NASHVILLE (AP) - The Tennessee Valley Authority expects to spend as much as $1 billion to reduce harmful emissions from a coal-fired power plant by up to 95 percent.

According to The Tennessean (http://bit.ly/MVmo9x ), the work at the Gallatin Fossil Plant, northeast of Nashville, is projected to be completed by 2017. Four large scrubbers are planned at the plant, which burns 13,000 tons of coal per day and generates enough electricity to power 300,000 homes.

Without the upgrades, the plant would eventually likely not meet government environmental standards, according to plant manager Scott Hadfield.

The government utility expects the improvements to make a huge difference in emissions.

"SO2 is sulfur dioxide, and by removing 90 to 95 percent, it is cleaning up the atmosphere of the Tennessee Valley," said Larry Nathan, who works with TVA's generation construction group.

Some environmenta l groups, however, say TVA should instead invest in energy efficiency, saving enough power to shut down the plant.

"Seriously, invest the money in energy efficiency that you intend to waste on unhealthy and dangerous technologies," Louise Gorenflo, a Cookeville resident and volunteer with the Tennessee Chapter of the Sierra Club, told the TVA board last week.

A spokesman with the Natural Resources Defense Council said the planned upgrades will work.

"This is not new technology, but technology that has been absent from too many dirty dinosaurs," said John Walke, the clean air director for the NRDC.

TVA spokesman Scott Brooks said a recent court case in which a judge struck down a rule on pollution crossing state lines will have no effect on TVA's plans to curtail harmful emissions.

TVA has signed an agreement with the U.S. Environmental Protection Agency; officials of Tennessee, Kentucky, Alabama and North Carolina; and three environmental groups to resolve longstanding disputes over the federal Clean Air Act.

Joe Hoagland, TVA's senior vice president of policy and oversight, said the Gallatin plant is reliable and cost-effective.

"It makes sense to build the controls and put them on," Hoagland said.

The utility intends to have the scrubbers online by 2016 and additional pollution controls in operation by 2017.