KARLSRUHE/BERLIN (dpa-AFX) - The expansion of hydrogen production is threatened by a lack of raw materials, rising prices and dependence on a few exporting countries. To counteract this, experts believe that research and development as well as precise supply planning are needed.

Hydrogen is expected to gradually replace natural gas as part of the energy transition. It can be produced by splitting water into hydrogen and oxygen. The process is called electrolysis. If it is powered by renewable energy, it is referred to as green hydrogen.

There are various forms of electrolysis. The problem: Some work with chemical elements such as scandium and iridium, which are in short supply. According to a study by the German Raw Materials Agency (Dera), the demand for scandium in 2040 could be around 24 metric tons in a scenario that is very focused on sustainability - that would be more than two and a half times the amount produced in 2018. In the case of iridium, the forecast even assumes that demand will then be five times as high at 34 tons.

Iridium is currently considered irreplaceable, says Viktoriya Tremareva of Dera. The precious metal is mainly extracted in South Africa and Russia as a byproduct of platinum and palladium, she said. "A significant increase in iridium production is unlikely," Dera says. "In the event of production losses, dramatic price increases may then occur - as observed in 2021."

Scandium, in turn, comes primarily from China. Also followed by Russia, which since the attack on Ukraine is no longer a desirable trading partner for the West. Here, however, the Dera sees more mining opportunities - for example in Canada and the Philippines.

However, it takes several years to prepare a deposit for production and to make the raw materials really available, says Christoph Hilgers from the Institute for Applied Geosciences at the Karlsruhe Institute of Technology (KIT). However, he says, the market only invests when demand is long-term. That's when people look to see how serious their hydrogen intentions are, Hilgers says. To assess that, he says, a global view is needed. "Germany is a large industrialized country, to be sure. But you don't open new storage facilities just for one country."

Alkaline electrolysis does not require rare metals, says Maike Schmidt of the Center for Solar Energy and Hydrogen Research Baden-Württemberg. However, nickel is needed, which Germany and Europe used to import from Russia 35 to 50 percent of the time before the war in Ukraine began. Although there are alternatives, nickel processing in particular is heavily concentrated in China. "This may give rise to new geopolitical dependencies that, while not an acute bottleneck, need to be monitored."

With the shortage comes the threat of rising prices for raw materials and, as a result, growing costs for electrolysers - plants for electrolysis - as well as for hydrogen. "It is currently impossible to foresee in what dimension these increases will be," Schmidt says. However, research and development to reduce the use of critical raw materials should counteract such a scenario.

This includes using less iridium in so-called polymer electrolyte membrane electrolysis, he says. "Other technologies for hydrogen production, such as pyrolysis processes, are under development," Schmidt says, "but would only be able to substitute electrolysis technology to a small extent in a future large-scale, climate-neutral hydrogen production."

Research is also being conducted into substitutes for iridium, explains Dera geologist Tremareva. In addition, it can be recycled well and could be used in the future for more components with then less loading. "We expect that the research activities to improve the economics of water electrolysers will have an overall positive effect on the future demand of potentially critical raw materials."

Claudia Nehring of Siemens Energy, a manufacturer of electrolyzers, explains, "For the ramp-up of the hydrogen economy, it's important to build robust supply chains and also get into volume production with suppliers." At Siemens Energy, the company relies on strategic purchasing and uses a broad global supplier base, for example. The efficiency of the products is continuously being increased and the use of materials is being improved. About 90 percent of the raw materials could be reused.

However, KIT researcher Hilgers pointed out that recycling also requires high temperatures and a lot of energy. Digging for metals left holes in the ground. Such aspects are sometimes left out when talking about green technology and renewable energies./kre/DP/stk