Assessing optimized time-of-use pricing for electric vehicle charging in deep vehicle-grid integration system

Abstract

The expansion of electric vehicles (EVs) and renewable energy (RE) are the two major strategies countries are adopting to achieve energy transition. However, the discrepancy between intermittent RE generation and EV charging load may impose burden on the RE-dominant power grid of the future. For the issue, Time-of-Use (ToU) pricing for EV charging has been widely discussed or adopted as its potential is well acknowledged by previous studies. While ToU mechanism has been primarily based on drivers' price-responsive behavior, this research highlights that EV charging decisions are influenced by various factors beyond price, such as time of a day, charger accessibility and waiting time. Here, we conducted the discrete choice experiment to measure drivers' preferences for EV charging, and developed an EV charging behavior model which incorporated drivers' situational-responsiveness as well as price-responsiveness. Also, the model was used to design optimal ToU tariffs to minimize net-load variation. The results showed that strategic ToU tariffs can shift EV charging load, but achieving desirable load shifts requires a significant price gap. Additionally, combining ToU pricing with strategic deployment of charging infrastructure can effectively shift EV charging load, reducing RE curtailments by 22.14%, and LNG generation and carbon emissions by 10.12%, compared to the Business-as-Usual (BaU) scenario with current tariff rates. Thus, this study highlights the importance of flexible EV charging pricing and the importance of considering charging infrastructure deployment when designing EV ToU pricing.