Battery Performance Index
The net revenue index for batteries estimates the annual revenue of an electricity storage asset located in France and operated using a multi-market strategy. For each month, the battery’s allocation and the associated profits are simulated based on actual market prices.
The result is then normalized to €/MW/year, assuming that the conditions of that month persist throughout the entire year.
This index thus highlights the direct financial impact of monthly market conditions on the performance of a storage asset. Although its calculation is based on several assumptions, these are derived from our operational expertise to ensure that the estimate is both relevant and realistic.
A detailed analysis of this index’s performance is published monthly in our newsletter.
- Capacity mechanism; it is considered constant over the course of a year.
- Primary reserve: capacity, energy, and cost of correcting deviations.
- Secondary reserve: capacity revenue (upward and downward), energy revenue (upward and downward activation), and cost of correcting deviations.
- Wholesale markets: buying and selling on the day-ahead and intraday markets.
- TURPE: Variable TURPE Cost in HTB2 Short-Term Use
The calculation is performed sequentially: first, the allocation of battery capacity to FCR, aFRR, and day-ahead markets is calculated the day before for the following day. Then, in parallel for the current day, the battery is re-optimized financially, activated, and adjusted based on aFRR marginal prices and intraday prices.
- Perfect forecast: FCR capacity prices, aFRR capacity prices (UP and DOWN), and day-ahead prices are known exactly in advance. Marginal prices, spread prices, and intraday prices are not.
- Efficiency: 85% round-trip efficiency
- Continuous SoC correction: When participating in SSYf, any activation is corrected as soon as possible.
- No overlapping markets: At any given moment, the battery can participate in only one market. For example, it is not possible to allocate capacity to both the day-ahead market and the aFRR market within the same 15-minute interval.
- No market impact: executed orders do not affect market prices
For a complete list of assumptions or a detailed index, please contact sales@stackease.ai.
Feb. 2026: 96 windows for grading.
October 2025: 15-minute intervals on the day-ahead market.
Jan 2025: Optimization using asymmetric aFRR instead of symmetric aFRR.