ISO/TS 21219-25:2017

Intelligent transport systems - Traffic and travel information (TTI) via transport protocol experts group, generation 2 (TPEG2) - Part 25: Electromobility charging infrastructure (TPEG2-EMI)

ISO/TS 21219-25:2017 defines the TPEG application electromobility charging infrastructure (EMI). It has been specifically designed to support information about charging infrastructure for electric vehicles (not just cars), the location of e-charging points and their suitability for the respective vehicle (e.g. connector type, charging modality). As electric vehicles will occupy a "charging space" for a longer period of time, information on availability/waiting time and reservation options are highly relevant for a user of an electric vehicle to optimally plan his route/trip and are therefore also accounted for. The standardized delivery, through a TPEG technology, of information on charging infrastructures has the following benefits to an end user of this TPEG service: a) Identifying suitable charging units for his vehicle, thus preventing unnecessary driving around to find a fitting unit (also has environmental benefits). b) Verifying the real-time availability of charging units. c) Being able to plan ahead and reserve a spot in a charging park and thus optimize the planning of his trip. d) Being able to select a financially attractive charging point in a charging park the operator of which has billing agreements with the user's electromobility provider. In addition to these end-user benefits, also electromobility providers and charging park operators benefit from a standardized TPEG format as it allows an easier harmonization of the electromobility charging infrastructure information with the data formats used for the exchange of information between management systems of electromobility providers and charge park operators and according specifications (e.g. Open Charge Alliance[1], eMobility ICT Interoperability Innovation (eMI3)[2], etc.). The TPEG application electromobility charging infrastructure, as add-on service component next to, for example traffic information, is laid out to support large numbers of charge parks with only modest bandwidth requirements. [1] http://www.openchargealliance.org/ [2] http://emi3group.com/

Systèmes intelligents de transport — Informations sur le trafic et le tourisme via le groupe expert du protocole de transport, génération 2 (TPEG2) — Partie 25: Infrastructure pour l'alimentation en électromobilité (TPEG2-EMI)

General Information

• Status: Published
• Publication Date: 12-Jan-2017
• ICS: 03.220.01 - Transport in general
• ICS: 35.240.60 - IT applications in transport
• Technical Committee: ISO/TC 204 - Intelligent transport systems
• Drafting Committee: ISO/TC 204/WG 10 - Traveller information systems
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 13-Dec-2024
• Completion Date: 13-Dec-2025

Relations

• Revised: ISO 21219-25:2024 - Intelligent transport systems - Traffic and travel information (TTI) via transport protocol experts group, generation 2 (TPEG2) - Part 25: Electromobility charging infrastructure (TPEG2-EMI)
• Effective Date: 06-Jun-2022

Overview

ISO/TS 21219-25:2017 - also published as TPEG2-EMI - specifies the TPEG (Transport Protocol Experts Group) application for electromobility charging infrastructure information. It defines how to encode and deliver structured data about electric vehicle (EV) charging parks, stations and points so that navigation systems, telematics, and ITS services can provide accurate, timely charging information to drivers and fleet managers.

Key search terms: ISO/TS 21219-25:2017, TPEG2-EMI, electromobility charging infrastructure, TPEG2, intelligent transport systems, EV charging, charging point availability.

Key topics and technical requirements

• Information scope: Location of charging parks/stations/points, connector types, charging modalities, suitability for specific vehicle types, pricing/billing models, operator contact details and logos.
• Dynamic data support: Real‑time availability, free places per connector type, waiting times and reservation request/response mechanisms to plan and secure charging slots.
• Message architecture: Defined message components (e.g., EMIMessage, ChargingParkLocation, ChargingParkAvailabilityVector, ReservationRequest/Response) and structured datatypes to standardize payloads.
• Data modelling and formats: UML-based TPEG2 modelling with two physical representations-TPEG-Binary and TPEG-ML (XML)-shown in normative annexes for efficient transmission and parsing.
• Operational constraints: Ordered components, version signalling, extension mechanisms and considerations for aggregation level (park vs station vs point), and separation of static vs dynamic information to optimize bandwidth.
• Scalability and bandwidth: Designed to support large numbers of charging parks while keeping bandwidth modest for broadcast and cellular delivery.
• Interoperability: Alignment with electromobility exchange specifications (e.g., Open Charge Alliance, eMI3) to ease harmonization between operators and service providers.

