1. What is plug & charge?
Plug & Charge, commonly referred to as PnC, is a standardised charging solution designed to simplify and automate the EV charging process, making it more efficient and user-friendly. Enabled by the ISO 15118 standard, PnC eliminates the need for drivers to carry and use various forms of identification or payment, such as RFID cards, mobile apps, or credit cards, at EV charging points. Instead, drivers can simply plug their vehicle into a compatible charging station, where the vehicle automatically identifies itself, verifies the owner’s payment credentials, and begins charging without further input from the user.
In addition to streamlining the charging experience, PnC creates a level of interoperability across networks, allowing EV drivers to charge seamlessly at any compatible station, regardless of the operator. This universal compatibility is a significant step forward in making EV ownership more convenient and supporting global e-mobility goals. As PnC adoption grows, it is expected to become the preferred charging method in both public and private charging scenarios, transforming the way EV drivers interact with infrastructure worldwide.
2. The history of plug & charge
2.1 Early challenges in EV charging
In the early days of EV adoption, drivers encountered a fragmented charging landscape, with varying standards, inconsistent payment processes, and lack of universal access across different charging networks. This led to frustration and confusion, as drivers often needed to manage multiple accounts and payment methods for different charging providers. These obstacles were particularly inconvenient for EV drivers travelling across regions or countries where different standards and payment protocols were in place. The need for a more unified, streamlined charging process became apparent, paving the way for a solution that could simplify and standardise interactions across charging networks.
2.2 The ISO 15118 standard: a milestone in EV interoperability
Recognising the challenges facing the EV industry, a consortium of automotive, energy, and technology leaders came together to create a unified standard that would enhance interoperability and security in EV charging. This led to the introduction of the ISO 15118 standard in 2014, which established a framework for seamless communication between EVs and charging infrastructure. This initial version of ISO 15118 focused on basic vehicle-to-grid (V2G) interactions, enabling the transmission of essential data between EVs and charging stations but stopping short of full Plug & Charge functionality.
2.3 Evolution to ISO 15118-20: a comprehensive solution
The release of ISO 15118-2 expanded the capabilities of the standard by introducing Plug & Charge, enabling EVs to communicate directly with charging stations using encrypted digital certificates. This version brought PnC functionality closer to reality, although many challenges, such as certificate management and cross-network compatibility, remained. It was not until the release of ISO 15118-20 in 2022 that PnC achieved its current form, with enhancements including bidirectional charging capabilities, support for multiple contracts, and cryptographic agility. With these developments, ISO 15118-20 solidified PnC as the benchmark for EV charging, setting the stage for widespread adoption and paving the way for future advancements in V2G interactions.
3. How plug & charge works
PnC uses Public Key Infrastructure (PKI) to establish a secure, automated interaction between EVs, charging stations, and backend systems. Each stage in the PnC process—from identification to payment—is managed through encrypted communication and digital certificates, ensuring data integrity and protecting against fraud.
3.1 Digital contracts and certificates
At the heart of PnC are digital contracts, which contain the EV driver’s payment details and unique identifiers. When an EV owner registers for a PnC-enabled service, a Mobility Operator (MO) creates a digital contract associated with the owner’s account. This contract is stored within the vehicle’s Electric Vehicle Communication Controller (EVCC) as a digital certificate, similar to a secure, encrypted key. The contract enables the EV to identify itself and authorise payments each time it connects to a compatible charging station.
3.2 Automated authentication and billing
Once the EV is plugged in, it initiates an encrypted “handshake” with the charging station, during which it presents its digital certificate for authentication. The charging station verifies the EV’s credentials against its own system, ensuring that the user’s contract is valid and that payment will be processed. This process occurs automatically and is completed within seconds, making PnC faster and more efficient than traditional methods. After the session is authorised, charging begins, and billing is managed in the background, eliminating the need for any manual steps on the driver’s part.
3.3 Security protocols
PnC transactions are secured using PKI, with cryptographic keys authenticating and encrypting each interaction. The certificates associated with each EV and charging station are verified through trusted certificate authorities, ensuring that each session is secure from external interference. This focus on data security not only protects user information but also strengthens the trustworthiness of the entire PnC ecosystem, helping prevent fraud and unauthorised access.
4. Benefits of plug & charge
4.1 A streamlined user experience
PnC transforms the EV charging experience by allowing drivers to simply plug in and charge without needing to interact with multiple apps or payment methods. This ease of use is expected to improve overall user satisfaction and make EVs a more attractive option for those considering the transition to electric vehicles. Furthermore, by eliminating steps in the process, PnC reduces the time it takes for drivers to charge, making it a more efficient solution.
4.2 Simplified billing and payment
With PnC, all billing and payment operations are automated and handled through the driver’s existing digital contract, which reduces administrative overhead for charging operators. This leads to fewer billing errors, faster payments, and greater transparency in the charging process, benefiting both drivers and charging networks. Operators can also save time and resources that would otherwise be spent managing manual payment systems and customer inquiries.
4.3 Enhanced data security
PnC’s foundation in encrypted PKI transactions makes it a secure option for managing EV charging data. Each transaction is authenticated through digital certificates, which protect user information and prevent unauthorised access. Compliance with global security standards, such as ISO 27001, also ensures that PnC meets stringent data protection regulations, which is crucial for building and maintaining user trust.
