Solar panels on a green roof

Green roofs are known for their benefits to the environment, people and communities. Now there is increasing evidence that green roofs are beneficial to solar energy technologies too. By combining a green roof with a solar installation on a building’s rooftop, the efficiency of the solar panels is increased and the workload of the array is lowered.

Efficiency: Green roofs reduce the surrounding air temperature. If a solar array is installed above a green roof, the solar panels are cooler and operate at higher efficiency. More of the solar energy collected is captured and used for the building’s electricity. This effect has been known for years where green roofs have been installed near conventional HVAC equipment.

Lower Demand: Green roofs help cool buildings. The plants’ process of evapotranspiration reduces summer roof top temperatures, thereby decreasing the transfer of warmer outside air. This can greatly affect the indoor temperature, keeping it more stable. As a result, heating and cooling equipment switches on less frequently and has a reduced work load, ultimately lowering the demand for energy. The energy collected by solar panels can then be used more sparingly, over greater periods of time.

Solar panels do good things for green roofs too.Because of the shade provided by the panels periodically through the day, a wider range of species can be planted on individual green roofs. These array-created microclimates improve the water use and promote biodiversity on vegetated roof systems. The result: good neighbors indeed!

Written and Re-published with permission by DC Greenworks – www.dcgreenworks.org

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