Applications and who uses it

• EV navigation and route‑planning apps that identify compatible charging units and offer real‑time availability.
• Telematics and fleet management systems for optimizing charging schedules and minimizing downtime.
• Charging park operators and electromobility service providers for publishing standardized station data, availability and reservation interfaces.
• ITS data broadcasters and content aggregators delivering TTI (traffic and travel information) as add‑on services.
• Developers implementing TPEG2 receivers/decoders and system integrators aligning back‑end management systems.

Related standards

• ISO/TS 21219 series (TPEG2 core rules and location referencing)
• TPEG-Binary and TPEG-ML representations (annexes in ISO/TS 21219-25)
• Open Charge Alliance specifications
• eMI3 (eMobility ICT Interoperability Innovation) guidelines

ISO/TS 21219-25:2017 helps ensure EV users and operators benefit from standardized, interoperable charging information - improving trip planning, reducing unnecessary driving, and enabling efficient use of charging infrastructure.

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 21219-25
First edition
2017-02
Intelligent transport systems —
Traffic and travel information (TTI)
via transport protocol experts group,
generation 2 (TPEG2) —
Part 25:
Electromobility charging
infrastructure (TPEG2-EMI)
Systèmes intelligents de transport — Informations sur le trafic et le
tourisme via le groupe expert du protocole de transport, génération 2
(TPEG2) —
Partie 25: Infrastructure pour l’alimentation en électromobilité
(TPEG2-EMI)
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviated terms . 3
5 Application specific constraints . 4
5.1 Application identification . 4
5.2 Version number signalling . 4
5.3 Ordered components . 4
5.4 Extension . 5
5.5 TPEG Service Component Frame. 5
6 EMI structure . 5
6.1 Overview . 5
6.2 EMI structuring considerations . 6
6.2.1 Information aggregation level: Charging parks, charging stations,
charging points . 6
6.2.2 Static vs. dynamic information: Charging park information, charging
park availability . 7
6.2.3 Request and response . 8
6.3 Pricing information .10
6.4 EMI message structure.11
7 EMI message components .16
7.1 EMIMessage .16
7.2 MessageManagementContainerLink.17
7.3 ChargingParkLocation .17
7.4 ChargingParkAvailabilityVector .17
7.5 ChargingParkInformation .18
7.6 ChargingStationInformation .19
7.7 DetailedChargingParkLocation .19
7.8 ParkEntryLocation .20
7.9 ParkExitLocation .20
7.10 DetailedChargingStationLocation .20
7.11 StationLocation .20
7.12 EMIMessageRequest .20
7.13 MessageManagementContainerLinkRequest .21
7.14 ReservationRequest .21
7.15 ReservationResponse .23
8 EMI Datatypes .24
8.1 ChargingParkAvailability .24
8.2 ChargingStationAvailability .25
8.3 FreePlacesForConnectorType .25
8.4 ChargingParkSiteDescription .25
8.5 Logo .26
8.6 OperatorContactInformation .26
8.7 SizeRestrictions .27
8.8 PricingInformation .27
9 EMI Tables .27
9.1 emi001:BillingModel .27
9.2 emi002:Connect orType .28
9.3 emi003:Qualifier .28
9.4 emi004:P aymentMethodType .29
9.5 emi005:F acilityType .29
9.6 emi006:Associat edServiceType .29
9.7 emi007:UserT ype .30
9.8 emi008:StationT ype .30
9.9 emi009:V ehicleType .31
9.10 emi010:R eservability .31
9.11 emi011:ContactT ype .31
Annex A (normative) TPEG application, TPEG-Binary Representation .32
Annex B (normative) TPEG application, TPEG-ML representation.47
Bibliography .61
iv © ISO 2017 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www . i so .org/ iso/ foreword .html.
The committee responsible for this document is ISO/TC 204, Intelligent transport systems.
A list of all parts in the ISO/TS 21219 series can be found on the ISO website.
Introduction
History
TPEG technology was originally proposed by the European Broadcasting Union (EBU) Broadcast
Management Committee, who established the B/TPEG project group in the autumn of 1997 with a brief
to develop, as soon as possible, a new protocol for broadcasting traffic and travel-related information
in the multimedia environment. TPEG technology, its applications and service features were designed
to enable travel-related messages to be coded, decoded, filtered and understood by humans (visually
and/or audibly in the user’s language) and by agent systems. Originally, a byte-oriented data stream
format, which may be carried on almost any digital bearer with an appropriate adaptation layer,
was developed. Hierarchically structured TPEG messages from service providers to end-users were
designed to transfer information from the service provider database to an end-user’s equipment.
One year later, in December 1998, the B/TPEG group produced its first EBU specifications. Two
documents were released. Part 2 (TPEG-SSF, which became ISO/TS 18234-2) described the Syntax,
Semantics and Framing structure, which was used for all TPEG applications. Meanwhile, Part 4 (TPEG-
RTM, which became ISO/TS 18234-4) described the first application for Road Traffic Messages.
Subsequently, in March 1999, CEN/TC 278, in conjunction with ISO/TC 204, established a group
comprising members of the former EBU B/TPEG and this working group continued development work.
Further parts were developed to make the initial set of four parts enabling the implementation of a
consistent service. Part 3 (TPEG-SNI, ISO/TS 18234-3) described the Service and Network Information
Application used by all service implementations to ensure appropriate referencing from one service
source to another.
Part 1 (TPEG-INV, ISO/TS 18234-1) completed the series by describing the other parts and their
relationship; it also contained the application IDs used within the other parts. Additionally, Part 5, the
Public Transport Information Application (TPEG-PTI, ISO/TS 18234-5), was developed. The so-called
TPEG-LOC Location Referencing method, which enabled both map-based TPEG-decoders and non-map-
based ones to deliver either map-based Location Referencing or human readable text information,
was issued as ISO/TS 18234-6 to be used in association with the other applications parts of the
ISO/TS 18234 series to provide location referencing.
The ISO/TS 18234 series has become known as TPEG Generation 1.
TPEG Generation 2
When the Traveller Information Services Association (TISA), derived from former forums, was
inaugurated in December 2007, TPEG development was taken over by TISA and continued in the TPEG
applications working group.
It was about this time that the (then) new Unified Modelling Language (UML) was seen as having major
advantages for the development of new TPEG Applications in communities who would not necessarily
have binary physical format skills required to extend the original TPEG TS work. It was also realized
that the XML format for TPEG described within the ISO/TS 24530 series (now superseded) had a greater
significance than previously foreseen, especially in the content-generation segment and that keeping
two physical formats in synchronism, in different standards series, would be rather difficult.
As a result, TISA set about the development of a new TPEG structure that would be UML based. This has
subsequently become known as TPEG Generation 2.
TPEG2 is embodied in the ISO/TS 21219 series and it comprises many parts that cover introduction,
rules, toolkit and application components. TPEG2 is built around UML modelling and has a core of rules
that contain the modelling strategy covered in ISO/TS 21219-2, ISO/TS 21219-3, ISO/TS 21219-4 and
the conversion to two current physical formats: binary and XML; others could be added in the future.
TISA uses an automated tool to convert from the agreed UML model XMI file directly into an MS Word
document file, to minimize drafting errors, that forms the annex for each physical format.
vi © ISO 2017 – All rights reserved

