From Guest Blogger Mathias: Combining Green Roofs and Solar Panels for Improved Efficiency

Green roofs are engineered vegetated roofing systems where plants and soil have replaced, or been put on top of, traditional concrete, roof tiles or shingles. 

The breathing living roofs provide numerous benefits to buildings including protection against stormwater runoff, conservation of energy and noise reduction. They provide a good ecosystem for plants and bugs, which further enhance the benefits. In fact, green roofs have also been shown to increase people`s productivity.

Maybe most important is the impact green roofs have on reducing the heat island effect. The EPA estimates that five to ten percent of community-wide demand for electricity is used to compensate for this effect (source).

There`s a lot of energy (and money) to save if the heat island effect is reduced. Not surprisingly, a recent study found that green roofs could lower the annual energy demand by as much as 6%.

What about combining green roofs with solar panels? We know that when it comes to photovoltaics (conversion of sunlight into electricity), temperature goes hand-in-hand with efficiency rates. It turns out that the evaporation that plants on a green roof facilitate actually cools the rooftops.

Several studies are well underway, one of them suggesting that the efficiency boost is as much as three percent if solar panels are combined with green roofs, which is of great significance in the solar panel industry. It will be interesting to get more data on larger scale and more rigorous studies in the near future to help us determine in what degree green roofs will affect solar panels cost.