Modeling and simulation of integrated solar PV - hydrogen systems

Abstract

This work provides a novel model for solar PV – hydrogen (H2) systems that uses weather data and electrical variables of the components to perform PV-H2 design for different hybrid configurations. The objectives are to size and operate the systems optimally to reach a target production (QH) and minimize cost of H2. The component sizes and hydrogen production (QH) are optimized by PV-EL direct coupling where the EL curves are determined by the number and area of EL cells connected to PV modules. The use of maximum power point (MPP) tracking increases the coupling factor (and QH), but this gain is not significant vs. optimal PV-EL coupling. Battery assisted electrolysis has the advantage of reducing the EL size, showing how convenient is also to operate it at part loads (e.g., at night) so that the PV array and EL are larger to grant H2 production, but the batteries are much more effective. The optimal configuration, design and operation will finally depend on the evolution of unit cost of the components (PV, MPPT, EL and batteries): direct coupling leads to a cost production of 5.03 Є/kgH2 with 26 (20 cm2) EL cells per PV module; this is slightly increased by MPPT use (5.20 Є/kgH2) and notably reduced with batteries (4.07 Є/kgH2), but MPPT would be optimal if cost drops to 1/5 of base prices considered in this work and batteries are not favorable if cost per m2 of EL is reduced to less than 1/3 (depending on MPPT cost).