Quarterly Performance

Introduction

This blog marks the launch of our quarterly performance series for the Capalo Zeus VPP™ (Virtual Power Plant). These reports provide a clear and data-driven analysis of portfolio performance across the Nordic electricity markets and the market dynamics that shaped the results.

The analysis highlights the interplay between regulatory reform, system volatility, and grid constraints, demonstrating how battery energy storage systems (BESS) contribute to system stability and deliver commercial value. Each quarter, we will detail how Capalo Zeus VPP responds to evolving conditions in real time, ensuring sustained performance through advanced optimization and full market access.

This report covers Q2 2025 (April–June), a period characterized by structural market changes, seasonal variability, and regional transmission limitations. The results underline both the adaptability of flexible storage assets and the strategic advantage of comprehensive multimarket participation.

Capalo Zeus VPP Monthly Trading Performance (€/MW)

Q2 2025 results reflect strong trading and optimization performance across Finnish electricity markets. In April, Capalo Zeus VPP delivered €27,600/MW in average earnings for our customers (average BESS duration: 1.16 hours), more than double the industry benchmark of €13,000/MW (FCR-N + FCR-D), which is the Finnish conventional trading approach. Performance remained strong throughout the quarter, with €21,100/MW in May and €18,900/MW in June.

Revenue Composition and Market Drivers

Q2’s revenue stack highlights the advantages of fast-response BESS assets. The underlying market drivers shifted month by month, from structural market reforms, wind production volatility, and the Olkiluoto 3 maintenance in April to low-wind dynamics in May and cross-border transmission constraints in June. This illustrates how a multimarket approach enables storage assets to capture value under highly variable system conditions.

Capalo Zeus VPP Monthly Revenue Stack Composition

April

aFRR Up Dominates, Driven by Supply Constraints and Volatility

When diving into the drivers behind monthly performance, strong results in April built on major Nordic market reforms implemented in March, including:

• The launch of the mFRR Energy Activation Market (EAM)
• The transition to cross-border 15-minute Intraday trading intervals
• The region’s integration into the pan-European aFRR PICASSO platform

These structural shifts boosted short-term price volatility and unlocked new trading opportunities across balancing and wholesale markets. Capalo Zeus VPP was well-positioned to capture value in such dynamic market conditions, thanks to its integrated design, which brings together forecasting, trading algorithms, and VPP optimization. Additionally, the ability to respond at increasingly granular MTU levels across markets positioned Capalo AI well to realise strong revenues within its fleet.

April’s performance was led by strong aFRR Up revenues, driven by high volatility in wind production during the final third of the month. The volatility was particularly evident during peak load periods, coinciding with reduced baseload capacity due to a maintenance break of the Olkiluoto 3 nuclear plant, which lasted until April 29th.

Market Prices 1.4.2025-30.4.2025

These conditions led to high Spot and aFRR Up capacity and energy prices, resulting in substantial growth in BESS revenues towards the end of the month. Additionally, a trend that began following the mFRR EAM go-live in March, notable relative revenues from mFRR Down regulation continued to be observed.

Market Prices 20.4.2025-30.4.2025

By deploying multimarket trading across all seven Nordic markets, FFR, FCR-D, FCR-N, aFRR, mFRR, Spot, and Intraday, the portfolio captured early upside as the new dynamics settled in and trading conditions remained favorable. The system’s responsiveness and access to all revenue streams materially enhanced performance in the most volatile weeks of the quarter.

May

FCR-N and mFRR Down Lead in a Low-Wind Environment

In May, the two main revenue sources were FCR-N and mFRR down-regulation.

An interesting pattern emerged: mFRR down prices peaked during low-wind periods. Wind power is currently a major contributor to the supply side of mFRR down-regulation in Finland. During periods of low wind generation, procured volumes decline, yet the limited availability of alternative flexible resources often requires Fingrid, the Finnish TSO, to clear the entire offer book at times.

This further emphasizes the strategic value of multimarket participation with BESS and its role in maintaining grid stability. As one of the few technologies capable of providing flexibility for both upward and downward regulation across various durations, BESS is uniquely positioned to address these balancing challenges.

June

Regional Constraints Reshape Revenue Distribution

In June, transmission capacity between Finland and Sweden (FI–SE1) was restricted due to scheduled maintenance. This constraint increased local procurement needs for both FCR-D and mFRR Up. Fingrid, which typically sources a portion of these services from Svenska Kraftnät and vice versa, had to rely more heavily on domestic providers.

Consequently, FCR-D and mFRR Up accounted for a larger share of monthly earnings. At the same time, mFRR Down’s contribution declined significantly, following a drop in procurement volumes on the Finnish side.

Conclusion

Q2 2025 demonstrated how regulatory reform, system volatility, and cross-zonal constraints shape the BESS revenue landscape in the Nordics. Capalo Zeus VPP responded to each shift in real time, delivering strong trading and optimization performance through automation, full market access, and trading precision.

Each month highlighted a different dominant revenue stream: aFRR Up in April, FCR-N + mFRR Down in May, and FCR-D + mFRR Up in June. The portfolio’s ability to dynamically allocate capacity, adjust to evolving procurement needs, and extract value across seven markets reinforces the competitive advantage of full-stack BESS optimization.

About Capalo AI

Capalo AI is a sustainable tech company specializing in optimizing energy storage systems. We maximize the value of battery energy storage systems (BESS) across all electricity markets by combining the most accurate forecast data with cutting-edge AI and optimization models.

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