Interview with Chief Developer Henk Oldenkamp
Interview with Chief Developer Henk Oldenkamp
Henk Oldenkamp, inventor of the world’s first microinverter and Chief Developer at Solarnative, tells us all about the technical and commercial buildout of the groundbreaking “Power Stick” in his interview with the Dutch Solar Magazine. Read the English translation here…
English translation of Solar Magazine’s full article:
The solar industry outside the Netherlands has many pearls. In some of them the course is (partly) determined by Dutch. Solar Magazine visits this time Henk Oldenkamp, co-owner of Solarnative. He developed an inverter that fits into the frame of a solar panel. “I’ve wanted to do this for 30 years, and now I’ve succeeded.”
Oldenkamp is not only one of the pioneers in solar energy, his impact on the industry is great – in Netherland and beyond. His fascination for solar energy started at a young age, but the technology was still in its infancy when he was conscripted in 1982. There he got out of that by arranging a job with the wind energy group at the Eindhoven University of Technology.
Tens of Thousands of Guilders
“I developed, among other things, software and electronics for testing wind turbines”, Oldenkamp explains. In 1984, I started up a company in that field. But PV continued to attract me. The turnaround came in 1992 during a conversation with Wim Sinke, at the time already the face of the dutch solar energy community. At that time, the smallest possible PV systems still cost tens of thousands of guilders. The inverters were at least 5 kilowatts. He said, “Actually, we should make those very small, preferably one inverter per solar panel”. I said: “I can do that. I’ve always been very good at that.”
A Ridiculous Signal
Oldenkamp put his money where his mouth is. His first micro-inverter came onto the market around 1996, in collaboration with Shell Solar and cable manufacturer NFK. In total, some 80,000 units were installed, which at the time was a lot. However, the ship was to sink soon after. NFK was taken over by DRAKA and received a new management. “I had almost completed the next generation, but was dismissed from one day to the next like a thug, I had to hand in the keys. Later some residual material was put on my doorstep, but that was it. That fickleness was also seen at Shell Solar, which suddenly left the Netherlands in 2003 with the message, that things would never work out here. The government went along with this ridiculous signal; the subsidies for PV were stopped at once. So, it often blew with all the winds along. When Philips started making inverters, they put a lot of tax money because ’if it is Philips then it must be good‘. In retrospect, it all turned out to be pointless. I was fed up with it.”
The German company SMA bought the technology of Oldenkamp in 2009 and attracted him as a consultant. But that company pulled the plug on its micro inverter business. Oldenkamp had to start all over again, and took his future into his own hands. Together with Julian Mattheis, he founded Solarnative and took the next step in miniaturization of his technology with the JT-350. “It took me years, this is a real breakthrough. The secret lies in the switching frequency. The higher that is, the smaller you can make it. You can transfer smaller energy packets. The downside, however, is that without innovative measures, efficiency will drop. I managed to raise the resonance frequency up to 1,000 kilohertz, while it can deliver 350 watts to the grid. This allows us to make a microinverter that fits into the frame of a solar panel. An important advantage is the lifespan. A metal frame of a solar panel dissipates heat and is usually between 15 and 20 degrees Celsius cooler than the solar panel. This also applies to an inverter that you put in. As a result, its life is extended by a factor of 2 to 3.”
Another advantage of the JT-350 is according to Oldenkamp, that it is cheap. It is clicked directly into the frame, that saves cables, connectors and work. There are also no bypass diodes required. All this also makes it safe. The occurrence of an electric arc is impossible. The mains voltage is separated from the solar panel voltage by a double safety insulation. This eliminates the risk of electrocution in the event of damage to the solar module. The gateway has an automatic mapping function that determines the order of strings and any missing connectors. It is also in direct contact to the Internet via Long Term Evolution (LTE) technology. The LoRa in the gateway provides wireless communication with other devices. Data cables are therefore not required, and it is prepared for apparats in a smart energy household.
Oldenkamp: “At Intersolar Europe we received orders for 1,000 units per month, while production has not even started yet. Our own factory should be up and running, probably in Frankfurt. Then we will soon be putting hundreds of thousands away. The installers are already lining up. This has partly to do with what we call balcony PV here. In Germany it is permitted to plug PV systems up to 600 watt peak directly into the wall socket. This is now also permitted in Austria, Spain and Poland. The rest of Europe will probably follow soon. This development will give Solarnative a kickstart. Our technology fits perfectly. I have wanted this for 30 years, and now I’ve done it. I am finally going to finish the story and that feels really good.”
Original article: © SOLAR Magazine NL