Toronto's clean secret. Using 75% less energy than conventional chillers, Enwave has been cooling a handful of buildings in downtown Toronto since 1997. Five-km pipes draw water from 83m below the surface of Lake Ontario, where it is 4 degrees Celsius year-round. The system will have the capacity to cool 100 office towers, or 20 million square feet of office space, making a significant dent in the city's electricity demand.