Analysis of electric vehicle user recharging behaviour and the effectiveness of using financial incentives to manage recharging demand

Abstract

An anticipated increase in the number of electric vehicles (EVs) on the road has created the need to understand and manage recharging demand in order to prevent localised overloading of power distribution networks during peak hours. Smart meters at home, in conjunction with off-peak energy tariffs, have been proposed as a demand management tool. This has not been tested in a region with a high density recharging infrastructure whereby drivers pay an annual fixed fee for unlimited use of non-domestic recharging infrastructure networks. This research quantified daily recharging demand profiles and assessed the effectiveness of incentivising off-peak recharging in such a region. The North East of England was used as the study area. Between 2010 and 2013, 401 home, 312 workplace and 412 public non-domestic recharging posts were installed. Recharging data were available from SwitchEV; a three year, real world EV deployment study that commenced in 2010. Sources of data were in-vehicle loggers, focus groups and questionnaires. There were 23 Private, 43 Organisation Individual users and 74 Organisation Pool users in total. Five statistically significantly different representative recharging profiles were identified. None of these profiles had high demand peaks during the off-peak hours between midnight and 07:00hrs. Interventions took place for 21 users. A 50% reimbursement for off-peak recharging was offered. At home, off-peak recharging increased by 23%. No significant changes in recharging behaviour occurred at any other recharging location. There was also no statistically significant change in the proportion of total recharging recorded at each location. Focus groups and questionnaires revealed the common theme of drivers using EV recharging posts as they offer free and convenient parking bays, rather than out of a need to recharge the battery in order to complete an upcoming trip. Furthermore, the absence of timing devices and organisation policy dictating that EVs must be recharged immediately upon returning to the premises limited the ability of organisations to deliver behavioural change. It is recommended that pay-as-you-go access to non-domestic recharging infrastructure be implemented to reduce unnecessary daytime recharging and that workplace recharging infrastructure is fitted with smart meters. These changes are required as this research has highlighted limitations of the current proposed policy.