By Kennedy Maize
There’s a new leader in the nuclear power plant cost overrun derby, and it isn’t even in the clubhouse yet. Britain’s Hinkley Point C — being built in Somerset by France’s government-owned EDF — is now going to cost at least £49 billion ($65 billion) if it goes into service in 2030 and another £1 billion ($1.3 billion) if the first unit is delayed to 2031.
The two-unit, 3,200-MW French-designed “European Pressurized Reactor” or “EPR” was announced in 2015 at a then-estimated price of £18 billion in 2015 pounds sterling, the Financial Times reported. Construction began in 2016. The new cost estimate — which EDF purposely underplayed — came in a company news release February 20 of its 2025 financial performance. Buried deep in the release, EDF said of the project, “Schedule for the start of production by Unit 1 adjusted to 2030 and action plans for the electromechanical work; completion cost estimated at £35 bn (in 2015 sterling).”
Of course, the plant won’t be paid for in 2015 currency, but in contemporary pounds (or dollars), as the FT correctly reported. The newspaper noted that the new estimate “compares with a previous ‘best case’ target of 2029, itself a two-year delay from an earlier timetable. When the project was given the go-ahead in 2016, it was due to come online in 2025.”
The FT added that EDF, “Europe’s biggest nuclear power operator, which manages France’s fleet of 57 reactors, is under pressure to show it can improve on its record of reactor construction. Recent projects have been severely delayed and hugely over budget, taking well over 10 years to complete.”
The EPR, originally designed by France’s Framatome, a joint venture of EDF (80.5%) and Mitsubishi Heavy Industries (19.5%), has had a troubled history. In Finland, work on the 1,600-MW Olkiluoto 3 began in 2005 by France’s Areva and German Siemens A for Finnish operator TVO, scheduled to go into service in 2009 at an estimated cost of €3 billion.
The project experienced a cascade of problems, many of them embedded in the design. The plant went into commercial service in 2023 at an estimated cost of €11 billion ($12 billion), at the time the most expensive single nuclear unit in history. The plant has operated well.
France itself has had a problematic adventure with the EPR. EDF’s Flamanville 3 EPR in France began construction in 2007 with an estimated date for full 1,600-MW of power in 2012. The plant reached full power in December. Commercial operation is expected this year. When that happens, Flamanville 3 will become the first French power reactor to come online in 23 years.
The project faced a series of technical hurdles. NuclearNewswire reported in December, “Originally estimated to cost €3.3 billion (about $3.9 billion), the project’s price has ballooned over the course of repeated delays and difficulties. In December 2022, EDF announced a new cost estimate of €13.2 billion ($15.5 billion). In January 2025, the French Court of Auditors released a new estimate that includes the interest accrued during construction: €23.7 billion (about $27.8 billion). In all, the project is set to enter commercial operation at a price tag anywhere from four to seven times its original budget.”
The most expensive commercially operating reactors are Georgia Power’s two new units at its four-unit Vogtle site. Units 3 and 4 are two Westinghouse 1,000-MW advanced reactors. Construction began in 2009, with an estimated completion estimated at 2016 and 2017 at a cost of $14 billion combined. Unit 3 went into service in 2023 and unit 4 in 2024, at a total cost of $36.8 billion.
Could Hinkley Point lose its position in the cost overrun race? Watch out for Britain’s Sizewell C near the village of Suffolk. This EDF project calls for two — that’s right — 1,600-MW EPR reactors. It’s a Hinkley Point clone. Construction began in January 2024, while the financing packing was still being constructed. The planned operating date is 2035, although that depends on progress at Hinkley Point, which has priority.
The current estimated cost for Sizewell C is £38 billion ($50.6 billion). Don’t hold your breath on that.
