Innovative Thermal Thinking Powers This Project

Enbridge Gas is getting its feet WET with another clean energy solution.

That’s WET, as in wastewater energy transfer—a process that harnesses the dormant energy of wastewater, and creates a lower-carbon method of heating and cooling buildings.

Enbridge Gas and its group of partners—Canada Infrastructure Bank, VanCity Community Investment Bank, Toronto Western Hospital (part of the University Health Network) and Noventa Energy Partners—announced the world’s largest raw wastewater energy transfer project at Toronto Western Hospital. The Canadian federal government also provided a grant from Environment and Climate Change Canada’s Low Carbon Economy Fund.

The $42.9-million retrofit project will use cutting-edge technology to transfer thermal energy to and from wastewater in the city’s sewer system to provide low-carbon heating and cooling to the hospital—about 90% of its needs in total.

The heating and cooling of buildings accounts for nearly a third (31%) of all global greenhouse gas emissions.

“This is an important step in protecting our natural resources as well as leveraging ‘waste’ to create clean energy solutions,” says Cynthia Hansen, Enbridge’s Executive Vice President and President, Gas Distribution and Storage. “We are committed to reducing greenhouse gas emissions through a variety of initiatives, and this is one example of how we are investing our resources to further assist Ontario’s transition to a greener future.”

Wastewater is an abundant and underutilized source of renewable thermal energy that can provide both heating and cooling. Wastewater can act as a heat sink or heat source—reducing the amount of electricity, natural gas and water required for conventional systems.

Using proprietary Huber ThermWin® technology, this project will extract carbon-free heat from the sewer to provide Toronto Western Hospital with winter warmth, and expel facility heat to the sewer in the summer.

For this project, a self-cleaning heat exchanger will be used to extract or reject thermal energy from wastewater flowing through the City of Toronto’s sewer system. The thermal energy from wastewater will then be transferred to a closed loop heat pump system to ensure no contamination (learn more about how the technology works here).

In one year, wastewater thermal heat will provide 1.7 million megawatt hours of thermal energy to Toronto Western Hospital. Over the next 30 years, the hospital will see a cumulative reduction in greenhouse gas emissions of more than 250,000 tonnes—displacing 1.35 million cubic meters of natural gas, 143,000 megawatt hours of electricity consumption, and 1.4 million cubic meters in water usage, the equivalent of 560 Olympic-sized swimming pools.

Enbridge Gas is an equity partner in this project, while also offering operational knowledge and expert guidance for management of energy systems, and is looking forward to participating in future lower-carbon opportunities.

Project construction will soon be underway.