33. Landfill gas: How old garbage can generate electricity

Tags: Renewable Energy

Published March 1, 2013

Blog: Tapping (mountains of) trash for landfill gas

Apple cores, pumpkins, Christmas trees and the crusts your mom cut off your sandwich 27 years ago. They all ended up at Cloverbar landfill in Edmonton and as that material breaks down it releases methane.

While the landfill isn’t accepting new waste that methane (which we know from our biogas episode is a valuable resource) can be collected and burned for electricity. It’s called landfill gas recovery and in this case the methane powers a 4.8-megawatt power plant, generating enough electricity to power 4,600 homes.

Neil Burkhard was our very enthusiastic host as we toured Edmonton’s waste management facility, a place that sports a very spiffy landfill diversion rate of 60 per cent. It was 21 years ago in 1992 when Edmonton started sucking landfill gas out of its landfill.

Today there are 60 active wells in the old landfill site and a star-like pattern radiates out from each well to collect the methane. These pipes are 20 metres under the surface and they all feed into a network of pipes that ring the perimeter of the landfill.

What’s collected in those pipes is typically a mixture of methane, carbon dioxide and water vapour. It’s collected by massive vacuum pumps, cleaned up and burned in three different 20 cylinder converted diesel engines. More…

Podcast: Landfill gas: Drilling for gas in garbage

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There are 64 landfill gas recovery projects in Canada diverting more than seven million megatonnes of C02 equivalent a year and making money for their operators either through electricity and heat or carbon credits. We explore Edmonton's landfill gas operation, a 4.8 megawatt project that can power up 4,600 homes with nothing more than methane that's collected from an old landfill. 

 
Quick Facts
  • In Canada, landfill sites produce about 27 million metric tonnes of carbon dioxide equivalent in methane emissions annually.
  • Sixty-four facilities across Canada recover landfill gas, reducing greenhouse gas emissions from landfills by 6.9 million metric tonnes of carbon dioxide equivalent each year.
  • The recovery of landfill gas has increased by 40 percent since 1990.
  • The decomposition of organic waste in landfills produces a gas which is composed primarily of methane, a greenhouse gas contributing to climate change. Landfill gas can be recovered and utilized to generate electricity, fuel industries and heat buildings. 
  • There are two major benefits to recovering and utilizing landfill gas. The first is that capturing and combusting landfill gas prevents substances like methane from escaping to the atmosphere; the second is that using the energy from landfill gas can replace the use of non-renewable sources of energy such as coal, oil, or natural 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.
 
Resources

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Statistics Canada’s Waste Management Industry Survey: Business and Government Sectors

The latest stats and surveys from the waste management industry courtesy of the federal government GO >

Tags: Renewable Energy

 
Extras

The latest numbers on the amount of landfill gas recovery operations in Canada - ClimageChange.gc.ca

Municipal solid waste and greenhouse gases - Environment Canada

Official page on Edmonton's landfill gas recovery project - City of Edmonton 

Official page on Edmonton's waste-to-biofuels project - City of Edmonton