Reliability of Open Public Electric Vehicle Direct Current Fast Chargers

Abstract

Objective

The aim was to systematically evaluate the usability of all public electric vehicles (EV) direct current fast chargers (DCFC) in the San Francisco region.

Background

To achieve a rapid transition to EVs, a highly reliable and easy to use charging infrastructure is critical to building confidence among consumers.

Methods

The functionality and usability of all 182 open, public DCFC charging stations with CCS connectors (combined charging system) in the 9 counties of the Bay Area were tested (655 electric vehicle service equipment (EVSE) ports). An EVSE was classified as functional if it charged an EV for 2 minutes.

Results

Overall, 73.3% of the 655 EVSEs were functional. The causes of the nonfunctioning EVSEs (23.5%) were blank or unresponsive screens or error messages; payment system failures; charge initiation failures; network failures; or broken connectors. In addition, the cable was too short to reach the EV inlet for 3.2% of the EVSEs. A random sampling of 10% of the EVSEs, approximately 8 days after the first evaluation, found no overall change in functionality.

Conclusions

The level of functionality found with field testing conflicts with the 95–98% uptime reported by the EV service providers (EVSPs) who operate the EV charging stations. There is a need for precise and verifiable definitions of uptime, downtime, and excluded time, as applied to public EV chargers.

Application

The level of failure of the existing public EV DCFC charge infrastructure highlights the importance of improving the system design and maintenance to improve adoption of EVs.

Keywords

electric vehicle charging infrastructure renewable energy zero emission vehicles

Get full access to this article

View all access options for this article.

References

Alinia

Hajiesmali

M. H.

Crespi

(2019). Online EV charging scheduling with on-arrival commitment. IEEE Transactions on Intelligent Transportation Systems, 20, 4524–4537. https://doi.org/10.1109/TITS.2018.2887194.

Alliance for Automotive Innovation . (2022). Planning for the electric future: Charging station attributes. https://www.autosinnovate.org/about/advocacy/Recommended_Attributes_for_EV_Charging_Stations_09DEC2021.pdf (Accessed March 3, 2022).

CARB . (2022b). Final regulation order, attachment A. https://ww2.arb.ca.gov/sites/default/files/2020-06/evse_fro_ac.pdf (Accessed March 3, 2022).

CARB . (2022a). Electric vehicle supply equipment standards technology review. California Air Resources Board.

CEC . (2021). GFO-21-604- clean transportation program rural electric vehicle (REV) charging. California Energy Commission.

CPUC . (2006). California energy efficiency evaluation protocols: Technical, methodological and reporting requirements for evaluation professionals. http://www.calmac.org/events/EvaluatorsProtocols_Final_AdoptedviaRuling_06-19-2006.pdf

DOE . (2022). Evaluation, measurement and verification. https://www.energy.gov/sites/prod/files/2014/05/f16/what_is_emv.pdf (Accessed March 20, 2022)

Fabianek

Madlener

(2023). Multi-Criteria assessment of the user experience at E-Vehicle charging stations in Germany. Transportation Research Part D: Transport and Environment, 121, 103782. https://doi.org/10.1016/j.trd.2023.103782.

FHWA . (2022). The national electric vehicle infrastructure formula program guidance (p. 22). US DOT Federal Highway Administration. https://www.fhwa.dot.gov/environment/alternative_fuel_corridors/nominations/90d_nevi_formula_program_guidance.pdf

10.

FHWA . (2023). National electric vehicle infrastructure standards and requirements. Federal highway administration. Federal Register, 88(39), 12724–12757.

11.

Hardman

Tal

(2021). Understanding discontinuance among California’s electric vehicle owners. Nature Energy, 6, 538–545. https://doi.org/10.1038/s41560-021-00814-9.

12.

Henderson

Grace

Gulbransen-Diaz

Klaassens

Leong

T. W.

Tomitsch

(2023). From parking meters to vending machines: A study of usability issues in self-service technologies. International Journal of Human–Computer Interaction, 1–15. https://doi.org/10.1080/10447318.2023.2212228.

