Munich Hydrogen is considered the energy carrier of the future – if it is produced in a climate-neutral manner. Experts speak of green hydrogen, in contrast to gray hydrogen, which is produced using natural gas or coal. The Berlin start-up Yellow SiC wants to build environmentally friendly hydrogen factories on roofs in the future. With the help of sunlight, the energy source is to be generated directly at the consumer.
Green hydrogen is currently produced where green electricity is generated in larger quantities. Water is broken down into oxygen and hydrogen by electrolysis. The hydrogen is then fed into the gas network or used directly on site. Yellow SiC wants to produce the hydrogen now and without the detour of electrolysis in solar cells. This should enable a more efficient, decentralized energy supply.
The name Yellow SiC stands for the so-called yellow silicon carbide (3C-SiC). In a different form than 4H/6H-SiC, the material is being used more and more frequently and on a large scale in chips for electric cars. It provides a higher range there. 3C-SiC is a “game changer” because of other properties.
The founder of the young company, physics professor Siegmund Greulich-Weber, was the first to succeed in producing 3C-SiC in large quantities. The most important new application is the so-called photocatalysis. With the help of yellow SiC and sunlight, water can be split into hydrogen and oxygen.
According to the company, this is particularly attractive because yellow SiC converts sunlight into energy much more efficiently than silicon, the material previously used in solar cells. Since no electrolysis is necessary, the process is also more efficient and cheaper. The start-up claims that yellow SiC can generate the same amount of energy on half the area of a solar cell made of silicon.
Who is behind this?
At Yellow SiC, 65-year-old Professor Greulich-Weber from the University of Paderborn and former investment banker Christopher Höfener, 53, have teamed up. According to the company, the project has cost more than four million euros so far. Half of it comes from co-managing director Höfener.
The start-up works with 17 people at two locations: Development takes place in Berlin; The company produces yellow SiC on the premises of a paper mill in Osnabrück. Half of the factory is owned by Höfener, a physicist with a doctorate in mechanical engineering.
What are the chances of Yellow SiC?
“This is an excellent solution for decentralized hydrogen production,” says Professor Jennifer Strunk from the Leibniz Institute for Catalysis in Rostock. “The hydrogen factory could then be installed directly on the roof.” Yellow SiC can be produced comparatively cheaply because, unlike other materials, it does not require any precious metals, adds Strunk.
Therefore, the yield does not have to be quite as high as with more expensive substances. That lowers the hurdle to using it in everyday life. There is something else that speaks for this material, according to Strunk: “Many semiconductors only use short-wave light. Yellow SiC, on the other hand, can convert a large part of the light spectrum into energy and is therefore superior to other materials.” However, the start-up still has a lot to do, says the expert: “The efficiency has not yet reached an industrially relevant magnitude.”
What’s next?
“We can show that the principle works and that hydrogen is actually produced directly from light,” says co-head Höfener. “However, we have to further optimize the material.” The entrepreneur is currently in the process of collecting ten million euros from investors. At least one prototype of the new type of solar cell is to be created within two years with the new money.
The investor and physicist Pjotr van Schothorst is one of the early financiers and predicts a great future for the start-up: “In the future we will need a lot of hydrogen and products made from it if we want to say goodbye to oil, gas and coal.” Any technology that can reduce the price and technical complexity of producing hydrogen is “therefore very helpful,” says the Dutchman.
Founder Höfener assumes that his solar cells will initially be of particular interest to the chemical industry, but also to steelworks. Thyssen-Krupp has just placed a major order with a plant manufacturer to convert production to hydrogen in the long term.
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