Battery Index
What a battery earns on Europe’s power markets
Every day we run the same reference battery, 1 MW of power and 2 MWh of storage, on each country’s wholesale electricity prices. It decides when to charge and discharge using only the previous day’s prices, then gets paid at the prices that actually cleared. No hindsight, no subsidy, no sales pitch: what a battery could really have earned.
Latest day: 27 October 2026. Updated every day after the day-ahead auction.
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By country
| Country | Latest day | Last 30 days | Last 365 days | Captured | Hours below zero, 30 days |
|---|---|---|---|---|---|
| Germany | €457 | €7,505 | €79,583 | 81% | 1.8 |
| Netherlands | €511 | €7,840 | €78,226 | 78% | 15.8 |
| Belgium | €362 | €7,623 | €70,337 | 79% | 7 |
| France | €491 | €9,481 | €67,731 | 83% | 1.5 |
| Great Britain | €295 | €4,430 | €23,398 | 61% | 5 |
| Austria | €19 | €5,682 | €70,434 | 63% | 1.5 |
| Switzerland | €29 | €2,880 | €44,658 | 78% | 0 |
Euros per MW for a 1 MW / 2 MWh battery, 88% round trip, wear charged at €10 per MWh delivered. Captured: share of what a schedule built on the real prices would have earned. Prices: Energy-Charts (Fraunhofer ISE), data from Bundesnetzagentur | SMARD.de, CC BY 4.0. Great Britain: Elexon market index, converted at the ECB reference rate; contains BMRS data © Elexon Limited copyright and database right.
* Great Britain has no single day-ahead auction price in the public domain. The index uses Elexon's half-hourly market index price, a volume-weighted price of short-term trades, converted from pounds at the ECB reference rate of the day. Not directly comparable with the auction markets.
Day by day
Daily revenue, Germany, last 90 days
Euros per day for a 1 MW / 2 MWh battery, day-ahead market only. Red columns are days the schedule lost money.
Year by year
| Country | 2024 | 2025 | 2026 to date |
|---|---|---|---|
| Germany | €54,497 | €64,816 | €75,131 |
| Netherlands | €54,221 | €64,179 | €73,780 |
| Belgium | €42,009 | €55,570 | €67,053 |
| France | €33,826 | €44,685 | €63,281 |
| Great Britain | €13,499 | €19,241 | €20,821 |
| Austria | €43,734 | €60,682 | €66,300 |
| Switzerland | €22,329 | €35,356 | €42,962 |
How the index is calculated
- One price series. Day-ahead auction prices, at the resolution each market clears (quarter-hours since October 2025, hours before). Great Britain publishes no auction price, so it uses Elexon’s half-hourly market index instead.
- No foresight. Each day repeats the schedule that would have been best the day before. The schedule built on the real prices is published next to it as the ceiling.
- Physical limits. The battery starts each day empty, never charges or discharges faster than 1 MW, and loses 12% of the energy on a round trip.
- What it leaves out. Intraday trading, grid services, capacity payments, network charges and trading fees. A real project’s revenue will differ; the index is for comparing countries and following the trend.
Open data
Take the numbers
The last 90 days for every country, and monthly totals since January 2024, are free to download under CC BY 4.0. Cite “Aperture Battery Index” with a link to this page. The full daily history since January 2024, and a daily feed for your own models, are available on request.
One file per country: Germany · Netherlands · Belgium · France · Great Britain · Austria · Switzerland
Full access
The full history, and a daily feed
The free files cover the last 90 days. A subscription opens everything since January 2024, updated every day, with a personal key that works for as long as the subscription runs.
Battery Index
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Questions
- How much does a grid battery earn on the day-ahead market in Europe?
- Over the last 365 days, a 1 MW / 2 MWh battery earned between €44,658 (Switzerland) and €79,583 (Germany) per MW from day-ahead price arbitrage alone, scheduling each day with the previous day's prices. Figures as of 27 October 2026.
- Why is this lower than other battery revenue figures?
- It counts one revenue stream, the day-ahead market, and it uses no foresight. Real batteries also earn from intraday trading and grid services, and they pay network charges, trading fees and degradation the index only approximates. Treat it as a like-for-like comparison between countries and over time, not as a forecast for a specific project.
- What does "scheduled with the previous day's prices" mean?
- Each day the battery charges and discharges at the times that would have been best the day before, then is paid at the prices that actually cleared. A schedule built on the real prices is also computed and published as the ceiling; the share of that ceiling the battery captured shows how predictable each market is.
- Why do electricity prices go negative?
- When solar and wind output exceeds what the grid can use, and some plants cannot or will not switch off, sellers pay buyers to take power. A battery is paid to charge in those hours, which is one reason storage earns most where negative prices are frequent.
- Can I use the Battery Index data?
- Yes. The last 90 days are free to download as CSV under CC BY 4.0: cite "Aperture Battery Index" and link to this page. The full daily history since January 2024 is available on request.