On 3 November 2026, EPEX SPOT’s Swiss day-ahead auction moves from one price per hour to one price per quarter-hour. The first quarter-hour prices will be published that day for delivery on 4 November. Switzerland’s most liquid power market will therefore show 96 prices a day instead of 24. The European Union made the same transition a year ago, and its experience tells us what to expect.
What changes on 3 November
- Quarter-hourly day-ahead. The Swiss day-ahead auction now sets a price for each of the 96 quarter-hours. 30- and 60-minute products remain possible thanks to cross product matching: a participant can still buy or sell a full hour.
- Intraday auctions. The Swiss intraday auctions follow the same move to quarter-hours.
- What stays hourly. Swiss cross-border capacity, allocated in explicit auctions (JAO) before the Swiss auction, remains hourly at the start. Quarter-hourly capacity products are planned later (late 2026 to early 2027, depending on the source).
Why the change
Swissgrid already settles imbalances per quarter-hour, but the day-ahead market only sold full hours. Take a supplier whose consumption ramps from 85 to 115 MW within an hour: it used to buy a flat 100 MW block. It was therefore long at the start of the hour and short at the end, and had to correct in intraday or pay for balancing energy. With quarter-hour products, it can buy its actual profile directly in day-ahead.
What Europe has learned since October 2025
The EU introduced the 15-minute time unit in its day-ahead market coupling (SDAC) on 30 September 2025, for delivery on 1 October. Four lessons stand out.
1. Prices form a “sawtooth”. Quarter-hour prices do not follow the smooth demand curve. During the morning solar ramp, the first quarter-hour of each hour is often the most expensive, then the price falls until the next hour; in the evening, the pattern reverses. The causes: coupling capacities still calculated per hour, power plants that schedule output hour by hour, and hourly block bids.
2. The conventional fleet adapts slowly. On launch day, about half of German thermal volumes were still offered as one-hour blocks (Modo Energy). The pattern weakens as participants adjust their bids, but it has not disappeared.
3. Part of intraday moves up to day-ahead. In Germany, the first intraday auction (IDA1), mainly used to “reshape” hourly solar profiles into quarter-hours, fell from about 28,000 MWh a day in late September to about 17,000 MWh in the first week of October 2025 (Montel). Continuous intraday kept its activity: about 900,000 trades on 1 October, in line with the September average (Modo Energy).
4. Volatility becomes visible, not necessarily larger. An hourly price is an average: it hides the differences between quarter-hours. The move to 15 minutes does not create those differences; it makes them visible and tradable in the most liquid market. Montel measured a day-ahead price standard deviation about 15% higher in the first week than a year earlier, while stressing that 2025 was already a more volatile year, so the figure should not be over-interpreted.
And in Switzerland?
Switzerland has its own features. Day-ahead is far more liquid than continuous intraday, so part of the quarter-hour shaping can be expected to happen directly in day-ahead. Conversely, two factors should dampen the sawtooth at first:
– cross-border capacity stays hourly, which limits quarter-hour arbitrage with Germany, France, Italy and Austria;
– hydropower can keep bidding one-hour blocks; the size of the pattern will depend on how much volume it actually offers per quarter-hour.
For suppliers and balance groups, the most direct consequence is an expected fall in imbalances during ramp hours, since they can buy their quarter-hour profile the day before. Combined with the single imbalance price introduced in January 2026, this reduces the systematic imbalances some strategies relied on.
What it means for flexibility
A battery charges and discharges within minutes: the quarter-hour is its natural time scale. As long as the most liquid market only gave one price per hour, part of its value stayed hidden in the average. With 96 prices a day, those differences become price signals that can be acted on the day before.
Two caveats apply, however.
The 15-minute step does not create flexibility. It reveals its value; flexibility itself depends on physical assets able to respond (batteries, pumped hydro, controllable loads).
Battery revenues do not depend on this change alone. In Germany, in September 2026, the theoretical revenue of a 2-hour battery from energy arbitrage alone reached about €148,000/MW/year, almost 20% more than a year earlier, with an average day-ahead TB2 spread of €220/MWh. But this increase is also largely explained by higher gas prices. Over the same period, total revenue fell by about 39%, because reserve markets (aFRR) filled up with batteries (Modo Energy, October 2026). The message is clear: value is shifting from reserves to energy markets, where time granularity matters.
What Optimal Energy does
Optimal Energy makes the capacity of physical batteries available as virtual batteries that can be reserved at short notice via API, with no investment from the user. With a quarter-hourly spot market, suppliers, balance groups and traders who want to hedge imbalances or capture intra-hour price differences get a more precise signal, and battery capacity that can be called on at the right moment becomes all the more useful.
Want to assess what the move to quarter-hours means for your portfolio? Write to us: contact@optimalenergy.ch
Sources
– EPEX SPOT, “15-minute products in Market Coupling” (Swiss go-live: 3 November 2026, first trading day): https://www.epexspot.com/en/15-minute-products-market-coupling
– European Commission, “EU electricity trading in the day-ahead markets becomes more dynamic”, 1.10.2025: https://energy.ec.europa.eu/news/eu-electricity-trading-day-ahead-markets-becomes-more-dynamic-2025-10-01_en
– Montel, “The rhythm of electricity”, 13.10.2025: https://montel.energy/resources/blog/the-rhythm-of-electricity
– Modo Energy, “Five lessons from the first 15-minute day-ahead auction in Germany”, 2.10.2025: https://modoenergy.com/research/en/germany-day-ahead-sdac-15-min-quarter-hour-hourly-epex-update-sawtooth-intraday-trading-bess-batteries
– Modo Energy, “German BESS revenues rose to €215k/MW/yr in September 2026 but fell 40% on the year”, 8.10.2026: https://modoenergy.com/research/English/germany-bess-revenue-benchmark-me-vbess-de-september-2026-gas-prices-afrr-saturation
– Next Kraftwerke, “The Day-Ahead Market switches to 15-minute products”, 10.9.2025: https://www.next-kraftwerke.com/energy-blog/day-ahead-switch-15-min
– APG, “Day-Ahead 15 Min MTU CH-AT” (cross-border capacity): https://pb1-medien.apg.at/im/dl/apg-631671136/Day-Ahead%2015%20Min%20MTU%20CH-AT.pdf
– A. Millet, “Switzerland moves to 15 minutes: what to expect?”: https://alexandremillet.substack.com/p/switzerland-moves-to-15-minutes-what
