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Storage Index: July 2026 is out!
September 22, 2026 Clean Horizon delivers the latest snapshot of BESS performance across Europe – clear, concise, and focused on the trends that matter most to developers, investors, and policymakers.
Below is our latest snapshot of regional insights:
In August, Finnish BESS benefited from an increasing volatility on the day-ahead market. Indeed, the daily spread averaged 65 €/MWh, tripling compared to the previous month. The volatility on aFRR and mFRR EAMs followed the same trend.
Prices for ancillary services remained low in the DK1 zone during the month of August. Volatility in the wholesale markets (DA and ID) declined, reducing opportunities for batteries. As a result, revenue for a 2-hour battery fell by 13.8% compared to the previous month.
Volatility on the DA increased during August in the DK2 zone, but intraday revenue fell slightly (by about 3%). Ancillary service prices are down slightly on the FFR and mFRR. A 2-hour battery generated 8% less revenue than in July, but the figures remain very attractive in this zone.
In August, Finnish BESS benefited from an increasing volatility on the day-ahead market. Indeed, the daily spread averaged 65 €/MWh, tripling compared to the previous month. The volatility on aFRR and mFRR EAMs followed the same trend.
Revenues for August increased by 6.1% compared with the previous month, reaching 294 k€/MW/year, mainly driven by higher aFRR capacity prices (+17.7%), aFRR energy spreads (+12.3%), and DA energy spreads (+11.5%), while mFRR energy spreads remained broadly stable and FCR prices increased by 7.9%.
In August, BESS revenues are slightly below revenues from previous month, with a reduction of 1% to 6% depending on BESS durations. aFRR DOWN prices remain elevated as they are positively correlated with solar production. However, the decrease in aFRR UP reservation prices has driven the decrease of revenue for BESS.
The DA spread reached 131 €/MWh in August (a 34% increase), bringing BESS opportunities upward. This resulted in 2.2% increase in the total gross revenues for the 2h battery, reaching 331 k€/MW/year this month.
The 2-hour index dropped by 8.6% this month, still reaching 532k€/MW/h. Most of the revenues still come from ancillary services capacity reservation markets, whose prices increased by 8% on average. The DA spread shows a 32% increase, reaching 237€/MWh this month.
Revenues for August increased by 16% for a 2-hour BESS in Portugal compared to July. This is explained by a significant increase in wholesale power price volatility in Portugal. The accessible spread on the DA market increased by 32% and the Intraday Continuous price also increased by 36% compared to July 2026.
Revenues for August decreased by around 35% for a 2-hour and 4-hour BESS in Romania compared to July reaching 246k€/MW/year for a 4-hour batteru. The can be explained by a decrease of the aFRR energy spreads. The commsisionning of new BESS assets also increase the competition among BESS on the market, leading to smaller revenues on the small markets
Revenues for August remain quite similar compared to July, with a 1 to 6% increase depending on BESS durations. This slight increase in revenues is driven by an increase in aFRR capacity prices and Intraday Continuous prices. The accessible spreads on aFRR energy and Day Ahead also increased.
The 2-hour index got increased by 9.5% in August, due to a slight increase in ancillary services prices. The DA spread also increased by 27.4%. As a result, the index reaches 138k€/MW/year this month.
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