Corridor-scale coupling of stochastic passenger EV charging demand and photovoltaic power supply at expressway service areas

Expressway service areas have become corridor-scale hotspots of passenger electric vehicle (EV) charging demand under transport electrification, while their coordination with distributed photovoltaic (PV) supply remains insufficiently quantified at the corridor level. This study develops a coupled assessment framework that integrates stochastic passenger EV charging demand with PV power supply across consecutive expressway service areas. A Monte Carlo-implemented Markov state-transition framework is used to simulate passenger EV state evolution and charging decisions, with key behavioral parameters informed by 102 valid questionnaire responses from passenger EV users. PV deployment potential is evaluated under rooftop, parking-area, and roadside deployment configurations. A case study of 26 service areas along the Gansu section of the G30 Lianhuo Expressway is conducted. The results reveal distinct corridor-scale heterogeneity in passenger EV charging demand. Under the baseline scenario, charging probability ranges from 0.08 to 0.29 in the east-to-west direction and from 0.07 to 0.26 in the west-to-east direction, while the average energy replenished per charging vehicle remains relatively stable within 46.89–54.81 kWh. Daily charging demand varies from 27.5 to 56.2 MWh/day across service areas and is strongly associated with the cumulative distance to adjacent service areas ( R 2 = 0.799, p < 0.001). Sensitivity analysis identifies the maximum available driving range ( R max ) as the dominant parameter affecting corridor-scale charging behavior. Optimal tilt-angle PV deployment reduces the required installed capacity to 4.94–11.67 MW, with an average capacity reduction of 14.5% compared with horizontal-angle deployment. However, rooftop and parking-area PV resources alone are constrained by available built-environment space, requiring supplementary roadside PV deployment of 168–837 m at several service areas. Economic and carbon-reduction assessments show that optimal tilt-angle deployment yields average annual return ratios of 5.09%–9.50% and cumulative CO₂ emission reductions of 137–281 kt over a 25-year lifecycle. The proposed framework provides quantitative support for coordinating passenger EV charging infrastructure with distributed PV deployment at expressway service areas.