Equitable, affordable, and deep decarbonization pathways for low-latitude developing cities by rooftop photovoltaics integrated with electric vehicles

Identifying effective development and rapid decarbonization pathways for developing countries are essential to realize sustainable and equitable future global societies. Increasingly cheaper solar photovoltaics (PV) on rooftop is one of the keys to build such urban power systems, integrated with battery and/or electric vehicles (EVs). Here, we explore potentials of rooftop PV combined with EVs for urban decarbonization of Jakarta, Indonesia using techno-economic analysis, in comparison to Kyoto City, Japan. We found that rooftop PV system is already costcompetitive in Jakarta in 2019 but with cost-saving of only 3-4 %. However, "PV only" system becomes increasingly cost-effective (cost-saving of 8-15 %) by 2030. Further, by combining with EV as battery, rooftop PV system can supply affordable CO2 free electricity to 75-76 % of Jakarta's electricity demands with 33-34 % potential cost saving and 76-77 % of CO2 emission reduction from electricity generation and driving, which also greatly improve air quality in the city. Notably, Jakarta has no space heating demand through a year but persistent cooling demand positively correlating with PV generation, which increases decarbonization potentials of "PV + EV" system by 9 % than that of Kyoto. Also, rooftop PV generation in Jakarta is less affected by rooftop slope angle and orientation than those of Kyoto owing to year-round higher "sun altitude angle" in Jakarta. As the Indonesia government aims to reach the level of developed country by 2045, rooftop "PV + EV" system can be a no-regret strategy for the rapid growth and decarbonization for Indonesia, and so for other low-latitude developing cities.