Green roofs are becoming a phenomenon, an integral part of green design.
Besides their abundant benefits in countering the heat island effect in cities, reducing energy demand in buildings, and providing habitat for birds and green spaces for people, there’s could be another important one – they increase energy production of solar panels.
Emerging research suggests the vegetation on a green roof helps keep the ambient air around solar panels cooler than if they were installed on a black, bitumen roof – which helps solar panels run more efficiently.
At least two studies pointing to this finding have emerged in recent months – one from Berlin, which shows a 6% improvement in solar production, and another from the Bronx Design and Construction Academy in New York, which demonstrates a 3% boost, reports Green Building Elements.
The article notes:
"The combination of green roofs and solar panels does seem to yield significant benefits. A green roof does not only conserve energy and reduce the workload for the solar system, but also increases energy output. The extra performance boost will help offset the cost of the green roof and the solar panels on top of it, which in the long run will lower solar panels cost."
The Green Roof business is growing rapidly, expected to reach a $7 billion market by 2017, forecasts Lux Research. Besides the benefits we mentioned above, they also provide thermal and acoustic insulation, remove airborne pollutants, stormwater management and absorb carbon dioxide.
Examples of governnent policies pushing green roofs forward:
- Switzerland: Basel mandates that 30% of all flat roofs be green roofs by 2016.
- US: New York offers a one-year tax abatement of up to $48 per square meter, up to a $100,000 maximum per building
- Canada: Toronto requires green roofs on all new buildings with a floor area exceeding 2,000 square meters. It offers a cash rebate of $50 per square meter, up to a $100,000 maximum per project.
The main barrier to adopting green roofs is the cost, which ranges from $300-$500 per square meter, estimates Lux. The biggest growth areas will be commercial and institutional buildings such as universities, hospitals, airports and corporate headquarters.
Some of the green roofs we’ve recently written about are: Millennium Park, which covers 25 acres in Chicago; FedEx Express 175,000 square foot roof at Chicago’s O’Hare International Airport; a 2.5 acre roof on the Post Office’s NYC distribution center; and an apartment complex in China.