The Charge Point Operator’s
Guide to OCPI

1. What is Open Charge Point Interface (OCPI)?

Companies in the realm of electromobility often assume various roles, extending beyond the confines of charge point operators (CPOs) managing charging stations or eMobility service providers (eMSPs) serving EV drivers. This creates complexity on both technical and business fronts, emphasizing the necessity for a standardized means of connection and communication among these key players.

To address these challenges and foster greater interoperability within the e-mobility sector, the industry has turned to the Open Charge Point Interface protocol (OCPI). OCPI is an open, independent, and freely available protocol that supports data exchange and connections between eMSPs and CPOs. It offers a robust framework for essential information exchange, including authorization, transaction events, charge detail records, and smart-charging commands between involved parties. OCPI can operate through direct bilateral connections or by connecting multiple parties via a roaming hub.

Developed and managed by the EVRoaming Foundation, OCPI’s ultimate goal is to empower every EV driver to charge at any charging station, regardless of location or operator. OCPI aims to achieve this by accelerating the EV market and improving mobility services.

A short history of OCPI

OCPI was first introduced in 2012 by ElaadNL, the knowledge and innovation center specializing in Smart Charging and charging infrastructure in the Netherlands, along with major Dutch grid operators focused on EV infrastructure development. OCPI aimed to standardize the exchange of information between EV charging operators and service providers, making it easier to connect and use various charging networks.

Initially governed by the Netherlands Knowledge Platform for Public Charging Infrastructure (NKL), the management of OCPI transitioned to the EVRoaming Foundation in May 2020. The inaugural release of OCPI, OCPI 2.0, debuted in 2015. Since then, it has undergone numerous updates and enhancements, culminating in the latest version, OCPI 2.2.1.

The main application

The primary goal of OCPI is to create standardized rules to facilitate seamless communication between charge point operators (CPOs) and eMobility service providers (eMSPs) so that EV drivers can access charging stations outside of their primary provider’s networks. Similar to how you use your cell phone on different networks when traveling, roaming in EV charging makes it easy for drivers to charge on stations regardless of the operators. 

OCPI allows EV drivers to access, authorize, and pay for charging services across various charging providers. It supports real-time status updates, pricing information, and data exchange, promoting a standardized and user-friendly experience for EV users.

Development and licensing

OCPI is an open standard developed by the OCPI Community. The protocol is registration-free and available at no cost, published under the Creative Commons Attribution-NoDerivatives 4.0 International Public License. While distribution is free with proper credit, it does restrict the distribution of modified versions of the protocol.

As OCPI evolves to accommodate technological advancements and industry requirements, these updates are typically developed collaboratively, with contributions from interested parties.

In some cases, organizations may seek certification to ensure that their implementation of OCPI complies with the standard. Certification programs or organizations may provide this service to verify compatibility and adherence to the protocol.

Regulatory compliance

OCPI’s global endorsement highlights its importance. It has gained recognition and support from governments, local and national initiatives, and companies in various regions such as:

• United States: The Corporate Electric Vehicle Alliance is actively advocating for the adoption of OCPI and OCPP as standard charging protocols. The NEVI funding also  mandates incorporating OCPI standards for enhanced compatibility and efficiency in EV charging initiatives
• United Kingdom: The UK government has proposed the adoption of OCPI as a standard protocol to ensure reliable and accessible EV charging.
• European Union: The international project evRoaming4EU, involving organizations from Austria, Denmark, Germany, and the Netherlands, aims to enhance roaming services for EV drivers and improve transparency using the OCPI protocol.

2. How OCPI works

Standardized communication

OCPI functions as a common language, providing a set of standardized rules and guidelines that ensure different EV charging software systems can communicate effectively with one another. This standardization is the key to enabling network operators to exchange crucial information, including reservations, charging histories, financial transactions, and location data, thereby enabling seamless tracking of their clients across disparate charging networks. Consequently, EV drivers gain access to all OCPI-compliant chargers in their vicinity, equipped with up-to-the-minute details on pricing and availability.

