The idea behind landfill gas is simple. Capture the methane gas that is naturally created by decaying waste matter in landfills and burn that gas to power electricity generators. The end result has many benefits: reduced methane emissions into the atmosphere, a cleaner burning electricity generation process compared to fossil fuels resulting in reduced sulfur dioxide and nitrogen oxides emissions (creating less smog and acid rain), and reduced dependence on foreign sources of energy. Two of our planned five landfill electricity generation plants are already operational and on-line delivering green electricity to industries, office buildings, schools, government buildings and consumers.
Eastern Sanitary Landfill The Challenge
The Baltimore County Department of Public Works operates the Eastern Sanitary Landfill approximately seven miles northeast of Baltimore, Maryland. Opened in 1982, with an expected life of 40 years, it has a design capacity of 12.5 million cubic meters of waste. The landfill holds about 4.5 million tons of garbage, with more than 160,000 tons added annually. It is located on a 367-acre site with an anticipated waste footprint of 200 acres. The challenge was to install an efficient landfill gas-to-energy system with no financial investment for Baltimore County.
The Solution
The project includes an electric power generating system, consisting of three massive engine/generator sets (with space and provisions for a fourth) that burns the collected landfill methane gas, and generates up to 3 megawatts of electricity daily, which is equivalent to 79 railroad cars of coal per year. That's enough energy to power 1,900 homes each year and greenhouse gases will be reduced to levels equal to the removal of 3,000 cars from the county's roads each year.
"Given its potency and short-term climate characteristics (methane breaks down in the atmosphere after 12 to 15 years, while carbon dioxide persists for decades), it makes it a very effective gas to go after,� said Paul M. Gunning, a branch chief in the EPA�s climate change office.
Construction activities at the site were confined to site preparation, installation of generators, connection to the electric grid and replacement of gas compressors. Combustion gases from each engine exit the building through a silencer-equipped exhaust stack approximately 20 feet above ground surface. The project uses existing overhead transmission lines to transfer power from the site to the power grid. The air emission rates meet all applicable federal and state emissions limitations. The system substantially reduces the operation of the existing gas burn-off flare which represented a loss of energy and contribution to greenhouse gases.
"The 350-acre landfill is expected to produce methane for at least the next 20 years. Pepco expects that methane output will increase, so there are plans to add a fourth generator within the next five years�, said David Weiss, Pepco Energy Services� President and Chief Operating Officer.
"Landfill gas not only reduces pollution, but it can act as a fuel source,� said James S. Wang, a climate scientist with the group Environmental Defense. He said the federal government�s encouragement of landfill gas energy projects represents "kind of an easy way to reduce greenhouse gases in an economically viable way.�
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