Cologne Nothing but helping to achieve a breakthrough for green hydrogen – Ulrike Beyer starts with that goal. This is to be done with the help of a new reference factory, for which the engineer with a PhD is responsible at the Institute of Machine Tools and Molding Technologies. Fraunhofer IWU in Chemnitz. “This is how we set the course for mass production of electrolysers,” says Beyer. These devices generate the desired hydrogen with the help of green electricity.
The electrolyser market in Germany is mainly determined by industrial groups or specialists. These include Siemens Energy, Thyssen-Krupp and Linde, but also the Dresden start-up Sunfire. “Until now, however, these manufacturers only produced systems in small series,” says Beyer. “Thanks to mass production, production costs will drop sharply.” The Fraunhofer project promises to cut costs by a good quarter.
Producers have to rebuild. “To do this, they need different machines and new automated production processes,” explains Beyer. This is where the reference factory comes in. Together with other Fraunhofer institutes, the Chemnitz-based company tests production processes and develops systems for the production of large series. The emphasis is on the efficient production of the individual components. In the future, interested parties from the industry will be able to plan their own production virtually on the Internet platform and in the network with other market participants.
Progress in production is essential on the path to a climate-neutral hydrogen economy. Until now, hydrogen in Germany was usually obtained in the process of the so-called steam reforming of natural gas. It is then referred to as gray hydrogen.
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The element can be produced more sustainably using electrolysers. They use electricity to divide water into its components, oxygen and hydrogen. If it comes from solar or wind farms, green hydrogen is produced. It would be needed, but it helps as an alternative to natural gas, the share of which as an energy supplier should decline.
The market is still relatively small. According to the International Energy Agency, 0.3 gigawatts of hydrogen electrolysis capacity were installed worldwide in 2020. In Germany alone, according to the plans of the federal government, by 2030 it should be ten gigawatts. Industry and science are working hard across Germany to improve the production of green hydrogen.
It’s not just about new production processes. Scientists are also trying to replace expensive and polluting materials or increase the efficiency of electrolysers. Because the green electricity they need is scarce and expensive.
Optimizing electrolysis processes – this is the goal of Martin Müller, head of the Forschungszentrum Jülich. PEM electrolysers, such as those produced by Linde, are relatively new. In systems, a hair-thin membrane separates two chambers through which positively charged particles diffuse during electrolysis. One chamber produces oxygen and the other produces hydrogen. Müller’s team is working on the possibility of using the thinnest possible membranes in cells.
“In this way, we dramatically increase the power density,” says Müller. “The systems are getting smaller and therefore cheaper to produce.” However, thin membranes limit their durability. “In experiments, we still have to find out under what conditions they are sufficient for their operation.” The technology should be ready for practical use in about three years.
Another key is the selection of materials. Until now, precious metals such as iridium, one of the rarest metals in the world, were needed in PEM electrolysis to get the reaction going. “This could become even rarer with upcoming mass production,” says Müller. The new PEM electrode design has now reduced the need for iridium by 80 percent.
At the same time, scientists at Jülich are working on improving two other electrolysis processes: alkaline electrolysis and high-temperature electrolysis. “Each of these methods has advantages and disadvantages,” says Müller. Alkaline electrolysis is used, inter alia, in in the chemical industry for the production of chlorine. “One advantage is that it works with relatively cheap catalyst materials,” says Müller.
However, existing systems would have to be adapted to operate with varying amounts of electricity and higher powers. High temperature electrolysers are especially useful if the waste heat can be used in industry. “Then they are very efficient,” says Müller. However, the size of the systems is still limited today, so powers in the megawatt range are rare.
Performance record thanks to waste heat
The steel producer Salzgitter uses the world’s largest high-temperature electrolyser at its plants, he says. The system comes from the Dresden-based manufacturer Sunfire and operates at 850 degrees Celsius. High temperatures generate water vapor. This in turn is obtained from waste heat from steel production. Both companies recently reported that the electrolyzer achieved a record efficiency of 84 percent.
Wolfgang Weigand takes a different approach. A professor of inorganic chemistry at the University of Jena is working on an alternative to electrolytic hydrogen production. Nature is the model, more precisely: hydrogenases. These enzymes can produce hydrogen in organisms. They are found in unicellular organisms such as green algae. Weigand’s team recreated the active sites of these enzymes in the laboratory. They serve as biocatalysts. Hydrogen is formed under the influence of sunlight.
The chemical reaction itself takes place without electricity. But there is something else that is revolutionary about this process. “The big scientific breakthrough was that we could make more hydrogen without using expensive platinum or highly toxic cadmium and selenium,” says Weigand.
There are still many obstacles. “We are still in the early stages of research in terms of research,” says Weigand. You can imagine a small-scale use in ten to 15 years – for example, in places with no electricity or hydrogen connection. “If fuel cells are to supply energy to smaller devices, this method could supply the necessary hydrogen.”
A lot of work on fuel cells
Fuel cells convert hydrogen back into electricity. For example, they could cushion carbon phasing – because they also generate electricity at night, when solar systems are not delivering any energy. Fuel cells could replace fossil drives in aircraft – for example, the engine manufacturer MTU is already working on this. Fraunhofer engineer Beyer also wants to speed up the production of fuel cells at the reference factory. He says it’s even more of a challenge than with electrolysers. “The cost of fuel cells has to drop drastically over the next few years to be able to be used economically.”
In Chemnitz, scientists are also investigating various processes that enable faster and cheaper production of bipolar plates – 800 of which are installed in a fuel cell. So-called continuous roller extrusion has been successfully tested. This means you can produce twice as many records per minute as before in the industry, explains Beyer.
Scientists are building a virtual replica of the machine needed for this. Goal: The platform should map the production chain for all components with optimized production processes. If a component is expected to have a longer service life, the system calculates the impact on the production chain.
“We can also judge whether production makes sense and whether it is economical,” says Beyer. The federal government supports the Fraunhofer project with EUR 22 million. Beyer presented the project to the public for the first time at the Hanover fair. Agreements with industrial companies are to be signed soon. Beyer believes that mass production of the electrolyser in three years is realistic, and that would bring it one step closer to the goal.
Read more: New energy transition plan: now it’s about coal.