Optimal climate-responsive sizing of hybrid PV/BIPV/battery/fuel cell microgrids for zero carbon urban buildings under varying grid integration ratios

Zero Carbon Urban Buildings (ZCUBs) are difficult to reach due to space constraints, high clean technology costs, and integration complexity. Furthermore, factors such as local climate variability, building archetype, operational modes, and the requirement for reliable energy storage further complicate the planning and optimization of hybrid renewable energy systems (HRES) for urban applications. In that sense, this paper introduces a novel approach that balances on-site solar generation, energy demand, storage, and grid integration while considering techno-economic, environmental, and spatial constraints. More specifically, the study focuses on the techno-economic optimization evaluation of grid-connected hybrid Photovoltaic (PV)/Building-Integrated Photovoltaic (BIPV)/Battery/Fuel Cell (FC) microgrids using a Genetic Algorithm (GA)-based approach, accounting for the dynamic interrelation between hourly spatiotemporal variations in solar energy output and energy demand across six different climate zones in Morocco. To this end, a three-step process systems engineering framework was proposed. As a first step, a digital workflow developed in the Grasshopper environment allowed the assessment of the energy demand of a parametric mid-rise office building, accounting for the effects of a variable shading system, which also integrates BIPV. Following that, the sizing of the PV/BIPV/Battery/FC microgrid system was undergone using GA. Finally, a holistic comparative techno-economic and life cycle emissions (LCEs) assessment was conducted under different Grid Integration Ratios (GIRs). Interestingly, the findings underscore the critical contribution of the BIPV, which supplies 41.9–47.4% of total solar output across the studied cities, while also enhancing performance by increasing the annual average daily load cover factor γload) by 13.95-16.5%, raising it to between 59.6% and 63.4%. Furthermore, the optimized off-grid system achieves a LCOE of $0.52–0.7/kWh while avoiding 4.2-4.74 ktCO2 compared to the fully connected-to-the-grid configurations. Besides, the hydrogen system is beneficial from the economic viewpoint, reducing LCOE by 10.9-15.9%. Moving to 50% GIR, although costs decrease by approximately 70%, LCEs rise significantly to 313 gCO2/kWh, indicating the compromise between economic and environmental considerations. In our context, as grid electricity is cheaper yet carbon-intensive, the study explores the cost–carbon trade-off across different GIRs, identifying low-carbon, cost-effective pathways.