German storage revenues remained high in July, says Enervis

Enervis’ monthly battery storage index tracks the historical and potential revenues available to large-scale battery energy storage systems (BESS) in Germany across the spot and balancing markets.

For July, the modeled revenues fell by around 6% from June to approximately €16,950/MW, but remained around 40% above the unusually low level recorded in July 2025.

The decline was mainly due to narrower spot-market spreads, with day-ahead spreads falling by around 20% from June as major price spikes and negative-price events became less frequent.

Market volatility nevertheless remained relatively high, with elevated evening prices driven in part by rising gas prices and prices close to zero during periods of high PV generation. Relatively stable balancing-market prices partly offset the weaker spot-market spreads.

Summer volatility

Monthly battery storage revenues varied significantly over the past 13 months. The highest level was €18,900/MW in September 2025, while the lowest was €5,700/MW in December 2025.

Enervis said revenues tend to be higher during the summer months because of strong PV generation and lower overall electricity demand. Conventional generation capacity is also seasonally lower, partly because of maintenance and potentially lower gas-plant efficiency at high temperatures. Wind generation also tends to be lower during summer than in winter or fall.

These conditions mean that short-term changes in generation or forecasting deviations from PV output can produce greater market volatility during the summer, which is reflected in increased intraday trading.

Battery storage revenues averaged slightly more than €12,900/MW per month over the past 12 months, equivalent to around €155,000/MW for the year.

Revenue outlook

Enervis also models the potential revenues of a typical stand-alone battery storage system for 2026 using its latest electricity price forecasts.

The forecast is based on Enervis’ Current Efforts Q3/2026 scenario, which was not updated this month. It projects annual revenues of €151,500/MW, around €3,800/MW below the average achievable revenue over the previous 12 months.

The modeled storage parameters remain unchanged. The index assumes a 1 MW/2 MWh system with a two-hour duration, limited to 1.5 cycles per day, a 90% depth of discharge, 97% technical availability, and 87% round-trip efficiency. It considers intraday, primary reserve, and secondary reserve markets, with imperfect foresight and no revenue from secondary reserve energy activation.

The historical analysis uses market prices published by transmission system operators and EPEX Spot, while the forward outlook applies the same model and parameters to prices from Enervis’ Current Efforts Q3/2026 electricity price scenario.

Mirko Schlossarczyk is managing director of Enervis Energy Advisors and a power-market specialist focused on electricity price forecasts, market scenarios, and battery storage asset valuation.

Jonas Anthonioz is a consultant at Enervis specializing in battery storage. He developed the Enervis BESS Index and its associated report and works on revenue assessments and economic analyses of battery storage projects.