TPEG2 has a three container conceptual structure: Message Management (ISO/TS 21219-6), Application
1)
(several parts) and Location Referencing (ISO/TS 21219-7 ). This structure has flexible capability and
can accommodate many differing use cases that have been proposed within the TTI sector and wider
for hierarchical message content.
TPEG2 also has many location referencing options as required by the service provider community, any
of which may be delivered by vectoring data included in the Location Referencing Container.
The following classification provides a helpful grouping of the different TPEG2 parts according to their
intended purpose.
— Toolkit parts: TPEG2-INV (ISO/TS 21219-1), TPEG2-UML (ISO/TS 21219-2), TPEG2-UBCR
(ISO/TS 21219-3), TPEG2-UXCR (ISO/TS 21219-4), TPEG2-SFW (ISO/TS 21219-5), TPEG2-MMC
(ISO/TS 21219-6), TPEG2-LRC (ISO/TS 21219-7), TPEG2-LTE (ISO/TS 21219-24);
— Special applications: TPEG2-SNI (ISO/TS 21219-9), TPEG2-CAI (ISO/TS 21219-10);
2) 3)
— Location Referencing: TPEG2-ULR (ISO/TS 21219-11 ), TPEG2-GLR (ISO/TS 21219-21 ), TPEG2-
4)
OLR (ISO/TS 21219-22 );
— Applications: TPEG2-PKI (ISO/TS 21219-14), TPEG2-TEC (ISO/TS 21219-15), TPEG2-FPI
(ISO/TS 21219-16), TPEG2-TFP (ISO/TS 21219-18), TPEG2-WEA (ISO/TS 21219-19), TPEG2-RMR
(ISO/TS 21219-23), TPEG2-EMI (ISO/TS 21219-25).
TPEG2 has been developed to be broadly (but not totally) backward compatible with TPEG1 to assist
in transitions from earlier implementations, while not hindering the TPEG2 innovative approach and
being able to support many new features, such as dealing with applications having both long-term,
unchanging content and highly dynamic content, such as Parking Information.
This document is based on the TISA specification technical/editorial version reference:
SP13010/1.0/001
1) Under development.
2) Under development.
3) Under development.
4) Under development.
TECHNICAL SPECIFICATION ISO/TS 21219-25:2017(E)
Intelligent transport systems — Traffic and travel
information (TTI) via transport protocol experts group,
generation 2 (TPEG2) —
Part 25:
Electromobility charging infrastructure (TPEG2-EMI)
1 Scope
This document defines the TPEG application electromobility charging infrastructure (EMI). It has been
specifically designed to support information about charging infrastructure for electric vehicles (not
just cars), the location of e-charging points and their suitability for the respective vehicle (e.g. connector
type, charging modality). As electric vehicles will occupy a “charging space” for a longer period of time,
information on availability/waiting time and reservation options are highly relevant for a user of an
electric vehicle to optimally plan his route/trip and are therefore also accounted for.
The standardized delivery, through a TPEG technology, of information on charging infrastructures has
the following benefits to an end user of this TPEG service:
a) Identifying suitable charging units for his vehicle, thus preventing unnecessary driving around to
find a fitting unit (also has environmental benefits).
b) Verifying the real-time availability of charging units.
c) Being able to plan ahead and reserve a spot in a charging park and thus optimize the planning of
his trip.
d) Being able to select a financially attractive charging point in a charging park the operator of which
has billing agreements with the user’s electromobility provider.
In addition to these end-user benefits, also electromobility providers and charging park operators
benefit from a standardized TPEG format as it allows an easier harmonization of the electromobility
charging infrastructure information with the data formats used for the exchange of information
between management systems of electromobility providers and charge park operators and according
5) 6)
specifications (e.g. Open Charge Alliance , eMobility ICT Interoperability Innovation (eMI ) , etc.).
The TPEG application electromobility charging infrastructure, as add-on service component next to,
for example traffic information, is laid out to support large numbers of charge parks with only modest
bandwidth requirements.
2 Normative references
The following documents are referred to in text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/TS 18234-11:2013, Intelligent transport systems — Traffic and Travel Information (TTI) via transport
protocol experts group, generation 1 (TPEG1) binary data format — Part 11: Location Referencing
Container (TPEG1-LRC)
5)  http:// www .openchargealliance .org/
6)  http:// emi3group .com/
ISO/TS 21219-1, Intelligent transport systems — Traffic and travel information (TTI) via transport protocol
experts group, generation 2 (TPEG2) — Part 1: Introduction, numbering and versions (TPEG2-INV)
ISO/TS 21219-5, Intelligent transport systems — Traffic and travel information (TTI) via transport
protocol experts group, generation 2 (TPEG2) — Part 5: Service framework (TPEG2-SFW)
ISO/TS 21219-6, Intelligent transport systems — Traffic and travel information (TTI) via transport
protocol experts group, generation 2 (TPEG2) — Part 6: Message management container (TPEG2-MMC)
ISO/TS 21219-9, Intelligent transport systems — Traffic and travel information (TTI) via transport
protocol experts group, generation 2 (TPEG2) — Part 9: Service and network information (TPEG2-SNI)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
3.1
electric vehicle
EV
vehicle that is (partly) electrically powered and operated
Note 1 to entry: With respect to the TPEG requirements, other electric vehicles such as e-bikes are considered.
Note 2 to entry: EV batteries can typically be charged at any regular power socket. In case fast charging is
required, e.g. during longer journeys, higher demands on the technical infrastructure are made. Specific sockets
and high-power connector cables have been developed to allow a simple and secure usage of boost charging
stations (3.3). It is necessary for the end user to know which options are supported by a charging station. EVs
may have an “identity” for electronic readout, e.g. by means of a certificate. Also, other information which can be
communicated by an EV to the infrastructure may be relevant for the execution and planning of charging orders.
The current battery charge condition, the power requirements during the charging procedure, as well as the
cruising range are parameters that may be relevant for the planning of charging orders. The vehicle and charging
station can communicate using a connector cable, but also other mechanisms are possible, e.g. using the back-end
system of an EV manufacturer, to which an EV is connected (using mobile data connection).
3.2
charging park
park that consists of multiple physical charging stations (3.3) which technically and/or logically belong
together and are being operated together
Note 1 to entry: This may be the case, for example, in a commercially operated car park or in a city district where
publicly operated charging stations are grouped together. Charging parks are being operated by charging park
operators (3.7).
3.3
charging station
station that consists of a physical unit (typically a column or cabinet-like structure) containing and
managing one or more charging points (3.4) offering the end-user the possibility to be authorized
(typically by means of a card reader) and activate one of the charging points at the charging station,
hook up the electric vehicle (3.1) and start the charging procedure
2 © ISO 2017 – All rights reserved

