The use of second life electric vehicle batteries for grid support

Matching electrical power supply to customer demand is an ongoing problem for electricity distribution network operators and it is increasing with the growth of distributed renewable energy generation at the low voltage (LV) level. A battery energy storage system (BESS) has been suggested which would help the control of voltage levels, optimise renewable generation and supply the evening peak demand. In addition a BESS could offer ancillary support to the network including balancing services as well as deferring network asset upgrade, with ensuing financial advantages. Until now the cost of providing a BESS has been prohibitive except for the most isolated and essential supply. The main contribution of this paper will be to demonstrate that afterlife electric vehicle (EV) batteries can be used in BESS for the provision of such services with particular emphasis on peak shaving and upgrade deferral. The size of the BESS is calculated using a simulation based on a LV load profile and the effect on voltage is modelled and displayed graphically. Considering that the market penetration of EVs has been hampered by high cost of Li-ion batteries and with projections of the first set of used automotive batteries becoming available from 2019 an investigation into the afterlife usage of EV batteries is timely and economic.