Using a City’s Excess Heat to Reduce Emissions

Wastewater and sewage currently provide 70% of the space heating and hot water for 43 buildings connected to the network, with the remaining 30% coming from natural gas, though the goal is to eliminate that by 2030. Hydroelectric dams provide 97 percent of the electricity needed to power the heat pumps.

Vancouver’s senior renewable energy planner Ashley St. Clair explains that “every time we take a shower, do the dishes, or do a load of laundry, the water is still hot when it goes down the drain.”

“To be able to tap into that waste heat is really the ultimate circular economy. It’s flowing under our streets and we’re already collecting it through the traditional wastewater pipe infrastructure.”

As the first North American utility-scale sewage waste heat recovery system, it went online in 2010, just in time for the 2010 Winter Olympics to heat the Olympic Village. Since then, it has grown and now has plans to heat 22 million square feet of space over the next few decades.

Since climate change has made extreme weather more likely and intense in Vancouver this year, including heat domes, wildfires and catastrophic flooding that cut the city off from the rest of Canada by road and rail. As a result of the project, Ms. St. Clair said, the building now has its own heat and hot water supply.

According to Erik Rylander, the head of heat recovery at Stockholm Exergi, a heating and cooling company, Stockholm, on the other hand, has used a district heat network since the 1950s. Sweden’s extensive forestry industry provides a large portion of the city’s heat, but data centres are increasingly becoming a part of the energy mix, he noted.

Companies can choose from a variety of locations to build new data centres in Stockholm and participate in the city’s heat recovery system since the Stockholm Data Parks project began in 2017. In exchange for the heat they provide to the network, companies are compensated.