3.4
charging point
unit in a charging station (3.3) at which an electric vehicle (3.1) can be supplied with power
Note 1 to entry: A charging station can provide multiple charging points, which again can contain multiple
sockets to support more than one charging connector type. In general, as soon as one socket at a charging point
is in use, the charging point is occupied. Typically for each charging point, a parking space is provided at the
charging station.
3.5
energy provider
provider that includes all relevant energy suppliers, local solar power generators, as well as traditional
major companies in the power industry sector
Note 1 to entry: It is their role to provide energy to the charging park operators (3.7).
3.6
electromobility provider
EM provider
business partner for the end-users who charge their electric vehicles (3.1)
Note 1 to entry: Typically, an end-user has a contract with an EM provider, the details of which are connected to
an (RF) ID card [having an (internationally) unique card number] that is used for authorization and billing. The
EM provider sees to it that his customers can charge their vehicles in as many charging parks (3.2) as possible
and bills the customer according to the respective contract.
3.7
charging park operator
operator who manages one or more charging parks (3.2)
Note 1 to entry: The charging park operator maintains the charging site(s) and is a business partner to the energy
provider and the EM provider (3.6). Typically, a charging park operator bills the end-user based on “roaming
agreements” with multiple EM providers.
3.8
electric vehicle supply equipment identity
EVSEID
ID that uniquely identifies a concrete charging point (3.4) globally
Note 1 to entry: If a charging station (3.3) has multiple charging points, multiple EVSEIDs are used. See also
DIN SPEC 91286.
4 Abbreviated terms
ACID Application and Content Identifier
ADC Application Data Container
CEN Comité Européen de Normalization
EBU European Broadcasting Union
EM ElectroMobility
EMI ElectroMobility Charging Infrastructure
EV Electric Vehicle
EVSE Electric Vehicle Supply Equipment
EVSEID Electric Vehicle Supply Equipment Identity
LRC Location Referencing Container
MMC Message Management Container
OSI Open Systems Interconnection
SFW TPEG Service Framework: Modelling and Conversion Rules
TISA Traveller Information Services Association
TPEG Transport Protocol Expert Group
TTI Traffic and Traveller Information
UML Unified Modelling Language
5 Application specific constraints
5.1 Application identification
The word “application” is used in the TPEG specifications to describe specific subsets of the TPEG
structure. An application defines a limited vocabulary for a certain type of messages, for example,
parking information or road traffic information. Each TPEG application is assigned a unique number,
called the Application IDentification (AID). An AID is defined whenever a new application is developed
and these are all listed in ISO/TS 21219-1.
The application identification number is used within the TPEG2-SNI application ISO/TS 21219-9 to
indicate how to process TPEG content and facilitates the routing of information to the appropriate
application decoder.
5.2 Version number signalling
Version numbering is used to track the separate versions of an application through its development and
deployment. The differences between these versions can have an impact on client devices.
The version numbering principle is defined in ISO/TS 21219-1.
Table 1 shows the current version numbers for signalling EMI within the SNI application ISO/TS 21219-9.
Table 1 — Current version numbers for signalling of EMI
major version number 1
minor version number 0
5.3 Ordered components
TPEG2-EMI requires a fixed order of TPEG components. The order for the EMI message component
is shown in Figure 1; the first component shall be the Message Management Container. This shall be
the only component if the message is a cancellation message. Otherwise, the MMC component shall be
followed by the one or more Application Data Container component(s) which includes the application-
specific information.
4 © ISO 2017 – All rights reserved

