Renewable energy all under one roof

Learn more about whether renewable energy is a good FIT for your building. View the presentations from our February seminar on Ontario's Feed-in Tariff program and other renewable options.

View presentations from our "Here Comes the Sun" session that looked specifically at solar applications for high rises.

Solar hot water

Solar hot water is a well developed and extensively used zero emissions technology (particularly in Europe and Asia). While using the free energy of the sun to pre-heat water is still relatively uncommon in Canada it is not because conditions here won’t support it. In fact, Toronto has better solar conditions than Germany, the world leader in the deployment of solar hot water systems. Solar hot water systems consist of panels that absorb and retain the sun’s heat to warm a fluid (water or glycol) circulating through tubes inside the panel. This fluid is then run through a heat exchanger that transfers the warmth to the intake water that feeds the conventional water heater or boiler. The boiler will then boost the water temperature only when necessary. In Southern Ontario, solar heating can provide half or more of the heat energy consumed for water heating in an average building. Even on cold winter days, systems can provide 30-40% of your water heating needs.

The technology is really a simple plumbing loop and easy to maintain. Panels have a lifespan of 20 years or more.

Another option is to purchase solar hot water through a “utility model.” Under this arrangement, the buyer signs an energy supply contract and pays a usage charge just as they would with a utility while the supplier retains ownership of the system. 

Combined Heat and Power

Just about every commercial building uses natural gas to provide one service – heat. But using a combined heat and power system (CHP), virtually the same amount of gas can be used to provide both heat and electricity. CHP systems capture the waste heat from a turbine or natural gas engine to displace the heat provided by boilers while also producing electricity. These systems can have efficiencies of 80-90%, meaning that you are not paying for wasted gas like with conventional boilers. CHP systems can also be used to replace diesel emergency backup generators (the natural gas distribution system does not rely on the conventional electricity grid for operation and so gas will flow even during a blackout). Combined heat and emergency power (CHeP) systems have a number of advantages:

• Can run throughout a blackout and keep all building systems operating (not just emergency loads) while also providing heat
• Don’t require fuel storage and checking
• Much lower air polluting and greenhouse gas emissions
• Avoid the cost of installing or replacing a rarely used diesel generator

Most CHP systems are interconnected with the electricity grid, which means power will still be available in peak periods or when the CHP system is offline. Power from the system can also be sold back to the grid. CHP system operators may also be able to take advantage of OPA programs for electricity demand reduction in peak periods. 

The Ontario Clean Air Alliance has produced two useful factsheets on CHP systems:

• Towers of Power: Advancing Combined Heat and Power in Multi Residential Buildings (Acrobat file)
• Place of Power: Advancing Combined Heat and Power in the Institutional and Municipal Sector (Acrobat file)

Geothermal

Geothermal (or geoexchange) systems use ground heat to warm your building. A fluid-filled pipe loop runs either horizontally (in trenches) or vertically (in drilled wells) to capture the warmth of the sun stored in the earth. Even in the winter, the earth's temperature remains approximately 10°C (50°F) at only six feet below the surface. A heat pump then optimizes the temperature level and transfers the heat to your building’s space or water heating system. In summer, the system works in reverse, with the cooler ground providing a chilling function by absorbing heat from the building. For more information on geothermal systems and suppliers, see the Canadian Geoexchange Coalition website.