Modelling and assessment of the applicability of a quasistationary model of the hydrogen subsystem of a PV–wind–H₂ hybrid system for power supply of irrigation pumping stations

The paper considers the hydrogen subsystem (electrolyser – storage tank – fuel cell) of a hybrid energy system based on photovoltaic (PV) and wind power units with hydrogen storage, intended for the power supply of irrigation pumping stations in the agro-industrial sector. A quasi-stationary energy model of the hydrogen storage subsystem is proposed, in which the powers of the electrolyser and the fuel cell are assumed to be equal to the prescribed setpoints, while the state of charge of the hydrogen tank is described by an energy balance equation. To account for the inertial properties of the electrochemical converters, a first-order dynamic model of the electrolyser and fuel cell power is developed. Numerical simulations for a representative operating scenario of the hybrid system are used to compare the quasi-stationary and dynamic models in terms of instantaneous power and state-of-charge trajectories. It is shown that the maximum relative power errors do not exceed 1.47 % and 0.63 %, while the maximum state-of-charge error is below 0.33 % of the scale, which is significantly lower than the 3 % acceptability threshold. The obtained results confirm the applicability of the quasi-stationary model for fast simulations and techno-economic analysis of hybrid energy systems for agricultural applications.