Electricity costs for an electric vehicle fueling station with Level 3 charging

Abstract

Three major perceived disadvantages of plug-in electric vehicles are limited driving range, slow recharge time, and availability of charging infrastructure. While increasing PEV range through larger and more efficient batteries may assuage concerns, public PEV charging infrastructure is required to increase the feasibility of widespread PEV adoption. In particular, Level 3 electric vehicle supply equipment (EVSE) can refuel a depleted PEV battery to 80% state of charge in half an hour. This work examines details of exact electric utility costs incurred by the operator of a public Level 3 EVSE used to refuel PEVs that perform two of the most common types of travel: driving to work and driving to shop. Both 44kW and 120kW EVSE refueling rates are considered. Utility rate models for Southern California are used to determine the cost of electricity. Cooperative game theory is then used to determine of the electrical demand charge incurred by each individual PEV that is charged. Results show that approximately 28–38% of typical travel results in a battery state of charge low enough to be eligible for Level 3 refueling. At low PEV total use, electric utility demand charges comprise an extremely high portion of electricity costs. Increasing PEV total use decreases demand charge contributions to the electricity costs, but must be coupled with parking management, such as valet parking, when dwell time at the destination is long (e.g., at work). Total energy costs to operate 44kW Level 3 EVSE exceed $1 per kWh at low PEV use, but decrease as PEV use increases. The lowest costs occurred at the highest level of PEV use examined, resulting in a total energy cost of approximately $0.20 per kWh during the summer and $0.13 per kWh during the winter. Parking management may be avoided if multiple EVSE are installed, which is particularly effective in improving access for travel with a short dwell time (e.g., while shopping). Increasing EVSE refueling rate improves access to PEV refueling only if parking management is implemented, but always increases demand charges.