User preferences for EV charging, pricing schemes, and charging infrastructure

This paper analyses user preferences related to electric vehicle (EV) charging decisions. The analysis includes both a qualitative as well as a quantitative assessment. The qualitative assessment consists of a literature review of existing studies about EV charging behaviour and an analysis of semi-structured interviews with Danish EV users. This assessment identifies the most relevant factors for charging. In addition, it highlights that the time horizon of the charging decision is an essential factor. We use this to design two stated-choice (SC) experiments explicitly taking these findings into account. The first SC experiment looks into long-term decisions related to regular charging practices. The second SC experiment captures decisions related to occasional charging needs on longer trips. The SC data consist of three responses from 558 EV owners for each of the two experiments. We model the data using mixed logit models to allow for unobserved heterogeneity and the repeated nature of the SC data. The main findings indicate a high preference for all-inclusive/flat fee pricing structures. Moreover, they show that respondents value interoperability between charging networks, both nationally and internationally. Related to occasional charging, we find willingness-to-pay measures describing the detour respondents are willing to drive to obtain lower costs, a higher likelihood of available chargers, and facilities at the charging location. Overall the analyses highlight many factors that influence the charging decisions of consumers that are relevant for policymakers and charging operators. In addition, they highlight the barriers in a charging context, such as network roaming, lack of charging etiquette, and congestion at chargers.