13.

Jonas

Daniels

Macht

(2023). Electric vehicle user behavior: An analysis of charging station utilization in Canada. Energies, 16(4), 1592. https://doi.org/10.3390/en16041592.

14.

NESCAUM . (2019). Building reliable EV charging networks: Model state grant and procurement contract provisions for public EV charging. Northeast States for Coordinated Air Use Management. https://www.nescaum.org/documents/model-contract-provisions-for-public-evse-5-24-19.pdf/

15.

NREL . (2022). Charging infrastructure terminology. https://afdc.energy.gov/fuels/electricity_locations.html#/find/nearest?fuel=ELEC; https://afdc.energy.gov/fuels/electricity_infrastructure.html (Accessed March 3, 2022).

16.

NREL AFDC . (2022). Electric vehicle charging station locations. https://afdc.energy.gov/fuels/electricity_locations.html#/find/nearest?fuel=ELEC (Accessed March 3, 2022).

17.

NYSERDA . (2021). DCFC program, program opportunity notice (PON) 4509. https://portal.nyserda.ny.gov/servlet/servlet.FileDownload?file=00Pt000000YDm19EAD (Accessed March 3, 2022).

18.

OCPI 2.2-RC1 . (2019). Open Charge Point Interface, version 2.2-d2. https://evroaming.org/app/uploads/2019/02/OCPI-2.2-RC1.pdf (Accessed March 23, 22)

19.

ORNL . (2004). A toolkit of reliability measurement practices. Oak Ridge National Laboratory. https://info.ornl.gov/sites/publications/Files/Pub57467.pdf

20.

Pevic

Babic

Carvalho

Ghiassi-Farrokhfal

Ketter

Podobnik

(2020). A survey-based assessment of how existing and potential electric vehicle owners perceive range anxiety. Journal of Cleaner Production, 276, 122779. https://doi.org/10.1016/j.jclepro.2020.122779.

21.

Plug In America . (2022). The expanding EV market. Observations in a year of growth.

22.

Rogers

Cabrera

Walker

Gilbert

Fisk

(1996). A survey of automated teller machine usage across the adult lifespan. Human Factors, 38(1), 156–166.

23.

Rogers

W. A.

Fisk

A. D.

(1997). ATM design and training issues. Ergonomics in Design, 5(1), 4–9. https://doi.org/10.1518/001872096778940723.

24.

SAE . (2022). SAE electric vehicle and plug in hybrid electric vehicle conductive charge coupler. J1772_201710. https://www.sae.org/standards/content/j1772_201710/ (Accessed March 28, 2022).

25.

Savari

G. F.

Sathik

M. J.

Raman

L. A.

El-Shahat

Hasanien

H. M.

Almakhles

Aleem

S. H. E. A.

Omar

A. I.

(2023). Assessment of charging technologies, infrastructure and charging station recommendation schemes of electric vehicles: A review. Ain Shams Engineering Journal, 14(4), 101938. https://doi.org/10.1016/j.asej.2022.101938

26.

Shahriar

Al-Ali

A. R.

Osman

A. H.

Dhou

Nijim

A. M.

(2021). Prediction of EV charging behavior using machine learning. IEEE Access, 9, 111576. https://doi.org/10.1109/ACCESS.2021.3103119.

27.

Thorgeirsson

A. T.

Scheubner

Funfgeld

Gauterin

(2020). An Investigation into key influence factors for the everyday usability of electric vehiclews. IEEE Open Journal of Vehicular Transportation. https://doi.org/10.1109/OJVT.2020.3031699.

28.

Vaidya

Mouftah

H. T.

(2020). Smart electric vehicle charging management for smart cities. IET Smart Cities. https://doi.org/10.1049/iet-smc.2019.0076.

29.

Yim

Kim

(2023). Design guidelines for future electric vehicle charging stations. In Taratukhin

Levchenko

Kupriyanov

(Eds.), Information systems and design. ICID 2022. Communications in computer and information science (Vol. 1767). Springer. https://doi.org/10.1007/978-3-031-32092-7_11