Comparison of Vehicle-to-Grid versus Other Grid Support Technologies

With the accelerating adoption of electric vehicles, using the batteries in the existing vehicle fleet to discharge to the power grid when needed (vehicle-to-grid, V2G) provides a potential alternative for supplying grid support. This master project focused on the often-overlooked side of V2G, the energy efficiency, and compared V2G versus other grid support technologies in terms of their efficiencies and emissions. Given V2G is most suitable for regulation service, other available technologies serving regulation were selected for the comparison. The project adopted a fuel-to-grid scope when conducting the comparison among different grid support technologies, meaning the efficiency at which fuels are converted into final grid support, along with the associated emissions, were analyzed and compared. The comparison led to three major findings: (1) energy storage-based technologies achieve a lower fuel-to-grid efficiency than gas turbines do; (2) V2G is less efficient in delivering grid support than grid-dedicated battery banks and flywheels; (3) storage-based technologies, especially V2G, would significantly increase CO2, SO2, and NOx emissions.