Optimal E-fleet charging station design with V2G capability

Electric vehicles are expected to play a fundamental role in the management of the future electricity infrastructure. Because of their good characteristics and ability to provide fast and reliable power, EVs could become active market players, offering valuable ancillary services to the main grid, through the V2G concept. In the present work, the design and the operation of a microgrid featuring an e-fleet parking lot, PV panels, a battery for stationary storage and serving an industrial load is presented. Starting from an existing e-fleet, whose recharging requirement and profiles of use are known, the capability of the system of providing several grid services has been investigated: from demand-side management to primary, secondary and tertiary reserve. The size of microgrid components as well as the optimal capacity to be allocated and shared between different reserve provisions has been selected through an optimization problem based on a detailed MILP formulation. Results showed that, when additional revenues from reserve markets are taken into account in the design optimization problem, significant economic incomes could be achieved, especially from energy-intensive reserve programs such as the secondary reserve while the contribution of the awarded capacity in the tenders for the primary and the tertiary reserve is more limited. Moreover, the downward bidding mechanism has been proven to be particularly effective for e-fleet management since it allowed to pursue a twofold objective: being paid for the service provided and, at the same time, recharging the EV battery stack.