Florian van Rijn van Alkemade: ‘One unicorn does not mean a successful industry’

First of all, what exactly does Eternal Sun produce, and how does it fit into the solar energy sector?
‘In essence, we make sunlight. Very accurately, very repeatably. Our solar simulators enable manufacturers and research institutes to measure the performance of solar panels with extreme precision. That may sound like a technical detail, but it is crucial. In today's market, a solar panel is not sold because it is more attractive or special, but because it generates more energy. The output literally determines the selling price, and we supply the machine that sets that price.
We operate at the upstream end of the solar industry, where panels are developed and manufactured. Our customers are the factories that manufacture solar panels and the research labs that develop the next generation of technology. We produce two types of simulators. Flash testers use a very short, intense flash of light to measure maximum output at the end of each production line. We also make steady-state simulators, which can mimic constant sunlight for hours on end. These are essential for research into new technologies like perovskite, which can significantly increase the efficiency of solar panels. In addition to this equipment, we also offer quality inspection services, such as import testing in the Port of Rotterdam.’

How did Eternal Sun grow from a university spin-off to a global company?
‘Our journey began in 2011 at Delft University of Technology. Stefan Roest, our founder, was team leader of the winning Nuon Solar Team and developed a new type of solar panel for his graduation project. To measure its performance, he needed a continuous light source that could shine stably for hours. Such a thing simply did not exist, so Stefan built the machine himself.
Delft University of Technology and TNO were immediately interested and wanted to buy the machine. That is how the idea for the company was born, but with that the Dutch research market also became immediately saturated. The next step then had to be international. The first international client was a research lab in South Korea. So, we were an international company from the very beginning, not out of strategic choice but out of sheer necessity.
A crucial step was when we expanded to factory lines. We did this in 2016 with the acquisition of the American company Spire Solar, an established name in the world of flash testers. This forced us to change our mindset. As a startup, you often get a pat on the back because you are doing groundbreaking research. But in a factory, where every minute of downtime costs tens of thousands of euros, you get dragged through the phone if your machine is not working. The quality requirements and the performance mindset had to be taken to a completely different level. From that moment on, we deliberately avoided the word startup.
After Spire, we continued our growth through strategic acquisitions such as SunChine in China in 2022 and, more recently, in 2025, the German company WAVELABS. As a result, we are active in more than 60 countries worldwide with a team of over 120 people.’

Which moments were truly decisive for your development?
‘Those aspects are closely intertwined. Product development began with Stefan's invention. The first customer, the Solliance research institute, affiliated with TNO, was crucial. Their doctoral research required a light source that could burn for 1,000 hours continuously. Our prototype could do this. In collaboration with them, a unique testing device was developed that not only measures performance but also tests service life under different climatic conditions. That focus on innovation and customization has always remained. The solar energy market is innovating at lightning speed. Every new technology requires a new, more accurate way of testing. We ensure that our customers, the most prestigious developers in the world, can perform the measurements they need to validate their innovations. We still regularly take clients to their labs in Eindhoven to demonstrate how our equipment is used in practice.’

How did you arrange the financing for this growth?
‘In the very beginning, we were bootstrapped, meaning we financed from our own resources and initial revenue. But in mechanical engineering, you quickly run into a working capital problem. To be able to scale up, we needed external capital. Our first investor, in 2014, was Vermec, a Belgian family fund. They also asked to expand the management team, which is when I came on board. In 2019, the ABN AMRO Sustainable Impact Fund joined as a new majority shareholder. And very recently, in May 2025, Bolster Investment Partners acquired the majority stake to support the next phase of growth.’

What did these investors bring you in concrete terms, besides capital?
‘Their contribution was essential and went far beyond just money. Each investor played a role that was appropriate to the phase the company was in. Vermec provided venture capital in the purest sense. They gave us the courage and financial backing to acquire Spire Solar. That is a step you do not take lightly as a small company, especially when the company is five times bigger than yours.
ABN AMRO was a real growth enabler. They challenged us to think bigger and provided the capital to focus. During their period, we further internationalized and acquired SunChine in China. Bolster is taking us to the next level. Now that we can finance our organic growth ourselves, they are helping us to further professionalize. They act as a strategic partner and sounding board for our buy-and-build strategy. The recent acquisition of WAVELABS is a direct example of this.
In the early stages, it was about daring. In the scale-up phase, the focus was on growth and scaling up. Now, as a medium-sized company, it is about strategic consolidation and professionalization. With Bolster, we have an investor that specializes in further growing medium-sized companies.’

How has your role as CEO changed as a result of this rapid growth?
‘My role has changed drastically and evolved along with the company. I can divide it into three phases. The first phase was very hands-on. I joined a team of about twenty people, mainly highly creative, innovative types. My task at the time was to professionalize and implement the crucial mindset change from a fun, innovative club to a company that delivers results and provides rock-solid guarantees to demanding industrial customers.
The second phase was that of organization builder. As we grew, I came to the conclusion that I myself am not scalable. That was the moment when we had to build a management layer. My role shifted from direct management to building and leading a team that could carry the organization independently.
In the current phase, my role is shifting back to strategy and vision. Now that the organization can support itself better, I am focusing on where we will be in three years. It is now about setting out the broad outlines and safeguarding the long-term vision.’

