France faces a winter of discontent, energy analysts say, as deep-rooted problems with its nuclear-heavy energy strategy raise serious questions about its preparedness for the colder months.

A long-standing source of national pride, France generates roughly 70% of its electricity from a nuclear fleet of 56 reactors, all operated by state-owned utility EDF.

It makes France home to the world’s largest fleet of reactors after the U.S. and ensured Paris was less exposed than its neighbors to a dramatic cut in Russian gas supplies.

However, more than half of EDF’s nuclear reactors have been shut down for corrosion problems, maintenance and technical issues in recent months, thanks in part to extreme heat waves and repair delays from the Covid pandemic. The outages have resulted in French power output falling to a near 30-year low just as the European Union faces its worst energy crisis in decades.

“I find the France nuclear relationship really interesting because it just bluntly shows you all of the pros and cons of nuclear,” Norbert Ruecker, head of economics and next generation research at Julius Baer, told CNBC via telephone.

“Yes, its low carbon but it’s not economic. You need to nationalize EDF to make it happen. Yes, it offers baseload but wait a second, sometimes a whole plant disappears for weeks and months, so that baseload promise is not really there,” Ruecker said.

French Energy Minister Agnes Pannier-Runacher said last month that EDF was committed to restarting all its nuclear reactors this winter, Reuters reported, with closed reactors reopening each week from October.

French grid operator RTE, meanwhile, reportedly said there is no risk of a total blackout this winter but some power cuts during peak demand periods cannot be ruled out.

“Most of the nuclear power plants should be back online before the winter, so basically by November or December. So, if you trust France’s grid operator, things will be fine,” Ruecker said.

“There should be some conservatism in terms of whether France will be able to bring these reactors back on time, but we shouldn’t be overly pessimistic. The track record shows they have more or less been on time as of late.”

French power prices climbed to a string of all-time highs this summer, peaking at an eyewatering level of around 1,100 euros ($1,073) per megawatt hour in late August. Analysts fear the country may struggle to produce enough nuclear energy to support both its own needs and those of its neighbors in the coming months.

Underlining the structural problems in the country’s nuclear fleet, France not only lost its position as Europe’s biggest exporter of electricity this year but also, remarkably, actually imported more power than it exported.

Data from energy analysts at EnAppSys that was published in July found that Sweden clinched the top spot as Europe’s largest net power exporter during the first six months of 2022. Prolonged outages in France’s nuclear fleet saw the country’s exports halve from the same period last year, and analysts at EnAppSys warned the situation showed “no signs of improving any time soon.”

To compensate, France imported expensive electricity from U.K., Germany, Spain and elsewhere.

“Thanks to the market, thanks to the power lines that we have, Europe saved France from a big blackout” this summer, Julius Baer’s Ruecker said.

“It was the U.K., Germany, Spain and to some extent Switzerland that all stepped in. So, for me, the past month really has just uncovered some of the political talk which was not always objective,” he added, referring to talk of nuclear energy as a climate solution among politicians.

In a bid to protect households and businesses over the coming months, President Emmanuel Macron’s administration last month announced plans to cap power and gas price increases at 15% next year.

It represents a substantial jump from this year when the added cost of electricity for homes and small businesses was capped at 4% and gas at 0%.

Mujtaba Rahman, managing director for Europe at political risk consultancy Eurasia Group, said the extended subsidies — the most generous in the EU — are likely to add to the French government’s difficulties in facing down fiscal and budgetary battles.

“Much will depend on two factors,” Rahman said in a research note. “First, the success of the government’s energy austerity programme (which will be voluntary for households and compulsory for public bodies and industry). Secondly, the weather. A harshly cold winter after a harshly dry and hot summer would test the country’s power supplies to the limit.”

“For now, we maintain our 65% base case that Macron will dissolve the National Assembly by the middle of next year, but only if he believes that his centrist alliance has a strong chance of restoring its majority, albeit under downward pressure if France suffers a cold and troubled winter,” Rahman said.

“A winter of discontent is not a good preparation for an election.”

Germany, which initially planned to shutter its three remaining reactors by the end of the year, decided to delay its nuclear phaseout to shore up energy supplies this winter. The U.K., meanwhile, is seeking to ramp up its nuclear power generation, and the EU has listed nuclear energy among its list of “green” investments.

“It is important to say that if France has a nuclear problem, Europe has a problem as well in terms of electricity,” Alexandre Danthine, senior associate for the French power market at Aurora Energy Research, told CNBC via telephone.

“They are, in general, a big exporter, but in winter they need energy from neighboring countries in order to satisfy demands — whatever the situation,” Danthine said.

In France, Eurasia Group’s Rahman noted, Macron reacted angrily last month to suggestions, including from outgoing EDF boss Jean-Bernard Levy, that his “stop-start approach” to nuclear power in the last five years was partly responsible for the crisis.

In what was widely seen as a policy U-turn, Macron announced in February his intention for France to build at least six new nuclear reactors in the decades to come, with the option for another eight. At the start of his presidency, Macron had committed to reducing the share of nuclear power in the country’s energy mix.

The reversal controversially placed atomic power at the center of France’s bid to achieve carbon neutrality by the middle of the century.

Advocates of nuclear power argue it has the potential to play a major role in helping countries generate electricity while slashing carbon emissions and reducing their reliance on fossil fuels.

To critics of the energy source, however, nuclear power is an expensive distraction to faster, cheaper and cleaner alternatives. Instead, environmental campaign groups argue technologies such as wind and solar should be prioritized in the planned shift to renewable energy sources.