Deep dive: Charging standards & interoperability (NACS, CCS) — the fastest-moving subsegments to watch

Tesla's North American Charging Standard (NACS) connector became the de facto standard for new EV models in North America after every major automaker, including Ford, GM, Rivian, Hyundai, BMW, and Mercedes-Benz, committed to adopting it between mid-2023 and early 2025 (SAE International, 2025). By the end of 2025, NACS connectors were available at over 72,000 charging stalls across North America, representing a 340% increase from the Tesla-only Supercharger network just two years earlier. In parallel, the Combined Charging System (CCS) remains the dominant DC fast charging standard across Europe, parts of Asia, and Latin America, with over 180,000 CCS-equipped stalls globally (International Energy Agency, 2025). For procurement teams managing charging infrastructure investments across emerging markets, understanding which interoperability subsegments are moving fastest determines whether today's capital expenditure will remain compatible with the fleets and vehicles of 2030.

Why It Matters

Charging standards fragmentation creates real financial risk. A single DC fast charger costs $100,000 to $250,000 to install depending on power level and site conditions. Deploying infrastructure on a connector standard that loses market adoption can strand assets with 10 to 15 year expected lifespans. The convergence around NACS in North America resolved one layer of uncertainty, but globally the landscape remains complex: CCS1 and CCS2 serve different regional variants, China's GB/T standard dominates the world's largest EV market, and CHAdeMO continues to operate across Japan's legacy infrastructure.

The interoperability challenge extends beyond the physical connector. Communication protocols, payment systems, and network roaming agreements determine whether a driver can seamlessly charge on any network. The Open Charge Point Protocol (OCPP) has emerged as the leading standard for charger-to-network communication, but implementation quality varies widely. A 2025 audit by the Joint Office of Energy and Transportation found that 23% of public chargers in the United States experienced session failures linked to OCPP implementation inconsistencies, costing network operators an estimated $380 million in lost revenue annually (Joint Office of Energy and Transportation, 2025).

For emerging markets, the standards decisions made today will shape EV adoption trajectories for decades. India's Bureau of Indian Standards adopted CCS2 with a domestic variant (IS 17017) for DC fast charging, but the market is simultaneously seeing deployment of GB/T-compatible chargers for Chinese-manufactured EVs entering the market at lower price points. Southeast Asian nations are split: Thailand has adopted CCS2, Indonesia is evaluating both CCS2 and GB/T, and the Philippines has not yet mandated a standard. This fragmentation creates procurement complexity and increases the cost of multi-market charging infrastructure deployment by 20 to 35% compared to unified-standard regions (McKinsey, 2026).

Key Concepts

North American Charging Standard (NACS) is a connector and communication protocol originally developed by Tesla and published as an open standard in November 2022. SAE International formalized it as SAE J3400 in June 2024. The NACS connector is physically smaller than CCS1, supports up to 1 MW of DC charging power, and integrates both AC and DC charging in a single port. Its adoption across the North American automaker ecosystem eliminated the need for dual-port vehicles in that region and simplified infrastructure procurement decisions.

Combined Charging System (CCS) encompasses two regional variants: CCS1 (Type 1 + DC pins) used primarily in North America's legacy infrastructure and parts of Asia, and CCS2 (Type 2 + DC pins) dominant in Europe, Australia, India, and several emerging markets. CCS supports power levels up to 350 kW under the current specification, with Megawatt Charging System (MCS) extensions targeting 1 MW and above for heavy-duty applications. CCS remains the standard endorsed by CharIN, the industry consortium of over 300 members coordinating global charging interoperability.

Open Charge Point Protocol (OCPP) is a communication protocol between charging stations and central management systems. Version 2.0.1, released in 2020, supports advanced features including smart charging, ISO 15118 Plug & Charge authentication, and device management. Procurement teams should require OCPP 2.0.1 compliance as a minimum specification for any new charger deployment to ensure future interoperability and avoid vendor lock-in.

