Turning the roof into an energy producer

Volume 16, Number 4, December 2011

A roof that produces energy? Yes, it is possible.

Researchers at the NRC Institute for Research in Construction and Natural Resources Canada are looking to the future when roofing products, such as membranes and shingles integrated as part of the building envelope, will produce energy.

This technology, Building Integrated Photovoltaic (BIPV), includes both the building envelope surface and the building energy source. On low-sloped roofing, the roofing membrane is laminated with thin film photovoltaic technologies to form BIPV. On residential roofs there are two options: the roof shingles are designed as photovoltaic shingles incorporating the solar cells, or thin film photovoltaic laminates are integrated with traditional asphalt shingles or a metal roof.

Clean Energy Fund

Through Canada's Economic Action Plan, the Government of Canada is taking action to ensure a healthy environment. The Clean Energy Fund is investing in large-scale carbon capture and storage demonstration projects, and smaller-scale demonstration projects of renewable and alternative energy technologies. Clean energy is energy that is produced, transmitted, distributed and used with low or zero greenhouse gas (GHG) and other air emissions.

Currently, thin film photovoltaic laminates are commercially available in North America, while photovoltaic shingles are expected to be launched in 2011-2012. Recently, half of the roof on the Canadian Centre for Housing Technology (CCHT) InfoCentre was transformed into an energy producer. The roof was stripped down to the bare plywood, a modified bitumen waterproof membrane was adhered to it, and fourteen 18-foot long photovoltaic (PV) films were laminated to the membrane.

This is a novel approach adapted from a roofing system that would typically be found on low-sloped roofs such as commercial supermarkets, industrial warehouses and school buildings. The roof system construction was completed in August 2011 and assessment has begun. It will not only determine the energy performance, but also evaluate its integration with traditional shingles and durability in the Canadian climate. On a sunny day in September, the system produced up to 1650 watts of electricity at its peak.

Researchers hope to continue to explore new roof-integrated PV technologies for both residential and commercial roofs, not only from the energy perspective, but also with regard to the durability of the roofing components as they emerge in the Canadian market.

This demonstration project was made possible with financial support from the Clean Energy Fund and SOPREMA Canada, who provided guidance and contributed roofing materials.

For more information

Contact Suda Molleti at sudhakar.molleti@nrc-cnrc.gc.ca or 613-993-9673.