To be sure, regulations such as the Mercury and Air Toxic Standards, plus a shift toward natural gas by utilities, has put the fuel source under pressure. Yet nearly 40 percent of U.S. electricity is currently generated by coal, with both domestic and international use on the rise—fueled in part by a winter surge in natural gas prices. In recent research, Bank of America-Merrill Lynch noted that low U.S. coal supplies coincided with volatility in natural gas, triggered by "demand rationing" in the power sector.
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Coal is a leading cause of global carbon emissions. However, in spite of predictions about its demise, demand for the fuel source is expected to rise by more than 4 percent this year, according to the Energy Information Administration.
"It's not surprising there's strong demand, because coal is a relatively cheap source of generating electricity when you don't account for social costs," said Jason Bordoff, director of Columbia University's Center on Global Energy Policy.
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The rise in coal use—especially in Europe, where natural gas prices are far higher than in the U.S.—"is driven by market economics, especially with the rebound in gas prices," said Bordoff, who noted that it's cheaper for utilities to scale back on nat gas and use coal. Despite that, the EPA is likely to "change the economics of coal" by stiffening emissions targets for carbon intensive fuel, he added.