|RECOVERY WORK Fred L. Wehran Jr. of the Wehran Energy Corporation checking gas collection lines at the Brookhaven Town landfill. - Phil Marino for The New York Times|
WHEN talk turns to alternative energy and global warming, let us not forget stinking piles of garbage.
Buried in airless pockets deep inside landfills, the organic matter in these great mounds of waste is consumed by bacteria that give off gas rich in methane, increasingly used to generate electricity and heat.
In fact, power from landfill methane exceeds solar power in New York and New Jersey, and landfill methane in those states and in Connecticut powers generators that produce a total of 169 megawatts of electricity - almost as much as a small conventional generating station. The methane also provides 16.7 million cubic feet of gas daily for heating and other direct uses.
There is ample opportunity for energy-producing projects at more landfills, according to the Environmental Protection Agency's Landfill Methane Outreach Program and officials and groups in the three states. As scouring for alternative energy intensifies, landfill methane is getting more attention from state, federal and local governments together with private energy and waste-management companies, landfill owners and energy entrepreneurs.
If it is not captured, the E.P.A. says, landfill methane becomes a greenhouse gas at least 20 times more potent than carbon dioxide, the principal greenhouse gas, when it rises into the atmosphere. The agency estimates that landfills account for 25 percent of all methane releases linked to human activity.
As a result, capturing methane at former and active landfills is a global housekeeping benefit as well as an important alternative energy niche.
In New York, power from landfill methane far exceeds solar power. In New Jersey, power from landfill methane surpasses both solar and wind power.
The Environmental Protection Agency lists more than 51 operating landfill methane projects in the three states, 7 under construction and 23 shut down. It lists opportunities at more than 90 other sites, most in New York and several on Long Island.
Landfill methane powers generators that produce 83 megawatts of electricity in New Jersey, 80 in New York and 6.1 in Connecticut, and more landfill energy could be on the way. Waste Management, the largest garbage hauler and landfill operator in the country, is in the midst of a five-year, $400 million plan to build methane-to-electricity projects at 60 landfills nationwide. It already has a project at the landfill in New Milford, Conn.
At some landfills, methane is not harnessed but is burned off, or flared, keeping it from the atmosphere but wasting its energy potential. That is changing.
"As the price of energy has increased, there is more interest in getting some energy production out of these landfills as opposed to simply flaring," said Janet Joseph, director of clean energy research and market development for the New York State Energy Research and Development Authority.
Ms. Joseph and others acknowledge that energy production from landfill methane, while desirable, will go only a short way toward meeting overall energy needs.
Still, available and anticipated incentives - including renewable energy credits, tax breaks and carbon offsets, linked with market forces and a regional initiative to reduce greenhouse gas emissions - are increasing interest in methane capture and use.
In New Jersey, more than half of captured landfill methane is now used. The state's largest project, at the 600-acre Ocean County landfill in Manchester, generates 20 megawatts, the E.P.A. said. Projects are in operation at more than 20 New Jersey landfills, under construction at 3 and possible at 8 others, E.P.A. data show.
On Long Island, the Wehran Energy Corporation project at the 8.1-million-ton Brookhaven Town landfill, which closed to garbage in 1996, has pumped 350,000 megawatt-hours of electricity into the power grid over the past 30 years. Wehran's president, Fred L. Wehran Jr., said the Long Island Power Authority pays 8.5 cents per kilowatt-hour for power the company delivers to its grid.
With gas from the closed landfill declining, Mr. Wehran said he was seeking ways to make power from the lower-methane gas coming from Brookhaven's adjacent and still operating landfill for construction and demolition debris. "I'd like to use every cubic foot of gas," he said, "because once it's gone it's gone."
In Connecticut, the Connecticut Clean Energy Fund, a state-created promoter of renewable energy that is financed through utility rates, calls methane's fuel potential untapped at many landfills, but there has been some activity. A project at the 837,000-ton East Windsor landfill in Broad Brook that began last year is producing 3.2 megawatts of power, the E.P.A. said. An older project at the 2.2-million-ton Hartford landfill produces 2.9 megawatts, the figures show.
The E.P.A. outreach program said landfills that were likely candidates for methane capture could add 27.3 megawatts in New York, 3.1 megawatts in New Jersey - where most landfills are already exploiting methane - and 7.3 megawatts in Connecticut. New York's figure is far below the 300 to 600 megawatts the state expects from upstate wind turbine projects.
Some plans for landfill methane use have fallen short of the goal. Proposals for the Croton Point landfill in Westchester County, at 108.4 million tons one of the largest in the metropolitan area, ended without a project.
"We thought about a lot of things, but basically nothing happened, because there was no payback to cover the initial costs," said Susan Tolchin, an adviser to the county executive, Andrew J. Spano. The landfill is now a park.
On Long Island, an attempt to generate electricity using landfill methane at the Babylon Town landfill in the late 1980s fizzled for lack of methane, the town said. Victoria A. Russell, the town's commissioner of environmental control, said large amounts of construction and demolition debris in the landfill made it a poor methane source.
EXPERTS said methane production depends on the type of garbage - organic-laden municipal solid waste is the best producer - how old and how tightly bundled it is, the quantity and, especially, weather conditions. Landfills in dry, hot climates produce less; those in steamy, rainy places do best because moisture hastens the decomposition that produces methane.
Landfill gas is about 50 percent methane and 50 percent carbon dioxide. Trace ingredients include hydrogen sulfide, which has a noxious odor. Collection systems and flaring largely eliminates odors from these ingredients, another benefit. Methane itself is odorless.
Margaret F. Brennan, the associate director of the New Jersey Agricultural Experiment Station at Rutgers in New Brunswick, said in a 2007 report that 5.5 million tons of the 8.2 million tons of biomass the state produces each year could be used to generate up to 1,124 megawatts of power, or more than 9 percent of the state's electric demand.
"New Jersey really has an opportunity here to lead the way in alternative energy from waste," she said. "It's truly a trash-to-treasure story."
This article has been revised to reflect the following correction:
Correction: September 21, 2008
Because of an editing error, an article last Sunday about the conversion of methane at landfills into energy misstated the process used to create power at the Covanta Energy Corporation's American Ref-Fuel incinerator in Hempstead, N.Y. The power results from the combustion of solid waste, not from the capturing of methane.