projects and services
oaks landfill gas-to-energy facility
In December 2007, the Montgomery County Department of Environmental Protection (DEP) teamed with the Northeast Maryland Waste Disposal Authority (NMWDA) and its engineering contractor, C B & I, to design/build/operate two (2) landfill gas-to-energy facilities at the Oaks and Gude Landfills. Design and permitting were completed within one year, after seven months of construction and start-up testing; the two beneficial use facilities that collectively generate 3.2 Megawatts (MW) of electricity came online in late June 2009 and are continuously producing “green” energy!
The Basics – During operation and closure, a landfill will generate various gases, including methane via waste decomposition. Under the Resource Conservation and Recovery Act (RCRA), solid waste management facilities are required to control the migration of landfill gas, primarily due to the explosive potential of methane. As a point of reference, natural gas typically consists of 90 percent methane, whereas landfill gas ranges from 40-50 percent methane.
The gases generated by waste decomposition are collected through a network of vertical and horizontal pipes, which are connected to a blower (e.g. fan) that exerts a negative pressure on the landfill. The blower draws the gas to a Flare Station for flame burning (no energy value) or to a gas-to-energy facility where the gas is burned in an internal combustion engine that will turn generators and subsequently produce electricity.
The Facility – The Oaks Landfill is approximately 170 acres and is located at 6001 Olney-Laytonsville Road in Laytonsville, MD. The gas-to-energy facility utilizes approximately 900 standard cubic feet per minute (scfm) of gas in two engines: Caterpillar 3520 and Jenbacher GS 316 (see above photo). The existing candlestick flare is utilized on an as-needed basis for gas control to supplement the gas-to-energy facility if gas migration is detected. The two engines in conjunction with support equipment (pretreatment skid, transformers, switchgear, etc.) generate and transmit approximately 2.4 MW of electricity, enough to power just over 1,500 homes year round.
The Green Aspects – The Oaks Landfill Gas-to-Energy Facility will produce enough electricity to power approximately 1,500 homes year round. Estimated environmental offsets from the Oaks Landfill Gas-to-Energy Facility include the reduction of approximately 4,780* tons of methane emissions and 12,150* tons of CO2 emissions with respect to diverting power generation from coal-burning power plants. This is equivalent to planting approximately 21,500 acres of trees or taking more than 19,500 cars off the roads.
* Estimate based on EPA Landfill Methane Outreach Program calculator.