We announce the latest update of our Storage Index, now featuring refreshed data for France, Germany, Spain, Poland, and Sweden, along with a newly added index for Denmark (DK1 & DK2)

Here are a few key takeaways from this month’s update:

Denmark: DK1 : Since 2023, revenues in Denmark’s DK1 zone have remained relatively stable, mainly driven by participation in trading (Day-Ahead and Intraday markets) and in FCR services. However, since October 2024, the opening of the aFRR capacity market and participation in the PICASSO platform have led to a significant increase in prices.

DK2 : In the DK2 zone, battery participation in Nordic FCR-N and FCR-D services has resulted in notable revenue gains, particularly in spring 2023 and 2024. The launch of the aFRR energy market in October 2024, also through the PICASSO platform, has provided batteries with a new and attractive revenue stream

France: In March, revenues from BESS in France saw a notable increase, mainly driven by high volatility in the energy markets. Particularly in the mFRR and aFRR markets, especially during the second half of the month.

The revenue uplift can be attributed to favorable weather conditions, which boosted renewable generation and increased the demand for grid flexibility.

Germany: DA and aFRR spreads have risen conjointly in March, along with aFRR down reservation prices, resulting in an increase in revenus for all sizes BESS in Germany

Spain: In March, revenues from BESS in Spain have seen a decrease (26% in average for the three BESS durations) driven mainly by a decrease in the aFRR up reservation prices. Between February and March 2025, the aFRR reservation up prices have been divided by two. Since the Spanish revenue stack is strongly dependent on aFRR, it has a significant impact on the overall grasped revenue.

In this monthly update of the Storage Index, the revenues for the Spanish stack for 2023 and 2024 have been updated to better reflect the 15-min pricing on aFRR reservation.

Poland: Capacity reservation prices have gone up recently, improving revenue opportunities for storage in Poland compared to this winter

Sweden: March marked a significant transition to 15-minute trading periods across mFRR energy, imbalance, and intraday continuous markets. The Clean Horizon Swedish Storage Index, which currently only models mFRR among these three markets, recorded a dramatic 150% increase in total net revenues compared to February. This surge coincided with the introduction of the Nordic automated mFRR energy market, which drove a corresponding 150% increase in mFRR capacity prices. Note that due to technical limitations in Svenska Kraftnät’s 15-minute data reporting, mFRR energy revenue estimates are currently understated. As Svenska Kraftnät refines their data reporting processes, we expect to gain a clearer understanding of the full market impact.

As promised, we’ll keep expanding — with a new country added to the Storage Index every month.

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