Development and comparative evaluation of integrated solar-driven off-grid energy systems with hydrogen production and storage options for sustainable buildings

This study presents the development of a new solar energy-based integrated system where hydrogen production, storage, and power generation and heat storage subsystems are designed in a combined manner to meet the energy demands of multiple buildings in a community. It is also comprehensively analyzed and assessed under various criteria comparatively. A comprehensive study is established for a community with 80 156 residential buildings in Southern Ontario, Canada. Solar-driven three different cases are investigated, which cover (i) solar energy and grid-assisted, (ii) solar energy-driven system integrated with hydrogen subsystems, and (iii) solar-driven system integrated with hydrogen subsystems and heat storage for both heating and cooling purposes. The studied cases are assessed over the energy and exergy efficiencies. The results of this study indicate that it is possible to achieve solar-driven and off-grid operating conditions with hydrogen and heat storage systems. Only about 15% of the energy demand can be met by solar energy without any energy storage options (Case 1). Case 2 shows that it can be achieved off-grid solar energy system with 1100 MWp of solar power plant capacity with the integration of hydrogen as an energy storage option. In the case of using hydrogen and heat storage together, off-grid operating conditions can be reached with 750 MWp of power plant capacity. The heat storage integration helps reduce the capacity of the photovoltaic power plant by 32%. Furthermore, hydrogen and heat storage options are needed to cover both cooling and heating demands simultaneously to provide sustainable buildings.