To help his students imagine how various energy sources contribute to the U.S. generation mix, Frank Clemente, professor of Energy Policy at Pennsylvania State University, encourages them to picture farm animals. Coal, at about 49 percent of the U.S. generating mix, would be about the size of a Clydesdale. Natural gas at 21 percent would be the size of a mule. Hydroelectricity at 6 percent would be comparable to a good-sized dog, perhaps a water dog of some sort. Nuclear at 19 percent would be a burro. And wind at 1 percent of total generation? Wind, Clemente says, would be about the same size as a pigeon.
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Clemente also says that by 2030 the world is projected to produce around 40,000 million tons of CO2 each year. The goal of having wind meet 20 percent of U.S. generating mix by 2020 would cut U.S. CO2 emissions by an estimated 170 million tons. That’s less than one-half of 1 percent of total worldwide emissions. “People are building new coal plants, just not in the United States,” says Clemente. For example, China built more coal generation in 2007 than Great Britain in its entire history, he said. “We forget that energy is good.”
Research shows that when people have access to electricity they tend to live longer, are more likely to survive childhood, drink cleaner water, eat better and are better educated. “Women and children benefit first from the presence of energy where it had previously been absent,” he says. For example, in Africa women carry an average of 20 kilograms of wood 5 kilometers every day to burn as fuel.
A Greener Greensburg
A 2007 tornado all but wiped the town of Greensburg, Kansas off the map. Now with the help of the National Renewable Energy Laboratory and companies like John Deere Wind Energy and Clipper Wind Power, the town is rebuilding in a green sort of way.
Within a few days after the storm killed 11 people, displaced another 1,400 and destroyed 90 percent of the town, advisers from NREL, the Department of Energy and other agencies were meeting with local officials under an emergency services tent to begin plans for rebuilding. One goal that was set was to have 100 percent of the town’s energy come from renewable sources.
“This model will serve as an example of how communities can meet their sustainable goals through collaboration,” said Steve Hewitt, city administrator. “Our efforts to be a green community hinge on our energy model.”
Plans now call for development of the Greensburg Wind Farm, which will consist of 10 1.25 MW wind turbines. Work could start this summer and commercial operation could occur in 2010.
Energy efficiency improvements are also part of many new construction projects. Tests on 100 new homes built since the storm show energy efficiency improved by an average of 40 percent.
As for local townsfolk’s reaction, it seems a popular t-shirt these days is one that reads “Greensburg, KS— It’s a Wind-Wind Situation.”
Ethanol vs. PHEV
Which goes farther, an SUV fueled by ethanol or an SUV powered by electricity generated from the same acre of biomass?
Seems the electric vehicle wins, at least according to research published in the online edition of Science. Research showed a small SUV powered by bioelectricity could travel nearly 14,000 highway miles on the net energy produced from an acre of switchgrass. A comparable internal combustion vehicle could travel about 9,000 miles.
“The internal combustion engine just isn’t very efficient, especially when compared to electric vehicles,” says Elliot Campbell of the University of California, Merced, who helped research the article. “Even the best ethanol-producing technologies with hybrid vehicles aren’t enough to overcome this.”
Campbell and his co-authors conclude the best bet is to convert biomass to electricity, rather than ethanol. Following the strategy also double the greenhouse gas offsets to mitigate climate change.
While the results favor bioelectricity, the researchers caution that the issue is more complex. For example, converting biomass to electricity rather than ethanol makes sense when transportation and climate are the key issues. Left unaddressed was how these options affect such variables as water consumption, air pollution and economic costs.