By leveraging OCPI, EV charging software systems can establish seamless communication channels, transcending the differences in charging station types and service providers. This ensures that EV drivers can effortlessly utilize a variety of charging stations from different providers while enjoying a consistent and user-friendly experience.

Information exchange

OCPI facilitates the exchange of vital information between network operators, including:

The real-time, modular, and flexible backbone of the EV charging ecosystem

OCPI operates in real-time, ensuring that all stakeholders have access to up-to-the-minute information. It offers a modular setup, allowing users to choose the specific modules that meet their requirements, promoting flexibility and scalability. Moreover, OCPI maintains both synchronous and asynchronous operations, accommodating various communication needs. 

3. The main use cases for OCPI

OCPI unlocks the following use cases that provide significant benefits to various stakeholders within the industry:

1. Direct peer-to-peer (P2P) connection

A direct P2P connection facilitated by OCPI eliminates the need for intermediary services. Instead, EV charging networks engage in direct communication and agreement establishment, allowing their respective customers to seamlessly utilize each other’s charging infrastructure. This process involves bilateral agreements between network operators, where rules for authentication and billing are established. Consequently, EV drivers can easily initiate and complete charging sessions on visited networks while their home network manages billing and settlements directly with the visited network. 

This use case is particularly valuable in scenarios where specific EV charging data necessitates sharing or integration with third-party software. Notable examples include:

• OCPI enables billing software to access user and charging session data to issue documents related to charging sessions.
• EV driver support software relies on OCPI to access charge point, user, and charging session data. It can process this information and may send commands back to charge points to address any issues or requests from EV drivers.
• Information about supported payment terminal software and payment options, such as credit cards, debit cards, or pin-code entry devices, can be transferred via OCPI, ensuring that payment terminals have the latest data for transaction processing.
• OCPI provides government and regulatory agencies with accurate and real-time information about charging sessions.
• Operators working in multiple countries with varying business models can use OCPI to establish connections between their tenants. This enables them to provide users with access to their charging points across borders while accommodating different business requirements in each country.

2. Roaming hub integration

For larger charging networks, direct P2P connections can become impractical. Roaming through a hub offers distinct advantages, particularly in efficiency and scope of operations. One primary benefit is simplified connectivity; network operators connect just once to a central hub, eliminating the need for multiple agreements and technical arrangements with various parties. Through a hub, operators can instantly expand their reach, tapping into its extensive network without pursuing individual negotiations with each party individually. This convenience comes with potential additional fees for CPOs; however, the hub model could save resources that would otherwise be spent managing numerous bilateral relationships.

4. The benefits of OCPI for charge point operators 

By serving as a common language for diverse stakeholders, OCPI addresses several critical challenges while fostering innovation and accessibility.

Implementing OCPI empowers CPOs to monetize their charging infrastructure more effectively. By expanding access to a broader range of eMSPs and EV drivers, CPOs can tap into a larger customer base, leading to increased utilization rates and revenue opportunities.

OCPI equips CPOs with a common language and framework, which simplifies day-to-day management tasks, reduces operational complexities, and ensures consistency in charging services, even amidst the industry’s growing complexity.

The latest version of OCPI, OCPI 2.2.1, introduces smart charging capabilities. CPOs can leverage this feature to interact with individual chargers across multiple networks and align with evolving industry demands for efficiency and sustainability. 

5. The main OCPI terms 

The following terms are the main building blocks that facilitate electric vehicle charging and data exchange.

6. The OCPI modules, roles and topologies

Modules 

The OCPI protocol covers 8 functional modules and 2 administrative ones:

Configuration modules

The Configuration Modules in OCPI are essential for setting up and maintaining OCPI connections but do not provide any information for the EV driver.

• Versions – This is the required base module of OCPI. This module is the starting point for any OCPI connection. Via this module, clients can learn which versions of OCPI a server supports and which modules it supports for each of the versions.

• Credentials – The credentials module is used to exchange the credentials token that has to be used by parties for authorization of requests. Every OCPI request is required to contain a credentials token in the HTTP Authorization header.

• HubClientInfo – This module provides parties connected to a hub with the connection status of other parties that are connected to a hub that they can communicate with. So, CPOs know which eMSP and other parties are online and vice versa.  Unlike the usual OCPI modules, this module is between eMSP/CPO and Hub instead of between eMSP and CPO.

