An innovative project using water from deep in Lake Ontario to cool downtown buildings in Toronto is one step closer to implementation. The city's Works Committee recently endorsed staff recommendations to execute an energy transfer agreement with Enwave District Energy Limited.

The Deep Lake Water Cooling (DLWC) project involves building a new intake for the Island filtration plant, upgrades to the plant and the John Street pumping station, and construction of a heat exchange facility with all costs borne by Enwave. It is expected to be operational by 2003.

"This is an excellent example of a public/private sector partnership delivering improved services to Toronto residents and business," said Works Committee Chair, Councillor Betty Disero. "The Deep Lake Water Cooling (DLWC) project provides a reliable source for cooling, long-term predictable costs and minimal impact on the environment compared with traditional methods of air conditioning."

"With each additional bad air day, it is becoming imperative that we take all necessary measures to improve the air we breathe," said Dennis Fotinos, president and CEO of Enwave.

The DLWC project will produce significant environmental and economic benefits. Using deep lake water as a cooling source will reduce the demand for electricity and enable removal of ozone depleting refrigerants from existing building cooling systems. Based on the estimate peak cooling capacity of 40,000 tons, carbon dioxide emissions will be reduced by approximately 30,000 tons a year, along with reduction in nitrous oxides, sulphur dioxide and fine particle emissions. There will also be economic benefits to consumers to the extent that district cooling using deep lake water is less costly than conventional cooling using electric chillers. In addition, the City will benefit from an improved raw water source that may result in reduced taste and odour occurrences during warm weather.

Deep lake water cooling entails the year-round supply of water at 4 degrees Celsius from an 85-meter depth in Lake Ontario through a new intake constructed for the Island filtration plant. Following treatment at the Island plant, the potable water would be transmitted to the John Street pumping station, diverted through an energy transfer loop to heat exchangers and then fed back to discharge mains at a temperature of approximately 13.3 degrees Celsius. The chilled water will then be distributed through Enwave's district cooling network to consumers in the downtown core.

The Deep Lake Water Cooling report will be considered by Toronto City Council at its meeting of July 24.