Crucial Communication

Need for communication protocols for electric mobility ecosystem

Sahana L, Junior Technical Expert, NDC-TIA India Component, GIZ

Communication in the e-mobility ecosystem refers to the unidirectional flow of information or bidirectional data exchange between two or more entities to ensure successful electric vehicle (EV) charging demand management and efficient integration of EVs with the grid. Effective and efficient information flow in the EV ecosystem is essential for secure, smooth and optimal operational activities. Communication includes the exchange of information between the EV and electric vehicle supply equipment (EVSE), between EVSE and charge point operator (CPO), between CPO and electric Mobility Service Provider (eMSP), between eMSP and the distribution system operator (DSO). There is a need for fast, reliable and secure communication between these entities for efficient management of the charging process. For each different communication layer, different communication protocols have been developed, with each protocol having its own sets of functionalities. Various communication protocols are necessary for the implementation of V1G (unidirectional controlled charging/managed charging), grid-to-vehicle (G2V) and vehicle-to-grid (V2G) technologies.

In EV rich countries, different combinations of communication protocols have been in place, including different protocols for similar functionality. It was observed that there were multiple occurrences of the same protocol between different stakeholders in the EV domain indicating the multifunctionality of the protocols. Presently in India, communication standards have only been mentioned for communication between EVSE and the CPO, however, the requirement of communication between the other relevant stakeholders in the EV domain is yet to be established. Due to a lack of adequate communication infrastructure, standards and protocols, currently, there is no provision of roaming facility for the EV user or the distribution company (DISCOM) to control the load. Smart charging, demand response and vehicle-to-everything (V2X) applications cannot be implemented without suitable communication protocols.

Functions and supporting roles of EV related communication protocols

For the management of EV charging, there is a need for communication and coordination among the various mobility and energy entities in the EV ecosystem. The critical hurdle in this journey is that many companies are developing proprietary communication protocols which could hinder interoperability and grid integration of EV charging infrastructure. Open protocols are also important for optimising the utilisation of EV load to provide flexibility in grid management.

The detailed communication flow of the entire chain between EV and DSO is as given below in Figure 1:

Figure 1: Communication links in EV ecosystem

Source: Elaadnl (2017) – EV Related Protocol Study

Integration of EV into distribution grid impacts the stability and voltage security of a grid. To protect the grid from instability, an exchange of information between the charge point and the distribution operator is necessary to perform smart charging. The information of available capacity and system limits are crucial in this regard. This information from DSO can be passed to the charging operator, but if it is not correctly interpreted or if ignored, it can lead to problems eventually resulting in grid failure.

The communication links between different charging participants with the specific standard and protocol used for communication are shown in Figure 1, where solid lines show the function-specific protocol, whereas the dotted lines show the generic protocols that can be adopted for different functionalities. Combinations of different protocols are also used to achieve the smart environment. Communication promotes bidirectional charging, real-time data exchange, and smart control environment. The communication between EV and DSO is a combination of different operation-specific and open protocols.

Table: Summary of communicating entities, protocols and data transferred in EV ecosystem

Communicating Entity 1 Communicating Entity 2 Communication Protocols Data transferred
EV EVSE ISO 61851-1

ISO 15118-2

Connector Communication – (CAN bus and PLC communication)

Information of the EV model, manufacturing specifications, SoC level of the battery, maximum allowable current, and power ratings
EVSE CPO OCPP 1.5/1.6/2.0

IEC 61850-90-8

IEC 61851-1

Open ADR and IEEE 2030.5

 

EV model specifications, SoC level, DOD level of battery, maximum allowable current limits, parking time, type of connector, charging type,

charging permission and charging power signal

CPO eMSP OCHPdirect

OICP

 

Communication via Clearinghouse

 

Open ADR and IEEE 2030.5

 

Authentication requests of EVs, charging time-related information, charging point information (address, location, type), time interval, charge point status and availability, transaction and billing information, tariff, connector type, voltage, reservation details, and timestamp of the last update
CPO Clearinghouse OCHP

OICP

eMIP

Open ADR and IEEE 2030.5

Authentication requests of EVs, charging time-related information, charging point information (address, location, type), time interval, charge point status and availability, transaction and billing information, tariff, connector type, voltage, reservation details, and timestamp of the last update
Clearinghouse eMSP OCHP

OICP

eMIP

eMSP DSO OSCP Real-time updates of energy required by EVs for charging, energy data and time
OpenADR and IEEE 2030.5 Demand response operations based on the load demand and the maximum available generation
EVSE DSO IEC 61850-90-8

(technical report and not a protocol in itself)

Chargepoint information, reservation of power, energy data
CPO DSO OSCP

IEC 608070-5-104

OpenADR and IEEE 2030.5

Real-time updates of energy required by the EVs for charging, energy data and time

Demand response operations based on the load demand and the maximum available generation

Source: IIT Bombay and GIZ India research

Detailed information on each of the protocols can be obtained from Chapter-4 (Page 59) of Report 1 – ‘Fundamentals of Electric Vehicle Charging Technology and its Grid Integration’.

