1. What is OCPI
OCPI, or Open Charge Point Interface, is an open and standardised communication protocol that enables the exchange of information between Charge Point Operators (CPOs) and eMobility Service Providers (eMSPs). Managed by the EVRoaming Foundation, OCPI aims to create a universal language that ensures seamless communication across the EV charging ecosystem. The protocol is available for free and has been widely adopted, supporting features such as real-time data exchange, billing, authorisation, and roaming capabilities. Its goal is to make EV charging as convenient as possible for drivers, regardless of the charging network they use.
2. How OCPI works
2.1 Peer-to-peer connections
At its core, OCPI functions as a technical handshake between CPOs and eMSPs, standardising data exchange to ensure compatibility between different systems. This standardisation allows for two main modes of operation: peer-to-peer (P2P) connections and roaming through hubs. The P2P mode allows direct communication between CPOs and eMSPs. It is ideal for situations where organisations have specific data-sharing needs or agreements. For instance, a CPO might directly connect with an eMSP to facilitate billing, session details, and authorisation processes. This approach can be tailored but requires individual agreements between each pair of operators.
2.2 Roaming through hubs
A more scalable approach involves using a roaming hub, which acts as an intermediary, enabling CPOs and eMSPs to connect through a single integration point. This setup reduces the complexity of managing multiple bilateral agreements. By connecting to a hub, network operators can quickly expand their reach and offer EV drivers access to a broader range of charging stations. OCPI’s modular design allows users to select specific features or modules based on their needs. This flexibility makes it a preferred choice for operators who require different levels of integration and functionality.
3. Key features and functionalities of OCPI
3.1 Authorisation and identification
OCPI provides a wide array of features that enhance the overall EV charging experience for drivers and streamline operations for service providers. It ensures that only authorised users can access charging services. This process involves verifying a driver’s credentials, allowing for secure and seamless access to charging points. It can be executed in real-time or through pre-authorised tokens.
3.2 Charging session data exchange
OCPI enables the exchange of critical data about ongoing and past charging sessions, such as start and end times, energy consumption, and costs. This data is vital for eMSPs to provide detailed billing information to their customers. The protocol supports the exchange of detailed pricing information, including energy costs, tariffs, and transaction records known as Charge Detail Records (CDRs). This ensures transparency in costs for EV drivers and accurate billing for network operators.
3.3 Remote start/stop and smart charging
OCPI allows drivers to remotely start or stop charging sessions through mobile apps, providing greater convenience and control over their charging activities. One of the advanced features of OCPI is its support for smart charging, which enables operators to optimise energy usage. Drivers can choose to charge based on preferences like lower costs, faster charging, or greener energy sources. These capabilities make OCPI an all-encompassing protocol for managing the complexities of EV charging networks, allowing for both local and international interoperability.
4. Benefits of using OCPI
4.1 Enhanced interoperability
OCPI offers several advantages to both EV drivers and charging network operators. These benefits are crucial in creating a robust and efficient charging ecosystem. By standardising communication between different EV networks, OCPI ensures that drivers can charge their vehicles at stations operated by various providers using a single account. This ease of use is similar to how mobile phone users can roam across networks without changing their service provider.
4.2 Improved user experience
With features like real-time updates on charging station availability, reservation options, and transparent pricing, OCPI enhances the overall charging experience for drivers. This user-centric approach is essential in reducing barriers to EV adoption, such as range anxiety and the complexity of using multiple charging apps. For CPOs, implementing OCPI can reduce the costs associated with integrating multiple networks, as it removes the need for intermediaries in transactions.
4.3 Cost efficiency and scalability
OCPI’s modular design allows networks to scale their services as they grow, making it ideal for both emerging and established operators. As an open protocol, OCPI is available without licensing fees, fostering innovation and encouraging widespread adoption. The freedom to modify and adapt the protocol also allows operators to develop new services and business models tailored to their specific market needs.
5. OCPI in practice: real-world use cases
5.1 Cross-network roaming
OCPI has become the standard choice for many operators due to its versatility and openness. A major use case for OCPI is facilitating roaming between different EV networks. For example, a driver subscribed to an eMSP in one country can travel across borders and use charging stations in another country without needing to set up a new account. This seamless access supports the growth of international travel for EV drivers.
5.2 Hub-based integration
Large operators often use OCPI to connect to roaming hubs like GIREVE or e-clearing.net, which aggregate multiple networks. This setup simplifies the process of expanding services and helps operators focus on delivering a better experience to their customers.
5.3 Smart energy management
With the growing importance of managing energy demand, OCPI’s smart charging capabilities allow operators to balance charging loads and integrate renewable energy sources. This feature is increasingly valuable as the grid adapts to higher EV penetration and the need for sustainable energy use.
