Highway-integrated vertical-axis wind turbines for harvesting induced wind for the generation of electricity: A critical review

Highway corridors are increasingly electrified for lighting, signalling, and monitoring, which in turn motivates renewable generation within transportation right-of-way. The aim is twofold: to supply corridor loads and to reclaim energy otherwise dissipated as drag-driven turbulence. This review consolidates and critically evaluates highway-integrated vertical-axis wind turbines (VAWTs) that harvest ambient winds and vehicle-induced slipstream/wake flows. Evidence is synthesised from highway wind/traffic measurements, field demonstrations, CFD modelling, techno-economic assessments, and deployment studies. Natural highway winds are commonly 2–6 m/s with occasional strong gusts, while traffic speeds of 38–107 km/h generate intermittent wakes that can exceed typical cut-in thresholds near the roadway. Field trials show that siting is decisive: median mounting generally increases rotor speed and output relative to shoulder placement. Furthermore, self-starting Savonius and hybrid Savonius–Darrieus rotors better tolerate turbulent, bidirectional wakes than pure lift-type rotors, which often experience start-up limitations under such conditions. CFD studies further explain these observations by linking turbine performance to wake structure and traffic configuration. Same-direction vehicle convoys can sustain useful inflow conditions, whereas opposing flows may partially cancel them. Although flow control devices and turbine arrays show promise for enhancing performance, these approaches remain sparsely validated under real highway conditions. Techno-economic analyses indicate that wind-only systems are viable primarily in niche, low-cost scenarios, whereas photovoltaic (PV) and led hybrid configurations provide more consistent favorable cost-performance metrics and temporal reliability. Despite encouraging findings, the review identifies persistent gaps in long-duration, standardised field datasets; incomplete reporting of current, power, efficiency, and system losses; and weak integration of aero–electro–structural modelling with safety, maintenance, environmental, and right-of-way constraints. The paper concludes by proposing targeted research priorities to support scalable, safe, and economically credible implementation.