What are BioSolar Roofs and How Do They Benefit You?

Biosolar roofs are innovative systems that combine solar panels with green roof technology. These roofs integrate photovoltaic (PV) systems, which generate renewable energy, with layers of vegetation that provide ecological benefits. The concept merges the environmental advantages of green roofs, such as improved biodiversity and stormwater management, with the energy-producing capabilities of solar panels, making it an ideal solution for businesses looking to enhance their sustainability efforts.

What Are Biosolar Roofs?

Biosolar roofs are dual-purpose systems that combine solar power generation with the ecological benefits of a green roof. The main components include photovoltaic panels that capture sunlight to produce electricity and a green roof layer consisting of various plant species. These elements combine to create a multifunctional roof contributing to energy efficiency, biodiversity, and urban environmental management.

How Biosolar Roofs Work?

Biosolar roofs harness sunlight through the photovoltaic panels to generate electricity, just like a traditional solar installation. However, adding a green roof layer enhances the system by cooling the solar panels through evapotranspiration from the plants. This cooling effect can increase the efficiency of the solar panels. Additionally, the green roof helps manage stormwater, reduce the urban heat island effect, and support local biodiversity, making the entire roof system more effective and sustainable.

Combining solar panels with green roofs can bring some amazing benefits. These ‘Biosolar’ roofs bring together the energy-generating capability of solar PV arrays and the water-storing, habitat creating benefits of green roof systems.

What are the benefits of biosolar roofs?

• Cooler temperatures: Ironically, on long, hot, summer days, solar PV panels can actually become less efficient; temperature plays an important part in their efficiency. Some reports suggest heat can reduce output efficiency by as much as 10-25% in certain cases. Research has shown that compared to flat un-vegetated gravel roofs, green roofs can be up to 21ºc cooler (Kaiser 1981), clearly providing some benefits for PV arrays.
• Opportunities for wildlife: Additionally, as the solar PV panels create shading on the roof surface, new habitats are created allowing a large range of species to be on the roof, bringing ecological benefits. Three different micro-habitats can be created; the first one ideal for growing sedum, the second is a more moist area, as the PV panels shed water onto the green roof when it rains, and the third is the dry shade where the panels cover the green roof. Each of these areas can be used to attract an abundance of wildlife that would not otherwise be a part of the city or region.
• No damage to the roof: There are additional technical advantages to Biosolar roofs; due to the integrated nature of the two systems, the green roof system can be used as ballast for the PV panels, meaning that they can be fixed to the roof without any risk of penetrating waterproof membranes or the structure of the roof itself.
• Reduction of Urban Heat Island Effect: Biosolar roofs help combat the urban heat island effect, a phenomenon where urban areas become significantly warmer than their rural surroundings due to human activities and heat-absorbing materials like concrete and asphalt. The vegetation on biosolar roofs cools the surrounding air through evapotranspiration, thereby reducing the ambient temperature and contributing to a cooler urban environment.
• Stormwater Management: The green roof component of biosolar roofs acts as a natural sponge, absorbing rainwater and reducing the amount of stormwater runoff. This helps mitigate the risk of flooding and eases the burden on urban drainage systems. Additionally, the vegetation and soil layers can filter out pollutants from rainwater, improving the quality of water that eventually reaches natural water bodies.
• Cost-Effectiveness: Biosolar roofs offer significant potential for long-term savings and a favorable return on investment (ROI). While the initial installation cost of a biosolar roof may be higher than that of a traditional roof or standalone solar installation, the combined benefits of energy generation and reduced building operating costs contribute to overall cost-effectiveness.
• Incentives and Grants: Several government incentives and grants are available to encourage the adoption of biosolar roofs, making the financial investment more attractive for businesses. In the UK, businesses can take advantage of programs such as the Feed-in Tariff (FiT) or the Smart Export Guarantee (SEG), which provide payments for the electricity generated by solar panels and exported to the grid. These schemes help to reduce the payback period and improve the financial viability of biosolar installations.

Biosolar Roofs vs. Traditional Solar Installations

Compared to traditional solar installations, biosolar roofs offer enhanced environmental benefits. While standard solar panels solely focus on energy production, biosolar roofs add ecological value by supporting biodiversity, reducing urban heat, and managing stormwater. 

However, biosolar roofs may require more initial planning and investment due to the additional components and the need to ensure compatibility between the green roof and the solar panels. The long-term benefits, including potential energy efficiency gains and environmental impact, often outweigh these initial challenges, making biosolar roofs an attractive option for forward-thinking businesses.

How to maintain a biosolar roof?

Installation of green roofs increases the lifetime of roof surfaces protecting them from UV and other environmental damage. As the green roof is a living system it is a lot easier to maintain without disrupting energy generation when the roof system requires maintenance, simply replanting, or sowing seeds around the panels.

Biosolar roofs provide an opportunity to maximise roof spaces to generate electricity, increase the lifetime of the roof, and with thoughtful planting, provide a habitat for urban flora and fauna essential for future healthy cities.

Guest blog post from Hosta Consulting. Image credit: Dusty Gedge.

How can we help your business?

As the UK’s market leader in renewable energy solutions, we are in the best position to help your business realise the potential for electric vehicle charging infrastructure on your site. We also offer supplementary technologies, which would work in harmony with an electric vehicle charging facility, such as, site electrical upgrades, battery storage and solar PV, perhaps all combined into a private Smart Grid. These technologies would allow your business to harness the power of renewable energy and provide enough power needed to fast charge a wide range of electric cars.

Ultimately, it is down to us to make the change towards sustainability in order to create a greener future. Now is a good time to assess your net zero aspirations and talk to us about how we can help achieve them. Our team of renewable energy experts are available to provide Net Zero consultancy and renewable (Solar, EV, battery) quotations alongside installation operations and maintenance support to asset owners.