Negative prices: how to keep a solar project profitable when midday electricity is worth nothing

At the end of 2025, France had 30.4 GW of solar panels, 5.9 GW of which were installed during the year¹. Solar produced 32.9 TWh in 2025, or 6% of the country's electricity². This success has a downside: at midday in the sunny months, there is often too much electricity, and its price turns negative. For a solar project, this is no longer a detail.

Negative prices are becoming more frequent

The electricity market saw 147 hours of negative prices in 2023³, then 352 hours in 2024 and 513 hours in 2025⁴. In the first half of 2026, there had already been 407, or about 10% of the time⁵.

These hours almost always fall during the day: more than 90% of them between 8 am and 8 pm, mostly between 11 am and 5 pm⁶. They are concentrated in spring, especially around the May bank holidays, when the sun is strong and consumption is low; an episode lasts five hours on average⁷. The cause is simple: low-carbon generation then exceeds demand⁵.

The direct result: in 2025, the price earned by a solar plant that never stops was 32% lower than the price earned by constant output over 24 hours⁶. And 1.6 TWh of solar electricity was not produced in 2025 because installations stopped during negative prices⁸.

Sources: RTE, the French grid operator; the Energy Regulatory Commission (CRE).

What the contracts already say

Feed-in premium contracts

Installations that sell on the market and receive a top-up from the State get no top-up during hours of negative prices. In return, a bonus compensates them for stopping production, beyond the first 15 hours a year for solar⁶.

Feed-in tariff contracts (purchase obligation)

Since mid-April 2026, the buyer can ask installations of more than 10 MWp under feed-in tariff contracts to stop⁹. A government order from July 2026 lowers this threshold to 5 MWp from 1 December 2026, then to 1 MWp on 1 March 2027¹⁰.

Small rooftops

Since autumn 2025, the feed-in tariff for buildings only covers installations up to 100 kWp; larger ones must go through a tender. Since June 2026, owners can no longer sell all their output: only the surplus is bought, at €11 per MWh, and only when the market price is positive or zero¹¹.

What is being debated this autumn

The draft budget for 2027 plans to extend shutdowns during negative-price hours to smaller installations: the threshold would be set by order, no lower than 100 kW, by the end of 2027 at the latest. Shutdowns would be compensated at between 90% and 100% of lost revenue, and the bonus paid for negative-price hours in existing feed-in premium contracts could be cut by 10% at most¹². The National Assembly's economic affairs committee removed the article that contains this measure, but its vote is only advisory: the Assembly (France's lower house of Parliament) votes on the budget on 17 November¹³.

At the same time, the government wants to encourage storage. It has announced that, by the end of 2026, a solar site with a battery will be able to install up to 25 MW instead of 17 MW, as long as it never feeds more than 17 MW into the grid¹⁴. The rules on where batteries can be installed are due to be clarified by 1 December 2026¹⁵.

Five levers for a project

1. Consume on site. Each kWh the building consumes is a kWh it does not buy from the grid; a kWh sold as surplus earns very little, or even nothing at midday. Collective self-consumption is also growing: there were 1,945 active schemes at the end of March 2026¹⁶.
2. Shift consumption. The electricity system is already pushing in this direction: by the end of 2027, small customers with an off-peak tariff option (up to 36 kVA) will have at least two off-peak hours in the middle of the day in summer, between 11 am and 5 pm¹⁷.
3. Store energy. Battery prices have fallen sharply: in 2025, a turnkey system cost an average of $117 per kWh worldwide, down 31% in a year, and $177 in Europe¹⁸. Yet only about twenty of the roughly 1,500 projects selected in the latest solar tenders included a battery⁶.
4. Be willing to stop. When the price is negative and the shutdown is compensated, not producing costs nothing. 7.4 GW of wind and solar under feed-in tariff contracts can now stop at these times⁵.
5. Plan for this in direct sale contracts (PPAs). The industry's model contract says the producer stops as soon as the price turns negative, or falls below a threshold set by the buyer, with compensation to be agreed between the parties¹⁹.

What this means for choosing sites

For a long time, a good solar project was first of all a large roof with good sun exposure. That is still necessary, but no longer enough: the value of a project now depends on who consumes the electricity, and when. Buildings that run during the day, such as shops, cold stores, industrial sites or healthcare facilities, are becoming the best targets.

Briefing up to date as of 24 October 2026. The rules change fast: check each situation with a specialist adviser before deciding.