Parametric investigation and multi-objective optimization of building-integrated hybrid energy storage system with metal hydride tank

The present analysis investigates a hybrid energy storage system consisting of lead-acid batteries and a hydrogen storage tank using metal hydrides. A dynamic simulation is conducted for a 1000 m2 building, supported by photovoltaics and a hybrid storage system to meet annual appliance and lighting demands. The research focuses on optimal system sizing to minimize both grid electricity demand and total capital costs. Multi-objective optimization was conducted through a Dymola–Python NSGA-II algorithm interface, while energy simulations utilized the INTEMA.building tool. Results indicate an optimal solution with 118 lead-acid batteries (339.84 kWh) and a 4 kg H2 capacity of a metal hydride storage tank, achieving 99.2 % grid autonomy. Although the 40 kW and 50 kW PV systems achieve comparable energy autonomy (98 %), their total cost is doubled compared to the optimal solution due to increased demanded MH tank capacity (60 kg H2) to support the battery system, outperforming the total cost.