Green Roofs and Solar Energy – A Perfect Combination
With the movement for a greener environment and the increase of implementing renewable energy sources come new and improved innovations for using that energy. In the past few years a new option for environmentally friendly roofs seems very attractive – solar panels on green roofs.
There is an impression that a roof can either be a green roof or a roof with solar panels. This is not the case. A combination of both has proven to be ideal for both roof options and this technology is common in many countries in the world. Germany and Switzerland are the leading countries when it comes to this type of technology.
The solar panels are placed on special solar bases and fastened with solar base frames. The solar bases are later covered with system substrate as per the recommended load. The plants are then planted on that substrate. However, we need to make sure that the plants are not the type of plants that grow very tall so that they don’t cause shading to the modules.
Green solar roofs counteracts climate change, flooding and heat waves in two ways – through the effects of green roofs and renewable energy generation. Several advantages come with using green solar roofs:
– Increased module efficiency
The temperature of the Standard Test Conditions is set at 25°C. In reality, the temperature of the solar module increases due to the solar irradiation. The efficiency of the solar module depends on the temperature of the module and the ambient air temperature. As the temperature increases, the level of module efficiency decreases. The vegetation of the green roofs achieve a cooling effect to the modules, especially in the summer time. The foliage also absorbs some of the dust. According to PV magazine, green roofs improve solar panel performance by 3,6% on average which in turn increases the output power of the photovoltaic system. Not only do the plants provide a lower working temperature for the panels and absorbs some of the dust, but their leaves are also reflecting the sunlight onto the panel surface which also leads to and increase in module efficiency
– Provides more biodiversity
In addition to the increased performance of the photovoltaic systems, the green roofs also provide more biodiversity due to the water storage capacity of the base tray and support cities in their fight against climate change. The solar panels provide shade for the plants which is very important during the summer time. A healthy growing environment for the flora also attracts a variety of bees, butterflies, beetles and other species.
However, things can go wrong if these types of panel systems are not installed correctly. If wrong types of plants are used, i.e. if they are of the types that grow too tall, they can shade the panels causing the hot-spot effect.
There are a number of biosolar roofs around Switzerland, Germany and Austria. Hopefully, other countries will follow this example since this combination of green roofs and solar panels not only complement each other but it is also good for the building, the owner and the surrounding environment.