To what extent does social impact play a role?
‘For me personally, that is a fundamental motivator. I deliberately left strategy consulting because, after years of advising, I wanted to experience change from start to finish myself, in a place where you can really make an impact. Our mission is to advance the solar energy industry. We contribute concretely to increased global solar energy generation. Our precise test equipment enables manufacturers to improve the performance and reliability of their panels. A panel that is more reliable and efficient thanks to our measurements delivers significantly more clean energy over its lifespan.
We also play a crucial role by enabling innovation. The next generation of solar panels, such as those with perovskite technology, promise much higher efficiency. But to develop and validate them, research labs need the most accurate testing equipment available. We provide that.’

The Draghi report emphasizes that Europe must strengthen its technological autonomy. What role does Eternal Sun play in this?
‘This is a painful and complex topic. China has designated the solar industry as strategic, and the US and India are pursuing strongly protectionist policies. Europe, on the other hand, is wide open, which has effectively turned it into a dumping ground for the global overproduction of solar panels. Our role in this is that of a kind of the last of the Mohicans. Of the twenty different machines in a typical solar panel production line, we are the only remaining machine manufacturer in Europe in our specific segment. Almost all the rest have become Chinese.
However, true strategic autonomy cannot be achieved with a single company. It requires a complete ecosystem. Take ASML, for example. Their success is supported by a whole cluster of innovative suppliers in the Eindhoven-Nijmegen region. Such an ecosystem for the solar industry has largely disappeared in Europe. A simple example: if we want to assemble a solar panel, we have to import the aluminum frames from China, which are subject to a twenty-five percent import duty. But if a Chinese company exports a complete solar panel, including that same frame, to Europe, the tariff is zero percent. That is not a level playing field. Our strategy is therefore pragmatic. More than half of our sales now go to American factories. For that reason, we have concrete plans in place to relocate part of our production to the United States if necessary.’

How do you stay at the forefront of technology?
‘The key is very simple: by developing alongside our customers. Every year, panels become more efficient and new technologies are introduced. Each new development requires a new, more precise way of testing. Our strength is that we have a very fast innovation cycle. We strive to be more than just a supplier. We want to be a strategic partner for solar panel developers. By staying close to their research and development processes, we create a rapid feedback loop. This symbiosis enables them to innovate faster and ensures that we maintain our technological advantage.’

The solar industry experiences significant cyclical fluctuations. How do you organize resilience?
‘Our resilience comes from two sources. First, strategic diversification. We largely exited the Chinese mass production market in 2019. That market is dominated by local, state-supported competitors. We have shifted our focus to the more technologically advanced markets in America and Europe, where accuracy and innovation are more important than the lowest price. In addition, we have broadened our business model to include inspection services.
Secondly, the support of a long-term investor is crucial. A partner like Bolster does not look at quarterly figures, but at the vision for five or ten years down the line. They understand the cyclical nature of the industry and offer the stability to continue investing in innovation even in leaner times.’

What are the biggest risks for the coming years?
‘Geopolitics is undoubtedly the biggest. Protectionism and the dollar exchange rate can make our products thirty percent more expensive overnight. Another major risk is the further erosion of the European industrial ecosystem. Our European customer base has already shrunk significantly. If this trend continues, our position here will become increasingly difficult to maintain. Finally, there is the technological risk. If we fail to keep up with our innovation cycle, we could lose our market position very quickly.’

You just acquired WAVELABS. Where will Eternal Sun be in five years?
‘In five years, we want to be the undisputed strategic partner for the global leaders in the solar industry in the field of research and development. The acquisition of WAVELABS was crucial in this regard. They are the market leader in solar cell testing, while we are the market leader in complete solar panels. Together, we now offer a total solution, from the smallest cell to the complete end product.
Our ambition is to further expand the deep partnerships we have built in America and to establish this model in Europe as well. We do not just want to supply machines; we want to become an integral part of our customers' technological roadmap. If we have consolidated that position in five years’ time and are playing a key role in the emergence of new technologies such as perovskite, we will have achieved our goal.’

Finally, what is your message to policymakers who are now translating the Draghi report into practical policy?
‘Give concrete form to the most complex pillar of the Draghi report: strategic autonomy. In doing so, do not look at individual companies, or at measures aimed at a single unicorn. A single company does not make a successful industry; success only comes with a functioning ecosystem around it.
Identify a number of critical industries, such as the energy sector, in which Europe wants to be a global player. And then ensure that the entire chain can exist. Create a level playing field where European companies can compete with players receiving massive state aid elsewhere. This is not about subsidizing an industry that cannot stand on its own two feet. Solar has long been economically viable. It is about creating fair competition conditions. Without that ecosystem and a level playing field, the idea of ​​strategic autonomy remains a paper tiger.’

This interview was published in Management Scope 09 2025.