By using the natural low temperature from water in Lake Ontario, Enwave Energy Corporation air conditions 29 million square feet of high-rise building space in downtown Toronto, reducing CO2 emissions by 79,000 tons and reducing electricity consumption by 90% compared to conventional chilling.

What is it?

Canada's first renewable energy project to provide air conditioning using cold lake water from the depths of Lake Ontario to remove thermal energy from a district chilled water cooling system. Deep Lake Water Cooling serves 51 high-rise buildings in a high density area of downtown Toronto, which have a combined cooling load of 54,493 tons. The system will ultimately produce 75,000 tons of cooling when completed.

Energy efficiency

By using the deep lake water to cool, the Enwave project will save 128 million kWh annually in electricity.

How does it work?

  • Enwave owns and operates Toronto's downtown district energy system
  • OMERS, Ontario Municipal Employees Retirement System (a pension fund) and the City of Toronto are shareholders of Enwave District Energy. OMERS owns 57% and City of Toronto owns 43%.
  • Through three large intake pipes, stretching-out 5.1 kilometers from the shore and lying 83 meters below the surface of the lake, Enwave Energy Corporation has been able to tap into the coldness of Lake Ontario to provide air conditioning.
  • Using this infrastructure, the City of Toronto can potentially pump 100 million gallons per day of 4º Celsius water to its Island Filtration Plant (IFP). There, the cold water is conventionally treated and then allowed to flow via gravity to the City's John Street Pumping Station.
  • The water drawn from the lake continues on its regular course through the John Street Pumping Station (JSPS) for normal distribution into the City water supply. However, before leaving the JSPS, the water is diverted through a series of heat exchangers where the coldness is used to remove thermal energy from water returned by Enwave's district cooling customers. The heat exchangers' metal plates, in addition to other precautions, ensure that Enwave's treated chilled water and the City's potable water never come into contact with each other.
  • The coldness of the incoming City water is used to cool the warmer water on the other side of the heat exchanger metal plates that is being returned by Enwave's customers after it has cooled their collective facilities.
  • Enwave's water, once re-cooled, then continues once again through the closed-loop distribution system to provide cooling to the company's many customers.
  • The water on the City side of the heat exchangers, which has been warmed-up to conventional drinking water temperatures, makes its way to the City's water consumers.
  • Enwave's district cooling loop is designed to provide air conditioning to approximately the same geographical area served by Enwave's district heating system, which is one of the largest in North America.


  • Enwave Energy Corporation owns and operates a district heating and cooling system in downtown Toronto.
  • OMERS, Ontario Municipal Employees Retirement Savings System (a $40 billion dollar pension fund with several investments in infrastructure projects around the world) and the City of Toronto are the two shareholders of Enwave Energy Corporation. OMERS own 57% and City of Toronto owns 43%.
  • The City of Toronto receives from Enwave an annual "Energy Transfer Fee" of approximately $1 million for the use of City Water infrastructure as well as dividends through its minority Shareholder position.
  • Due to the sustainable nature of the business, it will provide stable, utility rate returns and cash flow to its shareholders for a very long time.

Next steps

Enwave's Deep Lake Water Cooling project currently has a maximum capacity of 75,000 tons of refrigeration. The facility was at 73% of capacity as of February 2007 – less than 3 years after commencement and two years ahead of the projected sales schedule. It is conservatively anticipated that the system capacity will be sold-out by the end of 2007. Given the huge public demand, there is a possibility that Enwave will invest further to expand the system capacity by an additional 25%.


  • A system such as this requires a concentrated high cooling demand
  • Source of water with 4 degrees Celsius or cooler is necessary
  • Patient investors with long-term investment horizons
  • Environmentally conscious consumers