Figure 1 — Composition of TPEG messages
5.4 Extension
The requirement of a fixed component order does not affect the extension of EMI. Future application
extensions may insert new components or may replace existing components by new ones without losing
backward compatibility. An EMI decoder shall be able to detect and skip unknown components.
5.5 TPEG Service Component Frame
EMI makes use of the “Service Component Frame with dataCRC and messageCount” according to
ISO/TS 21219-5 (TPEG2-SFW).
6 EMI structure
6.1 Overview
In Clause 6, the main structure of EMI and its capabilities are explained.
The EMI design is based on a distinction between information with a generally static reference style
with an expected low refresh rate, and information of a more dynamic nature status with an expected
high refresh rate.
6.2 EMI structuring considerations
6.2.1 Information aggregation level: Charging parks, charging stations, charging points
Figure 2 — EMI Structure
EMI (see structure in Figure 2) must provide an end user with enough information to find a suitable
and available charging point to charge his electric vehicle. From an end user point of view, it is sufficient
to obtain information at the level of a charging station: the physical location of a charging station
matching user needs by providing sufficient information. It is not relevant for the user to know e.g.
which physical charging point at a charging station would be available.
Therefore, in EMI information is aggregated either at charging park or charging station level. By doing
so, EMI also takes into account that the number of charging points within a TPEG service may become
too high to transmit all descriptive data as part of the general service. Thus, this approach supports
efficient use of the transmission channel.
Detailed information on a specific charging point may become relevant to an end user wanting to make
a reservation at a specific charging station. Therefore, in addition to the information provisioning
on charging parks and charging stations, EMI supports a request and response session, to allow a
reservation for a specific charging point at a given charging station (or in a charging park, respectively);
see 6.2.3.
6 © ISO 2017 – All rights reserved

