The operating costs of electricity generation by TVA:
* Existing coal: 2.5 to 3.5 cent per kwh
* Nuclear: 2 cents per kwh
* Hydroelectric: 0.5 to 0.8 cents per kwh
* Renewable fuels: 5 to 30 cents per kwh
Source: Tennessee Valley Authority
CHALLENGES TO COAL
* Court-ordered smog controls: A federal judge ordered TVA to install more than $1 billion of pollution control equipment on four of its coal plants after finding TVA is public nuisance to North Carolina.
* Global warming legislation: Congress is debating a cap-and-trade proposal to force utilities to cut carbon emissions from coal plants or pay fines for such greenhouse emissions linked to global warming. By 2021, 15 percent of TVA's power may have to come from renewable sources or energy conservation.
* Fly ash regulations: EPA is writing new rules this year to regulate how utilities dispose of coal ash.
BY THE NUMBERS
* $5.1 billion: TVA's investments so far in pollution controls
* 21: Number of selective catalytic reduction devices installed by TVA to limit nitrogen oxides
* 8: Number of coal scrubbers installed by TVA to cut sulfur dioxide emissions
* $3.7 billion: Anticipated spending for additional pollution controls on coal plants in the next decade
Source: Tennessee Valley Authority
By the numbers
* 7,539: Number of pounds of coal consumed each year by the average American
* 600: Number of coal-fired power and industrial plants in the United States
* 11: Number of TVA coal-fired power plants, which collectively have 59 boilers
* 240: Estimated number of years of coal supplies in the United States from nearly 268 billion tons of recoverable reserves.
Sources: U.S. Energy Information Administration. National Mining Association, TVA
The Tennessee Valley Authority was created to harness the power of the Tennessee River and has invested the most money in its nuclear power plants.
But the majority of the electricity generated by America's biggest government utility comes from burning coal, which is igniting a political firestorm this year.
Changing political and global climates -- spurred, in part, by environmental problems at TVA's own coal plants -- are threatening some of the workhorses in the power stable of the federal utility. Coal may be TVA's most abundant and reliable power source, but it faces its biggest environmental challenge this year since TVA erected its first fossil plant 60 years ago in Johnsonville, Tenn.
New regulations from Congress, EPA and the federal courts could double the cost of TVA's coal-fired generation within the next decade and also push up generating costs at the seven coal power plants in Georgia operated by the Southern Co., according to utility officials and environmental regulators.
"Coal is our lowest cost and most abundant domestic energy resource for electricity production so it has been a mainstay of our generation for decades," TVA Chief Operating Office Bill McCollum said. "Going forward though, there are a number of challenges that would indicate that the cost of coal generation is likely to be much higher in the future."
Unless TVA replaces its coal plants or consumers learn to use less power, average monthly electric bills could rise by more than $100 by 2020.
Mr. MocCollum said energy production from fossil fuels faces a triple threat:
* A federal judge ordered TVA this year to install more than $1 billion of additional pollution controls at four of its coal plants;
* Congress is debating limits on carbon and mercury emissions from coal plants;
* EPA is writing new rules to require better handling of coal ash.
Complying with the each of the new rules likely will add to the capital and operating costs of TVA's coal operations, Mr. McCollum said.
"It's not clear yet where those costs will wind up," he said. "The future is always uncertain, but it's a lot more uncertain right now."
Critics of coal contend that TVA needs to retire some of its aging fleet of 59 coal-fired boilers spread out over 11 plants in three states.
"Some of TVA's oldest, dirtiest and least efficient coal units should have been phased out years ago and replaced with renewable power," said Stephen Smith, executive director for the Southern Alliance for Clean Energy and a former member of TVA's Regional Resource Stewardship Council.
Matt Landon, a volunteer leader of a 4-year-old group fighting against coal usage in East Tennessee -- United Mountain Defense -- blames coal plants for much of Tennessee's air pollution.
"From the cradle to the grave, coal is dirty and destroys our environment," said Mr. Landon, who was arrested by TVA police in March for trespassing on the site of a major ash spill in Kingston.
repair or replace?
In its 76-year history, TVA has shut down only one coal plant -- the former Watts Bar Steam Plant in Rhea County. But TVA officials said the agency also is studying whether it still makes sense to maintain and upgrade its oldest plants, including units in Johnsonville and Widows Creek which already are senior citizen age.
A federal judge has ordered TVA to install scrubbers on the six oldest units at its Widows Creek Fossil Plant near Stevenson, Ala., within the next five years. Mr. Kilgore said the agency is now studying the costs of installing the court-ordered pollution controls. To recover such an investment, the units normally would be expected to operate for at least another two decades.
