Study Finds That Green Roofs Improve Solar Panel Efficiency

By Cass Jacoby, RCS Reporter. 

Combining green roofs with solar panels is proven to be smart green architecture.  

Solar power and green roofs are often thought of as separate solutions, however, a new study offers insight into how these two technologies have a synergistic relationship that makes combining them of greater benefit.  

Led by Peter Irga from the University of Technology Sydney and funded by the City of Sydney Council, the study looked at two adjacent office buildings in Sydney’s Barangaroo precinct, finding that a solar array fitted above plant beds had an average daily power output of 39 kW, or 13.1% greater than a conventional roof. 

This means that the panels on the green roof were 3.63% more efficient on any given day. Following this information, PV magazine calculates that over the eight-month study period the green roof produced an additional 9.5 MWh of green electricity, corresponding to a retail market value of $2,595. 

This has given researchers a rare glimpse at the real-world effects of green roofs on solar arrays and the benefits of combining these two technologies. Plenty of studies suggest that green roofs and photovoltaic panels are complementary technologies, but this breakthrough proves that biosolar roofs perform better. 

The reason for this, according to Living Roofs, lies in the micro-climate around PV panels. If it is too hot, the panels can lose efficiency. The green roof element can have a cooling effect, which makes the PV function more efficiently. 

This study is a landmark in determining more ways to make our cities sustainable, finding that “for the size of the positive impacts generated relative to the costs, green infrastructure is perhaps the easiest and most efficient initiative we can make.” 

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Photo credit: University of Technology, Sydney