Storage · Storage + PV
Battery storage and solar PV combined
A PV system on the roof and a battery on site complement each other: the battery holds solar power until it is needed. We plan both together, as a new installation or as a retrofit to your existing system.
What the combination delivers
Use your own solar power
Whatever the PV system generates at midday beyond what the site needs at that moment charges the battery. In the evening and early morning the battery covers consumption instead of expensive grid power.
Peaks and grid connection
The same battery can absorb short load peaks. With demand metering, this lowers the capacity charge in the network tariff and relieves a tight grid connection.
Negative power prices
For PV systems commissioned since 25 February 2025, feed-in support generally lapses during hours with negative wholesale prices (Section 51 EEG). Whatever the site consumes or stores itself during these hours is unaffected.
Metering concept and grid charging
Whether the battery may charge only solar power or grid power as well is decided by the metering concept. Applicable today is the mode in which the battery charges exclusively renewable power (Section 19(3a) of the German Renewable Energy Sources Act, EEG); the PV system then keeps its feed-in support.
For mixed operation with grid charging and feed-in support (Section 19(3b) EEG), the implementing decision of the Bundesnetzagentur (Federal Network Agency) is still outstanding. Until then we do not plan on it but calculate with the rules that apply today.
New or retrofitted
For a new installation we size PV and battery together. In practice, an existing PV system can usually be retrofitted; we then check the inverters, meter location and metering concept and agree the change with the network operator.
Whether a battery pays off for you depends above all on daytime consumption, your electricity purchase price and your load peaks. When a battery pays off
For an initial assessment
Helpful are the load profile from your meter for the last twelve months (quarter-hourly values), a recent electricity bill and, if available, the data of your PV system. You receive the fixed price in writing once we have seen your data.
Planning PV and battery storage together? We will look at your data.