International practices on implementation of EV standards and communication protocols

Presently in the US, consumers are facing interoperability issues with regard to the connectors used. For example, the Level 2 chargers use the standardised SAE J-1772 connector while for DC fast chargers, there are mostly 3 types of connectors used namely; CHAdeMO (Nissan, Mitsubishi), CCS (remaining Asian, all American and European car manufacturers) and Tesla’s proprietary connector (MJB&A, 2019). In Germany, it is mandated that any AC (≥ 3.7 kW) charging station should be equipped with a Type 2 connector and any DC (> 22 kW) charging station should be equipped with a Combo 2 connector to facilitate interoperability (Maarten Venselaar, 2019).

Roaming is a service that allows the EV to charge at any charging station irrespective of the contracted mobility service provider. To achieve roaming for increased interoperability, roaming protocols with the desired functionalities are introduced globally. Among all the available roaming protocols, four protocols namely Open clearing house protocol (OCHP), Open charge point interface protocol (OCPI), Open intercharge protocol (OICP), and E-Mobility interoperation protocol (eMIP) are majorly adopted for EV roaming and used primarily in Europe (Mart van der Kam, 2020). A large portion of the public charging network in the US is managed by charging service providers and they operate on a variety of business models. As a result, each one has a proprietary software that offers different pricing structures and service offerings to subscribers and non-subscribers (EPRI, 2019).

The Netherlands was one of the first countries to introduce interoperability in terms of payment mechanism for EV users. Presently, an EV user in the Netherlands can charge his EV from any public charging station using a single RFID card (MJB&A, 2019). In the UK, there are mostly two types of payment methods available to the consumers: subscription method using RFID cards or pay as you go (PAYG) option. Still, a majority of the EV users use RFID cards of the CPO that they have subscribed to and the PAYG option is rare. The UK government is encouraging CPOs to provide the dual option to consumers in recent times. The counter argument to providing the PAYG option is that it reduces customer relationship and loyalty to the CPO network (Keith Chamberlain, 2021). The support for harmonised roaming charge point system known as EV roaming or charge point roaming is growing in the UK.

Considering that there is a need for a common communication protocol between the EV and EVSE to enable bidirectional smart charging for V2X applications, the communication ISO 15118 is under discussion to become a long term solution in Germany. The key relevant feature of ISO 15118 is the use of digital certificates for security and enabling secure exchange of tariff and metering data (Maarten Venselaar, 2019). California Public Utilities Commission has specified that the IEEE 2030.5 standard is the default protocol for utilities to communicate with distributed energy resource (DER) and in future when EVs are capable of providing grid services then they will also be considered as DER (EPRI, 2018).

Conclusion

Many countries are apprehensive of mandating common communication protocols since many standards and protocols are in the development stage and not yet finalised. Yet it is necessary to achieve a minimum level of interoperability which would facilitate in providing a wider network of an EV charging network for the users and augment EV uptake. Interoperability provides freedom of choice to the consumer and creates a level playing field for fair competition among the charging service providers. Ultimately, this would result in reaching competitive prices for EV charging services.

In India, by 2030, more than 30 per cent of new vehicles are expected to be EVs (IEA, 2020) and within a decade, the country is likely to experience a major challenge of coordinating EV charging for millions of EVs. Smart charging will play a crucial role to accommodate higher EV penetration with the least possible grid upgradation cost implications. In this regard, communication protocols are essential to ensure interoperability between the key entities in the e-mobility ecosystem. In the next article, we will present more details on how India could approach this challenge of implementing EV communication protocols.

This article is the second of series of articles related to various aspects of grid integration of EVs in India. The next article of this series will delve deeper into the status quo on communication protocols applicable in India and the future outlook for India.

GET ACCESS TO OUR ARTICLES

Enter your email address