The economic feasibility of Vehicle-to-Grid (V2G) technology is subject to a lot of debate due to the battery degradation costs associated with it. In this paper, the daily operational cost of a V2G system is calculated for three different types of Li-ion batteries and one new Li-S battery, and a comparative study is conducted to understand the conditions required to deploy a successful V2G system. Different models are applied in estimating the degradation of batteries with different battery chemistries. The best Li-ion battery for this system is found to be LiFePO4 even though it is the most expensive battery considered. It is also noted that the starting state-of-charge (SOC) relates to the operational costs non-linearly and an optimal starting SOC is calculated for minimizing operational cost. When these Li-ion batteries are replaced by the new double SEI layer Li-S batteries, additional cost benefits of about 17% are expected.
Keywords Li-ion battery, Li-S battery, Vehicle-to-Grid, Battery degradation