Concepts · Chapter 14
Grid rules: §9 EEG, §14a and iMSys
Sounds like a bureaucratic trap, but is usually harmless — what the rules mean and why they barely touch your self-consumption.
As of 2026 — rules and thresholds can change; verify with your grid operator if in doubt.
A few paragraphs always come up with PV + heat pump and sound threatening. For a self-consumption-oriented household they're usually harmless. Here's the essence.
§9 EEG & the intelligent metering system (iMSys)
Above a certain system size (typically > 7 kWp) an intelligent metering system (iMSys) is mandatory. Importantly, it's installed by the metering point operator, not your PV company.
Until the iMSys with control box is active, a temporary 60% feed-in cap often applies (Solarspitzengesetz). Two reassurances:
- It affects only feed-in (export), not your self-consumption.
- It lifts once the smart-meter gateway + control box are commissioned.
For a self-consumption-designed system (battery, heat pump, car) this is nearly irrelevant.
§14a EnWG — controllable consumers
Heat pump and wallbox count as controllable consumers. Under §14a you get reduced grid fees, and in return the grid operator may briefly throttle them at peak times. This needs a controllable meter-cabinet setup. In practice the throttling is rare and mild — and the saving runs continuously.
What you must do — little
- Ensure the vendor handles the grid registration and coordination with the metering operator (most do).
- Know that modern inverters are curtailment-ready ("Eins-Man-Ready") anyway.
- Don't forget the Marktstammdatenregister registration (more in the funding/execution part) — you do this yourself, free, online.
The positive twist
The controllability these rules require is exactly the controllability you want anyway: it's the infrastructure for dynamic tariffs and self-consumption optimisation. Rule compliance and your own strategy use the same technology.
In short: §9/iMSys = installed by the metering operator, the 60% cap is temporary and hits only export; §14a = reduced grid fees for brief throttling. For self-consumption, none of it is a big deal.
That nearly completes the technical round. Now it gets practical: comparing offers honestly — and the hidden costs.
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