Landfill gas is produced from the anaerobic decomposition of waste in landfills. Methane is one of the main components of landfill gas--an odourless, colourless gas generated by the anaerobic decomposition of degradable organic waste. Although its composition can vary, landfill gas is typically half methane and half carbon dioxide, with trace levels of sulphur compounds and volatile organic compounds. Landfill sites begin producing landfill gas in their first year, and can continue producing for up to half a century.

Over the past decade, innovative technologies have been developed to capture this gas by drilling deep into landfill sites and pumping it out through a network of pipes. The captured gas is either flared or piped to nearby facilities for use as fuel in heating buildings or generating electricity. Burning landfill gas not only converts methane to carbon dioxide, but also destroys most of its harmful components--which can cause nuisance odours, stress on vegetation, smog, and a risk of fire, explosion and asphyxiation. The methane produced by Canadian landfill sites contains enough energy to heat more than 600 000 homes a year.

Environment Canada supports the utilization of landfill gas and has been working with Natural Resources Canada, provincial departments and the private sector to raise awareness of the energy potential of landfill gas by holding workshops and publishing guidebooks on the subject, as well as supporting research into new and innovative technologies. These include a new cryogenic purification process that can separate landfill gas into liquefied natural gas and high-purity carbon dioxide, and the use of microturbines to generate electricity on small landfill sites.

The increased availability of cost-effective and efficient technologies has resulted in a 40-per-cent increase in landfill gas capture in Canada since 1990. Today, nearly 300 000 tonnes of methane are recovered at 42 sites across the country annually, reducing greenhouse gas emissions equivalent to six megatonnes of carbon dioxide, the equivalent of removing 1.4 million cars off the road. However, this still represents just a quarter of the total landfill methane produced in Canada each year.

About 70 per cent of the recovered gas is used as energy, most of it at large-volume landfills located near major urban centres. However, the potential also exists for many medium and small sites to generate energy from landfill gas recovery projects.

Experts estimate that the volume of landfill methane captured in Canada could be doubled within the next five years--significantly decreasing Canada's greenhouse gas emissions, and reducing the impact of human activity on global climate change.