Amsterdam’s Bolster Investment Partners acquires Majority Stakes In Eternal Sun

Eternal Sun, a company based in The Hague specializing in solar panel testing technology, has announced that Amsterdam's Bolster Investment Partners has acquired an 80% stake in the company. Previously, the shares were held by Vermec and ABN AMRO Sustainable Impact Fund, who supported Eternal Sun during its early and expansion phases.

With this transaction, Eternal Sun aims to continue its growth, develop technology, and advance internal operations. The company provides solar panel testing technology to manufacturers, laboratories, and developers in more than 60 countries. Eternal Sun operates from six locations across four countries and offers simulators and inspection services.

Stefan Roest, after leading the winning Nuna Solar Car Team of TU Delft in 2007, founded Eternal Sun in 2011. The company has since expanded into a global provider of solar testing equipment.

Stefan Roest says, “Our technology is essential for accurately determining the performance and thus value of solar panels, which plays a critical role in the development and scaling of next-generation technologies such as tandems and perovskite.”

Eternal Sun also provides flash and steady-state solar simulators, along with inspection services for importers and solar project developers. Roest adds, “Thanks to our deep expertise, flexibility, and focus on customisation, we continue to lead in a rapidly evolving market.”

CEO at Eternal Sun, Florian van Rijn van Alkemade, says, “We grew as a scale-up, and now we welcome an investor focused on scaling mid-sized companies. We are 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. It is also a great tribute to our team, we could not have reached these milestones without their continued enthusiasm and drive.”

CCO Erik Bentschap Knook adds, “We’re playing in the solar industry’s Champions League. Our clients are the most advanced PV developers in the world. We work with them to enable a fast to new technologies like tandem and perovskite, we see a bright future for Eternal Sun.”

Bolster Investment Partners, established in 2017, is a long-term investor based in Amsterdam. The firm specializes in collaborating with exceptional Dutch companies that have proven business models. Bolster partners with entrepreneurs to help them realize their company's full potential through equal and strategic collaboration. This approach enables Bolster to support companies in achieving sustainable growth and success.

Mark van Rijn, Managing Partner at Bolster, says, “The global leadership position of Eternal Sun, combined with its innovation capabilities, creates a unique position. The solar testing market is growing rapidly, driven by new technologies and energy independence trends. Eternal Sun is exceptionally well-positioned, and we look forward to working with their strong and visionary team.”

ABN AMRO Sustainable Impact Fund (SIF) has sold its shares in Eternal Sun, handing majority ownership to Bolster Investment Partners.

ABN AMRO SIF is one of the largest private funds in the Netherlands focused on environmental and social impact. With €500 million to invest, it supports businesses in areas like clean energy, sustainable buildings, and eco-friendly consumption.

The fund backed Eternal Sun in 2019, joining early investor Vermec, based on the growing demand in the solar energy market. With their support, Eternal Sun expanded globally, acquiring Spire Solar (USA) and SunChine (China).

This exit reflects ABN AMRO SIF’s goal of earning a return while making a positive environmental impact, as Eternal Sun’s solar testing technology boosts the efficiency and reliability of solar panels.

Florian van Rijn van Alkemade, CEO of Eternal Sun, says, “ABN AMRO SIF was a true growth enabler for Eternal Sun, challenging us to think bigger and providing the capital to focus. As we scaled, they remained a valuable sounding board for our organisation and stood by us in good and challenging times. We’re grateful for their contribution to our journey.”

Thijs Nijland, Investment manager of ABN AMRO SIF, adds, “We are proud to have supported the company and its highly committed management team through a pivotal growth phase, and to have witnessed its transition from startup to a well-established global market leader.”

About Eternal Sun

Eternal Sun is a company from the Netherlands that makes machines to test solar panels. They offer different types of solar simulators, like LED and Xenon-based ones, which help manufacturers and labs check the quality and performance of solar panels.