Factors affecting the techno-economic and environmental performance of on-grid distributed hydrogen energy storage systems with solar panels

Abstract

Deployment of on-grid distributed hydrogen energy storage (HES) systems, which are more economically advantageous than off-grid systems, requires not only optimization for minimizing system costs but also analysis for clarifying the factors that affect the optimization results. In this study, an on-grid system with solar photovoltaic (PV) panels, an electrolyzer (EC), fuel cell, hydrogen tank, and compressor was modeled. This model was used to analyze the changes in the system cost and greenhouse gas (GHG) emission with an increase of device capacities under different PV capacities and self-sufficiency rates (SSRs). The analyses quantitatively showed that the optimization under massive PV implementation, which generated large amounts of surplus electricity and did not need seasonal storage for more than half a year, makes HES system more economically attractive while reducing the GHG emission. The unit cost reduction of the HES devices made the optimal EC capacity increased, which reduced the curtailment of surplus electricity. When an SSR constraint was imposed, the unit cost reduction of the HES devices decreased the optimal PV capacity while reducing the curtailment of surplus electricity. The maximum installable PV capacity in a microgrid was also discussed in terms of the electricity demand density and grid transmission capacity.