Turned on by trash
Most people are turned off by the smell of landfill gas (LFG). But, to some cities and counties, LFG smells like money. They are finding that using LFG to generate electricity, heat or steam can help them save considerable cash by minimizing their use of non-renewable energy sources.
LFG is made up of about 50 percent methane, about 45 percent carbon dioxide and usually less than 5 percent varying amounts of nitrogen, oxygen and other non-methane organic compounds. Most of the time, it simply is burned off by flares installed in landfills. But some local governments are harnessing it to do everything from power trucks to heat buildings.
“Landfill gas-to-energy (LFGTE) projects started as far back as the 1970s (in part as a response to the oil crisis). However, substantial growth really didn’t occur until the late ’80s and early ’90s, which mainly was a result of federal tax incentives that were made available,” says Brian Guzzone, program manager for the USEPA’s Landfill Methane Outreach Program (LMOP), Washington, D.C.
LMOP was founded in 1994 as a voluntary program to provide technical assistance and outreach to landfill owners and operators, communities, states, energy services organizations and the LFG industry. LMOP can provide technical services in the form of feasibility studies; it can identify different end users for the gas; and it can help landfills form strategic partnerships to move projects forward. Since 1995, it has helped almost 200 landfills get LFGTE projects under way.
Today, there are about 335 operational LFGTE projects in the United States. More than 200 are under construction or are planned. “LMOP estimates there are about 500 more landfills that we would consider really good candidates for this type of project,” Guzzone says.
Using gas to grow
LFGTE projects are as varied as the landfills that use them. In Sugar Grove, N.C., methane from the closed Yancey-Mitchell landfill is helping the city heat its greenhouses. (The carbon dioxide in LFG is an additional benefit because it enhances plant growth.)
Yancey County Commissioner Leon Taylor first proposed the project after a trip to Florida where he saw a newspaper clipping outlining an LFGTE project in that state. County officials presented the idea to Blue Ridge Resource Conservation & Development (RC&D), an area non-profit organization, which helps people in western North Carolina care for and protect their natural resources.
“We invited Shelley Cohen from [LMOP] to come down and meet with a few local people to let us know what the [LFGTE] possibilities were and what kinds of assistance they could give us,” says Stan Steury, coordinator for RC&D. “She came in and got everybody all excited about the possibilities of [an LFGTE project], even though our landfill was just a tiny rural landfill.”
LMOP conducted a feasibility study that provided an estimate of how much LFG would be generated by the landfill’s garbage, how long it would last and how it could be used. “We had to identify one thing we wanted to use it for, and we identified greenhouses as something that could be heated by this gas,” Steury says.
The project now provides heat to a complex of greenhouses, which are home to a native plant cultivation project called Branch Out. “Plants like azaleas and rhododendrons are native here, and people have harvested them in the wild for years. But some of the plants are actually becoming really rare. So our objective is to help people learn how to raise them rather than to harvest them in the wild,” Steury says.
The greenhouses are used to get seedlings started. Once the plants are established, they are sold at a reduced cost to local farmers and nurseries where they are grown to retail size.
LFG also plays an important role for the complex’s craft workshops, which are high energy-use businesses. For instance, prior to the LFGTE project, area glass blowers spent about $1,000 to $1,500 a month just on fuel. Now they pay close to $300 a month, which includes gallery space, studios, glass-blowing furnaces, pottery kilns and all the fuel that it takes to operate them.
“We laugh about this, but we are actually bringing tourists to the landfill now,” Steury says. “It is a great place because they can see native plants being grown in the greenhouses; they can watch glass blowers and potters at work in the studios; and there is a gallery where they can buy some of that stuff. We are getting a lot of visitors.”
The $1.2 million project was funded by grants from organizations such as the Rocky Mount, N.C.-based Golden Leaf Foundation and the Asheville, N.C.-based Community Foundation of Western North Carolina.
Going full circle
In San Diego, in a roundabout way, LFG soon will be used to create more LFG. The gas will be tapped to power the trucks that bring trash to the landfill that supplies the LFG.
In exchange for the rights to the LFG at the city’s South Chollas Landfill, ALT, an Amarillo, Texas-based company that provides liquefied natural gas (LNG) to commercial markets, has committed to making $250,000 in upgrades at the 120-acre landfill. The company will convert the landfill’s LFG to LNG, which the environmental services department will buy back to power its garbage trucks.
“The environmental services director, Richard Hays, wanted to pursue alternative fuels as a way to reuse the LFG,” says Bob Ferrier, San Diego’s deputy environmental services director of refuse disposal. Hays envisioned a closed-loop system in which the trash trucks would collect the waste and bring it back to the landfill. There, the trash would produce the methane gas that would be converted to LNG to fuel the trucks.
The trucks are converted by installation of a system developed by San Diego-based Clean Air Partners and licensed to Peoria, Ill.-based Caterpillar. “It includes installation of a 119-gallon LNG cryogenic tank, fuel lines, a computer control box, and an intake manifold and fuel injection system. The conversion costs a little under $30,000 per vehicle,” says Charles Woolever, San Diego’s deputy environmental services director of refuse collection.
Down to earth
In Maryland, LFG eventually will be used for the down-to-earth purpose of heating NASA’s Goddard Space Center. Methane from Prince George’s County’s Sandy Hill Landfill in Bowie soon will be transported through a five-mile pipeline to the space center in nearby Greenbelt. The gas will be used to fire two boilers that produce steam for the center.
Toro Energy, a Dallas-based company that developed the LFGTE project at the Sandy Hill Landfill, and Houston-based Waste Management, the operator of the landfill, proposed the project to the county. After Due Diligence procedures, which included studying combustion and deciding how to best use the LFG, the county agreed to pursue the idea.
The project involves modifying two boilers and upgrading the controls system at the powerhouse, as well as installing the pipeline, compression and dehydration facilities at the landfill. Toro will take care of those aspects, and it will operate the compression facilities and the pipeline from the landfill to the space center. Waste Management and the county will maintain the well field collection system.
“Prince George’s County has been an active proponent of beneficial uses for landfill gas,” says William Chamberlin, associate director of the waste management division for the county’s Department of Environmental Resources. “The Sandy Hill/Toro Energy project is a natural extension of the county’s landfill gas program.”
Currently, the landfill holds about 6 million tons of waste. That waste generates 1,800 cubic feet per minute of LFG that could then generate 42 million kilowatt hours per year — enough energy to power more than 14,000 homes for one year. According to LMOP, using that LFG yields the same reduction in greenhouse gases as displacing the emissions from more than 46,000 cars for one year. In addition, using LFG has the same impact on greenhouse gas as planting more than 64,000 acres of trees.
Not going to waste
Current EPA regulations under the Clean Air Act require many landfills to collect and burn LFG. LFGTE projects allow the landfill to be in regulatory compliance while at the same time creating a renewable energy source.
“Almost every community across America has a landfill, and that landfill is generating landfill gas,” Guzzone says. “So, when feasible, why not do something with it?”
Steury identifies several benefits at the Yancey-Mitchell LFGTE project. “I think [they] fall into four main areas,” he says. “One is the benefit to the environment because we are reducing the emissions of these greenhouse gases. Secondly, we are demonstrating the use of fuels that otherwise would just be wasted. Education — of both the visitors that are coming to the landfill, and the apprentices that work at the landfill — is the third benefit. Economic development is the fourth benefit. By creating these new businesses and helping farmers get started with new cash crops, we are stimulating the economics of the region.”
