Methane from landfills is providing electricity


Decaying garbage is lighting up homes across America.

Today, more than 300 megawatts of electricity, just a fraction of the overall potential, is being generated from landfill methane and sold to electric utilities by independent power companies and solid-waste management firms.

That's enough to supply the residential needs of a city the size of Wichita, Kan.

Landfill gas-recovery projects in the United States have proliferated from a handful in 1980 to some 155 today. Another 30 are in planning and construction stages.

About 70 percent of the sites generate and sell electricity; the rest sell gas directly to industrial customers. On average it takes a 30-acre landfill with waste 40 feet deep to produce enough gas to generate 1 megawatt of electricity.

Like most alternative power sources, landfill gas competes with conventional fuels and suffers when fossil-fuel prices are low. But pending regulations requiring gas-collection systems at sanitary landfills should stimulate the development of new plants.

Guidelines set by the Environmental Protection Agency for controlling emissions of landfill gas already have encouraged waste-management companies to enter the recovery business.

Browning-Ferris Industries, a $2.9 billion-a-year solid waste giant, has 21 gas-extraction systems, four with gas or electricity sales. "BFI intends to first control gas migration and emissions in an environmentally safe way and then look for opportunities to offset these costs by selling alternative energy," says spokesperson John Bean.

The guidelines have been drawn up in response to several concerns, says EPA environmental engineer Susan Thorneloe. These include the explosive potential of migrating gas within the landfill (more than 100 sites have had accidents) and emissions of volatile organic chemicals and methane, a greenhouse gas. Odor also poses a nuisance.

Landfills producing 100,000 megagrams or more of non-methane organic compounds will have to install gas-collection systems. According to Alice Chow of EPA's policy office, about 12 percent of the country's existing landfills will be affected by the (x guidelines. The nation has 6,000 active sites and about 30,000 closed sites.

How much will installation cost landfill owners? In the "worst-case scenario," if all the gas were vented and flared and none recovered for energy, costs could total $300 million a year ++ nationwide, Chow says.

However, the "smart landfill operator" will recover gas to offset these costs, she says. And while energy recovery is not mandatory, the EPA will strongly encourage it for environmental reasons.

Besides the price of oil and the emissions guidelines, tax credits are another factor that will dictate how fast the landfill-gas business continues to grow. "The systems are ... not economical without the credit," says Jane Seigler, government-affairs counsel for Waste Management Inc. A one-turbine landfill gas project costs about $4.5 million to construct. The smallest system -- with an 800-kilowatt generator -- costs $1.5 to $2 million.

Waste Management (at $5.4 billion the nation's largest solid-waste company) operates 16 landfill-gas recovery plants ranging in size from 0.8 to 15 megawatts. Together, the 16 plants can produce 71 megawatts. Fourteen plants generate electricity site for sale to utility companies; two sell gas directly to customers.

If EPA guidelines require landfill owners to install gas-collection systems, that's fine by third-party developer O'Brien Energy Systems, of Philadelphia, says Fred Lawrence, manager of O'Brien's biogas division.

O'Brien installs and operates projects at a customer's site, selling the electricity either wholesale to local public utilities or retail directly to industrial users.

The company operates seven biogas projects with a total capacity of 21 megawatts, 80 percent of which is sold to utilities. The biogas division is expected to generate $5 million in revenues this year, and its resources are substantial: O'Brien has an estimated $100 million worth of landfill gas, including the Edgeboro Landfill in East Brunswick, N.J. It is estimated that methane reserves there could support a 15-megawatt power plant.

Landfill-gas recovery fits in nicely with the national effort to be less dependent on foreign oil. And recovery plants provide a double benefit because they capture pollutants and turn them into energy.

Grant Ferrier is editor of the Environmental Business Journal, San Diego, Calif.

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