ElaadNL accelerates interoperability for a flexible energy system

From separate devices to coordinated flexibility

Many smart devices can already be monitored or controlled digitally, but installation is not straightforward for consumers. Different manufacturers still use different interfaces, protocols and cloud environments. As a result, connecting an EV charger, heat pump, battery or PV inverter to a Home Energy Management System (HEMS) often requires a dedicated integration. This increases development effort, complicates installation and limits adoption and as a result scalability.

Once installed, HEMS can in theory provide the coordination layer between the home and the broader energy system. It can receive external signals, combine these with household preferences and device availability, and coordinate how flexible devices behave in time.

The paper identifies three priority use cases for fully interoperable HEMS: dynamic tariff optimisation, self-consumption and limiting peak grid demand. By combining all three use cases, device usage can be optimised on grid capacity and costs, whilst respecting the needs of the individual households connected.

A limited protocol set creates room to scale

Interoperability does not mean that every device needs to support every protocol. The approach described by ElaadNL is deliberately limited. For communication from the outside world towards the home, OpenADR has been selected. For communication between HEMS and devices, EEBus, Matter, OCPP and S2 are in scope, with OCPP specifically positioned for EV charging.

A HEMS should support all selected protocol sets, while a smart device only needs to support at least one of the selected in-home protocols. This gives manufacturers freedom in their technical choices while creating a common basis for interoperability.

ElaadNL turns interoperability into implementation

Interoperability does not emerge from standards alone. It has to be implemented, tested and improved in practice.

ElaadNL has initiated the development of reusable open-source software modules for the selected protocols and has also commissioned the development of a converter to include legacy devices that operate on Modbus. These building blocks will soon be released to manufacturers, who will be able to increase the applicability of their devices.

Testing will show whether independently developed products can actually work together. For this, ElaadNL organises interoperability test events in which HEMS providers, device manufacturers and protocol organisations test their implementations and identify differences in interpretation at an early stage. This creates a practical cycle in which implementation, testing, market adoption and standards improve in parallel.