The new, more-conservative political climate in Washington could thwart hopes for climate control legislation.
But even without carbon controls, the emission of greenhouse gases linked to global warming plunged in the Tennessee Valley last year to the lowest level in 25 years and shouldn't return to peak levels of five years ago anytime soon.
The recession-induced drop in power sales, combined with a strong year for cheaper nuclear and hydroelectric generation, idled many of the Tennessee Valley Authority's 59 coal-fired generating units during much of 2009. That pushed the utility's carbon dioxide emissions down by nearly 30 percent last year.
Southern utilities are considering idling or canceling plans for more than 15,000 megawatts of existing or planned coal-fired generating capacity.
Mw/coal ' Utility
4,300 ' American Electric Power
3,751 ' Progress Carolinas
1,525 ' Duke Carolinas
1,200 ' Georgia Power
1,000-4,700* ' TVA
* TVA says it will cut 1,000 megawatts at Widows Creek units 1-6, two units at its John Sevier plant near Rogersville, Tenn., and the Shawnee Unit 10 in Kentucky.
Sources: Progress Energy, Tennessee Valley Authority, Wall Street Journal, Charlotte Observer, Atlanta Journal-Constitution
Coal-fired generation rebounded in fiscal 2010 with the overall economy. But emissions of carbon dioxide gases in the past year were still 10 percent less than the historic rate of the previous decade. And TVA officials say emissions are likely to be similar or even lower in coming years.
"TVA has decided that, in advance of a national energy policy being set, to create our own vision for the future based upon cleaner and greener energy from new nuclear energy, more energy efficiency and less reliance upon coal," said Steve Lomax, senior manager of clean and renewable energy at TVA.
Given how much money and time it takes to build new capacity, he said, "you have to consider the potential for regulation or legislation to limit carbon dioxide and other greenhouse gases."
The long-range power plan now under review calls for idling up to one-third of TVA's coal-fired plants while building up to a half dozen more nuclear reactors. It also encourages energy conservation and the use of renewable solar, wind and geothermal energy.
TVA idled two of its Widows Creek coal units near Stevenson, Ala., this fall and is preparing to put seven more units at the Widows Creek, John Sevier and Shawnee coal plants into lay-up status by 2015.
The utility generated more than 60 percent of its electricity from coal last year. But plans call for TVA to get only half of its power from coal or natural gas sources by 2020 and for possible further coal cuts in the following decade.
Across the Southeast, other electric utilities are making similar moves. The five biggest utilities in the Southeast already have announced plans to possibly shut down or scrap 15,000 megawatts of coal-fired generation -- that's equal to nearly half of TVA's total power-generating capacity.
"We're absolutely encouraged," said Stephen Smith, executive director for the Southern Alliance for Clean Energy, a Knoxville-based environmental group that wants stricter limits on greenhouse gas emissions. "The question is whether this is just a temporary downturn because of the economy or whether it is a long-term decline."
Smith has urged TVA to permanently shut down its oldest, dirtiest and least-efficient coal plants. With an average age of nearly 50 years, TVA's coal plants are among the oldest of any major U.S. utility.
But most utilities are rethinking coal because of stricter smog and ozone emission rules and new regulations on mercury, even before Congress or the U.S. Environmental Protection Agency adopts any rules to limit carbon emissions at power plants.
The U.S. Electric Information Administration reports that carbon dioxide emissions from all U.S. utilities dropped 7 percent in 2009, reversing the previous annual growth rate of 1.4 percent.
The U.S. House approved a "cap and trade" measure to limit overall carbon dioxide emissions by allowing utilities to buy and sell carbon credits based upon the amount of their carbon dioxide emissions.
The measure stalled in the U.S. Senate, however, and President Barack Obama conceded last week that the next Congress is unlikely to pass such a bill.
But the U.S. Supreme Court last year ruled that carbon dioxide is a pollutant linked with global warming and directed the EPA to develop carbon controls, which the agency is expected to announce early next year.
Luke Popovich, a vice president for the National Mining Association, the coal industry trade group in Washington, D.C., said coal still generates 49 percent of all electricity in the United States and does so with a declining volume of emissions linked with smog, ozone and other air pollutants.
"We're not saying that some rules may not need to be tightened somewhat, but we're concerned that EPA may issue rules that unduly hamper electricity generation and push up its costs at a time when the economy is still in perilous shape," he said.
Coal industry backers hope Congress may overturn and delay EPA rules if they are too onerous on coal generators.
Despite the cutbacks being considered by utilities in the Southeast, Popovich said 40,170 megawatts of additional coal-fired power generation is either announced or progressing toward completion nationwide.