A framework to evaluate the energy-environment-economic impacts of developing rooftop photovoltaics integrated with electric vehicles at city level

Building a smart energy system to promote photovoltaic (PV) utilization has become an important task for cities to achieve a low-carbon future. With a focus on the rooftop PV integrated with the electric vehicle (EV) system (PV + EV), this study developed a framework to simulate the interaction between the PV + EV systems and load and evaluate the energy–environment–economic influences at the city level. Shenzhen, China, was used as a case study. The results showed that with EVs batteries providing storage service to PV, PV self-consumption can be significantly improved from 78% in the PV only system to 95% in the PV + EV system by 2030. The system can supply 37% of the total power demand in Shenzhen, which is double the current electricity generation capacity. With reduced grid power consumption and oil combustion in vehicles, citywide CO₂ emissions can be reduced by 42%. Avoided expenditures on fuel and electricity outweigh the additional capital investment of PV and EVs, leading to a total net cost savings of 21%. Compared to the PV system alone, the PV + EV system could provide more comprehensive benefits for Shenzhen. The analytical framework is generalizable to most cities in China and abroad that have yet to experience an increase in EV uptake.