4.4 Broader compatibility and interoperability
The PnC standard is designed to be interoperable across different EV charging networks, allowing drivers to charge their vehicles at compatible stations globally. This level of compatibility is especially valuable for drivers who frequently travel across regions or countries, as they can access a wide range of charging points without needing to create new accounts or obtain additional access credentials.
5. Challenges facing plug & charge
5.1 Infrastructure limitations
Implementing PnC requires infrastructure upgrades, as many existing charging stations do not support ISO 15118 standards. To become compatible, stations must be outfitted with updated hardware and software capable of interfacing with PnC systems. For smaller charging providers, these upgrades represent a significant investment, which could impact the speed at which PnC becomes widely available.
5.2 Security and complexity
While PnC’s PKI-based security provides robust protection, managing the cryptographic keys and certificates involved is technically complex. Each charging station must securely handle these certificates to prevent misuse or hacking attempts. Additionally, managing the lifecycle of these certificates, including expiration and renewal, requires careful coordination and presents an ongoing operational challenge for charging operators.
5.3 Market fragmentation
PnC’s success hinges on cooperation between various market players, including automotive manufacturers, charging network operators, and MOs. Different business models, priorities, and regional regulations can create fragmentation, making it difficult for PnC to gain universal acceptance. Standardisation efforts are underway, but until full alignment is achieved, EV drivers may encounter inconsistent access to PnC services.
5.4 Navigating regulatory requirements
Implementing PnC across borders introduces regulatory complexities, especially in regions like the European Union where stringent data privacy and consumer protection laws apply. Operators must ensure that PnC systems are compliant with regulations such as GDPR, which can add an extra layer of complexity and operational cost, particularly for providers that operate across multiple jurisdictions.
6. Implementing plug & charge: a practical guide
6.1 Infrastructure upgrades and requirements
Charging point operators (CPOs) aiming to offer PnC must invest in compatible hardware and software that meets ISO 15118 standards. Each station should be equipped with an Electric Vehicle Supply Equipment Communication Controller (SECC) that can securely communicate with the vehicle’s EVCC. By establishing this infrastructure, CPOs create the conditions necessary for seamless PnC interactions, allowing users to experience automated authentication and billing.
6.2 Cybersecurity and compliance
To ensure security and compliance, CPOs must integrate PKI systems that manage digital certificates used in the PnC process. Each transaction requires an encrypted exchange of credentials, meaning CPOs must work with trusted certificate authorities and adhere to cybersecurity standards like ISO 27001. The implementation process should also include regular security audits to protect user data and maintain trust within the PnC ecosystem.
6.3 Collaboration with mobility operators
Effective implementation of PnC requires close collaboration with MOs, as they are responsible for creating and managing the digital contracts used by EVs during the charging process. CPOs and MOs need to establish processes for securely provisioning and updating these contracts, which may involve integrating backend systems and synchronising data flows to ensure that all PnC interactions are secure, efficient, and compliant.
6.4 Market examples of successful implementation
PnC is already implemented in regions with high EV adoption, such as Europe and North America. Notable automotive manufacturers and charging providers, including Volkswagen, Mercedes-Benz, and Tesla, have incorporated PnC into their vehicles and infrastructure. Charging networks like Electrify America in the U.S. and Ionity in Europe are also early adopters, providing drivers with a seamless charging experience and showcasing the potential for PnC to scale globally.
7. The future of plug & charge
7.1 Expanding interoperability across networks
As more players adopt ISO 15118-20, PnC’s interoperability will extend further, potentially allowing cross-compatibility with multiple standards and enhancing the user experience for global EV drivers. This broader interoperability may also foster competition, encouraging charging networks to offer more innovative features and services to retain customers.
7.2 The role of bidirectional charging
One of PnC’s most promising advancements is its support for bidirectional charging, which allows EVs to not only draw power from the grid but also return it during peak times. This functionality positions EVs as mobile energy storage units, which could stabilise the grid by providing temporary power relief. As bidirectional charging technology matures, it is expected to become an integral part of smart grid initiatives, further solidifying PnC’s role in the future energy landscape.
7.3 Future-proofing for security and compliance
PnC systems must evolve to keep up with cybersecurity threats and regulatory changes. This includes implementing cryptographic agility, where charging networks can quickly adopt stronger algorithms as technology advances. Staying compliant with data protection regulations, especially in regions with stringent privacy laws, will be crucial as PnC expands globally.
8. Conclusion
The Plug & Charge (PnC) standard is transforming the EV charging landscape, making EVs more accessible and user-friendly than ever before. By enabling seamless, secure charging and billing through an automated process, PnC is bridging the gaps that once existed in the EV infrastructure. Through its reliance on ISO 15118 and PKI-driven security, PnC not only simplifies the user experience but also enhances data security and trustworthiness across networks, addressing key issues that have previously hindered EV adoption.
While challenges remain—including infrastructure costs, the complexity of implementing and managing PKI systems, and the need for industry-wide cooperation—the progress so far demonstrates PnC’s strong potential to unify and streamline EV charging on a global scale. Major players in the automotive and energy sectors are adopting and refining PnC-compatible technology, indicating that PnC is on a trajectory to become the standard for EV charging.
Looking ahead, Plug & Charge will continue to evolve, driven by advancements in technology, regulatory requirements, and a shift towards smart, bidirectional energy use. As the standard matures, it will not only enhance the user experience but also play a critical role in supporting renewable energy integration and grid stability, positioning EVs as active participants in the energy ecosystem. In this way, Plug & Charge represents not only a practical solution for EV drivers but a pivotal technology in the transition to a sustainable, electrified future.