The Oak Grove Landfill flare was visible for miles. Lighting up the night sky, local residents became so accustomed to the 24/7 glow that they dubbed it the “eternal flame.” Located in Winder, Ga., just outside metro Atlanta, the Oak Grove flare burned the landfill gas (LFG) generated from the decomposition of local residential trash.
In April 2008, construction began on what would become the first high Btu LFG facility in the Southeast. The facility was completed by year's end. In January 2009, the eternal flame vanished, and residents began receiving clean, renewable energy from the Winder Renewable Methane Facility. The facility uses methane from Oak Grove and converts it into high Btu renewable gas that is pumped into the distribution line.
It took more than three years of discussions and meetings before the facility became a reality. The involved parties included Pittsburgh-based Renewable Solutions Group, which owns and operates the facility; Phoenix-based Republic Services, which owns and operates the Oak Grove Landfill; the city of Winder; the city of Buford, Ga.; and the Municipal Gas Authority of Georgia.
Converting LFG to energy offsets the need for non-renewable resources, such as coal and oil, and reduces emissions of air pollutants that contribute to local smog and acid rain. In addition, LFG projects help curtail global climate change, because they reduce emissions of methane, a greenhouse gas 23 times more potent than carbon dioxide.
According to the U.S. Environmental Protection Agency, there are approximately 2,300 currently operating or recently closed municipal solid waste landfills in the United States. Of those, more than 420 have LFG utilization projects. But only a handful of these produce pipeline-quality natural gas.
While LFG to electricity projects provide economic and environmental benefits, high Btu projects provide for significantly greater energy output when compared to the landfill gas-to-electricity approach. With ample opportunity for more high Btu projects, the Southeast can particularly benefit given its continued emissions constraints and limited options when it comes to wind and solar renewable energy projects. In fact, Republic Services alone plans to have many high Btu projects in place in the next few years. The Winder facility is their fourth Btu project in the United States, with another coming on-line soon and an additional five to seven potential sites in the Southeast alone.
“Landfill gas to electricity projects have flourished over the past several decades, primarily as a means to capture federal tax benefits, but they produce limited environmental benefits when compared to high Btu applications,” says David Wentworth, president of Renewable Solutions Group. “The next evolution is landfill gas to pipeline-quality gas projects, which can be used to heat homes, power natural gas vehicles and illuminate city streets, all while providing financial and environmental benefits.”
The conversion of LFG to pipeline-quality gas requires five basic steps:
Remove hydrogen sulfide.
Remove volatile and non-methane organic compounds.
Remove carbon dioxide.
Compress the gas to pipeline pressure.
Even before the Winder facility was up and running, the community benefitted from job creation, employing engineers, construction firms, equipment vendors and many others. Moreover, much of the initial construction cost was spent locally for drilling, piping, construction and operational personnel.
The entire Winder facility is less than 5,000 square feet, yet at capacity can process 4,000 standard cubic feet per minute (scfm) of LFG, generating enough fuel to heat 10,500 homes at its current capacity and even more by the end of 2009.
The completed facility promises substantial energy savings. Unlike other clean sources of energy, which are sold at a premium, the gas produced by the Winder facility is sold to end-users at a discounted rate. It is estimated that local residents will see up to a 10 percent monthly discount on their gas bills.
In addition to the financial benefits, the Winder facility also provides significant environmental benefits. In addition to converting harmful methane into energy, the processes used at the Winder facility eliminate 44,500 tons of carbon dioxide released into the atmosphere each year.
“By participating in LFG project development, a community is being innovative and responsible with local resources, and can enhance its image as an environmental leader,” says Bill Held, director of landfill gas projects for Republic Services. “Reducing landfill gas emissions by converting them to energy improves local air quality, contributes to reducing climate change and improves overall landfill management. This makes the area surrounding the landfill a better place to live.”
Currently, the Winder facility is running at about 60 percent of its design capacity (2,400 scfm of landfill gas feed). Long-term plans include installing additional wells at the Oak Grove Landfill to increase the LFG feed to the design capacity of 4,000 scfm. As the facility's output continues to grow, so do the opportunities to provide a clean source of renewable energy.
“There is at least a 20-year capacity at this facility, and our long-term goal is to provide renewable methane as a fuel source for fleet vehicles like mass transit buses, taxis and mail trucks,” says Wentworth. “One day, we hope to have the very trucks that dump the trash into the landfill using the converted landfill gas as a renewable source of fuel.”
Dr. Martin L. Pomerantz is the executive vice president of technology and engineering for Renewable Solutions Group, Pittsburgh.