Satellites detect large methane plume over Terrebonne, Que.

A plume of methane is seen in the centre of this handout satellite image, over a waste management facility in the Montreal suburb of Terrebonne, Que., in a Nov. 9, 2022, handout image. THE CANADIAN PRESS/HO-GHGSat

A large methane plume has been located over Terrebonne, Que. by GHGSat, a Montreal-based company that uses satellites to detect methane emissions produced on Earth.

On Wednesday, a plume with a methane concentration estimated at 1185 kilograms per hour was located over the Complexe Enviro Connexions, in Terrebonne's Lachenaie sector.

This waste site, one of the most important in the province, treats the residual materials of greater Montreal.

Methane is a powerful greenhouse gas that, when released directly into the atmosphere, has a warming power over 80 times that of carbon dioxide (CO2), according to the United Nations (UN) Environment Programme.

"One thousand kilograms per hour is a pretty serious level," said Jean-François Gauthier, vice president of strategic measurements and initiatives at GHGSat.

Some landfills "in India, Pakistan" or "Argentina" can reach "tens of thousands of kilograms per hour," Gauthier noted, but "for what we usually see in Canada, in the U.S., it's a pretty significant emission."

ONE PHOTO A DAY DURING COP27

During the COP27 conference, GHGSat, which provides data to the UN's International Methane Emissions Observatory, is publishing one photo a day of a place in the world where significant amounts of methane are escaping.

Prior to releasing the information about the Terrebonne site, the company posted photos of methane clouds escaping from a coal mine in Poland on Wednesday, a gas site in Iran on Tuesday, and a coal mine in New Mexico on Monday.

The initiative aims to raise awareness among leaders and the public, "because reducing methane emissions is one of the easiest ways to reduce greenhouse gases," said Gauthier.

When GHGSat discovers a significant methane leak, he explained, it contacts the emitting company "to try to work with them and correct the situation."

At the time of publication, neither GHGSat nor The Canadian Press were able to contact officials at Enviro Connexions, a subsidiary of Texas-based Waste Connections Inc.

"It is certain that there will be a certain amount of methane coming out of landfills, it is not rare, but technologies exist to capture this methane" and "generate energy for example," explained Gauthier.

Waste Connections has a biomethanization plant on its landfill site in Terrebonne.

"Complexe Enviro Connexions was the first company in Quebec to valorize biogas by producing green energy," says the company's website, whose mission is to "promote the protection and quality of the environment."

The landfill treats residual materials from the agglomeration of Montreal, the city of Laval and the Deux-Montagnes, Thérèse-De Blainville, Mirabel, La Rivière-du-Nord, Les Moulins, L'Assomption, Joliette, and Montérégie regions.

GHGSat estimates the uncertainty associated with the emission rate of 1185 kilograms per hour to be 48.7 per cent.

"The idea is to understand that this is an important emission, whether it is 935 kg/h or 1275 kg/h, it's a very important amplitude," said Jean-François Gauthier, adding that "the uncertainty is associated with the emission rate, not with the presence of the emission."

This report by The Canadian Press was first published in French on Nov. 11, 2022.