Zeitversetzte PV-Einspeisung – zwischen Regulierung und Rendite

For companies, energy supply is becoming an increasingly strategic issue - one reason why photovoltaic systems are booming in the commercial and industrial sectors. In times of rising electricity prices, ambitious climate goals, and technological innovations such as battery storage, the time-shifted feed-in of solar power is gaining importance. But how economically attractive is this model really - and what regulatory hurdles must be overcome?

Status quo of EEG remuneration

According to the EEG 2023, the financing of larger PV systems is based on the market premium model (§ 20 EEG). Here, the generated electricity is marketed directly on the spot market. The difference between the market proceeds and the legally defined so-called “value to be applied” is offset by the market premium. Billing is carried out every 15 minutes by the transmission system operators.

For systems on buildings or noise barriers, an additional building bonus applies if the system is fully installed on or adjacent to a building (§ 48 EEG). In the case of partial feed-in - when part of the electricity is consumed on-site and the rest is fed into the grid - the following values to be applied apply (as of July 2025) (Federal Network Agency):

These values refer to the case of market premium marketing with building bonus. The actual proceeds consist of the respective market value solar plus the individual market premium. The monthly determined “market value solar” reflects the average proceeds at the electricity exchange achieved through the direct marketing of solar power subsidized under the market premium model.

For commercial or industrial PV projects, this means: The larger the system, the lower the remuneration rate - although this can often be economically offset by higher self-consumption shares, storage integration, and the avoidance of electricity costs through self-supply.

Exclusivity principle, delimitation option, exclusivity option - and what applies in the event of re-feed

Exclusivity principle (§ 3 No. 1 EEG)

A central component in the EEG regulations is the so-called exclusivity principle (§ 3 No. 1 EEG). It stipulates: Only if electricity is exclusively generated from a renewable energy plant, it is considered eligible EEG electricity. For operators of photovoltaic systems with battery storage, this means specifically: Only if the storage is exclusively charged with PV electricity, the stored and later fed electricity remains eligible - for example, within the market premium in direct marketing.

Once the storage is even partially charged with grid electricity (“grey electricity”), this claim to remuneration is lost. The stored electricity loses its “EEG status” and is treated like conventional electricity - without support but with charges. Network fees, electricity tax, and other levies may apply.

Delimitation option (§ 19 Para. 3b EEG)

To counter this risk, the legislator has created the delimitation option. Operators can through a technical measurement concept - such as with separate meters - prove seamlessly which share of the electricity in storage comes from their own PV generation. This cleanly delimited share remains recognized as EEG electricity despite later feeding and can be remunerated with the market premium. The delimitation is thus a technical solution to “save” the exclusivity principle, even if the storage also uses other sources.

⚠️ Important: Measurements must be precise and comply with legal requirements. Without reliable proof, the entitlement to remuneration for the entire storage electricity is lost.

Technically required are exact balance steering and active participation in direct marketing. Storage systems must be integrated via remote control, forecast values, and market value notifications in accordance with § 9 EEG. Measurement concepts require smart meters that precisely distinguish between PV, grid, and storage electricity.

Legally, the topic remains complex: The delimitation option can only be successfully used if the operator proves seamlessly and technically impeccably which share of the stored electricity comes exclusively from their own EEG plant. If this proof is not clear - for example, due to a measurement error or unclear allocation - all stored electricity is considered non-eligible. In this case, the claim for market premium or feed-in remuneration for the entire storage content disappears, even if PV electricity was actually stored in part.

Exclusivity option

The exclusivity option is another way to meet the exclusivity principle - a kind of regulatory shortcut: The storage is operated exclusively with PV electricity by design. This can be achieved, for example, through structural separation, programmed control, or deliberate avoidance of grid storage. In this case, no technical delimitation is required - the storage is systemically considered EEG-compliant. This means: It suffices if the operator credibly assures the network operator and the Federal Network Agency that the storage is operated exclusively with PV electricity.

The exclusivity option is often attractive for smaller operators because it saves measurement and retrofitting effort. In return, it severely restricts the flexibility of storage operation.

Future of EEG remuneration

The foregoing assumes a decision for fixed EEG remuneration. However, this is not absolutely necessary. EEG remuneration, especially for larger plants, is steadily decreasing and its future is uncertain. For operators, this means: The later the commissioning, the lower the guaranteed remuneration rate. Therefore, marketing outside the EEG - such as through PPAs, participation in the balancing energy market, or self-consumption - is becoming increasingly attractive.

Feed-in without EEG remuneration

If EEG remuneration is waived, the marketing of the PV surplus is carried out directly on the electricity market at the current exchange price. This is volatile and often falls below the previous guaranteed remuneration rates during times of high solar radiation (lots of PV surplus). A battery storage can help in this scenario to shift feed-in times. Thus, electricity can be delivered in phases with higher market prices, increasing proceeds and reducing dependence on current price peaks in the electricity market. At the same time, the abolition of EEG remuneration allows for more flexible operation of the storage: Grid electricity could also be stored sensibly - such as during negative market prices - creating additional application cases that are economically viable.

Conclusion

The combination of declining EEG remuneration and growing market volatility is increasingly shifting the focus towards flexible direct marketing. Battery storage plays a central role in this: Not only do they enable the time-shifted feed-in of PV electricity at better market prices, but they also open up new application fields beyond the EEG logic. Those who take regulatory requirements into account can use storage as a strategic marketing instrument in the future - both for economic optimization and for system-beneficial grid integration.

Sources:

• EEG support rates and market premiums (Federal Network Agency) swlandau.de+4Federal Network Agency+4geb-info.de+4

• Delimitation and exclusivity principle (EEG §§3, 19)

• Market value solar, network charges, network design