A thorough analysis of the solar energy potential and the utilization cost is necessary to form a public consensus on the active adoption of solar energy in Seoul. This study strives to answer two questions: How much solar energy can all the building rooftops in Seoul produce, and how does the feasibility of rooftop solar energy change, depending on the future development in economic and technological factors until 2050. The research simulates rooftop solar energy production in Mapo District of Seoul and combines it with future scenarios analysis, considering the technological advance in solar PV production systems and the change in economic factors such as wholesale electricity tariff and systems management cost. The study adopts the Ladybug tool, an energy modeling tool connected to a 3D CAD interface of the Rhinoceros program, to simulate hourly rooftop solar energy production in each season based on a digital map and weather data of Seoul. The simulation shows that 72% of the Mapo District’s total building electricity consumption in 2020 could have been covered by rooftop solar energy if solar PV panels covered every building rooftop. The three scenarios of benefit-cost analysis project that rooftop solar energy will start to play a crucial role in carbon mitigation between 2026 and 2044. However, the scenarios indicate that the explosive growth of PV panel installation would mean both the exponential increase of benefits and the escalation of costs, resulting in a slower expansion of the technology and higher costs for users. The research result also implies that increasing the supply of rooftop solar energy is not the sole essence of bringing solar city development to realization. As the transition to green energy involves uncertainty, a precise prediction of the potential amount of the source and consideration of the technological and economic usability will help achieve a feasible energy supply plan aiming for a slight burden on consumers in urban areas.
Keywords Carbon neutral strategy, techno-economic analysis, renewable energy supply system, rooftop solar energy