‘It’s an amazing view, isn’t it?’ says Wim Sinke. TNO’s solar energy lab in Petten is surrounded by dunes, with a strip of sea in the distance. Sinke stands on the roof, between two steel structures for test panels. A quarter of the constructions are occupied, each panel is different. Downstairs, Sinke proudly displays all the new machines that do precision work to make the most advanced solar panels. This lab is brand new, the grand opening for the staff has yet to take place. But he himself will not work here. After forty years of solar cell science, he is leaving this month as principal researcher in solar energy at TNO and professor of solar energy at the University of Amsterdam.
Sinke is optimistic about the role of solar energy. Always been too. “Solar cells can also play a more than marginal role in electricity generation in the Netherlands,” he wrote in his thesis in 1985. At that time there was not yet a solar panel in the streets.
What drew you to that ‘marginal’ topic of solar energy?
“I went to study physics in 1974, with the Club of Rome report and the first oil crisis fresh in my mind. I was a concerned and committed student and I looked for opportunities to use physics for something that would make the world a better place. The trade was then contaminated because it formed the basis of modern weaponry. Towards my graduation I heard about new physics research to make cheap solar cells, which I immediately thought was fantastic. Not long after that, I started as a somewhat shy PhD student at the FOM Institute for Atomic and Molecular Physics, which is now called Amolf.”
What was being done about solar energy then?
“It was still a wonderfully innocent subject. The industry still represented very little, the interests were not yet great. The satisfaction of contributing to something great like now was not there yet, but you did have the opportunity to take big steps within the subject. A few dozen people were working on it, spread over the Netherlands, a few with a permanent appointment and surrounded by PhD students and students.”
The insight at the time was that the basic material had to become cheaper
Was it taken seriously?
“It was taken seriously in the sense that solar energy might be an option for the long term, but it was not yet in the picture as something you can use to make the Netherlands more sustainable. When you are at such an early stage, you have to make all kinds of extrapolations and estimates of developments to come. Depending on how optimistic you estimate it, you will arrive at a future in which this may or may not play a major role.
“In a sense, those first years it was a small club against the rest, we really already believed in solar energy. But I’ve always resisted the idea that you’re not taken seriously, then it becomes a self fulfilling prophecy†
What was the technology like?
“I worked on silicon cells in the 1980s, which you often see today. At the time, they had a return of 10 percent. That could be higher, that was clear. But pure silicon in good crystal quality was especially expensive and the cells were also cumbersome and made on a small scale. That made it a niche product. A solar cell was not a few times more expensive than today, but 100 times more expensive.
“The insight at the time was that the base material had to be made cheaper by casting it in a crystal mold in a cheaper way. But that was much more sensitive, you couldn’t process it into the most efficient solar cell in the usual way at the time. We worked on a process in which you can still make a good solar cell from that material at a low temperature.”
A breakthrough will come from making tandems, two layers of solar cells from different materials
So the research was aimed at bringing the price down?
“In a sense yes. I have always found it important to conduct research with a specific goal in mind. We were in a vicious circle of small volumes and high costs. A hugely important breakthrough for solar energy has been forcing higher volumes. Germany took the lead in this in the early 1990s, in the Netherlands it also happened a little later, through subsidies and stimulating the market. In line with this, we broadened the research. In addition to the cells and panels, whose efficiency is now between 10 and 15 percent, we also started working on systems for connecting solar panels to the electricity grid.”
What is important now in terms of research?
“Basically, solar energy should become a factor of three cheaper. That makes the difference between solar energy in the current situation with a relevant but modest share and solar energy as the cornerstone of the global energy supply. The scale on which production is now gigantic, and all the low-hanging fruit in terms of improving systems and processes has been picked. The question of how the return can be increased now returns in all its glory.
“I think it’s possible. The current silicon panels are heading towards a 25 percent efficiency. That is close to the physical maximum that is possible with one material. A breakthrough will come from making tandems, two layers of solar cells made of different materials on top of each other. With stacks of more layers, a 40 percent return is possible in the long term.
“More applied, we are investigating how solar energy can be integrated into all kinds of surfaces. With panels in different shapes and colours, translucent panels and flexible foils.”
The dependence on China as a production country has become enormous in the last decade
Generating cheap solar energy everywhere, cornerstone of the global energy supply. That almost sounds too good to be true.
“I think I am optimistic. I haven’t seen much fail. In fact, a lot of things have been done that I thought was impossible. It seemed unimaginable to me that the extremely advanced processes we use in the lab are also cheaply applied on a large scale in factories. It is unbelievable how much technology you get for how little money when you buy a modern solar panel.
“Recycling and circularity, that is now a concern, we will certainly solve. Technically it will work, but here too low costs and regulations are important to be able to apply it on a large scale. The dependence on China as a production country has become enormous in the last decade. A real problem, which we have encountered hard in Europe. Since that realization descended, about three years ago, everything has been set up in no time to get the manufacturing industry up and running again. Very hopeful.
“Now I say: without notice anything is possible. And if something doesn’t work out, there are always five alternatives. The question is not whether solar energy will succeed, but in what form.”
#Solar #energy #factor #cheaper