Analysing and Optimising Electricity Prices under the EEG

For PV operators in Germany, the price you actually earn is not the exchange spot price alone — it is the combination of your guaranteed EEG value, the official market premium, and the deductions triggered by negative prices. This page explains how the EEG market premium is calculated, which reference price is the correct one, and how the §51 negative-price rules reduce revenue, so you can analyse and optimise your electricity earnings on a factual basis.

How the EEG market premium is calculated

The EEG market premium closes the gap between your guaranteed anzulegender Wert (applicable value) and the official market value of solar power. In the Stromfee reference case the applicable value is 71 €/MWh (7.10 ct/kWh) from an EEG 2023 auction, while the official quarterly solar market value published by the BNetzA was 55.8 €/MWh for Q1 2025 (5.58 ct/kWh). The market premium fills the difference between these two figures.

On top of the applicable value, a management premium is paid for the effort of direct marketing. In the documented Stromfee case this management premium is 1.2 €/MWh (0.12 ct/kWh). Both the applicable value and the management premium come from the specific contract and auction round, so they must be read from the operator's own tariff documents rather than assumed.

Which reference price is the correct one

A recurring source of error is mixing up three different price references. For the EEG market premium the correct figure is always the official BNetzA quarterly solar market value (MW_Solar) — for example 55.8 €/MWh in Q1 2025. This is the value that legally determines the premium.

The annual average solar market value (47.6 €/MWh in the referenced dataset) is only a forecast assumption and must not be used for the actual premium settlement. The hourly spot price is a third, separate figure: it is used for internal direct-marketing margin calculations, not for the EEG premium itself. Keeping these three references apart is essential for any correct EEG price analysis.

§51 EEG: when the negative-price rule cuts your payment

Under §51 EEG, EEG payment is set to zero during sustained periods of negative exchange prices. The rule has been tightened in stages. The older 'soft' variant (commissioning 2021–2023, from about 500 kW) applied after six consecutive hours of negative prices. The 'mid' variant under Solarpaket I (from 2024, from about 400 kW) shortened this to four hours.

The current 'hard' variant (from 2025, from about 100 kW) applies the four-hour negative-price cut to a much larger fleet of smaller installations. For an operator, this means the number of hours during which generation earns nothing has grown, and the size threshold at which the rule bites has dropped to 100 kW. Analysing how many of your hours fall under this cut is a direct lever on annual revenue.

Direct marketing and the FRE obligation

Installations of 100 kWp and above have been subject to mandatory direct marketing since 2021, which also requires remote-controllability (Fernsteuerbarkeit, FRE). Direct marketing means the electricity is sold on the exchange and the operator receives the market premium on top, rather than a fixed feed-in tariff.

The reference price source for this settlement is the EPEX day-ahead auction for the DE/LU zone, using the day-ahead hourly contracts. Because the day-ahead auction sets the price for each hour of the following day, it is also the price signal an operator can plan against — the same hourly structure used to decide when generation, storage or flexible loads are worth running.

Using day-ahead prices to optimise

Because the day-ahead auction publishes hourly prices for today and tomorrow, operators can see in advance which hours are high-priced and which turn negative. Stromfee's 'Strompreise live' tool shows these hourly exchange prices for today and tomorrow, and the Strompricemanager provides real-time pricing data and supports dynamic tariffs.

This hourly visibility is the basis for optimisation: shifting flexible consumption into low-price hours, curtailing or storing generation during negative-price windows that would otherwise trigger the §51 cut, and timing loads such as vehicle charging. The eTruck fleet simulator on stromfee.ai illustrates such load-shifting against a €/MWh price curve — note that it runs on example values, not live market data or measurements.