METHODOLOGICAL UPDATE PORTFOLIO PERFORMANCE
To provide a portfolio performance view that is neutral to asset availability, we introduced methodological updates at the start of 2026. Firstly, it applies a data-quality filter to exclude days where an asset was not operational for more than four hours. As a result, revenues from wholesale, aFRR, and FCR on these partial-availability days are removed, which can lead to slightly lower total revenues. However, the same filtering is also applied to the calculation of average marketable power (MW) and energy (MWh), meaning that averages are computed only on fully operational days. This creates a more representative performance metric.
Secondly, duration clustering has been refined. The 2h segment is now defined as 1.51-2.5h rather than extending to 3.5h. This change was requested by asset owners and market participants to create a cleaner benchmark that more closely represents a true 2h asset. The cluster description now also focuses on P10/P90 ranges rather than minimum/maximum values, reducing the influence of outliers.
However, when adjusting for these composition effects, the underlying performance remained nearly identical, confirming that the new methodology improves consistency and robustness rather than materially changing economic outcomes.
Market evolution and BESS revenues July 2026
July was characterized by a more renewable-driven German power system. Wind generation increased by 30.3% month on month, solar generation rose by 5.9%, and average load declined by 3.4%. Together, these developments reduced residual demand and contributed to softer wholesale prices and a significant increase in negative-price periods.
Higher renewable output, particularly during solar-rich midday hours, increased the frequency of very low and negative prices. However, the resulting decline at the bottom of the daily price distribution did not translate into wider day-ahead arbitrage spreads. Instead, it was more than offset by a compression of prices during the higher-priced hours.
This dynamic is consistent with the summer market structure. Longer daylight hours extend solar production further into the day, while seasonally lower demand reduces the intensity of the evening residual-load ramp. In July, significantly stronger wind generation also provided additional supply outside peak solar hours. Together, these factors reduced the frequency and magnitude of high-price periods, limiting the discharge-side value available to storage assets.
As a result, July exhibited a deeper and more frequent midday price trough, but a lower upper end of the daily price distribution. Average day-ahead prices declined by 4.6% to EUR 104.4/MWh, while intraday VWAP decreased by 6.6% to EUR 105.2/MWh. At the same time, the number of negative day-ahead quarter-hours increased from 199 in June to 306 in July, representing 10.3% of all quarter-hours during the month.
Despite the higher frequency of negative prices, conventional day-ahead arbitrage opportunities therefore weakened. The compression of high-price periods more than offset the additional value available from negative-price charging intervals. Consequently, the one-cycle day-ahead top-bottom spread declined by 22.9% for one-hour assets and by 20.3% for two-hour assets. This highlights an important feature of the summer market: more negative prices do not necessarily translate into stronger battery arbitrage economics when the corresponding discharge-side price opportunity is compressed.
Against this weaker day-ahead benchmark, the enspired portfolio continued to capture value through active multi-market optimization. The one-hour portfolio generated annualized revenue of EUR 178.6k/MW, an increase of 5.5% compared with June. Stronger aFRR capacity revenues more than compensated for lower FCR income. The two-hour portfolio generated annualized revenue of EUR 240k/MW, representing an 8.7% month-on-month decline. FCR revenues improved, but these gains were outweighed by reductions in aFRR capacity and energy arbitrage revenues.
Daily revenue distributions indicate that portfolio performance was broadly distributed across the month rather than being driven by a small number of exceptional trading days. Although one upper-tail observation was recorded, July revenues were more concentrated around the central range than in June, pointing to a more consistent daily revenue profile.
Compared with July 2025, one-hour portfolio revenue increased by 16.6% to EUR 178.6k/MW/year, and two-hour portfolio revenue increased by 15.3% to EUR 240k/MW/year. Both cases benefited from generally higher price levels YoY: 21-22% higher day-ahead and intraday price levels, 24% higher FCR capacity prices, and 50% higher aFRR up capacity prices.