6.2.2 Static vs. dynamic information: Charging park information, charging park availability
An EMI service provider needs to be able to provide a TPEG client with a large amount of data at a
relatively low transmission data rate. The typical TPEG concept, in which a single TPEG message
equates with a single content item, cannot be applied for EMI, as it would take too much time to provide
clients without any pre-existing information (e.g. transit users) with some useable data. Some form
of transmission at high repetition rates for minimum content, augmented with low repetition rate for
additional detailed content is then required.
Moreover, EMI contains information that are generally static (see Figure 3, typically descriptive
information on charging parks) and information that may be updated frequently (see Figure 4, such
as the availability information). EMI must also consider this information quality to support different
repetition rates.
EMI has been designed to allow service providers to arrange their transmissions flexibly, depending on
the volume of data to be transmitted and the available data rate. A TPEG message may contain partial
or complete content for a charging park/charging station. A service provider may choose to aggregate
descriptive information at the level of charging park in case only limited data rate is available. This
typically static information shall be combined with location information.
Figure 3 — Static information (example)
The availability information for charging parks/charging stations (typically highly dynamic
information) is contained in separate data structures, which have been kept limited and compact to
allow it to be transmitted with a higher refresh rate than the descriptive information. TPEG messages
containing availability information shall not contain location information. Based on respective ID keys
the TPEG client can recombine the availability information with the other information for charging
parks and charging stations.
Figure 4 — Dynamic information (example)
6.2.3 Request and response
EMI supports a request and response session, to request the reservation of a ChargingPoint that matches
the end user’s requirements and the vehicle‘s attributes and to convey the required parameters to a
reservation service (typically offered by an EM provider).
A sample EMI request message is shown in Figure 5. In the EMI request, either the charging station must
be referenced directly or alternatively at a point near which an available charging station is searched.
One of three options for this location referencing shall be included in the request message:
— internal TPEG reference (parkID_Key and optionally stationID_Key);
— external reference (stationExternalID, e.g. EVSE ID);
— coordinates of a point (longitude, latitude) and optionally parkOperator and/or providerExternalID.
8 © ISO 2017 – All rights reserved

