Two Pine Landfill is turning yesterday’s waste into tomorrow's energy. The landfill, located in Pulaski County, operates a state-of-the-art gas conversion plant that supplies electricity to approximately 4,500 homes in North Little Rock.
According to the Environmental Protection Agency (EPA), every American produces, on average, 4.6 pounds of garbage a day. Much of the trash ends up in landfills, where it decomposes and produces methane and carbon dioxide. Both are greenhouse gases, which are widely believed to contribute to climate change.
“Methane gas, a component of natural gas, is a potent gas that remains in the atmosphere for about 9 to 15 years. Methane is about 21 times more powerful at warming the atmosphere than carbon dioxide. If landfills can capture methane and use it as an energy source, it makes sense to do so,” said Suzanne Hirrel, associate professor and waste management specialist at the University of Arkansas’ Cooperative Extension Service.
Federal and state environmental laws mandate that landfills must monitor their methane production and prevent landfill gases from being released into the atmosphere when they exceed permitted levels. The Solid Waste Management Division of the Arkansas Department of Environmental Quality (ADEQ) regulates activities and facilities involved in the processing and/or disposing of solid waste. Most landfills use a flare system or other combustion device for disposing of landfill gases. This process reduces odors, addresses safety concerns, reduces methane emissions and air pollution but does not provide energy benefits.
There are many ways to generate energy from landfill gas. The gas from the landfill can generate electricity, heat water into steam, be converted to fuel for vehicles or purified to be used in natural gas pipelines. The Department of Energy Act of 1977 created the U.S. Department of Energy, which was authorized to fund and regulate wasteto- energy research projects and energy research. Federal tax credits enacted in 1980 encouraged the development of private enterprises to participate in the landfill gas market. A federal production tax credit of one cent per kilowatt hour is available for energy produced from landfill gas.
David Conrad, an engineer for Waste Management, which operates Two Pine, said the landfill is the only one in the state that generates electricity from landfill gas. There are six Caterpillar engines located at Two Pine that generate 4.8 megawatts of power from roughly 500,000 tons of garbage a year. ADEQ recently approved a 144-acre expansion of the landfill. Waste Management plans to build a second gas-to-energy plant on the new site, which should be operational in five years. In the meantime, the original plant will continue to supply electricity for many years to come.
According to ADEQ, EPA has identified four municipal solid waste landfill candidates for its Landfill Methane Outreach Program (LMOP). EPA defines a candidate landfill as one that is accepting waste or has been closed for five years or less, has at least one million tons of waste and does not have an operational or under construction project. Three additional Arkansas landfills have been listed by the EPA as having potential status, meaning the landfills may qualify for LMOP, but more data is needed before making a final determination.
There are several benefits to converting methane into energy. Such projects reduce annual greenhouse gas emissions by preventing landfill gas from being released into the atmosphere and help to lessen America’s dependency on fossil fuel-based electricity.
“We are proud to be contributing to the renewable energy resources of the state. We plan to enlarge our capacity to produce even more electricity for Arkansas citizens. Converting landfill gas to electricity is a win-win situation for Two Pine, the communities we serve and the environment as a whole,” said Conrad.
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