‘Solar Farms should be on roofs not farms ’ to paraphrase the UK Minister for Energy. The debate on whether farmland should be used for food or renewables is not for these pages. However, whilst there is now guidance on how to make solar farms biodiversity hotspots in the countryside, there is little understanding how this could be achieved at roof level in the UK. In Switzerland specifically there has been much work over the years of combining green roof and solar technology to create roof top biodiversity hotspots.
Many developers, architects and consultants see roofs as the perfect place to deliver renewable energy. We at biosolarroof would not disagree. However, all too often many designers will dismiss the idea of a green roof because of the need for solar roofs. Nothing could be further from the truth. The synergy between solar roofs and green roofs is unfortunately little understood or appreciated amongst the UK’s construction industry.
There is another issue here, one of compartmentalization. Sadly most designers view situations as a one or the other solution. That part of the roof will be solar and that part of the roof will be green roof (if you are lucky). Whilst the idea of ecosystem services and green infrastructure is slowly taking root, the built environment still tends to work in a linear fashion. Such an approach misses the opportunities to provide multi-beneficial services.
A recent audit of London has shown that there are over 175,000m2 of green roofs in what is known as the Central Activity Zone. At least 20 of these individual roofs have solar panels. However there are many more roofs in the area that only have solar roofs. Whilst carbon free energy is an important and pressing goal for new buildings, there is a need to understand the wider implications of climate change in terms of biodiversity and sustainable water at roof level. Furthermore there is growing evidence that soil and vegetation at roof level can make solar roofs more efficient at producing energy, especially in the summer time. So bees, biodiversity and pollinators may not be something that architects and mechanical engineers consider at the top of their priorities. However the biosolarroofs project provides an opportunity for such professionals to engage in a productive and meaningful way across the full spectrum of the sustainability agenda.
This is real ecosystem services and green infrastructure design – hitting
- More efficient solar energy production
- More diverse vegetation and biodiversity
- And all the other sustainable benefits green roofs bring to the urban realm (sustainable drainage, amelioration of air pollution, noise benefits etc.)
The future of our cities is one of buildings that harbour biodiversity and energy.