What is §14a EnWG and when does it apply?
§14a EnWG (Energy Industry Act) regulates how grid operators can temporarily reduce - but not turn off - the power consumption of assets, known as controllable consumption units, during periods of grid stress. In exchange, the homeowner receives a reduction in grid fees.
§14a applies to newly installed assets with a nominal connected load of more than 4.2 kW, including:
electric vehicle (EV) charging stations
Heat pumps
Battery storage systems (via inverter)
Night storage heaters
Air conditioning systems
When one or more qualifying assets are installed, the home energy management system (HEMS) gateway acts as the EMS (energy management system). It receives power limits from the grid operator via a control box and distributes them across all assets relevant to §14a. The gateway ensures that their combined energy consumption remains within the specified limit. As a result, one asset can consume more than 4.2 kW as long as another asset consumes less, thereby balancing overall energy usage.
§14a only applies to installations located in Germany. The §14a step appears in the commissioning wizard only when you select Germany as the system's location.
How do I configure §14a during commissioning?
The §14a step is included in the commissioning wizard. By default, all assets identified during the system scan that qualify are pre-selected as relevant for §14a. However, you can exclude assets with a maximum power consumption of less than 4.2 kW from §14a on an individual basis.
After confirming the legal acknowledgment, the selected assets are marked as §14a relevant, and the HEMS gateway is configured to monitor and control them whenever a grid operator's power limit is active.
The asset selection in the commissioning wizard must align with the §14a registration submitted to the grid operator. The §14a registration process is handled separately from the commissioning wizard.
How do I find the HEMS gateway EEBUS SKI?
The EEBUS SKI (Subject Key Identifier) uniquely identifies the HEMS gateway for the grid operator and the control box. It is necessary to submit the §14a registration to initiate EEBUS pairing.
You can see the SKI on the commissioning success screen, and it is also available in the XENON Dashboard and the end-customer app.
How do I pair the HEMS gateway with a control box?
The control box is installed by the metering service operator (MSO) and enables the grid operator to send §14a control signals to the HEMS gateway through EEBUS. Pairing can be initiated at any point during the commissioning process or afterward. For successful pairing, both the control box and the HEMS gateway must be connected to the same home network.
The EEBUS connection screen can be accessed through the troubleshooting flow in the Installer Hub or directly via the XENON Dashboard. If the HEMS gateway SKI is already saved on the control box, pairing will occur automatically. However, if the SKI is not stored, the HEMS gateway will keep attempting to pair. Please refer to the scenarios below for more details.
Pairing scenarios
The pairing process varies depending on whether the control box is installed at the time you commission the HEMS gateway. The different scenarios are detailed in the VDE FNN Hinweis Inbetriebnahmeprozess der Verbindung zwischen Steuerungseinrichtungen und steuerbaren Einrichtungen (Version 1.0, October 2025).
Scenario A: The control box is not yet installed
The control box will be installed by the MSO at a later date.
Commission the HEMS gateway as usual; pairing is not yet possible.
On the success screen, make sure to copy the HEMS gateway SKI.
Next, notify the grid operator by reporting the §14a-relevant assets. Choose "EMS" as the steering method and submit the HEMS gateway SKI to either the grid operator or the MSO, typically through the installer portal.
Once the MSO installs the control box, they will import the HEMS gateway SKI.
After the SKI is stored on the control box, pairing will automatically complete during one of the HEMS gateway's periodic EEBUS scans.
The customer's grid fee reduction begins in the month the installer submits the §14a notification, rather than when pairing is completed.
Scenario B: The control box is already installed
After the asset scan completes, proceed to the EEBUS connection screen in the commissioning wizard and initiate the pairing.
Situation 1: Pairing succeeds immediately
The HEMS gateway SKI was already saved on the control box. The system can immediately receive and act on §14a control signals.
Situation 2: Pairing does not complete
The HEMS gateway SKI has not yet been saved on the control box. Please continue the pairing attempt, complete the commissioning process, and submit the HEMS gateway SKI to the grid operator or MSO. Once the MSO stores the SKI on the control box, the pairing will complete automatically.
Situation 3: The control box is not found
Check the Ethernet cabling between the control box and the home network and trigger a new scan. If the control box is still not found, contact support.