6. Comparing OCPI with other protocols
6.1 OCPP: The Open Charge Point Protocol
The Open Charge Point Protocol (OCPP) is another popular protocol that differs from OCPI in its primary focus. While OCPI facilitates communication between CPOs and eMSPs for roaming purposes, OCPP is designed to manage interactions between EV chargers and back-end systems. OCPP allows operators to control charger settings, monitor device status, and manage charging sessions at a detailed level. This makes OCPP more suitable for hardware management, whereas OCPI is focused on ensuring interoperability across different service networks.
6.2 OICP: Open InterCharge Protocol
The Open InterCharge Protocol (OICP) is another key protocol in the EV charging ecosystem, developed by Hubject. OICP focuses primarily on enabling seamless EV charging through a central hub. It facilitates ad-hoc payments, real-time data exchange, and the management of authorisations. OICP is particularly strong in markets like Germany, where it supports compliance with calibration laws (Eichrecht). Unlike OCPI, which supports both P2P and hub-based roaming, OICP is more centered around hub-based solutions. This makes it an excellent choice for networks looking for centralised management but less flexible than OCPI for direct connections.
6.3 OCHP: Open Clearing House Protocol
The Open Clearing House Protocol (OCHP) is designed for managing connections between CPOs and eMSPs through a clearing house, specifically the e-clearing.net platform. It supports functionalities like remote charging control and session information sharing. OCHP’s asynchronous communication allows for white-listing users, ensuring that charging sessions continue even if a central server becomes temporarily unavailable. However, it lacks the same level of real-time interactivity that OCPI offers, making OCPI better suited for applications that require immediate updates on availability and session status.
6.4 eMIP: eMobility Interoperation Protocol
eMIP, managed by GIREVE, is widely used in France and focuses on providing a range of data-sharing functionalities, including authorisation, billing, and charge point information. It is known for its ability to adapt quickly, allowing CPOs and eMSPs to add new features without needing to wait for protocol updates. eMIP supports both peer-to-peer and hub-based connections, much like OCPI, but its flexibility in adding new data fields makes it particularly useful for custom solutions. However, OCPI’s broader international adoption and comprehensive smart charging features give it an edge in more diverse markets.
7. The evolution of OCPI
OCPI has evolved over the years to meet the changing needs of the EV industry. The latest official version, OCPI 2.2.1, offers advanced features such as improved billing mechanisms, enhanced support for smart charging, and better integration with regulatory requirements like the German calibration law (Eichrecht). OCPI 3.0, currently in development, aims to further refine the protocol with a focus on more efficient communication, expanded smart charging functionalities, and support for ISO 15118, which includes advanced vehicle-to-grid communication. This evolution reflects the collaborative nature of OCPI’s development, with contributions from various stakeholders in the EV industry, including CPOs, eMSPs, and technology providers.
8. Challenges and considerations in adopting OCPI
8.1 Technical complexity
While OCPI presents numerous advantages, implementing the protocol does come with certain challenges. Setting up OCPI connections requires a solid understanding of its API structure and the ability to integrate it with existing systems. Companies may need to invest in technical expertise or partner with software providers to ensure a smooth implementation.
8.2 Interoperability with other protocols
Although OCPI is widely used, it coexists with other protocols like OCPP (Open Charge Point Protocol) and OICP (Open InterCharge Protocol). Organisations need to navigate these overlaps and decide which protocols best suit their specific needs.
8.3 Data security
As with any system that handles user data and financial transactions, ensuring robust data security is paramount. OCPI’s open nature means that operators must adhere to best practices in data protection to maintain trust and compliance with regional regulations.
9. The future of OCPI
Looking ahead, OCPI is poised to play a critical role in the global expansion of EV charging infrastructure. Its adaptability and focus on seamless connectivity position it as a cornerstone for future developments in the industry. As new versions like OCPI 3.0 are rolled out, we can expect greater integration with smart city initiatives, more efficient use of renewable energy, and enhanced capabilities for managing complex charging networks. The protocol’s commitment to open standards and community-driven development ensures that it remains relevant in a rapidly evolving industry. This flexibility will be crucial as the world continues to shift towards sustainable transportation and as new challenges emerge in the EV charging landscape.
10. Conclusion
The Open Charge Point Interface (OCPI) has emerged as a key enabler of interoperability in the EV charging ecosystem, offering a flexible and user-friendly framework for connecting CPOs and eMSPs. By standardising communication and streamlining the charging experience, OCPI helps to break down the barriers that can slow the adoption of electric vehicles. As the protocol continues to evolve, it will remain an essential tool for building a more connected, accessible, and efficient EV charging network, empowering drivers and operators alike to embrace the future of sustainable mobility.