Figure 5 — Reservation request (example)
A sample EMI response message is shown in Figure 6. Use of the reservationConfirmed attribute
indicates whether or not the reservation request is confirmed. In the case where the request is not
confirmed, the reservationFreeText can be used to give additional information. In the case where the
request is confirmed it is recommended to use venueExternalID (to address either a charging station or
a charging point) and reservationID to unambiguously identify the reservation.
Figure 6 — Reservation response (example)
6.3 Pricing information
The pricing and billing models in the current electromobility market place are very different from
fuel pricing/billing and currently also differ very much from one to the other. This mainly is caused
by the many business actors in the “habitat” related to charging procedures, their relationships and
business models.
The end-user typically has a business relationship with an EM provider, by means of a contract, based
on which the end user is billed. This contract is somewhat comparable to a mobile phone contract, can
take many different forms [e.g. prepaid (possibly differentiating rates based on vehicle type or amount
of power used, …), flat rate or other].
The charging park operator or infrastructure provider in such case typically requires an end user to
identify/authorize himself by means of the customer card issued by his EM provider. The charging
park operator does not bill the end user, but rather gets paid by the EM provider based on “roaming
agreements” (such “roaming” allows end users to make use of the charging infrastructure independent
of the actual provider on-site). The infrastructure and power provider have business relationships with
the EM provider (typically more than one), in which wholesale prices (rather than end user prices) are
set. Thus, these wholesale agreements on pricing are transparent to the end user; for him only the
contract with the respective EM provider counts.
Hence, for the end user is most important that he knows that with the customer card from his EM
provider he can identify and authorize himself at a charging station, use it and be billed.
Moreover, the charging park operator is oblivious to the agreements an end user made with his EM
provider and hence cannot make any reasonable assumption as to which costs will arise for an end user
— these may differ from one user to another. To make things even more complicated, at some charging
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parks the charging park operator will offer charging possibilities independent of any EM provider and
bill these in other ways. For example, to name just a few, following billing models in such cases may
occur (not an exhaustive list):
— Based on usage (e.g. per hour, …)
— Combination with parking fee
— “Buying costumers” can charge for free or get a price reduction
— Dependent on maximum current (“slow” vs. “ fast” charging)
— .
TPEG EMI should support all the different, flexible, but amongst each other incompatible billing models.
All the different options are very difficult to support in a single, fixed data structure. Moreover, doing
so has a high risk that another, unforeseen billing model will be invented in the future by a provider,
which cannot be covered by such a data structure.
Therefore EMI only refers to a “Price”, to give end users an indication, e.g. of maximum or minimum
price and to distinguish between normal and premium offers and to allow comparison of charging
parks. Additional information, e.g. on special offers, can be given as free text.
6.4 EMI message structure
The structure of the top-level EMI message is illustrated in Figure 7. An EMI message is designed to
either contain descriptive (largely static) information or availability (largely dynamic) information for
a charging park and/or charging station.
The following types of information can be transmitted in an EMI message:
— Information on a charging park (typically: capacity, site description, etc.). Pricing/billing information
can be included.
— Information on charging stations belonging to the charging park (typically: available connector
types, supported vehicle types, vehicle size restrictions).
— Availability information for a charging park (number of free places).
— Availability information for a charging station (e.g. the number of free places per connector type).
— Location information on a charging park (in addition to the obligatory coordinates in the
LocationReferencingContainer), optionally enhanced by location information for charging stations.
Typically, charging park information should be transmitted in an EMI message with a long expiry time
as this type of information is very stable for a given service. EMI messages containing availability
information can refer to this via a cross reference by the parkID_Key and the stationID_Key. Thus, EMI
supports the transmission of full or partial descriptive information for charging parks and charging
stations, which may be recombined in the TPEG receiver. This allows a service provider to fit the amount
of information and repetition rate for EMI messages to the available data rate for his service.
The following is the minimum information needed for a TPEG client to present useful information to
its user:
— ChargingParkInformation containing the parkID_Key and a minimal ChargingParkSiteDesription
(parkName and the name of the parkOperator), ideally complemented by the
— ChargingParkAvailabilityVector containing a timestamp and minimal information on the
ChargingParkAvailability (parkID_Key and overall number of freePlacesForPark).
The attributes of the ChargingParkInformation may be used by the end user to select an appropriate
charging park and/or by the TPEG client to (automatically) filter out those charging parks not matching
the end user’s requirements.
Figure 7 — Main structure of an EMI message
12 © ISO 2017 – All rights reserved

Figure 8 — Structure of EMI ChargingParkSiteDescription
The data structure ChargingParkSiteDescription extends the ChargingParkInformation with more
detailed descriptive information on the ChargingPark; see Figure 8.
Figure 9 — Structure of EMI ChargingStationInformation
Information on charging stations can b
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