LAUSR

The increasing levels of variable renewable electricity (VRE) generation-such as wind and solar power-will create important opportunities for the charging of electric vehicle (EV) batteries during low-cost hours with a lot of VRE generation and for the discharge of EV batteries back to the grid (i.e. vehicle-to-grid; V2G) during high-cost hours. This study investigates how different EV charging strategies influence the cost-competitiveness of generation and storage technologies other than EV batteries in the electricity system, using a regional electricity system investment and dispatch model. The charging requirements of the EVs, which are used as an input to the optimisation model, are derived from the yearly driving patterns of 426 vehicles measured with global positioning system. The study is carried out for four regions in Europe with different conditions for wind, solar and hydro power generation. The results show that optimised EV charging with V2G can: (i) reduce investments in peak power capacity in all the regions investigated; (ii) reduce the need for short-term and long-term storage technologies other than EV batteries (i.e. stationary batteries and hydrogen storage); and (iii) stimulate increased shares of solar and wind power generation, as compared to direct charging in some regions (mainly Hungary). This study also shows that EV battery capacities as low as 30 kWh, which are connected to the grid only at their home location, can to a large extent contribute with flexibility to the electricity system in the way mentioned. The present study also investigates the influences of different shares of the fleet participating in V2G, and shows that the additional benefits for the electricity system level off when approximately 24% of the vehicle fleet participates in V2G.