Plug & Charge (ISO 15118) enables automatic authentication and billing when a vehicle is connected to a charger, eliminating the need for RFID cards, mobile apps, or credit card readers. The vehicle and charger exchange digital certificates during a TLS handshake that occurs within 2 to 5 seconds of cable connection. Adoption has accelerated from fewer than 5% of public DC fast chargers supporting the standard in 2023 to over 28% in 2025 (CharIN, 2025).

What's Working

NACS Adapter and Dual-Standard Retrofits

The NACS transition in North America has created a fast-moving retrofit and adapter subsegment. ChargePoint, EVgo, and Electrify America collectively announced plans to retrofit over 18,000 existing CCS1 stalls with dual NACS/CCS1 capability by the end of 2026. The retrofit cost ranges from $3,500 to $8,000 per stall depending on whether the upgrade involves a cable swap or a full dispenser replacement. Tesla began distributing free NACS-to-CCS1 adapters to non-Tesla EV owners in early 2025 and sold over 2 million adapters within the first six months at $170 each, generating approximately $340 million in adapter revenue alone (Tesla, 2025).

For procurement teams in emerging markets, the NACS precedent demonstrates how quickly a connector standard can shift. Charger manufacturers including ABB E-mobility, Tritium, and Kempower now offer modular dispenser designs that allow field-swappable connector cables, reducing the risk of standard obsolescence. A modular DC fast charger with swappable connectors adds 8 to 12% to the upfront cost but eliminates the need for full unit replacement if standards evolve.

OCPP-Based Network Interoperability

The deployment of OCPP 2.0.1-compliant charging networks is accelerating across emerging markets. India's Central Electricity Authority mandated OCPP 2.0.1 compliance for all publicly funded charging infrastructure starting in 2025, and Brazil followed with a similar requirement for chargers receiving BNDES financing. Hubject, the largest EV roaming platform, processed over 45 million cross-network charging sessions in 2025, up from 18 million in 2023, demonstrating that protocol-level interoperability is translating into real user behavior (Hubject, 2025).

In Southeast Asia, the ASEAN EV Charging Interoperability Framework, endorsed by energy ministers in October 2025, requires OCPP 2.0.1 and ISO 15118 compliance for all cross-border charging corridors. Thailand's PTT-operated charging network, the largest in Southeast Asia with 3,200 stalls, completed its OCPP 2.0.1 migration in Q3 2025 and reported a 40% reduction in session failure rates within four months of the transition.

Megawatt Charging System (MCS) Development

The Megawatt Charging System standard, targeting 1 MW and above for heavy-duty trucks and buses, is the fastest-moving subsegment for commercial fleet applications. CharIN published the MCS connector specification in 2024, and pilot installations are now operational at five sites across Germany, the Netherlands, and the United States. Daimler Truck and Volvo Group jointly tested MCS at a 3.75 MW power level at their Portland, Oregon test facility, achieving an 80% state-of-charge recharge in under 30 minutes for a Class 8 battery electric truck with a 600 kWh battery pack. The California Energy Commission allocated $150 million for MCS corridor deployment along the I-5 and I-10 freight routes, with the first public MCS stations expected online by mid-2027.

What's Not Working

Regional Standards Fragmentation in Emerging Markets

The lack of a single global DC fast charging standard continues to increase costs and slow deployment in emerging markets. Charging point operators (CPOs) deploying across multiple Southeast Asian and South Asian markets must stock and maintain inventory for CCS2, GB/T, and sometimes CHAdeMO connectors. A CPO operating in India, Thailand, and Indonesia reported that multi-standard support adds 25 to 30% to per-stall costs and increases maintenance complexity due to different communication protocols between GB/T and CCS2 systems. Efforts to harmonize standards through organizations like CharIN and the IEC are progressing slowly: the IEC 61851 revision incorporating both CCS and GB/T interoperability requirements is not expected to reach final publication until 2028.

