Unlocking the benefits of solar green roofs

The newly published Solar Green Roofs Resource Guide - developed by World Green Infrastructure Network (WGIN), European Federation of Green Roof and Green Wall Associations (EFB), and SolarPower Europe, highlights the multiple benefits of combining solar panels with green roofs. This integration allows buildings to transform underutilized rooftops into thriving ecosystems that generate clean energy, support biodiversity, and promote urban sustainability.

1. Boost biodiversity

Solar green roofs do more than generate energy - they create new habitat niches for plants and animals. The shade and shelter provided by photovoltaic modules reduce heat and wind stress, allowing vegetation to thrive and supporting a variety of urban wildlife.

Studies show that solar green roofs in Vienna host 18 different wild bee species, highlighting their role in pollinator conservation. Research in Switzerland across Basel, Zurich, and Aarau found 21 locust species and even the European praying mantis on 20 green roofs surveyed. These rooftops provide critical microhabitats that help species survive and flourish in urban environments.

By mimicking natural habitats, solar green roofs contribute to more liveable cities, offering urban wildlife spaces to feed, shelter, and reproduce where such niches were previously absent.

Thriving greenery with vertical solar panels

2. Temperature control and energy efficiency

Green roofs naturally regulate temperature, helping buildings stay cooler in summer and warmer in winter. A vegetated layer beneath solar panels can reduce rooftop temperatures by around 4.5°C, while cutting heat flow through the roof by up to 90%.

This cooling effect reduces the need for air conditioning, lowering energy consumption and easing pressure on urban cooling systems. In some cases, green roofs can moderate day-to-night temperature swings from 50°C to just 10°C, protecting building materials and improving occupant comfort.

3. Enhanced Solar Panel Performance

Solar panels benefit directly from the cooling effect of vegetation. Evaporative cooling lowers PV module temperatures, often boosting energy yield by around 2–3%, and in some conditions up to 4–5% higher compared to conventional dark rooftops like bitumen.

Across studies, efficiency gains from combining PV with a green roof range from 0.8% to 8%, depending on climate and design. This synergy demonstrates that the combination is not just additive - it’s mutually reinforcing, producing cleaner energy while supporting healthy plant growth.

4. Easier maintenance with vertical panels

Traditional rooftop solar panels usually require a 30 cm clearance for irrigation, plant growth, and accessibility, which can reduce usable space and complicate maintenance. Vertical solar panels change the game - they require less clearance, maximize roof space, and make access to both vegetation and panels simpler and safer.

In practice, this means more energy generation, healthier plants, and lower maintenance costs, all while improving safety and efficiency on the rooftop.

Vertical solar panels provide easy access for roof inspections and maintenance

5. Return on Investment (ROI)

The temperature benefits of green roofs directly translate into financial savings. By reducing the need for cooling, buildings consume less electricity, which lowers operating costs. Solar green roofs offer multiple economic advantages:

• Reduce energy consumption by 2.2–16.7% in summer

• Save around €6,000/year for a 5,000 m² roof

• Solar PV systems typically pay for themselves within 5–10 years

• Green roof construction can be as low as 0.4% of total building costs

Green roofs paired with solar panels deliver both environmental and economic benefits, making rooftops a sustainable investment that pays off over time.

Solar green roofs are more than a sustainable trend - they are a strategic solution that transforms rooftops into multifunctional assets. By combining energy generation, temperature control, financial savings, biodiversity support, and long-term benefits, rooftops across the globe can contribute to greener, cooler and more resilient cities.