Cooperation and coordination on the technical protocols and standards used for charging facilities will be essential for widespread adoption of electric vehicles, according to a paper released Wednesday.
Interoperability across a widespread, open-access public charging infrastructure will be essential to support EV drivers beyond early adopters, according to the white paper, Interoperability of Public Electric Vehicle Charging Infrastructure. The paper is a collaborative effort of the Electric Power Research Institute, the American Public Power Association, the Edison Electric Institute, the Alliance for Transportation Electrification, and the National Rural Electric Cooperative Association.
The paper identifies four key challenge areas related to interoperability, which it defines as the ability of multiple systems to work together without restriction. Those four areas are: interactions between charging networks, interactions between a charging station and a charging network, interactions between an electric vehicle and the electric distribution network, and incompatible physical designs of direct current (DC) charging interfaces.
According to the paper, public charging infrastructure has developed through a patchwork of grant funding, settlement funds, private investment, and electric company pilots and programs, which has resulted in a variety of standards that can hinder the proliferation of public charging stations and create confusion among consumers.
“This is a helpful guidepost for all industry players to ensure we look before we leap in implementing major changes, and to consider where other communities are moving so that we can take a smart approach together,” said Mike Hyland, senior vice president of engineering services at the American Public Power Association.
The paper notes a number of challenges or concerns that utilities and other potential electric vehicle service providers might face due to the lack of interoperability.
The paper calls for network-to-network charging ability through development of a common platform and a single network subscription or contract, often called “e-roaming,” that EV drivers would be able to access. This would allow EV drivers to access public charging stations run by any owner/operator, in the same way cell phone users can use a variety of cellular networks regardless of the kind of mobile device they use.
A related challenge is interoperability between charging stations and networks. Proprietary protocols can lock vendors, typically charging station owners, into a closed-network provider for the lifetime of the charging equipment. The paper asserts that such arrangements can limit competition and innovation by forcing vendors to purchase new equipment if they want to change network service providers. Efforts to integrate charging networks and make them interoperable are already under way through standards such as the Open Charge Point Protocol, which is widely used in Europe and is gaining acceptance in the U.S.
The lack of interoperability in EV charging networks inhibits the ability of electric utilities to manage public charging infrastructure securely, cost-effectively, and reliably, while also planning for future public charging growth.
The paper also points out that there is not a single standard interface for DC EV charging, and three different types of EV charge ports are in use today, which increases operational complexity and costs and can lead to customer confusion.
Unless interoperability issues are addressed, the paper argues, U.S. public charging infrastructure will continue to scale along “fragmented and inefficient paths, potentially resulting in higher costs, less than optimum customer experience, and stranded investments.”
The paper notes that a recent EEI/Institute for Electric Innovation report estimates that nearly one million public charging ports will be needed in the U.S. by 2030 to support nearly 19 million electric vehicles, and that fewer than 100,000 ports are currently available, many of which impose limits on their access and use.
