OpenADR

OpenADR uses a client-server topology where a Virtual Top Node (VTN) publishes event signals to Virtual End Nodes (VENs) at charging sites. Signals contain start time, duration, and signal type—either price-based (e.g., time-of-use rates) or reliability-based (e.g., grid emergency curtailment). The VEN autonomously executes a pre-programmed response, such as reducing charging rate or deferring sessions, without human intervention.

The protocol defines three transport mechanisms to ensure interoperability across diverse infrastructure:

• OpenADR 2.0a: Simple HTTP push/pull for basic price and event signals
• OpenADR 2.0b: Full-featured profile with XML payloads, reporting, and opt-out capabilities
• OpenADR 3.0: Next-generation RESTful API using JSON and WebSockets for real-time bidirectional communication

All profiles ensure that any certified EVSE can receive and act on utility signals regardless of manufacturer.

Unlike rigid direct load control, OpenADR preserves customer autonomy through mandatory opt-out mechanisms. A VEN can decline participation in a demand response event based on local constraints such as:

• Minimum State of Charge requirements for fleet departure schedules
• Critical operational needs (e.g., emergency vehicles)
• User-defined override preferences

The VEN reports its participation status back to the VTN, enabling utilities to accurately forecast available load reduction capacity.

OpenADR includes built-in telemetry reporting that closes the loop between signal dispatch and actual load reduction. VENs transmit interval meter data, baseline consumption, and calculated savings back to the VTN. This enables:

• Settlement of financial incentives based on verified performance
• Regulatory compliance documentation for utility demand response programs
• Continuous refinement of baseline models for more accurate forecasting

The M&V framework transforms EV charging from an uncontrolled load into a dispatchable grid resource.

OpenADR operates alongside other EV communication standards to create a complete demand response stack:

• OCPP: Manages charger-to-CMS communication; OpenADR signals inform the CMS's charging schedules
• ISO 15118: Handles vehicle-to-charger authentication; OpenADR provides the grid-side price signals that justify bidirectional discharge
• IEEE 2030.5: Alternative smart inverter protocol; OpenADR often bridges utility operations with behind-the-meter DER aggregation

This layered architecture ensures that grid signals propagate seamlessly from the utility control room to the EV battery management system.

The OpenADR Alliance maintains a rigorous certification program that validates conformance and interoperability. Certified products undergo:

• Conformance testing against the OpenADR 2.0b profile specification
• Interoperability testing with multiple VTN implementations
• Security validation including TLS encryption and digital signature verification

Certification ensures that utility procurement teams can confidently deploy OpenADR-compliant EVSE knowing they will interoperate with existing demand response management systems (DRMS).

A load management strategy that reduces grid power consumption during high-demand intervals using stored energy or load curtailment. OpenADR signals can trigger automated peak shaving routines in EV charging infrastructure by:

• Temporarily reducing charging rates
• Discharging stationary battery storage
• Activating on-site generation This avoids expensive demand charges for commercial fleet operators while relieving stress on distribution transformers.

A centralized software platform that monitors, schedules, and optimizes charging for multiple EVs while respecting operational constraints. A FEMS integrates OpenADR client capabilities to receive utility price and event signals, then uses Model Predictive Control (MPC) or Mixed-Integer Linear Programming (MILP) to compute optimal charging schedules that minimize cost while ensuring vehicles are ready for their scheduled routes.