France’s Negative Power Price Hours Hit a Record 800 in 2026 as Drought Squeezes Nuclear and Hydro
France’s power market has recorded around 800 hours of negative or zero electricity prices so far in 2026, an all-time high for the country, according to data from Storio Energy and French transmission system operator RTE. That compares with 359 hours in all of 2024 and just 147 hours in 2023 — a more than fivefold increase in two years.
The milestone, reported October 2 by pv magazine, marks a shift in what is driving French price volatility. Earlier bouts of negative pricing in France were generally blamed on solar oversupply on sunny spring afternoons. This year’s record is different: it is being driven as much by a shortfall in supply from France’s traditional baseload sources as by any surplus of renewables.
Drought, not oversupply, is this year’s driver
Compared with September 2025, nuclear availability in France was down 3.7 gigawatts, wind generation was down 2.3 GW, and hydropower was down 1.5 GW. Solar generation rose 1.8 GW and gas-fired generation rose 1.0 GW to help cover the gap. According to the data cited by pv magazine, the reduced availability of nuclear and hydropower is a direct consequence of this year’s summer drought, which lowered river and reservoir levels used for reactor cooling and hydro generation alike.
The result was wider, not narrower, price swings. September’s daily spot-price spread averaged €214 per megawatt-hour, with an average daily low of €32/MWh and an average daily high of €247/MWh — a gap that reflects a grid struggling to balance supply hour to hour rather than one simply awash in cheap solar power.
Approaching the price floor
The most extreme single moment came on May 1, 2026, when France’s day-ahead spot price fell to -€498 per MWh, within €2 of the market’s regulatory floor of -€500/MWh. Prices that low effectively mean generators must pay the grid to keep running rather than shut down, a situation that becomes more frequent as inflexible nuclear output collides with periods of weak demand or strong renewable output.
A record year for battery storage revenue
The widening price spread has been a windfall for battery operators able to buy power when it is cheap and sell it back when prices spike. Storio Energy’s modelling of a reference 1 MW/2 MWh battery found it could have charged at an average €73/MWh in September and discharged at an average €232/MWh — a spread that lifted the battery’s monthly revenue 135% above September 2025 levels. Cumulative 2026 revenue for the same reference battery is running 50% above 2025’s full-year total, and more than double 2024’s, even before the fourth quarter is counted.
That revenue growth helps explain why storage has become one of the fastest-growing segments of France’s power sector even as nuclear — historically around 70% of the country’s generation — faces recurring availability problems. Similar spot-market arbitrage dynamics have been emerging in other liberalized power markets as battery fleets scale up, though France’s price swings are now among the widest in Europe.
What to watch next
With roughly a quarter of the year still to run, 2026’s negative-price-hour count could climb further depending on autumn hydro inflows and the pace of nuclear fleet returns to service. RTE’s weekly generation-availability bulletins will be the next indicator of whether France’s baseload squeeze eases before winter demand arrives.
Sources:
- Storio Energy and RTE (Réseau de Transport d’Électricité) data, cited in “France hits record 800 hours of negative, zero electricity prices,” pv magazine, Oct. 2, 2026, by Gwénaëlle Deboutte — for 2026 price-hour counts, generation-mix changes and battery revenue figures. pv-magazine.com
Illustrative image. Photo: Florival fr, CC BY-SA 3.0, via Wikimedia Commons — source
