Sempergreen's headquarters in Odijk, Netherlands faced a challenge: despite having a large number of solar panels on the flat roof, there remained a shortfall of 10,000 kWh per year to fully cover the office's energy consumption with renewable solar energy. The question was clear: how could this enery gap be closed without exceeding the roof's load capacity? The innovative Over Easy Solar system provided the solution - enabling Sempergreen HQ to operate entirely on solar energy!
How to generate more energy without exceeding maximum roof load bearing capacity?
The challenge was that the roof of Sempergreen HQ already had a green roof weighing 41 kg/m². The roof's load-bearing capacity is limited to 60 kg/m², leaving no room to install additional solar panels without risking overload. So it was essential to find a solution that on the one hand allowed for the additional energy generation and on the other would not exceed the maximum roof load.
Solar panels while preserving the green roof
The aim was to maximise solar energy production without compromising the existing green cover. A solution was needed that both retained the benefits of the green roof and could provide the additional solar energy needed. And all this had to be accomplished with minimal impact on the existing green roof.
Over Easy Solar solution for lightweight green roof
At Sempergreen HQ, this challenge was solved with partners by using the Over Easy Solar system. This innovative system consists of lightweight, vertical PV units that weigh only 11 kg/m². This was well within the load-bearing capacity of the roof, providing the ideal solution. In close cooperation with installation partner SamenStromen, responsible for installing the solar panels and optimizing the system, the solution was implemented seamlessly. Although a small portion of the green cover had to be removed to accommodate real-time monitoring of the yield, all the Sedum roof's ecological benefits remained fully intact.
"At Sempergreen, we are committed to integrating innovative and sustainable solutions into all our projects. Our headquarters in Odijk is a great example of this. With the innovative Over Easy Solar system, we have not only solved our energy challenge but have also proven that sustainability and efficiency can go hand in hand. Thanks to this solution, we now generate 100% of our energy through solar power while maintaining the benefits of our green roof. This project embodies our core values: sustainability, innovation, and a positive environmental impact. We are proud of this achievement and see it as an important step towards a greener future."
Aldo Tognini | CEO Sempergreen
Green Effect: 30% more energy yield with Over Easy Solar system
One of the most striking aspects of this project is the use of the lightweight Over Easy Solar system, which in combination with the green roof provides a 30% increase in energy generation through the so-called Green Effect. The plants reflect sunlight to the solar panels (albedo effect) and provide cooling on the roof. Since the panels are vertically mounted, a large part of the green roof remains uncovered. This vertical design allows many more sun rays to hit the green surface, which then reflect to the solar panels. This significantly increases the amount of available light radiation on the panels and thus the energy output of this PV solution. Combining green roofs with solar panels in this way is a unique and highly effective approach, merging sustainability with high-performance energy production. In addition, installation is quick and easy, without the risk of overloading the roof. The Plug & Play units are 10 times faster to install than conventional Solar systems.
A green building powered by renewable energy
Thanks to the installation of the lightweight solar panels, Sempergreen HQ now generates 9,360 kWh per year, virtually equivalent to the office's entire energy consumption. The green roof remains intact, so the office now enjoys the benefits of both sustainable energy generation and a healthy, green building. The integration of Over Easy Solar with the Sempergreen green roof completely resolved the energy challenge.
With Over Easy Solar, office now runs entirely on solar energy
This project demonstrates how innovation combined with smart solutions can transform a building into a sustainable, circular and energy-neutral structure. By choosing Over Easy Solar's lightweight solar panels, Sempergreen HQ can now operate entirely on solar power without structural modifications or additional roof reinforcement. The lightweight solar system is the perfect solution in combination with a green roof. This allows the ecological benefits of the green roof to be maintained, while taking energy production to the next level. The seamless integration of green roofs and solar energy provides huge environmental benefits while moving us closer to a future where green infrastructure and renewable energy generation go hand in hand.
Project partners
- Over Easy Solar
- SamenStromen (installation and preferred installer for NL)
Project details
- Total roof area: 150 m²
- Green roof type: lightweight Sedum Roof of 41 kg/m²
- PV system: Over Eay Solar with 36 lightweight units x 200 Wp = 7,200 Wp
- Total expected output per year: 9,360 kWh per year (boosted by The Green Effect)
