Solar system with battery: the rules that apply
Short answer
A rooftop solar system with storage is not a plug-in balcony device, so you notify the grid operator and the Marktstammdatenregister. You also register a stationary battery there as its own unit.
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Registering the system and the battery
You register the solar system in the Marktstammdatenregister within one month after commissioning. You inform the grid operator before commissioning, and you do not register portable batteries or power stations.
What the battery changes about the tariff
The battery raises self-consumption, and the EEG payment for electricity fed into the grid remains. Current rates sit in the 2026 feed-in tariff tip, and the 800 VA balcony rules do not apply here.
What federal support the government names
KfW finances the solar system and the battery through the Erneuerbare Energien Standard programme as a loan. The federal government does not name a fixed grant amount for the battery. You file the application with your house bank before the project starts.
The overview is on the Solar PV system topic page, and selected providers sit in the provider list.
Official sources
Open the MaStR help on the duty to register →
Open KfW Erneuerbare Energien Standard →
More information
Open selected solar providers →
Open Solar PV system →