Assessment of Profitability of Electric Vehicle-to-Grid Considering Battery Degradation

Abstract: The electric vehicle (EV) fleet is expected to continue growing in the near future. The increasing electrification of the transportation sector is a promising solution to the global dependency on oil and is expected to drive investments in renewable and intermittent energy sources. In order to facilitate the integration, utilize the potential of a growing EV fleet and to avoid unwanted effects on the electric grid, smart charging strategies will be necessary. The aspect of smart EV charging investigated in this work is the profitability of bidirectional energy transfer, often referred to as vehicle-to-grid (V2G), i.e. the possibility of using aggregated EV batteries as storage for energy which can be injected back to the grid. A mixed integer linear problem (MILP) for minimizing energy costs and battery ageing costs for EV owners is formulated. The battery degradation due to charging and discharging is accounted for in the model used. A realistic case study of overnight charging of EVs in Sweden is constructed, and the results show that given current energy prices and battery costs, V2G is not profitable for EV owners. Further, a hypothetical case for lower battery costs is formulated to demonstrate the ability of our MILP model to treat a number of charging scenarios