Functional modules

The functional modules provide functionality and information for the EV driver and are grouped into four categories:

1. Modules for payment processing

• Tokens – Define the exchange of tokens (e.g RFID details) between eMSP and CPO. Tokens are used for access control and authentication at charging stations. They ensure that only authorized users can initiate and use charging sessions. When an EV driver subscribes to an eMSP or a charging network, they receive a token, typically in the form of an RFID card or a mobile app authentication. 

• CDRs (Charge Detail Records) – CDRs are essential for recording and tracking the details of each charging session. When a charge session concludes, a transaction record is generated, including cost, duration, energy consumption, and other details, which is then transmitted to the eMSP for payment. Although there is no requirement to send CDRs in (semi-) real-time, it is seen as good practice to send them as soon as possible. Because a CDR is for billing purposes, it cannot be changed or replaced once sent to the eMSP. Changes are simply not allowed. Instead, a Credit CDR can be sent.

2. Modules for navigation

• Locations – This module facilitates the exchange of charging location data, including charge point capabilities, availability, and cost. The CPO periodically sends this list to the eMSP, enabling the eMSP to offer a live charge map to users. 

• Tariffs – Complementing Locations, the Tariffs module provides specific pricing details associated with charge points. This helps EV drivers understand the costs involved at each location, enhancing their decision-making when selecting charging stations.

3. Modules for charging

• Sessions – The Sessions module enables the exchange of interactive session data between various entities. This data includes charging speed, energy consumption, and socket status (charging, complete, etc.). It empowers the eMSP to keep the mobile app users informed about the real-time charging status. The Session object is typically owned by the Charge Point Operator (CPO) back-end system and can be accessed either from the CPO system or pushed by the CPO to another system, such as the eMSP’s platform.
• Commands – The Commands module allows the eMSP to send charging-related commands to a specific charger point. These commands can include actions like reserving a charger for a user, initiating or terminating a charging session, or unlocking a connector that may be stuck. The eMSP can use these commands to implement in-app charging initiation and management, giving users more control and flexibility over their charging experiences.

4. The module that controls the behavior of the charge point

The module used by the eMSP (and others) to control the behavior of the charge point is called the “ChargingProfile” module. This module allows entities like Smart Charging Service Providers (SCSPs), Aggregators, Energy Service Brokers, and eMSPs to send (Smart) Charging Profiles to a Location/EVSE. It is also possible to request the ‘ActiveChargingProfile’ from a Location/EVSE.

The “ActiveChargingProfile” is the charging profile calculated by the EVSE itself. It is the result of the calculation of all smart charging inputs present in the EVSE, and it may also take into account local limits.

ChargingProfiles can be created by the owner of a Token on Sessions that belong to that token. However, if another party sends a ChargingProfile and the Charge Point Operator (CPO) does not have a contract allowing that party to set sessions, the CPO can reject such profiles.

Roles

The various roles in OCPI are defined to determine data ownership and to delineate the responsibilities and permissions of different entities involved in the EV charging ecosystem. These roles help establish order, security, and accountability within the system. 

In earlier versions of OCPI (2.0 and 2.1.1), the roles were strictly defined as either CPO or eMSP. However, this strict categorization didn’t align with real-world scenarios where companies perform multiple roles or offer services to others. In practice, many organizations may provide services to both CPOs and eMSPs, and this complexity requires setting up multiple OCPI connections.

OCPI 2.2 addresses this issue by introducing a more flexible and comprehensive approach to roles. It introduced the concept of a “Platform” that can provide services to multiple roles, making it more adaptable to real-world scenarios. The platform could be a pure CPO, an eMSP, or a combination of both. Here are some examples:

Topologies

OCPI topologies describe the communication patterns between various entities in the EV charging ecosystem. All topologies dictate how information flows, and transactions occur between charge point operators, eMSPs, and hubs.

Peer-to-Peer

The simplest topology is a bilateral connection where two platforms establish a peer-to-peer relationship where each platform assumes a single role.

