roland Hwang of the Natural Resources Defense Council say that rising acreage dedicated to sugar in Brazil might be forcing other farmers into the Amazon basin, causing deforestation that could negate some of the fuel’s benefits.

“Sugar’s emissions benefits compared to corn are like night and day, maybe twice as much, in reducing direct greenhouse gas impact,” Hwang said. “But if the loss of land to sugar plantations leads to someone cutting down the rain forest for cattle pasture, the impact is not so clear.”

Many U.S. motorists might be unaware that on average 8 percent of the fuel they put in their tanks these days is ethanol, the result of a series of federal and state mandates, clean air standards and tax incentives implemented over the years to boost alternative fuel development.

Add in growing worries about the global warming effect of gasoline, and U.S. ethanol production has tripled since 2003 to 9 billion gallons produced last year, according to the Renewable Fuels Association. But the use of corn to produce most U.S. ethanol, critics contend, diverts Midwestern grain from the global food supply, thereby raising commodity prices and creating scarcities.

“The main problem with corn-based ethanol is that it competes with agriculture, and that’s a huge social problem,” said Anna Stefanopoulou, director of the University of Michigan Auto Research Center.