Payment and Roaming Friction

Despite progress on OCPP adoption, the payment and roaming experience for EV drivers in emerging markets remains fragmented. A driver in India may encounter chargers requiring four different mobile apps, two different RFID cards, and at least one network that only accepts a proprietary payment method. The Open Charge Point Interface (OCPI) protocol, which enables roaming between networks, has been adopted by fewer than 35% of CPOs in emerging markets compared to over 70% in Western Europe (Gireve, 2025). This friction suppresses utilization rates: chargers in markets with strong roaming interoperability achieve 12 to 18% utilization, while those without roaming support average 5 to 9%.

Plug & Charge Deployment Lag

While ISO 15118 Plug & Charge dramatically improves user experience, deployment in emerging markets lags significantly behind Europe and North America. The standard requires a Public Key Infrastructure (PKI) ecosystem with certificate authorities, vehicle OEM participation, and CPO integration. In markets where domestic automakers and imported vehicles from multiple regions coexist, establishing a PKI chain of trust is complex. India's sole Plug & Charge pilot, operated by Tata Power across 50 chargers in Mumbai, found that only 12% of connected vehicles supported the ISO 15118 handshake, limiting practical impact. Until vehicle-side adoption reaches critical mass, the investment in charger-side Plug & Charge capability yields low returns.

Key Players

Established Companies

• ABB E-mobility: a global leader in DC fast charging hardware, offering modular chargers with field-swappable NACS, CCS, and GB/T connectors and OCPP 2.0.1 compliance across all product lines
• CharIN: the industry consortium with over 300 members coordinating global charging standards, leading MCS development, and publishing interoperability test specifications
• Schneider Electric: provider of EV charging management software and power distribution systems for large-scale charging depots, with deployments across 40 countries including emerging markets in India and Southeast Asia
• Tesla: operator of the largest global fast-charging network with over 72,000 NACS stalls and the driving force behind NACS adoption as an open standard through SAE J3400

Startups

• Kempower: a Finnish charging hardware manufacturer specializing in modular, scalable DC fast charging systems with dynamic power sharing and multi-standard connector support
• Hubject: a Berlin-based eRoaming platform connecting over 550 CPOs and 450,000 charging points globally, enabling cross-network session authentication and billing
• Exicom: an Indian EV charging infrastructure company offering CCS2 and GB/T compatible chargers with OCPP 2.0.1 compliance, deployed across 7,000 charging points in India

Investors

• BlackRock Climate Infrastructure: allocated $1.5 billion to EV charging infrastructure investments globally, with a focus on interoperable networks in high-growth emerging markets
• Asian Infrastructure Investment Bank (AIIB): providing $800 million in financing for EV charging corridor development across South and Southeast Asia, requiring OCPP compliance as a lending condition
• Macquarie Green Investment Group: invested in charging infrastructure platforms across India and Australia, backing operators committed to open interoperability standards

KPI Benchmarks by Use Case

Metric	Public DC Fast Charging	Fleet Depot Charging	Highway Corridor Charging
Session success rate	92-97%	97-99%	88-95%
OCPP compliance rate	65-85%	80-95%	55-75%
Average utilization rate	8-18%	70-90%	12-22%
Plug & Charge support	15-30%	5-15%	10-25%
Roaming-enabled sessions	25-45%	N/A	30-55%
Multi-standard connector coverage	60-80%	40-60%	50-70%
Charger uptime	93-97%	96-99%	90-95%

