Gas Utilities Should Ask A Simple Question: “What’s In Your Pipeline?”

Alternative sources of methane gas often get overlooked in America’s ongoing quest to relieve its dependence on finite fossil fuels and decrease its greenhouse gas emissions. However, what should not be overlooked is the reality that biogas can be a supplement to natural gas in this country’s natural gas transmission and distribution systems.

Across the country, municipalities are making that valuable discovery. Over the last several years, many cities and towns have become involved with alternative energy and renewable energy projects that deliver an alternative source of methane gas from non-traditional sources. And as a result, these communities are demonstrating how to be both economically savvy and environmentally friendly.

Landfill methane can provide fuel for a cogeneration (COGEN) plant. The organic matter in landfill waste is consumed by bacteria that give off gas rich in methane. Landfill methane becomes a greenhouse gas at least 20 times more potent than carbon dioxide - the principal greenhouse gas - when it is released into the atmosphere. In some instances, methane is burned off, or flared, to minimize the release of methane gas into the environment, but that approach is fast becoming archaic, as operators of landfill facilities are coming to realize it is a waste of potential energy. Capturing that gas and using it to generate electricity and heat is becoming a popular alternative.

According to the Environmental Protection Agency, there are 480 operational landfill gas-to-energy projects in the U.S. In addition, about 130 projects are under construction or under study.

One completed project is at the University of New Hampshire (UNH) in Durham. The recently launched EcoLine project gave the university the distinction of being the first in the country to depend on landfill gas for its primary fuel source. UNH purchases methane gas from the nearby Turnkey Recycling and Environmental Enterprise facility in Rochester, NH. The gas used to produce roughly 85% of the electricity and heat consumed on the university’s 5 million square-foot campus.

The methane gas produced at Turnkey is used to power UNH’s $28 million combined heat and power facility, or COGEN plant, which features a chilled water plant. The COGEN plant takes waste heat typically lost during the production of electricity and uses it to heat campus buildings, thus making more efficient use of the university’s energy resources.

At the landfill, 300 extraction wells, as well as a series of collection pipes, capture the methane-rich landfill gas, which is then cleaned of compounds such as siloxanes (typically produced by the decomposition of various materials, most notably health and beauty care products) through a variety of different methods, particularly compression refrigeration and heating, and activated charcoal.

Once it has been enriched and purified, the gas is odorized at the landfill site before being sent the roughly 12.7 miles from Turnkey to UNH.