Key month-on-month market indicators
| Metric | June 2026 | July 2026 | MoM | Unit |
| Day-ahead auction price (avg) | 109.50 | 104.42 | −4.6% | EUR/MWh |
| Intraday continuous VWAP | 112.67 | 105.23 | −6.6% | EUR/MWh |
| Negative DA quarter-hours | 199 | 306 | +107 (+53.8%) | count |
| FCR capacity (avg) | 24.22 | 21.82 | −9.9% | EUR/MW/h |
| aFRR capacity up (avg) | 15.66 | 10.12 | −35.4% | EUR/MW/h |
| aFRR capacity down (avg) | 18.04 | 18.42 | +2.1% | EUR/MW/h |
| aFRR energy mean (avg) | 100.82 | 93.61 | −7.2% | EUR/MWh |
| Imbalance generation price (avg) | 12.18 | 10.22 | −16.1% | EUR/MWh |
| DA TB 1h / 1 cycle | 221.25 | 170.52 | −22.9% | EUR/MW/day |
| DA TB 2h / 1 cycle | 411.82 | 328.42 | −20.3% | EUR/MW/day |
| Solar generation (avg) | 61,356 | 64,994 | +5.9% | MW |
| Wind generation (avg) | 8,334 | 10,857 | +30.3% | MW |
| Load (avg) | 52,341 | 50,560 | -3.4% | MW |
Key month-on-month portfolio indicators
| Metric | June 2026 | July 2026 | MoM | Unit |
| 1h BESS / 0.9–1.5h: total portfolio PnL | 169,338.8 | 178,569.7 | +5.5% | EUR/MW/year |
| 1h BESS / 0.9–1.5h: FCR | 95,176.6 | 83,521 | −12.3% | EUR/MW/year |
| 1h BESS / 0.9–1.5h: aFRR capacity | 43,779 | 65,333 | +49% | EUR/MW/year |
| 1h BESS / 0.9–1.5h: energy arbitrage1 | 30,382 | 29,715 | -2% | EUR/MW/year |
| 1h BESS / 0.9–1.5h: average cycling | 0.943 | 0.954 | +1.7% | FCE/day |
| 1h BESS / 0.9–1.5h: average duration |
1.175 | 1.185 | +0.9% | hours/day |
| 2h BESS / 1.51–2.5h: total portfolio PnL | 262,842.0 | 239,953.9 | −8.7% | EUR/MW/year |
| 2h BESS / 1.51–2.5h: FCR | 8,363.1 | 19,377 | +132% | EUR/MW/year |
| 2h BESS / 1.51–2.5h: aFRR capacity | 154,693 | 131,219 | −15% | EUR/MW/year |
| 2h BESS / 1.51–2.5h: energy arbitrage1 | 99,786 | 89,358 | -10% | EUR/MW/year |
| 2h BESS / 1.51–2.5h: average cycling | 1.355 | 1.201 | −11.4% | FCE/day |
| 2h BESS / 1.51–2.5h: average duration | 2.068 | 2.075 | +0.3% | hours/day |
1 Note: as of July 2026, portfolio revenues are being published in terms of FCR, aFRR capacity and energy arbitrage. Energy arbitrage comprises day ahead, intraday and aFRR energy revenues. This change was made to better align the presentation of portfolio results with trading behaviour and observed market fundamentals. Previously, aFRR capacity and energy revenues were combined and reported as aFRR revenues, while energy arbitrage only comprised day ahead and intraday revenues. As a result, some figures may not be comparable compared to the prior published performance report.
Portfolio performance: 1-hour BESS assets
The one-hour portfolio delivered a resilient result in July, with total annualized revenue increasing to EUR 178.6k/MW, up 5.5% month on month.
This improvement was achieved despite weaker wholesale benchmark spreads and lower average FCR prices. The portfolio successfully shifted value capture towards aFRR capacity, revenues from which increased by 49% to EUR 65.3k/MW per year.
FCR remained the largest individual revenue component at EUR 83.5k/MW per year, although it declined by 12.3% compared with June. Energy arbitrage revenue declined by 2%.
Operational behavior remained stable. Average cycling increased slightly from 0.943 to 0.954 full cycles per day, while average duration increased marginally from 1.175 to 1.185 hours. This suggests that the stronger result was primarily driven by improved market allocation rather than materially higher asset utilization.
