UC San Diego

ABSTRACT OF THE THESIS

Overstay at Electric Vehicle Charging Stationsat the University of California San Diego by Akanksha Harish Master of Science in Engineering Sciences (Mechanical Engineering) University of California San Diego, 2021 Professor Jan Kleissl, Chair

Electric vehicles (EV) have been gaining more popularity in the consumer market in recent years due continuous improvements in purchase price and driving range, thus amplifying environmental benefits and lower operating costs. While more public charging stations have been installed to cater to increasing numbers of electric vehicle users, charging demand has outpaced supply, especially at early adopter locations such as university campuses. Station overstay – when an EV remains plugged-in after completion of charging – adds to the shortage of charging opportunities as stations remain unusable while the parking space is occupied by a fully charged vehicle . Understanding user behavior is essential to develop a solution to solve station overstay.In this analysis, the effect of meteorological factors and school/work schedule on EV user behavior and overstay patterns was examined using charging data collected from EV charging stations at the University of California San Diego (UCSD). The statistics for duration and hourly rate of overstay were determined for different campus areas. Overstay patterns during school and non-school days were also examined to determine the impact of school/work schedules. The effect of high daytime temperature and rainfall on overstay was analyzed through comparison of overstay occurrence during these weather events with that observed during other weather conditions. The analysis showed that overstay at UCSD’s EV charging stations was found to be primarily influenced by school/work schedules of EV users. Most areas of the campus saw an increase in station overstay during the busiest hours on campus (9AM to 5PM) and on school days. On the hottest days, depending on the campus area, overstay was higher by 5-51% when daytime temperatures were very high. Station overstay during hours with heavy rainfall was 7-40% lower than when there was no rainfall.