Key facts

• In May 2025, the French wholesale electricity market (EPEX Spot) frequently experienced negative prices, especially during daytime hours.
• The monthly average price was 19 €/MWh, the lowest since April-May 2020 (the period of the pandemic demand decline).
• Price range: -118 €/MWh (1 May at 14:00) to 69 €/MWh.
• On 90% of days in May, the minimum price was zero or negative.
• Solar generation was a key driver of oversupply, especially between 11:00 and 17:00, when average negative prices were recorded for the first time over a six-hour period.

Reasons for negative prices

• Excess solar generation: France is actively increasing renewable energy sources, and on sunny days, generation significantly exceeds demand.
• Low flexibility of traditional generation: Nuclear power plants (70% of France’s energy balance) cannot quickly reduce generation, so they continue to supply electricity even at negative prices.
• Insufficient consumption during generation peaks: Consumers (especially households) are not adapted to dynamic pricing and do not shift consumption to cheap/negative hours.

Volatility and structural problems

• Sharp price fluctuations:
• The spread between the minimum and maximum is on average 95 €/MWh (since the beginning of 2025).
• In the evening (21:00–23:00), prices are 3 times higher than the monthly average due to a drop in solar generation and an increase in demand.
• Grid constraints:
• Insufficient development of storage and interconnections does not allow for the efficient use of excess daytime generation.

Comparison with other markets

• Germany: In May 2025, some consumers received negative prices for the first time thanks to dynamic tariffs.
• Global trend: Negative prices have become more common in countries with a high share of renewable energy (Denmark, the Netherlands, California).

Consequences and possible solutions

For generators:

• Losses when operating at negative prices, but shutting down a nuclear power plant can be even more expensive.
• Need for flexible capacity (pumped storage, batteries, demand management).

For consumers:

• So far, little benefit due to fixed/inflexible tariffs.
• In the future, dynamic pricing will become more popular (like in Germany).

For the market:

• Acceleration of the development of storage and electric vehicles with V2G (vehicle-to-grid). – Market reforms to stimulate demand flexibility.

Conclusion

Negative prices in France are a consequence of the rapid growth of solar generation with insufficient flexibility of the energy system. This is a signal for:

1. Development of storage and smart grid.
2. Introduction of dynamic tariffs for consumers.
3. Optimization of NPP operation (for example, reducing capacity during the day).

In the long term, such crises will become more frequent, and their mitigation will require a deep modernization of the energy market.