Landfill Energy FAQs

By volume, landfill gas is generally made up of 50 percent methane, and 45 percent carbon dioxide and small amounts of nitrogen, oxygen, and hydrogen, and non-methane organic compounds. Landfill gas can be an asset when it is used as a source of energy to create electricity or heat because it can often be used in place of conventional fossil fuels in certain applications. It is classified as a medium-Btu gas with a heating value of 500 to 600 Btu per cubic foot—approximately one-half that of natural gas.

Landfill gas is created from the decomposition of organic material contained in municipal solid waste landfills. The quantity of gas is influenced by a number of factors: types and age of waste in place, the quantity and types of organic materials in the waste, and the moisture content and temperature of the waste.

The U.S. EPA air quality requirements and the industry's advances in landfill gas-to-energy technologies have encouraged the utilization of landfill gas to benefit human health, safety and the environment, as well as providing economic opportunities. Landfill gas-to-energy projects provide a highly effective means of reducing overall gas emissions from landfills, whether the landfill gas is combusted by flare, electrical generation equipment, or another end use system.

Landfill gas is a reliable source of energy because it is generated 24 hours a day, seven days a week. By using landfill gas to produce energy, landfills can significantly reduce their emissions of methane and decrease the need to generate energy from fossil fuels.

Landfill-derived methane gas is used primarily in two ways:

• As a "direct-use" fuel, methane gas is recovered by a series of wells that have been drilled into a landfill. It is transported via a network of pipes to an on-site gas production facility and then piped to nearby industrial users. Typically, the gas is used to fuel boilers, furnaces, ovens, or other combustion equipment for large energy users.
• To generate electricity, recovered methane gas is used to fuel engine-generators that produce electricity on-site at the landfill. This electricity is then sold to a local utility or other electrical consumer.