Rapid decarbonisation of Paris, Lyon and Marseille's power, transport and building sectors by coupling rooftop solar PV and electric vehicles

Meeting the European Commission's 'Fit for 55' climate goals by the year 2030 in the context of the trilemma of security of supply, environmental sustainability, and competitiveness will require concerted efforts from the Member States on all fronts. Among others, it will require optimised techno-economic solutions that offer sus-tainable decarbonisation pathways for the concurrent decarbonisation of many sectors of the economy. This paper attempts to provide empirical evidence of the 'rooftop solar PV+EV concept' efficacy as a promising pathway to decarbonise France's transport, power and building sectors concurrently. Using the System Advisor Model (SAM), we find that if rooftop solar PV is installed on half of the available roof space, and if half of the passenger vehicle owners replace their internal combustion engine vehicles (ICEVs) with EVs by 2030, then France can meet 20 %-42 % of total electricity demand in the three most populous cities. Moreover, the solar PV + EV coupling can reduce CO2 emissions from passenger vehicle use and electricity generation by 43 %-48 %. Also, the coupling can be a potentially worthwhile investment with a payback period of 2-3 years, a levelised cost of energy (LCOE) of about euro0.04/kWh, and a net present value (NPV) of euro6-19 billion without a feed-in tariff. We analyse the potential implementation challenges of the 'rooftop solar PV + EV concept' and propose some solutions. Finally, we argue that coupling rooftop solar PV + EV in cities is a cost-effective strategy to decarbonise urban energy, transport and building sectors concurrently. Therefore, the government should consider enacting combined rooftop solar PV + EV decarbonisation policies that offer economic and environ-mental benefits.