Rolls-Royce to develop mtu hydrogen electrolyzer and invest in Hoeller Electrolyzer

• Holdings in start-up companies in northern Germany secure Rolls-Royce Power Systems access to key green hydrogen production technology
• Electrolysis systems for several megawatts of power
• First demonstrator in 2023 using a Hoeller stack

Rolls-Royce is entering the hydrogen production market and acquiring a 54% majority stake in electrolysis stack specialist Hoeller Electrolyzer, whose innovative technology will form the basis of a new range of mtu electrolyzer products from its Power Systems division. Hoeller Electrolyzer, based in Wismar, Germany, is an early-stage technology company that is developing highly efficient polymer electrolyte membrane (PEM) stacks, under the brand name Prometheus, for the cost-effective production of hydrogen.  

Hydrogen is an increasingly attractive power source to fuel the green energy transition and demand for ‘green’ hydrogen – whose production creates no CO2 – is expected to rise significantly. It is needed for fuel cells and hydrogen engines, for the production of synthetic ‘drop-in’ fuels and for industrial processes that currently use hydrogen that is not created in a carbon neutral process. Consequently, high-performance electrolyzers are a key component of any hydrogen system.

Dr. Otto Preiss, COO and Chief Technology Officer, Rolls-Royce Power Systems, said: “By developing our own mtu electrolyzers and by taking a majority stake in Hoeller Electrolyzers, we are methodically growing our hydrogen portfolio and securing access to this fascinating technology, which is not a pipe dream but has great market potential. This will enable us to supply complete hydrogen solutions and make a significant contribution to protecting the climate. Our complete hydrogen solutions will enable customers to store renewably produced energy in the form of hydrogen for use as and when required, or for further processing or onward sale.”  

In hydrogen electrolysis, water is subjected to DC electrical current, producing hydrogen at the negative pole and oxygen at the positive pole. In this way, it is possible to produce carbon-neutral hydrogen by using electricity from renewable sources such as solar or wind. The electrochemical reaction takes place in a cell between plate-shaped electrodes separated by membranes. Hundreds of cells located one above the other and pressed together form a 'stack', the heart of an electrolyzer.  

Founded in 2016, Hoeller Electrolyzer has positioned itself, with Prometheus, as one of the few highly specialized expert players in the field of high-efficiency PEM electrolysis stacks. Its founder, Stefan Höller, has more than a quarter of a century’s experience of developing electrolysis technology and has already registered 14 patents connected with Prometheus. Particularly high efficiency is promised by special surface technologies for the bipolar plates which significantly reduce the use of expensive precious metals platinum and iridium as catalysts, as well as increased output pressure.

Stefan Höller, Managing Director, Hoeller Electrolyzer, said: “Our stack is going to produce hydrogen at a price not previously thought possible.”

Rolls-Royce and Hoeller Electrolyzer are united by a shared belief in the opportunity of zero-carbon energy – both for power supply and the propulsion of heavy vehicles. With decades of experience and systems expertise, Rolls-Royce is going to develop a complete electrolyzer system and has a global sales and service network, which opens up the potential for significant worldwide sales.  

Matthias Kramer, CFO and Joint Managing Director, Hoeller Electrolyzer, said: “In Rolls-Royce, not only have we found an important customer for our stacks, we've also secured an ideal partner and supporter who shares our vision of putting stacks into full production.”  

Development work on the first mtu electrolyzer using a stack from Hoeller Electrolyzer is already underway. In 2023, it will go into operation at the Validation Center in Friedrichshafen to demonstrate how an electrolyzer fits into the overall architecture of a microgrid. An initial customer project is already planned for 2024.  

Armin Fürderer, who heads up the Net Zero Solutions business unit of Power Systems, said: “We're going to launch electrolyzers with several megawatts of power right from the start. A total output of over 100 megawatts is conceivable by combining several electrolyzers.”

The equity in Hoeller Electrolyzer now held by Rolls-Royce comes from departing minority shareholders and from an increase in share capital. Financial details of the transaction are not being disclosed. Stefan Höller and Matthias Kramer will continue to lead Hoeller Electrolyzer as a standalone company, with the goal of building a leading international stack manufacturer.  

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About Rolls-Royce Holdings plc

1. Rolls-Royce pioneers the power that matters to connect, power and protect society. We have pledged to achieve net zero greenhouse gas emissions in our operations by 2030. We joined the UN Race to Zero campaign in 2020, and have committed to ensuring our new products will be compatible with net zero operation by 2030, and all products will be compatible with net zero by 2050.
2. Rolls-Royce Power Systems is headquartered in Friedrichshafen in southern Germany and employs around 9,000 people. The product portfolio includes  mtu-brand high-speed engines and propulsion systems for ships, power generation, heavy land, rail and defence vehicles and for the oil and gas industry as well as diesel and gas systems and battery containers for mission critical, standby and continuous power, combined generation of heat and power, and microgrids.  
3. Rolls-Royce has customers in more than 150 countries, comprising more than 400 airlines and leasing customers, 160 armed forces and navies, and more than 5,000 power and nuclear customers.
4. Annual underlying revenue was £11.76 billion in 2020 and we invested £1.25 billion on research and development. We also support a global network of 28 University Technology Centres, which position Rolls-Royce engineers at the forefront of scientific research.
5. Rolls-Royce Holdings plc is a publicly traded company (LSE:RR., ADR: RYCEY, LEI: 213800EC7997ZBLZJH69).