As solar panels heat up beyond 25°C, their efficiency decreases markedly. Green roofs moderate rooftop temperatures. So we wanted to find out: could green roofs help with the problem of heat reducing the output of solar panels?
Our research compared a “biosolar” green roof — one that combines a solar system with a green roof — and a comparable conventional roof with an equivalent solar system. We measured the impacts on biodiversity and solar output, as well as how the plants coped with having panels installed above them.
The green roof supported much more biodiversity, as one might expect. By reducing average maximum temperatures by about 8°C, it increased solar generation by as much as 107% during peak periods. And while some plant species outperformed others, the vegetation flourished.
These results show we don’t have to choose between a green roof or a solar roof: we can combine the two and reap double the rewards.
