The role of transport sector integration in achieving high shares of renewable energy in African islands: The case of Santiago, Cabo Verde

Renewable energy sources offer the opportunity to decarbonize both the power and transport sectors through the adoption of electric vehicles, especially in resource-rich islands, such as those in Africa. However, the role of electric mobility, particularly vehicle-to-grid technology, as a system-balancing solution remains underexplored for these islands. This study addresses this gap by using the EnergyPLAN model with hourly resolution to assess the integration of electric vehicles, smart charging, and vehicle-to-grid services into a high-renewable energy system on Santiago Island, Cabo Verde. The analysis is based on scenario simulations for 2030 and 2050, assessing the impact on system reliability, carbon dioxide emissions, and system costs. Results demonstrate that vehicle-to-grid services can significantly increase the share of renewable energy penetration, with electric vehicles’ batteries providing short-term system balancing and storage services as early as 2030. By 2050, a fully renewable power system with a high share of electric vehicles is technically and economically feasible. However, it requires coordinated planning between the power and transport sectors. The insights from this study highlight the potential for Santiago Island to serve as a scalable model for electric mobility, smart and integrated energy systems in the West African region, offering insights for other Small Islands Developing States aiming for energy self-sufficiency, affordability, and sustainability. • Santiago integrated power and transport via V2G, boosting grid flexibility. • V2G meets Santiago's short-term storage needs by 2030, reducing curtailment. • Smart energy systems enable 100 % RE by integrating the transport and power sectors. • High solar capacity and flexible storage are key for a 100 % RE system. • BEV lower system costs via vehicle-to-grid and reduced fuel dependence.