MiSpeL delineation option in practice: How much does mixed operation really cost?
Feb 19, 2026
A sample calculation with real market data shows: The costs of the delimitation option are surprisingly low.
In the last article, we presented the MiSpeL key points of the Federal Network Agency and explained the three options: Exclusivity option, delimitation option, and flat-rate option.
The delimitation option allows flexible mixed operations — battery storage can charge both PV power and grid power and still receive a proportional EEG subsidy. But how high is the price for that? Many operators fear that the proportional loss of the market premium makes mixed operation unattractive.
We have recalculated.
The example project
Our calculation is based on a real industrial project:
PV system: 2,000 kWp
Annual consumption: ~2 million kWh
Compensation model: Market premium model with a benchmark value of 6 ct/kWh
Spot prices: Real data Germany 2025
The battery is charged in mixed operation with both PV power and cheap grid power and is discharged again at high prices.
How is the green power share created?
The delimitation option requires a quarterly allocation of all electricity flows. The crucial factor is the green power share: How much of the energy stored in the battery comes from the PV system?
In our example, 52% of the battery charge comes from PV and 48% from the grid. This green power share of 52.04% determines what share of the battery feed-in receives the full EEG compensation.
The formula: What changes in the feed-in compensation?
Without MiSpeL — that is, under the previous exclusivity option (only possible with green power storage) — the entire battery feed-in receives at least the benchmark value, so either:
Spot price, if it is currently higher than the benchmark value OR
Market premium + spot price = benchmark value (except at negative times)
With the delimitation option, the market premium is proportionally reduced:
Compensation = Spot price + green power share × market premium
The guaranteed minimum price (floor) drops from 6.00 ct to 3.12 ct per kWh. However: This floor only applies if the spot price is below 6 ct. At higher spot prices, the formula results in the spot price anyway — with or without MiSpeL.
When does the reduction actually apply?
That is the crucial question. We have divided all hours when the battery feeds into the grid according to spot price levels:
The result is clear: 81.4% of the battery exports occur at spot prices above 6 ct — there the compensation is identical, whether with or without MiSpeL. This is also logical: The battery discharges preferentially at high prices, as that is what mixed operation is for.
The MiSpeL reduction only affects the 17.8% of exports at low spot prices (average 3.12 ct/kWh). In these hours, the compensation drops from 6.00 ct to 3.12 ct — a difference of 2.88 ct/kWh on a relatively small volume of 15,227 kWh.
The result
The MiSpeL costs amount to 416 €/year. This is less than 1% of the total feed-in compensation.
What would be the alternative?
Those who use the delimitation option accept a proportional reduction of the market premium. But what is the alternative? Retaining the full market premium with mixed operation is not possible — that is exactly what MiSpeL regulates. Those who want to avoid the reduction must completely forgo the EEG compensation and go purely into direct marketing.
We calculated the same project with pure direct marketing:
Without the market premium, the battery achieves a higher average price per kWh — it only exports at high spot prices. However, the PV direct feed-in completely loses the market premium: instead of at least 6 ct/kWh, it only receives the spot price, which is often significantly lower. The different feed-in quantities in the table are explained by negative spot prices: With a market premium, the rate is set to 0 ct and the PV continues to feed in — in direct marketing, it is instead curtailed. Economically, there is no difference (both result in 0 €), but it explains the difference of around 60,000 kWh.
In summary, one loses over 5,000 € per year with pure direct marketing compared to the market premium with the delimitation option. Accepting the MiSpeL costs of 416 €/year is about 12 times cheaper than foregone market premium.
Conclusion
The delimitation option is practically very inexpensive. Mixed operation is clearly economically advantageous — the flexibility gained far outweighs the proportional reduction of the market premium.
Operators should not see the delimitation option as a cost risk, but as what it is: the opportunity to fully exploit the economic potential of their PV storage combination.
