Specific energy consumption of dynamic large-scale green hydrogen production with an alkaline electrolyser at the hydrogen lab Bremerhaven

The he specific energy requirement for hydrogen production is a key factor in determining the levelised cost of hydrogen (LCOH), which in turn is crucial to the profitability and implementation of hydrogen projects. This paper examines the specific energy consumption of two alkali electrolysis modules, each with an installed capacity of 450 kW, at the Hydrogen Lab Bremerhaven. The analysis is based on measurement data collected from January 1, 2025, to May 26, 2025, with a focus on the main operating hours between 09:00 and 17:00 local time. The results show the specific energy consumption for various days during this period as well as the average energy consumption achieved and illustrate the impact on the LCOH depending on the available energy price. Start-up faults, quality issues and necessary hydrogen venting operations led to significant peaks in specific energy consumption. The results show that the reliability of the balance-of-plant components has a significant influence on energy consumption and thus on hydrogen production costs. To remain competitive against imported hydrogen in the future hydrogen market, improved system reliability is essential.