Converting Landfill Gas to Energy

ImageThis aerial photo shows the La Crosse County Landfill in the lower right corner and Gundersen Health System’s Onalaska campus can also be seen at the top left of the photo near the State Highway 16 and Interstate 90 interchange. The landfill, which is operated by La Crosse County’s Solid Waste Department, is approximately 1.6 miles from the Gundersen Onalaska campus. The landfill is a well -managed, picturesque site that has a variety of native prairie grasses and includes hardwood bluffs where wildlife species such as song birds, wild turkey, white-tailed deer, bald eagles, red-tailed hawks, coyotes, and other species live. The Solid Waste Department also provides services for recycling and reuse of a number of materials so that they do not have to be put in the landfill but can be properly integrated into a higher-use purpose. It is a fine example of resource management for the community.

The landfill contains a number of closed cells that biologically breakdown waste. The bacteria that perform the decomposition process operate in an anaerobic (low oxygen) environment within these closed cells. The type of bacteria that survive in this environment consume the organic waste and give off methane gas as a byproduct. Methane gas is the principle component in natural gas. It is also more than 20 times worse than carbon dioxide as a greenhouse gas which has environmental implications. Often, as with the La Crosse County Landfill, the methane that is emitted from the site is destroyed by combusting it in a flare.

Landfill gas is a potential renewable resource of methane that can be used for heating and/or creating electricity. It is usually being wasted in the flare combustion process. When landfill gas can be effectively captured and utilized, it reduces the need for electricity or heat derived from fossil fuel sources. In 2010 and 2011, the La Crosse County Solid Waste Department and Gundersen Health System partnered to develop and implement a landfill gas to energy project on the Onalaska campus, which is comprised of several large clinic and office buildings which total over 350,000 square feet. The methane gas from the landfill is captured and pumped through a pipeline that runs under Interstate 90 and to the Gundersen campus. This gas is then combusted in a reciprocating engine and generator set that produces electricity for the local grid. The waste heat from this process (exhaust and oil) is captured and used to heat the buildings and hot water on the campus. More energy is produced by this project than is consumed at the Onalaska site making Gundersen’s Onalaska campus the first, known, energy independent healthcare campus in the nation. The project started operations in March, 2012.

 Look for renewable energy resources in your local area and for partners that may also benefit from a mutual project.

 

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