Methane is a greenhouse gas (GHG) produced naturally in
landfills that is 20 times more potent in warming capabilities than
carbon dioxide. Historically, waste gas was flared away, but
current technologies allow for the harnessing of this gas and its
conversion into many beneficial uses.
For example, landfill gas (LFG) can be used directly
as a substitute fuel in the generation of electricity for engines
or turbines in the on-site power plant of the landfill. Other
"medium-BTU" gas uses include the offsetting of fossil fuel in
steam boilers, burners and utility power plants for a single
customer which would require a dedicated delivery pipe to the
customer facility. A "high-BTU" application would initially
clean the product to natural gas specifications and then inject it
into a natural gas pipeline. This high-BTU gas could also be
compressed or liquified and stored on-site for use as a compressed
natural gas (CNG) or liquid natural gas (LNG) fueling
station. These applications also provide significant
environmental value through the reduction of GHG, and can offer a
typical online system reliability of more than 90 percent.
This allows the system to act as a long-term price and volatility
hedge against fossil fuels.
According to the Environmental Protection Agency (EPA), as of
June 2017 there were 634 operational landfill-gas-to-energy
projects in the United States and an additional 401 landfills that
are good candidates for such systems. The EPA estimates the
gas generation potential of these landfills is 250 billion cubic
feet per year, with an electric potential of 1,237 megawatts.