Leveraging renewable-energy–electric-vehicle synergies for deep decarbonisation: Technical frontiers, market barriers and policy solutions

As nations pursue decarbonization targets, coupling renewable energy with electric vehicles (EVs) has emerged as a promising pathway to enhance grid flexibility, reduce greenhouse-gas emissions, and drive sustainable mobility. This review synthesises 2013-2023 trends in clean-energy expansion, energy-use carbon intensity, and EV adoption. Regions that expanded wind and solar faster cut carbon intensity more steeply and adopted EVs more quickly. Coordinating clean power with flexibility raised renewable penetration and contained integration costs. Smart charging typically reduced peaks and curtailment by ~ 10-25%. We then map five frontiers that couple renewables with e-mobility. Intelligent bidirectional management delivered 5-8% CO₂ savings at the distribution level. Aggregator and VPP participation unlocked $3,000-$4,500 per EV per year after degradation costs. Hardware and charging-infrastructure innovations trimmed converter losses by 3-5% and stabilised voltage at high EV penetrations. Microgrid and hybrid renewable-V2G designs lifted self-consumption by up to 15% and cut diesel backup by ~ 70%. Lifecycle and circular strategies showed that second-life batteries retained > 80% capacity after ten years, could meet up to 50% of Europe's stationary-storage needs, and reduced raw-material demand by 7.5% and lifecycle emissions by 10-12%. We then diagnose the main barriers. Standards remain fragmented (ISO 15118, CHAdeMO, GB-T). Bidirectional chargers are costly. Many markets still enforce 1 MW bid floors and 15-min settlements. Interconnection and data rules are often unclear. Finally, we propose a sequenced roadmap: high-resolution pricing, clear aggregation access, harmonised technical and market standards, and cross-sector planning. Research priorities centre on integrated modelling, hardware-software co-design, large-scale pilots, and behavioural and market studies. This roadmap aligns policy, technology, and economics to accelerate a resilient, low-carbon energy-mobility transition.