Landfill Gas Recovery
(Above) Electricity generators at the EWMC - which use landfill gas as fuel - began operations in October 2005.
What is Landfill Gas?Landfill gas is produced when organic wastes like grass clippings and leaves decompose inside a landfill, where there is no oxygen.
It is a mixture of roughly 50% methane and 50% carbon dioxide and other trace gases. One tonne of organic waste can produce 125 cubic metres of methane, the energy equivalent of one barrel of oil.
The methane in landfill gas is poisonous, flammable and lighter than air. It can migrate to the surface and potentially become an explosion risk if it becomes concentrated in an area where there is an ignition source.
If not contained or extracted in a controlled program, methane could move through the ground and enter the basements of nearby buildings, creating health and explosion risks. It is also a potent greenhouse gas.
How does the City use Landfill Gas?Since 1992, the Clover Bar Landfill has been mined to produce electricity from landfill gas. Enough gas is captured each year to satisfy the electricity demands of approximately 4,600 homes. To date, over 101 gas wells have been drilled into the landfill's decomposing waste.
Sixty wells, each approximately 25 metres deep, are currently in service. They are connected to a pipe network that conveys the gas to a Landfill Gas Recovery Plant on the Edmonton Waste Management Centre (EWMC) site where it is cleaned of impurities.
For the first 10 years the cleaned gas was piped to a nearby Epcor electrical generating station where it was used as fuel to generate electricity.
In 2005 Epcor built smaller generators next to the Landfill Gas Recovery Plant. The new generators are able to supply 4. 8 megawatts of electricity into the electricity grid, again, enough to power over 4,600 homes annually.
Powerful facts about Landfill Gas Recovery
- The Clover Bar Landfill site is the only one in Alberta that both recovers gas and uses it to generate electricity.
- The volume of gas sent to the generating station each day would fill 8,000 hot air balloons.
- As of October 2005 more than 221 million cubic metres of landfill gas has been extracted from the Clover Bar landfill.
- The Clover Bar landfill is expected to produce gas until 2013.
- 52 landfills (measured in 2005) in Canada capture methane resulting in a reduction of greenhouse gas emissions. Of these, 14 use gas for electricity production and 9 for direct use.
Did you know?In 2008, 145,297 tonnes of CO2 equivalent emissions were captured - equivalent to removing 36,324 cars (24,216 SUVs) from the road for one year.
For more information:
In Edmonton: 311
Outside Edmonton: 780-442-5311