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Systems and Stacks: Electrolyser Testing

A central element of the German national hydrogen strategy is the use of "green hydrogen" for mobility and industry to ensure a sustainable, climate and environmentally friendly future. Hydrogen is considered "green" if it is produced from renewable energy sources, especially wind and solar power, by means of water electrolysis. This requires electrolysers which are tested at ZBT on stack and system level.

Electrolysis stack test up to 35 bar (anode and cathode), 2,000 A, 40 kW

3 Electrolysis systems on the hydrogen test field of ZBT (from left): SOEC, PEM and alkaline technology

Project Carbon2Chem 03EK3038B

The electrolysis of water to oxygen (O2) and hydrogen (H2) is a process known for decades. However, operation with fluctuating, regeneratively generated electrical energy presents the technology with new challenges. In the application scenarios currently under discussion, investment costs, efficiency, stability and maintenance requirements are important evaluation criteria on the basis of which suitable technologies are selected. In the Carbon2Chem® project, a test field for different electrolysis technologies was established at the ZBT with funding from the BMBF. An alkaline, a PEM and a SOEC system were installed there with the aim of determining evaluation parameters in dynamic operation. The electrolysis systems provide pure hydrogen (5.0) in a pressure range between 10 and 35 bar. Such application-oriented system tests can now be carried out in the existing infrastructure of ZBT on systems with a capacity up to 150 kW. We consider both the organizational and safety-related interrelationships and the actual operational management and applicability of such product-related systems.

However, the electrolysis stack itself is an essential technical component of such a system. Before it can be integrated into a complex overall system, a comprehensive test program should first be completed. In the stack test bench of ZBT, for example, the operating conditions can be varied in such a way that an efficiency- and lifetime-optimized media supply and operational management can be developed. The fully automated electrolysis stack test bench can ensure operating pressures up to 35 bar on anode and cathode, supply currents up to 2,000 A and thus characterize electrolysis stacks up to 40 kW in a realistic environment. Both operating cycles in endurance tests and manual tests are possible.

ZBT thus provides the essential tools for the investigation of commercial electrolysis stacks and systems. We are also happy to support you in the development of operational management strategies, safety concepts and quality assurance of your components. We can also investigate peripheral components for electrolysis systems in our laboratories.


  • Maximum connected load currently approx. 150 kW
  • further requirements system-dependent
  • Product gas analysis in the HyLab quality laboratory

Electrolysis stack tests

  • Maximum electrical power output: 40 kW
  • Maximum pressure anode and cathode: 35 bar
  • Electrolysis types: Low Temperature PEM Electrolysis Stacks
  • Water supply & temperature control also possible on the cathode side
  • Online analysis of O2/H2 & H2/O2
  • Gamry Reference 3000 AE + 30k booster
  • Product gas analysis in the HyLab quality laboratory

Further information and contact:

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