CNN - 5 May 06

Prof. Robert B. Laughlin
Department of Physics
Stanford University, Stanford, CA 94305
(Copied 22 Oct 09)

Converting Trash Gas into Energy Gold

By Daniela Chen
Friday, May 5, 2006

ATLANTA, Georgia (CNN) -- Growing concern about the U.S. dependence on foreign oil is raising more urgent calls for developing alternative energy sources.

"These oil prices are a wake-up call. We're dependent on oil and we need to get off oil. And the best way to do so is through technology," President Bush said, responding in an April 28 news conference to the high cost of gas.

Amid talk of water, wind, geothermal and solar power, another player is quietly proving its utility in the energy market -- landfill gas.

According to the Environmental Protection Agency, Americans produce an average of 4.5 pounds of garbage per person per day. All that trash goes into landfills, which are the largest human-related source of methane in the United States.

U.S. landfills are responsible for a third of all methane emissions worldwide.

As trash decomposes in landfills, methane is generated. The oxygen-free conditions in landfills and dumps support bacteria that break down the waste.

These bacteria produce a natural byproduct called landfill gas, which is roughly equal parts methane and carbon dioxide. Depending on the amount of methane produced, by EPA regulation the gas is either allowed to escape into the atmosphere or is sucked out and burned.

Methane is a potent greenhouse gas. In the atmosphere, it absorbs radiation reflected from Earth's surface, enabling the planet to maintain its livable temperatures.

However, according to the EPA, because methane is 21 times more powerful than carbon dioxide at warming the atmosphere, it plays a much larger role in global warming.

The EPA is a major proponent of landfill gas energy. In 1994, the agency formed the Landfill Methane Outreach Program (LMOP) under the United Nations Framework Convention on Climate Change.

LMOP team leader Brian Guzzone said that since methane is both a pollutant greenhouse gas and a source of energy, the government decided it could provide a good opportunity to reduce greenhouse emissions and provide energy.

About 50 percent of all of the waste America generates is put into municipal solid waste landfills, Guzzone said.

LMOP has partnerships with more than 500 entities, including industry groups, corporations, utilities, states and communities.

"The EPA's role is to work with communities that have landfills and help them realize the potential opportunity of their landfill," Guzzone said. That includes providing materials, technical services and community outreach.

The process of converting landfill gas into energy is relatively simple. Wells sunk into a landfill collect the gas, which is then used to burn in engines and boilers, heat greenhouses and fuel vehicles.

Guzzone said landfill gas can be used just as traditional fuels such as coal and natural gas are used. "It's comparable to natural gas," he said.

As of 2005, there were 396 operational landfill gas projects in the United States and more than 1,300 candidate landfills, according to Guzzone. The current projects produce the energy equivalent of providing electricity for 725,000 homes or heat for 1.2 million homes.

The reductions associated with these projects are equal to 13 million vehicles being removed from the road, Guzzone said. "You reduce air pollution by using landfill methane in lieu of fossil fuel," he says, thus improving air quality.

Another benefit of these projects is preventing the gas from drifting off and exploding. Siphoning landfill gas away also controls odor, a happy benefit for people who live nearby.

One of LMOP's partners is textile manufacturer Interface Flooring Systems. In January, the company received an Energy Partner of the Year award from LMOP. Located in LaGrange, Georgia, the company buys landfill gas from the city-owned landfill.

The gas is sucked up from the 90-acre landfill by 53 pipes, compressed, and piped 10 miles to the carpet production plant where it is used as fuel.

David Gustashaw, Interface's vice president of engineering, stumbled upon the project while trying to find cost-efficient sustainable energy. "I got tired of hearing what were considered to be green renewable opportunities always costing more," he said.

After Gustashaw ruled out other alternative energy sources for practical reasons, the only option left on his list was landfill gas energy.landfill gas was the perfect fuel for his 2005 project.

Gustashaw's goal was to ensure true sustainability in its environmental, social and financial impacts.

Landfill gas "significantly reduces the draw from environmental systems," Gustashaw said. "You're still going to have a landfill constituent, but now you're diverting a majority of that to be recycled." By converting air waste into energy, Interface has reduced its dependence on natural gas by 20 percent and reduced greenhouse emissions from the landfill.

On the financial side, though the initial financial outlay for new equipment for the project was in the $2.5 to $3 million range, Gustashaw said Interface will be able to recover its capital in two to three years and the city in four to five years.

"It's a great resource," Guzzone said. "You're taking what was a liability, and turning it into an asset."