Optimal power dispatch of a centralised electric vehicle battery charging station with renewables

Abstract

Historically, transportation electrification has been largely hindered by the limited battery capacity and the long charging time. Battery swapping has emerged as one promising technology to mitigate these problems. A centralised battery charging station (BCS) is responsible for charging depleted batteries (DBs) and providing fully-charged batteries (FBs) for multiple geographically-distributed battery swapping stations (BSSs) so that they can carry out battery swapping services. Facilitated by the recent advancement in sensor and communication technologies, one salient advantage of this centralised approach lies in its convenience to better utilise dual energy sources (i.e. the traditional power grid and local renewable energy generators). This is achieved via optimising the charging processes of a large number of DBs. In this study, the authors propose an optimisation framework for a centralised BCS to minimise the energy cost from the dual energy sources to satisfy the FB demands from multiple BSSs. Particularly, the power dispatch problem in the day-ahead and real-time electricity markets is formulated as a two-stage stochastic optimisation through consideration of the intermittent renewable energy. Numerical simulations show that the proposed optimised power dispatch is capable of achieving cost saving of 76% compared with the benchmark, subject to the limited information available in day-ahead.