Aug. 29--Duke Energy's first new Carolinas coal-fired power plants in three decades, to be built 55 miles west of Charlotte, promise cheap energy. And a debate: What are such plants doing to the environment?

Duke meets its public Wednesday in Charlotte, with a hearing on the plants before the N.C. Utilities Commission.

An abundant fuel, coal generates more than half the state's electricity. Duke says coal is a key to supplying "least cost" power for the 50,000 new Carolinas customers it adds each year.

Coal is also a leading source of the pollutants that form ozone, the irritating gas that's tormented Charlotte for years. Coal emissions help shroud skies in haze and warm the planet.

Duke plans to retire four 1940s-era power units and build two new ones at its Cliffside plant in Rutherford and Cleveland counties. The plant dumped 3.9 million tons of carbon dioxide, a greenhouse gas, into the atmosphere last year.

That number will grow, despite higher coal-burning efficiency, as Duke nearly triples the amount of power the plant generates. Releases of sulfur dioxide, which produces haze, are expected to drop sharply. Ozone-forming nitrogen oxides would grow slightly.

Local business leaders are eager for the 1,000 construction jobs to be created.

The half-dozen environmental and energy groups fighting the plant insist the $2 billion for Cliffside, which customers will pay, would be better spent on programs to save energy. Widespread use of energy- efficient lights, appliances and insulation, they say, could delay or erase the need for a new plant.

"We should be way beyond building an old-style, coal-fired power plant," said Michael Shore, air-quality analyst with Environmental Defense. "We have considerable low-hanging energy-efficiency fruit in North Carolina."

The Utility Commission's Public Staff, which represents consumers, says Duke makes an adequate case for new generating capacity. But the staff also noted "numerous opportunities" for efficiency and conservation programs if customers could be persuaded to take part.

North Carolina ranks 46th in spending on efficiency programs, says the nonprofit American Council for an Energy-Efficient Economy.

Critics jab Duke for extolling a goal of energy efficiency while its own efforts have stalled. And despite the utility's public concern over global warming, it won't use technology at Cliffside that captures carbon dioxide, the major contributor to global warming.

Duke president and CEO Jim Rogers has called energy efficiency "this nation's greatest energy resource and our most immediate and cost-effective means of tackling today's high energy prices."

Programs to cut power demand have saved Duke the equivalent of 766 megawatts this summer, nearly equal to one of the new Cliffside units. New programs are being developed to expand savings by another 100 megawatts, the company says.

But for years Duke hasn't enlarged its programs to curb power demand, which typically offer customers power-bill discounts in exchange for the right to interrupt service. Discounts often cost the company more than the power saved in such programs, Duke says.

Duke also champions equitable ways to reduce greenhouse gases, such as taxing carbon dioxide emissions. Coal-fired power plants release more carbon dioxide than any other segment of the U.S. economy, the government says.

Cliffside's new units, however, won't use emerging technology that can strip carbon dioxide from its emissions. Duke says the technology is too expensive and Cliffside can't store the captured gas underground.

"If they seriously believed there would be a carbon tax, they wouldn't be building a coal plant, I can promise you that," said Stephen Smith of the Southern Alliance for Clean Energy.

The new technology, called Integrated Gasification Combined Cycle or IGCC, turns coal into a clean synthetic gas that powers gas and steam turbines to produce electricity. IGCC plants can also be engineered to remove carbon dioxide. Duke is testing an IGCC plant in Indiana.

Demonstration plants have struggled with reliability, experts say, and would cost 10 percent to 30 percent more than conventional plants.

Duke says it's addressing climate change by building more efficient plants and proposing to build a new nuclear plant 20 miles southeast of Cliffside in Cherokee County, S.C. Nuclear plants don't emit carbon dioxide. But they do produce tons of highly radioactive wastes.

Carbon Dioxide Emissions

Coal-fired power plants are the largest U.S. source of the greenhouse gas that climate scientists say is altering Earth's climate. Duke Energy is the largest power plant source in North Carolina.Here are the emissions (in million tons, 2005) from Duke's N.C. plants:

Allen (Gaston County) 6.2

Belews Creek (Stokes County) 14.2

Buck (Rowan County) 1.7

Cliffside (Rutherford/Cleveland counties) 3.9

Dan River (Rockingham County) 0.8

Marshall (Catawba County) 13.3

Riverbend (Gaston County) 1.9

Total: 42.2

Sources: Environmental Protection Agency

The Proposed Units

Four of the Cliffside plant's five power units, all dating to the 1940s, would be shut down. Two new units would each produce 800 megawatts and together supply 1 million to 1.5 million homes. The first unit would start up in 2011.

Emission controls, which Duke calls state of the art, would reduce sulfur dioxide by 68 percent and increase nitrogen oxides by only 17 percent. The new units would burn coal about 30 percent more efficiently than the old ones, but release more carbon dioxide because they make more power.

Estimated cost, likely to be passed to customers: $2 billion.

Bruce Henderson: 704-358-5051.