From Blackout News

A report by the Inspector of Nuclear Safety at EDF, which has received little attention so far, sparks a heated debate about the future of the French electricity system. Former Admiral Jean Casabianca notes serious risks from the massive expansion of wind and solar plants. According to the author, the integration of these volatile energy sources endangers not only the security of the grid, but also the economic foundation of nuclear power. In particular, the frequent load changes in the grid are placing an increasing burden on nuclear plants – both technically and financially (aassdn: 04.03.25).

One-sided priority for renewables undermines stability

The report points to a one-sided preference for renewable energies in grid operation. On page 13, the report states unequivocally:
“The priority of renewable energies leads to power fluctuations, the consequences of which are anything but harmless – for safety, but also for maintainability, service life and operating costs.” The attempt to combine nuclear power and volatile energies has developed from a flexibility solution to a problem.

Without a reliable base load from nuclear power or hydropower, one would have to switch to fossil fuel power plants. The constant change between high and low load would put a considerable strain on the plants in the long term.

Fundamental doubts about green consensus

Casabianca’s statements put a long-cultivated political consensus in the twilight. For years, the wind power sector had sold the combination of nuclear power and renewables as an ideal model. As early as 2019, Jean-François Carenco, President of the Energy Regulatory Authority, expressed skepticism:
“Our CO₂ emissions are already low thanks to nuclear power and hydropower. The expansion of renewable electricity does not reduce them further. On the contrary, it is often ideologically glorified.”
After Carenco’s statements and the report of the National Assembly at the time, the wind power industry had to adapt its communication strategy. From then on, it was no longer to be used for decarbonization, but to serve as a gap filler for delayed new reactor construction.

Technical reality beats political wishful thinking

Despite political narratives, a different reality is emerging in practice. More and more engineers are warning that trying to adapt nuclear power to fluctuating production from wind and sun will lead to increased wear and safety risks. These warnings have been increasing for years – especially as renewables are given priority by European grid regulations.
On December 1, 2024, former energy managers addressed the prime minister in a public statement. In it, they sharply criticized the dual solution of nuclear power and fluctuating energies. They were particularly sharp in attacking the “illusion of official RTE reports” that the two forms of energy could complement each other.

Political pressure on the wind power industry is growing

The effects were not long in coming. On 13 January 2025, 80 MPs publicly called for a moratorium on the further expansion of intermittent energies in France. The wind power lobby reacted frantically: in an appeal on 30 January, it tried to relativise the contrast between nuclear energy and renewables. But Casabianca’s published report systematically undermines this attempt.
Its analysis removes the technical basis for the entire “both-and” energy policy strategy. The text gets to the heart of what many experts have been noticing for years – that the claim of a harmonious complement between nuclear power and volatile sources is not tenable.

A turning point in French energy policy

The report, published in early February 2025, marks a turning point. It reveals the design flaws of a policy that ignores technical limits and relies on ideological promises. At a time of global energy uncertainty, France’s energy future is a strategic question. The report calls into question nothing less than the economic viability of the energy transition – at least in its current form.
Political and economic decision-makers may not yet fully understand the implications of this document. But one thing is certain: this document cannot be suppressed. Its content will shape the debate on France’s energy mix in the long term.