Roofing Highways With Solar Panels Substantially Reduces Carbon Emissions and Traffic Losses

Photovoltaic (PV) installations are a leading technology for generating green electricity and reducing carbon emissions. Roofing highways with solar panels offers a new opportunity for PV development, but its potential of global deployment and associated socio-economic impacts have not been investigated. Here, we combine solar PV output modeling with the global highway distribution and levelized cost of electricity to estimate the potential and economic feasibility of deploying highway PV systems worldwide. We also quantify its co-benefits of reducing CO₂ equivalent emissions and traffic losses (road traffic deaths and socio-economic burdens). Our analysis reveals a potential for generating 17.58 PWh yr⁻¹ of electricity, of which nearly 56% can be realized at a cost below US$100 MWh⁻¹. Achieving the full highway PV potential could offset 28.78% (28.21%–29.1%) of the global total carbon emissions in 2018, prevent approximately 0.15 million road traffic deaths, and reduce US$0.43 ± 0.16 trillion socio-economic burdens per year. Highway PV projects could bring a net return of about US$14.42 ± 4.04 trillion over a 25-year lifetime. To exploit the full potential of highway PV, countries with various income levels must strengthen cooperation and balance the multiple socio-economic co-benefits.