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Polluter. Although coal-fired plants emit a lot of CO2, banning them alone won't curb climate change.

U.S. Geological Survey

Coal Plant Ban May Not Curb Climate Change

What would happen if the United States stopped building coal-fired power plants? The solution may not be the panacea some have predicted. Although the plants are the single biggest polluter in the United States, contributing to smog, acid rain, and global warming, a new analysis shows that banning them would increase the cost of natural gas while doing little to aggressively combat climate change.

Coal has faced strong opposition from policymakers and the public. In 2007, 59 out of 151 proposed U.S. coal plants were either denied licenses by state governments or abandoned, while environmental groups contested dozens in court. What's more, the governors of at least two states, Florida and Kansas, have said that they will not approve new coal-fired power plants.

But energy researchers Jay Apt and Adam Newcomer of Carnegie Mellon University in Pittsburgh, Pennsylvania, wondered if banning these plants would do any good. To find out, they modeled four different energy scenarios through the year 2030. One scenario takes a business-as-usual approach, with no ban on coal plants, keeps energy demand growth at historical rates, and new demand met by the current contribution of energy providers, including coal, nuclear power, natural gas, oil, and renewables. The next three scenarios ban the construction of future coal-fired power plants. In two of these, energy demand still grows at historical rates, but one scenario meets demand with increases in natural gas production, while the other assumes a large push for wind energy, supplemented by natural gas. The final scenario quenches increased energy needs with wind and natural gas as well, but it assumes that U.S. residents won't require any more energy than they do today--if, say, people become much more efficient in their energy usage; the only increase in demand would come from a growing population. The team applied the model to three main regions in the United States: the Midwest, Texas, and parts of the East Coast.

In every model, the use of natural gas skyrocketed, the researchers report online this week in Environmental Science & Technology. Under the wind scenario, for example, natural gas demand rose 55% by 2030 in Texas, 430% on the East Coast, and 470% in the Midwest. As demand for natural gas doubles, it can lead to anywhere from a 175% to 500% increase in price, says Apt. That could drive companies that rely on natural gas overseas, he says, especially those that aren't tied to working in the United States.

The researchers also found that carbon dioxide emissions didn't drop as much as they had expected. If coal plants are not banned, by 2030 emissions rise 43% in Texas, 24% in parts of the East Coast, and 17% in the Midwest, according to the model. But if they are banned, by 2030, emissions are cut anywhere from 6% to 15% in Texas, 18% to 48% along parts of the East Coast, and 10% to 27% in the Midwest. Overall, that's not enough to meet target emission reductions, says Apt. To avoid more than 2°C warming--and the deadly heat waves, intense droughts, and sea level rise it would bring--the United States needs to cut emissions about 80% by 2050. Only the scenario that assumes no increase in energy demand comes close to meeting this standard--and just on the East Coast.

Howard Herzog, an energy researcher at the Massachusetts Institute of Technology in Cambridge, says that a better approach would be to keep coal as part of the energy portfolio, but to find new ways to curb CO2 emissions from these plants. "Singling out any one fuel" is a bad idea, he says. Instead, "we need to look at technologies [such as carbon capture and storage] that allow us to reduce our carbon emission and still utilize our most important domestic supply [of energy]."