France records about 800 hours of negative or zero power prices in 2026
Victoria Shinder2 min readFrance has recorded around 800 hours of negative or zero electricity prices so far in 2026, an all-time high, pv magazine reports, citing the September price monitor of B2B storage company Storio Energy. At the same time the gap between cheap and expensive hours has widened sharply.
According to Storio, the average daily spread on the French spot market reached €214/MWh in September, a level not seen since 2022, with prices moving on average between daily lows of €32/MWh and highs of €247/MWh. Day-ahead prices have averaged €143/MWh since the start of the year, tracking higher gas prices. Generation has fallen: compared with September 2025, nuclear availability is down 3.7 GW, wind 2.3 GW and hydropower 1.5 GW, only partly offset by 1.8 GW more solar and 1 GW more gas. Storio attributes the lower nuclear and hydro output to the summer drought. France remains a net exporter, at 8 GW against 10 GW a year earlier.
The two trends coexist because they happen at different hours: surplus solar at midday pushes prices to zero or below, while tight conventional supply makes evenings expensive. For comparison, grid operator RTE counted 359 hours of negative prices in 2024 and 147 in 2023. The spot market hit a low of -€498/MWh on 1 May this year.
For batteries that gap is revenue. Storio says a 1 MW/2 MWh battery charged at an average of €73/MWh in September and discharged at €232/MWh, running about 1.5 cycles a day, and earned 135% more spot revenue than in September 2025. Its cumulative revenue for the year is up 50% on 2025 and more than double 2024.
Why it matters
Negative prices are a signal that the system has more inflexible supply at some hours than it can use. The figures here come from a storage seller and describe one battery, but the direction is consistent with RTE's own counts: the value in the French market is moving from producing energy to moving it in time.