Hinkley Point nuclear power stations on the Bristol Channel, near Bridgwater, Somerset, U.K | GETTY energy Trouble ahead for UK’s nuclear hopes Britain’s push for new reactors is coming under fire.

The next generation of reactors in the U.K. has been in the works for a decade, but now a looming challenge in the European Court of Justice attacking nuclear subsidies, growing technical problems and cost overruns are casting doubt on the idea of using nuclear to meet emissions reduction targets.

The original idea was launched under former Prime Minister Tony Blair, who said in 2006 that nuclear energy would have to be coordinated with renewables.

Prime Minister David Cameron’s government then put its nuclear hopes into French company Areva’s new European pressurized reactor (EPR) technology, with a deal reached in 2013 to provide as much as £17.6 billion in subsidies for two nuclear power units at Hinkley Point C in Somerset, which are expected to cost £24.5 billion in total.

But, nine years after Blair’s show of support, the future of Hinkley Point C looks increasingly uncertain, as the first EPR projects in France and Finland have been hampered by delays, cost overruns and safety concerns, and as the Austrian government prepares to challenge the European Commission on its approval of the U.K.’s state aid.

Austrian Chancellor Werner Faymann announced this week the government would lodge its complaint in the European Court of Justice next week; the Greens said it would be Monday. It is backed by Luxembourg, which takes over the European Council presidency next week, as well as a number of companies and cities.

Vienna opposes nuclear energy overall, on the grounds that it is expensive and environmentally dangerous. A long-time importer of nuclear power from the Czech Republic and Germany, the country decided in 2013 to ban all foreign supplies, beginning this year.

The complaint, however, does not seek to interfere with another member state’s choice of electricity supply, Austrian and Luxembourgish sources stressed. Instead, it targets the U.K.’s use of a so-called strike price, which triggers government subsidies if wholesale electricity prices fall below a certain level. Until now, the scheme has only been used to support wind and solar energy projects.

“The technology gives reason for security concerns, and cannot be considered environmentally nor socially sustainable, nor is it an economically competitive technology. It is therefore not qualified to support the energy and climate goals the EU has set,” said MEP Paul Rübig, a European People’s Party member from Austria.

The U.K.’s decision to subsidize the Hinkley project was a political one, based on “very shaky legal grounds,” added MEP Claude Turmes, a member of the Greens from Luxembourg.

“In the EU treaty, it says state aid should only be granted in exceptional cases, and Hinkley does not provide these exceptional security of supply issues, because the U.K. has other ways of ensuring its security of supply,” he said. “It has cheap alternatives, notably renewables like offshore wind, and also more interconnections. Technically, there is no emergency situation.”

Nuclear power was promised to be too cheap to meter. It is now too expensive to generate.

The Commission approved the U.K.’s state aid in October 2014, after Whitehall agreed to change the project financing terms to reduce the burden on taxpayers. The U.K. government succeeded in dispelling the Commission’s doubts about whether the state aid was needed to fix a market failure, and convinced it that consumers would be able to share in the project’s gains.

Europe’s climate action and energy chief, Miguel Arias Cañete, acknowledges there is a role for nuclear. “Nuclear is there, and member states are free to develop and commission nuclear,” he told POLITICO. “The Commission only establishes the best standards of safety; that’s our responsibility.”

Supporting Hinkley

In the deal it reached with energy utility EDF Group and Areva in October 2013, the U.K. agreed to set the price of electricity from Hinkley Point C at £92.50 per megawatt hour for 35 years, making up the difference if the price goes higher. The first unit was expected to start up in 2023.

At the time, the Department of Energy and Climate Change said this would save households £74/MWh per year by 2026-2030. The European Commission estimated it would cost the government between £4.78 billion and £17.6 billion over the period.

While Austria and Luxembourg argue this scheme should be reserved for solar and wind generation, the U.K. believes all three types of energy qualify as zero-carbon sources, which will help it achieve its emissions reduction goals.

The nuclear energy industry agrees. “If there’s any complaint about the U.K. model, it should reflect the fact that the model incorporates all zero-carbon technologies, not just one,” said Michael Kirst, vice president of strategy and external affairs at Westinghouse Electric, which has its own nuclear technology.

Austria’s challenge is unlikely to cause the Commission to reject the state aid outright, but it does raise further uncertainties for Hinkley, said Antony Froggatt, a senior research fellow at Chatham House.

“What is more likely than it being rejected out of hand is that it would be to required to make some modifications. But then the question becomes, what does that do to the business case for Hinkley, and how do the different parties react?” Froggatt said.

Faymann believes it will slow the project, and plans for others. “The purpose of suit is not only to have a postponing effect on the state aid, but especially be a deterrent for investors, not only in Great Britain but across the EU,” the chancellor said.

Make-or-break for Areva

The case also comes amid growing concerns about the cost and safety of Areva’s EPR technology.

Before construction starts on Hinkley, EPR is being put to the test with the Flamanville reactor in France, Olkiluoto in Finland, and Taishan in China.

The Flamanville and Olkiluoto plants are already behind schedule; Flamanville’s start up has been pushed back by a year to 2017, while Olkiluoto is now expected online around 2018, which would be a decade later than planned for a project that started construction in 2005.

Areva is also teetering on the brink of bankruptcy, and the French government has backed EDF’s plan to buy a controlling stake in the company to keep it afloat.

But now there could be even more delays and cost overruns. French safety regulators flagged up concerns earlier this month that the steel used for the pressure vessel, which contains the reactor’s radiation, was too weak. To test the vessel’s strength, Areva has said it would break the 110-ton spherical steel lid meant to sit on top of the Hinkley reactor.

This will likely add costs and time, particularly as it may cause U.K. safety regulators to more closely monitor the Hinkley construction, analysts said.

“The regulatory and government uncertainty, coupled with higher construction costs, may cause concern for some of the investors,” said Froggatt. “The industry’s recent record in France has not been good, and delays and uncertainties are likely as a result of further concerns over the material used in the new reactor pressure vessels at Flamanville, which may also affect reactors in China.”

20/20 hindsight

Meanwhile, there is growing talk in the U.K. of whether the government should cut and run from nuclear.

In a speech to the House of Commons last week, Labour MP Paul Flynn questioned whether Whitehall would have made the same decision if it knew what it knows now about the cost of nuclear.

“Nuclear power was promised as an energy source that would be too cheap to meter. It is now too expensive to generate,” said Flynn, adding that the fall in oil and gas prices since 2013 makes the strike price of £92.50/MWh twice the average rate for electricity nowadays.

While the European public has largely turned against nuclear since the Fukushima accident in Japan in 2011, the British have been shielded by a “skilled public relations operation,” Flynn added.

Renewables offer alternatives, he said, commending the government for providing funding to project that would harness energy from tides in Wales. “That is vast untapped energy — British, free, eternal and entirely predictable.”

Kalina Oroschakoff contributed to this article.