SolarEV City Concept for Paris: A promising idea?

Urban decarbonization is one of the pillars for strategies to achieve carbon neutrality around the world. However, the current speed of urban decarbonization is insufficient to keep pace with efforts to achieve this goal. Rooftop PVs integrated with electric vehicles (EVs) as battery is a promising technology capable to supply CO2-free, affordable, and dispatchable electricity in urban environments (SolarEV City Concept). Here, we evaluated Paris, France for the decarbonization potentials of rooftop PV + EV in comparison to the surrounding suburban area Ile-de-France and Kyoto, Japan. We assessed various scenarios by calculating the energy sufficiency, self-consumption, self-sufficiency, cost savings, and CO2 emission reduction of the PV + EV system or PV only system. The combination of EVs with PVs by V2H or V2B systems at the city or region level was found to be more effective in Ile-de-France than in Paris suggesting that SolarEV City is more effective for geographically larger area including Paris. If implemented at a significant scale, they can add substantial values to rooftop PV economics and keep a high self-consumption and self-sufficiency, which also allows bypassing the classical battery storage that is too expensive to be profitable. Furthermore, the systems potentially allow rapid CO2 emissions reduction; however, with already low-carbon electricity of France by nuclear power, CO2 abatement (0.020 kgCO2kWh-1 reduction from 0.063 kgCO2kWh-1) by PV + EV system can be limited, in comparison to that (0.270 kgCO2kWh-1 reduction from 0.352 kgCO2kWh-1) of Kyoto, also because of the Paris low insolation and high demands in higher latitude winter. While the SolarEV City Concept can help Paris to move one step closer to the carbon neutrality goal, there are also implementation challenges for installing PVs in Paris.