Principle Investigator: Gil Tal
Co-Principle Investigator: Alan Jenn
Project Manager: Erinne Boyd
Project Funder: California Energy Commission (CEC)
The reliability of the public charging infrastructure in California is critical to facilitating the adoption and utilization of electric vehicles (EVs) in order to meet the state’s zero-emission vehicle sales and emissions reductions goals. Currently, there are at least two perspectives with regards to reliability - that of the electric vehicle service provider (EVSP) and that of the customer. This project aims to investigate and understand the difference in these measurements, the cause of any reliability or charging failures, and provide potential solutions for providers to maximize the reliability of chargers. This project will be focused on Direct Current Fast Chargers (DCFCs) in California, and will separately explore the charging reliability experience in different communities in California including urban, rural, and low-income communities (LIC) and disadvantaged communities (DACs). A small sample of Level 2 (L2) chargers will be evaluated to determine if more investigation is needed.
BACKGROUND/PROBLEM STATEMENT
California currently has more than 3,000 publicly available DCFCs and nearly 30,000 L2 public chargers, numbers that are expected to grow dramatically in coming years. For EV drivers, charging infrastructure reliability means the ability to successfully use the infrastructure to charge their EVs with ease and certainty. The reliability of public chargers is crucial to the success of transitioning to EVs and transforming the transportation system to be electrically fueled to support California’s emissions and zero-emission vehicle sales goals.
In an electrical system, reliability measures the degree to which the performance of the system results in electricity being transferred to the customer in the amount the charger was designed to deliver. Therefore, from the perspective of an EV driver, a reliable charger successfully charges their EV, for the expected duration, at an expected rate, after accepting an appropriate payment method. However, from the perspective of most EVSPs, a reliable charger is typically one that meets the minimum uptime requirement of its jurisdiction. Uptime, the most commonly used charging reliability metric, is a measure of the time during which a charger is online and available for operation. This metric does not consider all of the possible technological and logistical challenges within the charging ecosystem that ultimately 1) determine the true reliability of chargers and 2) reflect consumer experiences. Since the definition of charger reliability may differ between consumers and EVSPs, there may be a discrepancy between uptime reported by EVSPs and user satisfaction scores reported by consumers. This study will measure the failures and explore the issue of reliability more holistically from the perspective of the driver.
GOALS/OBJECTIVES OF THE AGREEMENT
The goal of this agreement is to understand the reliability of the public charging infrastructure in California from the perspective of EV drivers. This agreement will examine the failure rate, and reason for failure, and any incompatibility or interoperability issues that arise through direct vehicle and charger testing.
Failure rates will be measured by testing EV chargers operating in California using a standardized testing protocol developed as part of this agreement. Data collected by field testers will be aggregated and analyzed to determine common failure modes and the elements of the charging ecosystem associated with them. Where feasible, repeat tests will be conducted to understand the time to repair failures. Success will be measured by completing the required number of tests, with minimal error rate, such that the data can inform the California Energy Commission (CEC) about the reliability of EV chargers in various communities (rural, urban, DAC, and LIC) throughout the state.