Green hydrogen production via floating photovoltaic systems on irrigation reservoirs: An Italian case study

This study investigates the potential for establishing a self-sufficient renewable hydrogen production facility utilising a floating photovoltaic (FPV) system on an artificial irrigation reservoir, located in a small municipality in southern Italy. The analysis examines the impact of different system configurations and operating conditions on the technical, economic, and environmental performance, with a particular focus on hydrogen production and water conservation resulting from reduced evaporation. Different sizes of the FPV plant are considered, with and without a tracking system. The electrolyser performance is evaluated under both fixed and variable load conditions, also considering the integration of battery storage to ensure consistent operation. The findings indicate that the adoption of the largest FPV plant can result in the conservation of approximately 1.87 million m3 of water annually, while simultaneously producing up to 4199 tons of hydrogen per year in variable load mode-more than twice the output compared to fixed load conditions. Although battery integration increases hydrogen production, it also leads to higher investment and maintenance costs. Therefore, the variable load operation emerges as the most economically viable option, reducing the levelized cost of hydrogen (LCOH) to 13.18/kg, a 26 % reduction compared to fixed load operation. Moreover, the implementation of a vertical axis tracking system leads to only marginal LCOH reductions (maximum 2.2 %) and does not justify the additional complexity. In all tested scenarios, the system proves to be self-sustaining. Given the case study's location in southern Italy-where a pilot project for fuel cell-battery hybrid trains is underway-the hydrogen produced is assumed to be used for railway applications as a possible offtaker. The analysis shows that the potential of the system in terms of hydrogen production is much higher (tens of times) than the estimated demand of the present hydrogen railway configuration, thus suggesting that a significant expansion of the number of trains and routes served could be considered. Although this work is based on a specific case study, its key findings are potentially replicable in other contexts-particularly in Mediterranean or semi-arid regions where water scarcity may otherwise act as a limiting factor for the deployment of hydrogen production systems.