Optimal Energy Bidding for the Italian Balancing Service by EVs: a Sensitivity Analysis

Thanks to their flexible power response, Battery Energy Storage Systems (BESSs) have gained attention as possible new suppliers of Ancillary Services (ASs) to the power system. BESSs in Electric Vehicles (EVs), in particular, could supply ASs during EV recharge. Here, some evaluations of how profitable the Balancing Service (BS) could be for the EV owner are carried out: an optimization problem is set up, returning the energy to be bid for the service on the Italian Balancing Market (BM) to minimize the cost of recharging the desired amount of energy; the bid prices and the bid acceptance/rejection status are assumed as known input values; hourly and quarter-of-an-hourly bids are considered, based, respectively, on the current product resolution on the market and on its foreseen evolution. The simulated case studies are for overnight recharge and involve two kinds of end user, with different values of the maximum recharging power, of the energy to be recharged and of taxes on energy exchanges; both one-directional (V1G) and bi-directional (V2G) recharge are analyzed. Overall annual results show that, if the energy to be recharged is small, moderate savings in the EV electricity bill can be achieved with respect to not supplying the BS; high savings can be achieved if such energy is larger (as in case of a non-domestic user) and V2G recharge is adopted, so that energy selling for the BS is enhanced.