Solar tester Eternal Sun changes hands

Bolster Investment Partners has acquired an 80 percent stake in Eternal Sun, a The Hague-based supplier of photovoltaic testing equipment. Bolster will provide the capital and strategic support to accelerate Eternal Sun’s growth. “We grew as a scale-up, and now we welcome an investor focused on scaling mid-sized companies. We’re very proud of our continuous and uninterrupted growth track in what have sometimes been difficult market conditions. It provides proof of how we’ve strategically diversified our business in recent years,” comments Eternal Sun’s CEO Florian van Rijn van Alkemade.

After leading the winning Nuna Solar Car Team of Delft University of Technology in 2007, Stefan Roest founded Eternal Sun in 2011. Since then, the company has grown into a global provider of advanced solar testing equipment and testing services. “Our technology is essential for accurately determining the performance and thus value of solar panels. This plays a critical role in the development and scaling of next-generation technologies such as tandems and perovskite,” explains Roest, now CTO at the company.

Eternal Sun’s early growth was supported by Vermec and the ABN Amro Sustainable Impact Fund. Bolster acquired the stakes of both these investors.