Portfolio performance: 2-hour BESS assets
The two-hour portfolio generated annualized revenue of EUR 240.0k/MW in July, representing an 8.7% decline compared with June.
The reduction was primarily driven by aFRR capacity revenue, which declined by 15% to EUR 131.2k/MW per year, partially reflecting the lower aFRR capacity up prices. aFRR capacity nevertheless remained the largest contributor to the two-hour revenue stack.
Energy arbitrage revenue decreased by 10% to EUR 89.4k/MW per year, broadly in line with the lower observed day-ahead spreads. FCR revenue more than doubled to EUR 19.4k/MW per year, albeit off a low base.
Average cycling decreased from 1.355 to 1.201 full cycles per day, while average duration remained broadly unchanged at approximately 2.075 hours. This indicates that the portfolio maintained a similar technical operating profile but encountered fewer high-value dispatch opportunities.
The histogram shows the frequency of daily revenue outcomes for the one-hour and two-hour BESS portfolios. Most observations are concentrated around the central revenue range, with only a limited number of upper-tail outcomes. This indicates that July performance was generated consistently across the month rather than being driven by isolated exceptional trading days.
Wholesale markets
German wholesale markets softened in July as renewable generation increased and electricity demand declined.
The average day-ahead auction price decreased from EUR 109.5/MWh in June to EUR 104.4/MWh in July. Intraday VWAP declined from EUR 112.7/MWh to EUR 105.2/MWh.
All three intraday auction price indicators declined. Intraday Auction 1 decreased by 6.4%, Intraday Auction 2 declined by 6.9%, and Intraday Auction 3 fell by 22.4%.
The one-cycle day-ahead TB decreased by 22.9% for one-hour assets and by 20.3% for two-hour assets. This indicates that a simple day-ahead charging and discharging strategy would have generated materially less value in July than in June.
The weaker benchmark environment was reflected more in the 2hr than the 1hr portfolio, which saw energy arbitrage revenues decrease by 10%, compared with a marginal 2% decrease in the 1hr portfolio. This is expected, as longer duration batteries tend to make more revenues from energy arbitrage than shorter duration batteries.
Ancillary services and balancing markets
Ancillary-market performance diverged between the two portfolios in July. One-hour FCR revenue decreased by 12.3%, broadly consistent with the 9.9% reduction in the average FCR capacity price. By contrast, two-hour FCR revenue more than doubled from a low June base, showing that portfolio-level outcomes were influenced by awarded volumes, availability and market allocation rather than price movements alone.
aFRR capacity was the principal differentiating factor. One-hour aFRR capacity revenue increased by 49% despite the decline in average upward aFRR capacity prices. The daily results indicate that this improvement was not driven by a general increase in the typical daily outcome: the median daily aFRR revenue remained close to its June level, while July displayed a substantially longer upper tail, including one exceptional outlier. The portfolio therefore captured specific high-value balancing opportunities while maintaining positive aFRR revenue throughout the month.
Fundamentals
Average solar generation increased to 65.0 GW (+5.9%) and wind generation rose to 10.9 GW (+30.3%), while average load declined to 50.6 GW (-3.4%). This combination increased the frequency of oversupplied quarter-hours: negative day-ahead quarter-hours rose to 306, equivalent to 10.3% of July’s 2,976 quarter-hours, from 6.9% in June.
At the same time, thermal generation economics became more expensive. Average TTF gas prices increased from EUR 44.92/MWh in June to EUR 56.67/MWh in July, representing a 26.2% month-on-month increase.
EU ETS carbon prices also moved higher. The average EUA Dec-2026 futures close increased from approximately EUR 79.0/tCO2 in June to around EUR 81.2/tCO2 in July, equivalent to an increase of approximately 2.8%.
The fundamentals were therefore more favorable for negative-price charging opportunities but less favorable for sustained peak-price spreads. That combination is consistent with more negative intervals alongside lower one-cycle DA TB proxy. It also helps explain why flexibility value depended more on intraday and balancing execution than on a simple day-ahead cycle benchmark.
