Landfill Gas-to-Energy Facility

EPA Clean Energy Initiative

The EPA recognizes clean energy initiatives for turning landfills into community assets and cutting greenhouse gases.

2007 Community Partner of the Year

Greater Lebanon Refuse Authority and PPL Energy Landfill Gas Energy Project has been recognized as the 2007 Community Partner of the year. Greater Lebanon Refuse Authority and PPL Energy created and built a renewable energy education facility that serves as an educational forum for local, national, and international visitors. With the goal of "empowering our future leaders with green energy," the project demonstrates the power of renewable energy from landfill gas (LFG), wind, and solar energy. For more project information, please visit the EPA website.

Landfill Gas as Energy

A significant by-product of waste decomposition is landfill gas, which is similar to natural gas. This gas is comprised primarily of methane, carbon dioxide and balance gases. The primary component of landfill gas, methane, is odorless and highly flammable and requires special management practices by landfills. The "balance gases" are neither flammable nor odorless, and require similar management practices to control the smell.

The Greater Lebanon Refuse Authority, in cooperation with Nextera Energy, currently has a collection program that burns landfill gas to produce electricity. What was originally a landfill hazard and a smelly problem is now a benefit to our integrated solid waste management system.

NextEra Energy Facilities

NextEra Energy, a methane recovery facility located on GLRA's property, has been in operation since 2007. The facility generates an average of 3,200 kilowatts of electricity per hour. This is enough to supply approximately 2,400 homes with electricity each day.

NextEra Energy vacuums the gas out of the Greater Lebanon Refuse Authority's landfills, burns the gas in an internal combustion engine to produce electricity, and sells the electricity to Met-Ed utilities. In return for the use of the gas by NextEra Energy, the GLRA receives a royalty payment from the sale of the landfill gas. The vacuum the landfill gas-to-energy plant uses to collect the gas eliminates the problem of dangerous methane gas escaping from the landfill and at the same time it recycles a by-product of the landfill into an extremely valuable resource.

Methane

Methane is a by-product of the decomposition of garbage. It is odorless, colorless, potentially deadly and also explosive! In a new landfill, emitted gases contain 40 to 50% carbon dioxide, 40 to 50% chloride and hydrogen sulfide, and only 10% is methane. After 5 years, these percentages reverse.

Collecting Landfill Gas

The landfill gas is actively collected by placing a vacuum on the landfill. Gas wells are drilled into the wastes and collection pipes are assembled into a network. A blower, located at the generation facility, uses the vacuum side of the system to pull gas into the pipe system, and the discharge side of the system to push the gas into the generation plant, similar to the two sides of a household vacuum cleaner; one side sucking up, one side blowing out. The methane gas pulled into this network then enters a central pipe known as a "trunk line". The temperature of the gas is between 70 and 80 degrees when collected and as a result it picks up water as it travels through the trash and enters the collection network. This "wet" gas is swirled around in a scrubber tank where moisture is removed. Then the gas travels to two filter tanks which remove dirt and other particles. Finally, the gas is forced into two 2,200-horsepower Caterpillar engines and create electricity.

Gas Control

Each engine has two carburetors which control the amount of gas entering into the engines. Each engine and generator has separate controls. The engine supplies the power and when the engine is in sync with the generator, it produces electricity. The generator has an arm that goes around a magnetic field, creating friction and producing electricity.

Landfill Gas Management Program Flaring Unit

As a secondary means of landfill gas management, the Greater Lebanon Refuse Authority has recently added a flaring unit to its landfill gas management program. In the event that Nextera Energy is unable to operate its facility to produce electricity, the gas will be directed from the network of gas collection pipes to an "Enclosed Flare." The "Enclosed Flare" is so named because its burners are located at the base of a 40 foot high stack. The flare uses the flammable portion of landfill gas, methane, to destroy the balance gases that are the cause of landfill odors, controlling both the explosive issues and the odor issues with one operation.

To accomplish this correctly the system is designed to burn at approximately 1,600 degrees Fahrenheit. To keep the unit operating correctly the temperature, landfill gas flow rate and air flow to the burners are closely monitored. In the event that something goes wrong, the unit will automatically shut down and call GLRA staff.

Carbon Credits

In addition to electricity generation, the GLRA’s power plant and flare operations make our site eligible for the creation and sale of Verified Carbon Units (VCUs). In simple terms, our site immediately avoids future streams of green house gas (GHG) emissions as a result of upfront intervention that permanently precludes further emissions from the source. Once verified, the GLRA partners with a third party broker (3 Degrees, Inc.) to sell these VCUs to organizations seeking to offset their own negative environmental impacts. It is noted that the GLRA does not retain claim over carbon credits and that carbon credits may be issued through the Verified Carbon Standard Project 5 for the greenhouse gas emission reductions or removals associated with Greater Lebanon Refuse Authority’s landfill waste management services.