Off grid PV system for hydrogen production using PEM methanol electrolysis and an optimal management strategy

In this paper, we present a modelling and simulation study of an Off grid PV system for hydrogen production (PVHPS) using methanol electrolysis process. The system consists mainly on a PV array, lead-acid battery, methanol electrolyser and hydrogen tank. Mathematical models of each component of the system are presented. Using a semi-empirical relationship between hydrogen production rate and power consumption, hydrogen production at 80 °C and 4 M concentration is estimated. Optimal power and hydrogen management strategy (PHMS) is investigated to achieve high system efficiency. Case studies are carried out on two tilts of PV array: horizontal and tilted at 36°. Parametric sensitivity analysis is also carried out to illustrate the effect of the battery depth of discharge (DoD) on the system components sizes and overall system performance. In the simulation, data of solar irradiation and ambient temperature obtained from radiometric measurements at Algiers city are used. Simulation results show that the system with tilted PV array presents performances better than in horizontal PV array configuration and produce greater hydrogen amounts. In addition, reducing the DoD value in order to increase the lifetime of the accumulator induces some power losses which decreases the amount of hydrogen produced and consequently reduces the system efficiency.