January Storage Index is out!

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:

Belgium:

Revenues in Belgium increased significantly month-on-month, supported by stronger market conditions. Performance rose by 20% under the 2-hour configuration and 50% under the 4-hour configuration. This improvement was primarily driven by a sharp increase in aFRR capacity prices, which rose from €8 to €21/MW/h, along with wider spreads in the imbalance and aFRR energy markets (+50%). Overall, stronger ancillary service pricing and increased market volatility materially enhanced revenue capture.

Danemark:

• DK1: Despite a decline in prices in the capacity reservation markets, market volatility increased – particularly in the intraday market. This allowed revenues to be captured more effectively, resulting in a slight increase in January 2026 compared with December.
• DK2: The inclusion of activation volumes in the COSMOS tool reduced profitability on the ancillary services market in the DK2 zone, as the markets are quite shallow. Thus, despite the increase in volatility, revenues were lower for the month of January.

Estonia:

Colder-than-usual temperatures (−7.8°C) increased electricity demand by 20% compared to December 2025. At the same time, regional supply weakened due to low wind generation, reduced Latvian hydro output, increased Finnish import demand, and local shale oil power plant maintenance, tightening conditions in the Baltic market. The day-ahead spread widened to €184/MWh, up 38% compared to December 2025. In balancing markets, average prices reached €77/MW/h for FCR and €53/MW/h for aFRR capacity (up and down). These stronger market conditions significantly boosted storage revenues, with 2-hour BESS revenues rising to €503k/MW/year, an 87% increase compared to December 2025.

Finland:

In January, the downward trend reversed, with BESS revenues increasing by around 40% compared to the previous month. This improvement was mainly driven by a sharp rise in day-ahead and energy activation market spreads, which more than offset capacity reservation prices that remained at low levels.

France:

BESS revenues in France increased slightly in January compared to December, supported by a 14% rise in aFRR up capacity prices, a 17% increase in day-ahead spreads, and a 41% widening of mFRR spreads.

Germany:

Revenues for storage projects for all discharge duration declined significantly this month compared to the previous month, with an average decrease of 35%, which is typically observed at the beginning of the year. Although FCR prices and aFRR activation spreads increased, the limited depth of these markets constrained the potential revenue gains. Meanwhile, other markets showed stable or declining opportunities, resulting in an overall reduction in BESS revenues.

Italy:

After two consecutive months of decline, the SUD zone index rebounded in January 2026, returning to levels last seen in October 2025. Ancillary services continued to contribute no revenues, mirroring the performance observed in December. Intraday trading accounted for around 80% of total revenues, with the remaining share generated in the day-ahead market.

Latvia:

In January, Latvia’s electricity market experienced a strong rebound. Generation increased 45% month-on-month, reaching 771 GWh, the highest level since spring 2024, while demand rose 15% to 780 GWh, marking its highest level since 2010. The surge was primarily driven by very cold weather, with average temperatures of −8.7°C. In balancing markets, average prices reached €77/MW/h for FCR and €67/MW/h for aFRR capacity (up and down), returning to October 2025 levels. As a result, storage revenues improved substantially, with 2-hour BESS revenues reaching €533k/MW/year, nearly double the December 2025 level.

Lithuania:

Cold weather in Lithuania last month drove a sharp increase in electricity consumption, with demand records broken multiple times. Meanwhile, wind and thermal generation remained high, and imports rose to meet peak demand. Balancing prices averaged €77/MW/h for FCR and €67/MW/h for aFRR capacity (up and down). As a result, 2-hour BESS revenues rose to €519k/MW/year, up 57% compared to December.

Poland:

Storage opportunities in the Polish market surged in January 2026. The day-ahead (DA) spread nearly doubled, rising from €84/MWh in December 2025 to €144/MWh, while all ancillary capacity reservation prices also increased, averaging a 32% rise across FCR, aFRR, and mFRR.

Portugal:

This month, Portugal was added to the Clean Horizon index. The Portuguese revenue stack exceeds that of Spain, primarily due to higher aFRR reservation prices and larger mFRR energy spreads. Between December 2025 and January 2026, monthly revenues increased by an average of 11%, driven mainly by rising aFRR reservation prices and wider aFRR and mFRR energy spreads.

Romania:

This month, Romania was added to the Clean Horizon index. The integration of available volumes in the COSMOS tool (new index methodology) has reduced profitability in ancillary services, particularly in the primary reserve, where revenues were very high in 2025 but are now declining due to relatively shallow markets. Between December 2025 and January 2026, monthly revenues fell by 28%.

Spain:

In January, BESS revenues more than doubled on average across all storage durations compared to December. This increase is primarily driven by the inclusion of the intraday (ID) market in the revenue stacking exercise under the updated methodology. The addition of ID has a particularly strong impact on the profitability of 1-hour storage systems, for which participation in ancillary services is more limited. In addition, aFRR up reservation prices increased by 14%, alongside higher day-ahead spreads. aFRR energy spreads rose by 71%, while mFRR energy spreads increased by 32%. The only service that declined at the start of the year was aFRR down reservation, which decreased by 24% on average.

Sweden:

Although capacity prices have recovered since December – with FCR-N up 44% to €23/MW/h and mFRR (up+down) capacity rising 33% – the 2-hour index fell by 27%. This decline reflects an updated index computation methodology, which now incorporates available market volumes and accounts for increasing competition from BESS in these markets.

You can find the updated Storage Index here.

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