How a Toronto university plans to use sewers to heat its campus

On Tuesday, York University announced a plan to tap into that wastewater to heat its Glendon campus, replacing gas-fired boilers and virtually eliminating its carbon footprint.

“It’s more of a circularity approach,” said Mike Layton, chief sustainability officer at York. “It’s wasted energy that’s just flowing underneath us. Let’s tap into it and see if we can give it new life.”

Layton said the project uses the same 100-year-old compressor technology that operates refrigerators.

“We extract the heat and send it up the hill to what is already a very beautiful and lush campus. Now, it’ll be one that won’t be belching out greenhouse gases,” he said. “We see a significant potential here to not only reduce our carbon but to reduce our costs associated with heating and cooling and at the same time showcase a technology for others.” 

Noventa, a Toronto-based renewable energy company that is partnering with York for the project, will design the system over the next year with an eye to starting construction in late 2024, Layton said. Once operational, the innovative solution would reduce emissions enough to make Glendon York’s first net zero campus well in advance of its 2040 net zero goal.

As Canada grapples with cutting its carbon emissions, one of the biggest challenges will be phasing out natural gas space heating.

Enthusiasm for heat pumps has emerged over the last few years — with sales skyrocketing in the U.S. Canada and Europe — not only as a climate change solution but also as a way to fight inflation and rising fuel costs. 

A Star-Corporate Knights project this year found heat pumps would save the average household almost $500 per year. 

However, concerns remain over the amount of additional electricity heat pumps would require if everyone adopted them. 

The solution — already in place in countries like Sweden — is grouping buildings together into district heating systems, which are far more efficient than having every home go it alone.

The office buildings of the financial core in downtown Toronto already use a massive district heating and cooling system called Enwave, which currently uses natural gas but could hypothetically be converted to geothermal or wastewater as its heat source and cut its carbon footprint to near zero.

University of Toronto recently embarked on a geothermal heating project, which involved ripping up the field at King’s College Circle to drill hundreds of holes into the ground, requiring a lengthy construction project with a large footprint.

Digging up the streets in this manner to install a district heating system across the city would be prohibitively expensive, which is why attention has turned to the network of pipes that already carries heat under the streets: the sewers.

“Geothermal’s got it’s place. But it’s got its limitations too,” said Dennis Fotinos, founder and CEO of Noventa. “Where geothermal doesn’t work, wastewater energy provides a really strong, viable alternative because in effect we are an open loop geothermal system.”

Noventa has been busy with its first project at Toronto Western Hospital, which is scheduled to begin operation next spring. 

“The dominoes are beginning to fall and interest in wastewater energy solutions is really picking up,” said Fotinos.

The city publishes a wastewater energy map online, which allows anyone considering a project to find the nearest sewer pipe and how much energy it carries.

University campuses and hospitals are good candidates for early adoption because they already group together a critical mass of buildings that can act as an anchor tenant to make a project financially feasible. 

But once it’s built and shown to provide reliable heat at a fraction of the cost of traditional sources, the wastewater heat could be extended to other buildings in the area.

“There’s a couple of big institutions around here that could potentially benefit,” Layton said. “The Toronto French School, a couple other schools in the Valley, a couple of condominiums too. This could be the beginning of a low carbon or no carbon heat source for all of them.”