This study proposes a digital twin–based method for large-scale optical simulation in urban environments. A digital twin of the Tokyo Metropolitan Government Building and surrounding buildings was used to simulate the building’s surface solar irradiance on 1 July 2025 (5:00 a.m.–6:00 p.m.) under clear-sky conditions. Results showed that about 5% of the surface area received more than 3.7 kWh/m² of daily global solar irradiance, while less than 50% exceeded 3.0 kWh/m². The method enables precise simulation of solar irradiance while accounting for complex urban geometries, supporting strategic photovoltaic placement to maximize energy yield.
Sato et al. (Wed,) studied this question.