This study addresses the challenge of designing cost-effective and energy-efficient solar energy systems for large-scale, multi-functional building complexes, which typically exhibit high and diverse energy demands. Although integrating solar power with energy storage has shown promise, existing research rarely considers the full complexity of such building types or the trade-offs between cost and renewable energy use. To fill this gap, this study develops a novel assessment framework that quantitatively evaluates system performance across both energy and economic dimensions. The framework is applied to a real-world airport cargo terminal comprising ten functional zones, evaluating six system configurations with different photovoltaic areas and battery capacities. Two optimization objectives are considered: maximizing the share of energy supplied by solar generation and minimizing the levelized cost of electricity. The results show that two of the six configurations stand out as most representative: Case 3 adopts full rooftop and façade photovoltaics with an 87.94 MWh battery, enabling 60 % renewable energy penetration and the highest overall performance score of 4.6 (out of 6), though it requires 14.5 % higher investment; Case 5 uses only façade photovoltaics without storage, delivering the maximum cost saving of 10.4 % and the lowest energy cost of 0.49 CNY/kWh. The findings reveal a clear trade-off between maximizing renewable energy use and minimizing cost. This work contributes a novel, scalable framework for evaluating and optimizing solar energy systems in complex building environments, offering practical decision support for designers, policymakers, and investors seeking to promote sustainable urban energy transitions.

Rooftop photovoltaic (PV) with battery storage offers a promising avenue for enhancing renewable energy integration in buildings. Creating microgrids with backup power from closely spaced solar buildings is widely recognized as an effective strategy. Nevertheless, a notable gap exists between the preferences and priorities of electricity consumers residing in these solar-powered buildings and the interests of microgrid investors. The electricity consumers focus on decreasing the levelized cost of energy, while the microgrid investors focuses on achieving high net profit. This study proposes a novel game theory-based microgrid optimal design approach for designing power generations of the microgrid system and PV installation with battery storage on the building roofs, considering the different requirements and interests of electricity consumers and microgrid investors. The design optimization is framed around the Nash Equilibrium of the Stackelberg game, incorporating a bi-level optimization cycle that addresses the conflict and cooperation of electricity consumers and microgrid investors. A win-win situation can be yielded using the developed optimal design approach compared to conventional optimal design approaches. The results demonstrate a significant improvement, with the microgrid power generation yielding a large net profit (up to 0.08 USD/kWh) and concurrently reducing the levelized cost of energy by approximately 14 %.