Four challenges that face EV charging station adoptionDavid Wagman | August 09, 2019
The Electric Power Research Institute, the Edison Electric Institute, the Alliance for Transportation Electrification, the American Public Power Association and the National Rural Electric Cooperative Association issued a white paper that identifies challenges and recommendations to enable greater interoperability and standardization of U.S. electric vehicle (EV) charging.
The paper, Interoperability of Public Electric Vehicle Charging Infrastructure, addresses four challenges and how each may impact customers, site hosts and electric companies:
- Charging network-to-charging network interoperability
- Charging station-to-network interoperability
- Physical charging interface interoperability
- Vehicle-grid interoperability
The eight-page paper frames interoperability as the "harmonizing of standards, technology and practices" for EV charging.
Charging network-to-charging network: The paper said that EV service providers tend to operate their networks as islands that lack communication or integration with other networks. In the current context, interoperability refers to a vision in which EV drivers can access public charge points from any owner/operator through a common platform and a single network subscription or contract (also called “e-roaming”).
The paper said that this sort of customer-friendly, public charging infrastructure depends on a web of business-to-business contracts between network providers and interoperability among their respective back-end systems. The structure could be similar to the interoperability of financial and banking systems to enable interbank and cross-border automated teller machine usage and mobile roaming capabilities enabled by interoperability among multiple wireless telecommunication networks.
Charging station-to-network: The paper said that networked charging stations must communicate with their supporting networks. Proprietary protocols can create “vendor lock-in” challenges that commit customers to a single, closed-network provider for the lifetime of the charging equipment.
An open standards-based approach that includes both technical capabilities and contractual rights would allow owner-operators to switch between network service providers without having to buy new charging stations and to install new charging stations without having to change network service providers. The report said that this can help stimulate competition and protect infrastructure investments against obsolescence.
The report said that the Open Charge Point Protocol (OCPP) is an open networking standard that is widely used in Europe and is growing in acceptance in the U.S. It said that while current versions (OCPP 1.5, 1.6 and 2.0) exhibit functionality gaps, their acceptance by most network providers and continued development may be important to addressing network interoperability.
Physical charging interface: The white paper said that a single standard for common AC charging is widely accepted in the U.S. (with Tesla vehicles requiring an adaptor), three different DC charge ports are used today. Issues with fragmentation of the early Level 2 AC charging market were mitigated by adoption of the SAE J-1772 standard. This provides automakers and those deploying charging infrastructure with a common system architecture. Meanwhile, the report said the lack of a single accepted standard for DC charging for light duty EVs increases operational complexity and costs, and can lead to customer confusion as public DC fast charging expands.
Vehicle-grid: Collaboration among EV and charging station manufacturers, network operators, site hosts and electric companies will be necessary, the report said, to implement emerging vehicle-grid integration technologies. At present, electric companies and grid operators are limited in their engagement to support secure, cost-effective, reliable public charging stations at scale by the lack of interoperability among networked systems and limited implementation of open protocols for electric company communications.
The paper also outlined four collaborative areas of focus necessary in building a charging system that offers convenience, confidence and security:
- Implementing a standard protocol for business-to-business connectivity that facilitates consumer roaming among charging networks or protocol for credit, debit or pre-paid card users.
- Implementing open, nonproprietary protocols that enable interchangeable services and operations among charge stations and networks.
- Adopting a single DC charging system, or alternative solutions to facilitate interoperability for light duty EVs (cars and small trucks) to improve charging access and efficiently scale infrastructure.
- Developing and implementing open standards to manage charging based on grid conditions.