Ottawa harnesses the power of trash

Toxic greenhouse gases from an Ottawa dump are being burned to produce enough electricity to power 5,000 homes in the city.

A 5-megawatt power plant that uses methane produced by decomposing garbage at the Trail Road landfill sites began operating Wednesday.

It is run by PowerTrail Inc., a partnership between a Hydro Ottawa subsidiary and a private two-company joint venture, and is expected to generate more than $150,000 in annual royalties for the city while reducing dump maintenance costs, a news release said.

Rosemarie Leclair, president and CEO of Hydro Ottawa, said this is the first such power project in Ottawa, although there are similar projects around the world.

"This is taking essentially landfill gas, a wasted product, and turning it into something useable," she said.

Engineer Paul Bulla of Comcor Environmental, one of the two private companies involved, demonstrated how wells drilled deep into the buried trash suck up carbon dioxide and methane, a greenhouse gas that traps 20 times more heat per molecule than carbon dioxide.

The wells will collect about 180,000 tonnes of gas a year, of which about 90,000 tonnes are methane fuel.

A vacuum pump sucks the gas through a system that cools and pressurizes the gas mixture, drying it in the process, then feeds it into five generators. There, it is burned, producing mainly carbon dioxide, water and electricity.

Before the plant was built, the methane was still burned or flared off, but wasn't used to produce power.

The power generatedcould potentiallyreduce the demand for power generated by other Ontario plants, including those powered by coal, reducing overall greenhouse gas emissions.

Unlike the old system for disposing of methane, the city didn't build and doesn't operate thenew plant. According to Hydro Ottawa, that meansthe citywill save $2 million in upgrades and repairs needed by the previous gas collection system and $200,000 in annual operating costs.

But Mayor Larry O'Brien said he is more interested in the environmental benefits than the financial payoff.

"I'm excited about that because it's one small step towards achieving my long-term goal of being able to convert waste into energy," he said.

A similar project is planned for Ottawa's Carp Road landfill.