BARTON - Steve Hargrove knows the perfect recipe for keeping Tennessee Valley residents happy no matter how dark the night or how hot or cold the weather.
The recipe consists of coal from Western mines, a few wood chips from Shoals furniture makers and water from the Tennessee River.
The coal and wood chips are burned to heat the water into steam, which turns the turbines at the Tennessee Valley Authority’s Colbert Fossil Plant where Hargrove is plant manager.
"Keeping the lights burning in the Tennessee Valley is a 24-hour-a-day, seven-day-a-week job at TVA’s generating plants," Hargrove said.
There are 265 employees at the Colbert plant, Hargrove said.
Generating plants that burn coal, like Colbert, are the backbone of the TVA system, producing 55 percent of the electrical power used by the utility’s almost 8 million customers in seven states.
TVA operates 11 coal-fired power plants.
The five generators at the Colbert plant can produce 1,204 megawatts of electricity, said L.A. Coffman, production manager of the facility.
The electricity from the plant is enough to light several cities. A megawatt is enough electricity to power more than 200 homes.
In addition, there are eight combustion turbines that burn natural gas or fuel oil at the Colbert plant. The combustion turbines, which are used during peak demands for electricity, produce 1,800 megawatts when all are running.
Hargrove said the combustion turbines, which use an engine similar to a large helicopter motor to turn an electrical power generator, are costly to operate because of the type and amount of fuel they burn. He said the combustion turbines are used only when it is extremely hot or cold and the demand for electricity is at its peak.
TVA has four power plants that use combustion turbines.
The coal-burning generators run every day. The coal, much of which is mined in Colorado, arrives at the plant on barges.
The plant’s location on the banks of the Tennessee River makes it easy to ship coal there by water.
From the barges, it is stacked in large piles outside the plant. Bulldozers move coal about in the piles to prevent spontaneous combustion.
From the storage piles, the coal enters the plant on a large conveyer belt. Inside the plant, the coal is crushed into a powder before being burned.
Last year, 3.2 million tons of coal were burned at the Colbert plant, Coffman said.
Scrap wood from area furniture plants is chipped into small pieces and burned with the coal to help reduce emissions of air pollutants.
The fires from the coal and wood, which burn at about 3,000 degrees, are used to turn water into steam.
As the steam, which is about 1,000 degrees, is released into the generating units, it pushes against the metal fins of the turbines. The force of the steam causes the turbines to rotate and turn electrical generators, Coffman said.
As large coils of copper wire inside the generators rotate inside an electro-magnet, an electrical current is produced. That current then passes through a series of transformers to prepare it for distribution to TVA’s customers.
Since it began operation in 1955, the Colbert plant has undergone numerous modifications to improve its efficiency and reduce pollution, Hargrove said.
TVA and other utilities that burn coal to produce electricity are coming under fire from environmental groups that contend pollution from the power plants is causing health problems, killing trees and other plants and reducing visibility in the Smoky Mountains.
Hargrove said TVA is aware of the problems caused by emissions from its fossil plants and is working to reduce the pollution they produce.
The burners for the coal-fired generators at Colbert have been modified to reduce the amount of nitrogen oxide they produce, Hargrove said.
Nitrogen oxide is a component of ground-level ozone, a by-product of air pollution that can cause breathing difficulties in some people. Nitrogen oxide also contributes to smog and haze.
Coffman said the coal that is burned at the Colbert plant is selected for producing less air pollution than coals from other regions of the country.
Hargrove said the plant is scheduled to receive additional pollution-reducing equipment in 2003.
He said TVA is also working to improve the environment around the plant. He said deer, wild turkey and other wildlife are abundant on the 1,352 acres surrounding the plant. Much of the land has been declared a wildlife refuge.
"We are going to do everything we can to help take care of the environment," Hargrove said.