Multiple peer-to-peer connections

A more real-world topology where multiple parties connect their platforms and each platform only has 1 role. (Not every party necessarily connects with all the other parties with the other role).

Peer-to-peer multiple the same roles

In a peer-to-peer configuration with multiple parties assuming the same roles, certain parties offer services such as CPO or eMSP to other companies. This topology is a bilateral connection between two platforms, where both platforms can assume multiple roles.

Peer-to-peer dual roles

In a peer-to-peer network with dual roles, some parties assume both the CPO and eMSP roles, reflecting the common scenario where companies serve in both capacities. This topology maintains a bilateral connection between two platforms, each of which simultaneously plays the roles of CPO and eMSP.

Peer-to-peer mixed roles

In a peer-to-peer network with mixed roles, parties may take on dual roles or provide them to others, subsequently connecting with companies that adopt similar practices. This topology is a bilateral connection between two platforms, where both platforms assume multiple roles, which can be both different and overlapping.

Multiple peer-to-peer

In a real-world topology where OCPI is used between market parties without a Hub, all parties are platforms with multiple roles. A significant drawback of this approach is the need to establish, test, and maintain numerous connections between these platforms.

Platforms via Hub

All platforms connect through a Hub, and all communication goes through the Hub.

Platforms via Hub and direct

Not all Platforms will only communicate via a Hub. There might be different reasons for Platforms to still have peer-to-peer connections. Some platforms maintain direct peer-to-peer connections for various reasons, such as the Hub lacking support for new functionalities or the use of custom modules by platforms for specific projects that are not supported by the Hub.

7. A quick overview of the main versions of OCPI

OCPI 2.1.1 (released in 2017)

OCPI 2.1.1 is a widely adopted standard in the EV charging industry. This version of OCPI provides a solid foundation for interoperability and communication among EV charging networks. It supports core functionalities, including authentication, tariff management, and session data exchange, ensuring a seamless and consistent charging experience for EV users and operators. While it may not have the advanced features of newer versions, OCPI 2.1.1 remains a reliable and widely used choice for EV charging network communication.

OCPI 2.2 (released in 2019)

OCPI 2.2 is a substantial upgrade over its 2.1.1 predecessor, introducing key features for a more efficient EV charging network. Notable additions include support for hubs, enhancing communication, and enabling parties to monitor each other’s online status. It also caters to platforms with diverse roles, offering detailed role information and country codes. The inclusion of Charging Profiles empowers eMPS to send specific charging instructions to EVSE, optimizing charging sessions. Moreover, the introduction of Preference-based Smart Charging allows eMPS to align charging with EV driver preferences, improving the overall charging experience.

OCPI 2.2.1 (2021)

OCPI 2.2.1 is the latest official release of the OCPI standard, addressing and improving upon issues identified in its predecessor, 2.2. This version introduces several crucial changes and enhancements, including message routing headers, and hub client information. It also allows for more comprehensive support of platforms with diverse roles and additional roles, empowering the EV charging ecosystem to function more seamlessly.

Notable improvements include Credit CDRs, VAT, Calibration law/Eichrecht support, Session_id, AuthorizationReference, CdrLocation, and more in the CDRs category. It refines Sessions, Tariffs, Locations, Tokens, and introduces the ability to cancel reservations in Commands. 

OCPI 3.0 (in development)

OCPI 3.0 will be a substantial overhaul of the OCPI standard, designed to enhance efficiency and address evolving needs in the EV charging ecosystem. Building on a the Business Use Cases published in November 2021, this version adopts a business-driven approach to develop functional use cases and specifications, ensuring alignment with industry challenges.

Major changes in OCPI 3.0 include architectural improvements to boost overall efficiency, along with a suite of new functionalities. These additions include support for ISO15118, enabling advanced EV communication and compatibility, statuses for CDRs, support for sending meter values to Distribution System Operators (DSOs), streamlined contract management, and robust implementation and testing support.

One standout feature of OCPI 3.0 is its embrace of advanced authentication protocols like Plug & Charge and Autocharge. These protocols authenticate the EV through the charging cable connection, eliminating the need for RFID tags or mobile apps, simplifying the charging process for EV drivers. 