But with growing concerns about the long-term future of coal, TVA may not want to invest more in its oldest and smallest fossil units.
"By 2025, we will have coal facilities that will be 75 years old," Mr. McCollum said. "While those coal facilities have added tremendous value in terms of keeping power prices low for people in the Valley for many years, it's kind of hard to imagine someone at TVA operating those coal plants when they get a whole lot older."
TVA has spent $5.1 billion on pollution controls for coal plants since the 1970s to cut its emissions of carbon and nitrogen oxides by more than 75 percent. John Myers, TVA's senior manager for environmental strategy and management, said the agency plans to spend another $3.7 billion over the next decade to install more coal scrubbers and other pollution control equipment.
Last year, the rate of sulfur dioxide emissions by TVA coal plants was nearly 11 percent below the U.S. average, while nitrogen oxide emissions during the ozone season were more than 18 percent below the national average for the amount of power the plants generate, according to TVA figures.
north carolina lawsuit
Nonetheless, a lawsuit from neighboring North Carolina claims the smog from TVA's coal plants are a public nuisance to the Tar Heel state and could soon force even more costly pollution upgrades by TVA.
A federal judge ruled and later affirmed a judgment against TVA this year that requires the utility to expedite installation of emission control equipment at four coal-fired plants. Most costly and challenging for TVA is the order for both coal scrubbers and selective catalytic reduction devices at the John Sevier Fossil Plant near Rogersville and the Widows Creek.
TVA, which is challenging the ruling, contends it can't meet the schedule for installing scrubbers and selective catalytic reduction devices on its John Sevier plant without shutting down the plant for 20 months. TVA wants more time to make the upgrades.
"We've spent a lot to clean up the air and we're going to continue to spend a lot," Mr. Kilgore said. "We have set a goal of getting at least 50 percent of our power from non-carbon sources (nuclear, hydro and renewable sources) by 2020."
But that may not be enough if the U.S. Senate goes along with a U.S. House-passed cap on carbons adopted Friday (or Saturday).
The U.S. House voted xxxxx to adopt a plan to reduce greenhouse gas emissions linked with global warming by 17 percent below 2005 levels by 2020. To do that, the legislative proposal will require utilities to use more renewable energy and create a cap-and-trade system, in which polluters would be required to accrue buyable, sellable credits for all the greenhouse gases they produce.
Mr. Smith and other environmental leaders complain that the measure is watered down from Barack Obama's campaign pledge to cut carbon emissions by 25 percent by 2025.
"Our analysis suggests that this bill would not help America make any progress towards that goal, at least through 2020," he wrote in recent blog.
But TVA officials said the measure will encourage the utility to look to energy sources other than coal in the future. Coal industry backers hope a method of carbon sequestration can be developed to bury carbon dioxide emission in underground caves and limit the greenhouse gases spewing from coal plants.
TVA has no plans to build any more coal plants, but it also has not defined any schedule for shutting down any existing coal units. Over the next 18 months, TVA will develop a new Integrated Resource Plan to help the TVA board evaluate future energy options.
coal ash regulation
As TVA spends billions of dollars to meet existing air pollution rules and studies potentially even more costly carbon limits, coal-fired generation is facing yet another challenge this year from its waste products.
The Dec. 22 spill of more than 1 billion gallon of toxic muck from a TVA coal ash pond in Kingston is projected to cost TVA nearly $1 billion in unanticipated cleanup expenses. The spill also is encouraging EPA, at the urging of Congress, to write new rules this year on how coal ash is disposed of in ponds, recycled materials or landfills.
The wet storage of coal ash used by TVA at six of its 11 coal plant sites may have to be replaced with dry storage, Mr. McCollum said. TVA has retained the Stantec Inc. engineering firm to assess all of TVA's ash and coal combustion byproduct impoundments to ensure that they are structurally sound and to evaluate options for the future.
Mr. McCollum said TVA doesn't yet have any estimates about ash conversion costs, but he said changes in coal ash disposal will add both capital and operating costs to TVA's fossil units.
With 60 percent of its energy coming from coal, TVA can't wean itself from fossil fuels anytime soon, Mr. McCollum said.
Tennessee is simply not an area of very significant wind or generation potential," Mr. McCollum said. "If you are going to replace that (coal-fired) power with something else, right now that is going to cost more money."
Luke Popovich, vice president of communications for the coal industry group, the National Mining Association, said America has a 240 year supply of coal reserves at current consumption rates.
"Coal is our most abundant and cheapest energy source and we can't afford not to us it," he said.