Sizing of a Hydrogen System for Green-hydrogen Production by Utilising Surplus Water Accumulation in a Hydropower Plant

The utilisation of surplus hydro energy can enhance the profitability of hydropower plant operation by cogeneration of green hydrogen along regular electricity production. Effective integration of the hydrogen system requires its appropriate sizing based on surplus hydro energy availability, its temporal dynamics, scheduled electricity generation, and expected hydrogen demand. The article introduces a decision-support tool designed for the optimal sizing of hydrogen systems in run-of-river hydropower plants with surplus hydropower. In contrast to conventional methods, the developed tool enables rapid configuration of key hydrogen-system components without relying on complex optimisation algorithms. Implemented in MATLAB App Designer, the tool provides a visual inspection of the entire search space, thus avoiding possible sub-optimal solutions. The tool has been tested on the case-study hydropower plant and it demonstrates the capabilities for proper sizing of a hydrogen system. The results show that the hydrogen system with 0.75-MW electrolyser and 20 m3 storage tank can generate up to 52,652 € in a rainy month and can produce up to 86 tonnes of hydrogen annually, achieving approximately 440,000 € of additional income. The tool can provide valuable insights into hydrogen system’s installation profitability, to guide investment decisions in sustainable hydrogen infrastructure and can contribute to broader energy transition strategies.