Action Checklist

• Specify OCPP 2.0.1 compliance and ISO 15118 readiness as mandatory requirements in all charging infrastructure procurement RFPs
• Select charger hardware with modular, field-swappable connector designs to mitigate standard obsolescence risk
• Evaluate roaming platform partnerships (Hubject, Gireve, or regional equivalents) to maximize network utilization and user access
• Assess vehicle fleet connector compatibility across all planned deployment markets before committing to a single standard
• Include MCS readiness requirements in depot and corridor charging specifications for heavy-duty vehicle applications
• Negotiate vendor contracts with technology refresh clauses that cover connector standard upgrades at predetermined costs
• Implement charger uptime monitoring with minimum 95% availability SLAs and financial penalties for non-compliance
• Establish a payment acceptance strategy that includes contactless credit/debit, mobile wallets, and RFID to minimize user friction

FAQ

Q: Should procurement teams in emerging markets standardize on CCS2 or plan for multi-standard deployments? A: CCS2 is the safest baseline for emerging markets outside China, as it has the broadest automaker support and is the mandated standard in the EU, India, Australia, Thailand, and Brazil. However, in markets with significant Chinese vehicle imports (Indonesia, parts of Africa, Central Asia), GB/T compatibility is essential. The recommended approach is to procure modular chargers that support CCS2 as the primary standard with GB/T as an optional add-on connector, adding approximately $2,000 to $4,000 per stall. Avoid CHAdeMO for new deployments unless serving a legacy Japanese vehicle fleet.

Q: What is the cost impact of requiring OCPP 2.0.1 compliance versus accepting proprietary protocols? A: OCPP 2.0.1-compliant chargers typically cost 3 to 8% more than proprietary alternatives at the hardware level. However, the total cost of ownership over a 10-year horizon is 15 to 30% lower due to reduced vendor lock-in, competitive software licensing, and the ability to switch network management platforms without replacing hardware. Proprietary chargers often carry annual software licensing fees of $200 to $600 per stall that compound over the asset's lifetime. OCPP compliance also qualifies infrastructure for public funding programs in India, Brazil, and several ASEAN nations.

Q: How soon will Megawatt Charging System stations be commercially available? A: MCS-capable chargers from ABB, Kempower, and Siemens are expected to reach commercial availability in 2027, with initial deployments concentrated along high-traffic freight corridors in Europe and North America. Emerging market deployment is likely 2 to 3 years behind, with China developing a parallel high-power standard through the GB/T framework. Procurement teams specifying depot charging for heavy-duty fleets should include MCS-ready electrical infrastructure (adequate transformer capacity, cable routing, and switchgear) even if MCS chargers are not yet available, as the civil and electrical preparation typically represents 40 to 60% of total installation cost.

Q: What metrics best indicate charging network interoperability quality? A: Track four metrics: session success rate (target >95%), cross-network roaming session percentage (higher indicates better interoperability), first-attempt authentication success rate (target >98%), and mean time to resolve interoperability incidents (target <4 hours). Networks scoring well across all four metrics typically achieve 30 to 50% higher utilization than those with poor interoperability, directly improving revenue per charger and shortening payback periods.

Sources

• SAE International. (2025). SAE J3400: North American Charging Standard Technical Specification and Adoption Update. Warrendale, PA: SAE.
• International Energy Agency. (2025). Global EV Outlook 2025: Charging Infrastructure and Standards Analysis. Paris: IEA.
• Joint Office of Energy and Transportation. (2025). National EV Charging Reliability Report: Session Success Rates and Failure Mode Analysis. Washington, DC: Joint Office.
• McKinsey & Company. (2026). EV Charging Infrastructure in Emerging Markets: Standards, Costs, and Deployment Strategies. New Delhi: McKinsey.
• CharIN. (2025). Annual Interoperability Report: Global Charging Standards Deployment and MCS Development Progress. Berlin: CharIN.
• Hubject. (2025). eRoaming Market Report 2025: Cross-Network Charging Session Volumes and Growth Trends. Berlin: Hubject.
• Gireve. (2025). Global EV Roaming Observatory: Adoption Rates and Market Fragmentation Analysis. Paris: Gireve.
• Tesla. (2025). Q2 2025 Earnings Report: Supercharger Network Expansion and NACS Adapter Sales. Austin, TX: Tesla.