The 300-acre landfill off East Club Boulevard has been shut these 10 years, and by this time next year it should be paying something toward its own keep.

Durham's got a deal. The city's going to sell methane, a.k.a. "swamp gas," which the decaying dump is making on its own. Methane Power Inc. of Tucson, Ariz., and Mooresville, N.C., is going to buy it, use it to make electricity, and sell the power to Duke Energy.

"We pay the city royalties," said Lewis Gay, Methane Power's marketer. "We make the investment."

The royalties will run about $170,000 a year, said Nancy Newell, engineer with the Durham water department. That income will offset some of the $300,900 Durham taxpayers spend each year to maintain and monitor the old landfill.

"It's an ongoing expense we have to cover," Newell said.

Even though the landfill has been closed since December 1997, the city is legally required to keep the gas naturally produced there from leaking out and creating health hazards and pollution.

According to the Environmental Protection Agency's "Overview of Landfill Gas Energy in the United States," methane is a "greenhouse gas" 20 times more effective than carbon dioxide at absorbing solar heat. The gas is produced by decomposing matter, and 22.6 percent of methane generated in the U.S. comes from city dumps.

So Durham has had to install and maintain a system of "wells," pipes and pumps to draw methane off to a place where it can be burned, or "flared." That greatly cuts the greenhouse effect. But selling it for electricity, Newell said, is a more beneficial way to go.

"This takes it from being a waste product going into the atmosphere to being something of use," she said.

Gay said his company will tap into Durham's existing collection system but direct the methane into internal-combustion engines that run electrical generators. Two custom-built engines, he said, are on order for Durham (delivery takes eight months). Once they are running they will produce one megawatt each. According to Duke Energy, that's enough to serve 1,600 households.

"It's a very prudent technology," Gay said.

Eventually, the landfill will cease production. Newell said it's now estimated to be putting out 1,200 standard cubic feet per minute (a measure of flow rate adjusted to "standard" conditions of temperature, humidity and pressure); by 2050, it's predicted to be down to 250.

In the meantime, it might as well contribute something for its own upkeep.

"We've been looking at [the business venture] off and on for a pretty good while," Newell said.

Selling methane is not the first idea for making money on the landfill, which had to close because it does not have an artificial liner to keep chemicals from leaching out of the trash and into the groundwater. (Newell said the underlying clay helps some.)

In 1998, then-City Manager Lamont Ewell suggested turning it into a golf course. The idea was kicked around City Hall for a couple of years, until Ewell departed for California.