The Swiss day-ahead electricity market is telling a story that battery storage operators need to hear: the midday-to-evening spread that has underwritten BESS arbitrage economics for the past three years is compressing.
The Numbers
In Q4 2024, the average spread between the midday trough (11:00–14:00) and evening peak (17:00–20:00) on EPEX Spot CH was €67/MWh. In Q4 2025, it was €52/MWh. The trailing three-month average as of January 2026 is €44/MWh.
That’s a 34% compression in fifteen months.
The Cause
Solar. Switzerland’s installed PV capacity crossed 7 GW in 2025, and the federal energy strategy targets 14 GW by 2030. Every additional GW of solar capacity pushes the midday trough deeper — but it also widens the window, meaning more hours at low prices but a less dramatic nadir.
The result: flatter midday prices, which means less energy to arbitrage per cycle.
What This Means for BESS Economics
For battery operators running pure day-ahead arbitrage, the revenue per cycle is declining. A 1 MW / 2 MWh system that was earning €134 per cycle in late 2024 is now earning approximately €88.
But the smart operators — the ones who stack revenue streams — are actually seeing improved total economics. FCR-D prices have increased as grid frequency volatility rises with renewable penetration. Intraday spreads remain volatile. And the capacity mechanism discussions in Bern are progressing toward a framework that would create a new revenue floor.
The Takeaway
Pure arbitrage is a declining strategy. Revenue stacking — combining day-ahead arbitrage, FCR participation, intraday trading, and eventually capacity payments — is the operational architecture that sustains BESS economics as the energy transition accelerates.
The batteries that win are the ones with the smartest dispatch algorithms, not the biggest cells.