OCPI 3.0 further enhances communication between CPOs, eMSPs, and EV drivers. It allows eMSPs to display pricing information and messages directly on charge point displays, improving user understanding and transparency. CPOs can send real-time push messages to EV drivers, offering updates and guidance during the charging process.

8. Getting started with OCPI

When implementing OCPI, consider your specific requirements and identify the relevant use cases from the OCPI suite that align with your needs, as outlined in the Supported Topologies section of OCPI documentation. Evaluate which functional modules are necessary for your implementation by referencing the “Typical OCPI implementations per role” image below, keeping in mind that these modules are not obligatory.

Push and pull models

OCPI operates with two communication models: Push and Pull. Push sends (semi) real-time updates and new objects to the receiver, while Pull involves the receiver requesting a list of objects at specific intervals. Pull is mandatory for OCPI, ensuring synchronization after connection loss, and can serve as a starting point for implementation. However, for production systems with heavy loads or multiple clients, implementing Push is strongly recommended as it conserves resources. 

Understanding request formats 

OCPI employs HTTP methods, such as GET, POST, PUT, PATCH, and DELETE, similar to REST APIs. GET retrieves objects or information, POST creates new objects, PUT updates existing ones, PATCH partially modifies existing objects, and DELETE removes objects or information.

Consider offline behavior in OCPI communication 

OCPI relies on event-based messaging. Messages and status updates are pushed between parties, and when communication is disrupted or a communicating party becomes unreachable for an unspecified period, updates cannot be delivered. Importantly, OCPI messages should not be queued. If a client’s request (POST, PUT, or PATCH) fails or times out, it should not be queued for later retry. Instead, when the connection is re-established, the target server should initiate a GET request to retrieve the current status from the source server, thereby resuming synchronization.

9. Unlock the full potential of OCPI with AMPECO

In today’s rapidly evolving e-mobility landscape, embracing the OCPI protocol is a strategic imperative for charge point operators looking to thrive. OCPI offers an automated and scalable framework for seamless EV roaming between CPOs and eMSPs, featuring capabilities like session authorization, charge point data sharing, transaction reconciliation, charger reservations, and more. 

CPOs can turn to AMPECO, a leading EV charging management software provider and a member of the EVRoaming Foundation, to fully capitalize on OCPI advantages, such as:

Roaming capabilities: OCPI facilitates roaming with trusted EV charging networks allowing charge point operators to expand their services through partnerships with other EV charging networks. This makes charging easier and more convenient for EV drivers as they can use a single account or app to access charging stations across different networks.

Advanced management tools: With AMPECO, you can efficiently oversee your charging stations, monitor real-time status updates, and access comprehensive session data, pricing, and availability information. These tools empower CPOs to optimize charging infrastructure utilization and identify revenue-generating opportunities.

Integration with industry leaders: EV charging network operators can leverage OCPI to integrate with prominent industry players like Zap-Map and Electroverse. By aligning their operations with established eMSPs, operators can attract a broader user base and increase the visibility of their charging network.

Smart energy management: OCPI’s load management features enable operators to optimize energy usage. They can control charging speeds, schedule sessions during off-peak hours, and support demand response programs. This not only benefits the grid by preventing overloads but also improves the network’s overall efficiency.

Regulatory compliance: In response to the growing importance of open standards in the EV charging sector, CPOs must prioritize compliance with evolving regulations. This includes providing and submitting regular reports to authorities on EV charging data such as sessions, transactions and EVSEs which is made possible through OCPI.

 Enhanced EV driver experience: AMPECO places great emphasis on delivering an exceptional user experience. By implementing AMPECO’s solutions, CPOs can provide EV drivers with real-time information on charging station locations, availability, and pricing. This user-friendly experience fosters customer loyalty, encouraging EV drivers to choose CPOs that prioritize convenience and transparency.

In an era where the EV charging landscape is rapidly evolving, AMPECO stands as a strategic partner to empower CPOs in realizing the full potential of OCPI, ensuring they stay competitive and customer-focused in the dynamic e-mobility industry.