H2-SMORE: Megawatt-Scale H2 Stack Test for Offshore Electrolysis

At a glance

• Testing of a megawatt-scale PEM electrolysis stack provided by Schaeffler at the Hydrogen Lab Leuna
• Use of Fraunhofer IWES 2-MW stack test infrastructure for PEM and alkaline electrolysis stacks on an industrial scale
• Approximately 3,000 operating hours including dynamic test profiles derived from wind turbine performance data
• Investigation of operational behavior, efficiency, dynamics, and aging under realistic conditions for the production of green hydrogen from offshore wind energy
• Fraunhofer IWES is responsible for data acquisition, gas and water analysis, commissioning and operation of the test rig, creation of test profiles, and evaluation of test results. Concepts, test profiles, and operational experience from H2Mare and H2Wind will be carried forward. This will contribute to the further development of test methods, operational strategies, and technology transfer for future offshore electrolysis projects.

The challenge

To date, there is only a limited amount of publicly available and reproducible operational data for PEM electrolysis stacks in the industrial power range. In particular, for dynamic load profiles -such as those that occur when coupled with wind turbines - there is a lack of reliable long-term studies on a megawatt scale.

Many of the available studies come from smaller power classes or from manufacturers internal system tests, which limits their transferability to future offshore electrolysis plants. In addition, standardized test profiles and evaluation methods are still lacking to systematically assess the operational and aging behavior of stacks under realistic dynamic conditions.

This data gap complicates the design, evaluation, and operational planning of future offshore hydrogen systems and increases both technological and economic risks.

The solution

H2-SMORE addresses this data gap through a reproducible test campaign on a megawatt scale. To this end, a PEM electrolysis stack provided by Schaeffler is integrated into the 2-MW stack test infrastructure at Fraunhofer IWES’s Hydrogen Lab Leuna and tested under realistic dynamic operating conditions.

The test profiles are derived from power data of wind turbines and adapted for operation on the test bench. This allows load cycling, partial-load phases, and dynamic operating conditions -such as those encountered in the production of green hydrogen from fluctuating wind energy - to be simulated in a targeted and repeatable manner on an industrial scale.

A particular focus is on evaluating aging behavior under these dynamic operating conditions. The aging of the stack is not considered in isolation but is evaluated in conjunction with the fluctuating load behavior of wind power generation. This is intended to enable reliable conclusions about how realistic load cycling affects the stack’s efficiency, operational behavior, and service life over the long term.

During the approximately 3,000 operating hours, Fraunhofer IWES continuously records process and operating data and supplements this with gas and water analysis. The data obtained is evaluated in a structured manner to assess operating behavior, controllability, changes in efficiency, and aging indicators under dynamic loading. In addition, Schaeffler will conduct further analyses on the stack after the test phase is completed.

The added value

For the first time, the project is generating manufacturer-neutral long-term data on the dynamic operation of PEM stacks at the megawatt scale under realistic offshore conditions. This allows for the reliable quantification of degradation mechanisms, permissible ramp rates, efficiency losses, and operational limits. This reduces uncertainties in the design and operation of future offshore electrolysis projects, lowers technological risks, and supports standardization and norm setting.

The Fraunhofer IWES’s permanently available MW test infrastructure also serves as a scalable platform for further industrial and research projects, thereby strengthening technology and innovation transfer toward large-scale, economically viable offshore hydrogen production.