French energy giant EDF said the plant in Somerset will now cost between £21.5 billion and £22.5 billion.
The company said the cost increases reflect "challenging ground conditions" which made earthworks more expensive than anticipated.
Action plan targets have been revised and extra costs are needed to implement the completed functional design, which has been adapted for a "first-of-a-kind application in the UK context", said EDF.
The company said that under the terms of the so-called Contract for Difference, the increased costs will have no impact on UK consumers or taxpayers.
A statement said:
The management of the project remains mobilised to begin generating power from Unit 1 at the end of 2025.
To achieve this, operational action plans overseen by the project management are being put in place. These involve the EDF Group's engineering teams in Great Britain and France, buildings and ancillary works contractors, and suppliers of equipment and systems throughout the supply chain.
– EDF STATEMENT
The costs of building the nuclear power station continue to rise.Stuart Crooks, managing director of the Hinkley project, said in a message to workers: "We are delivering on our milestones and although the risk of a delay has increased, the schedule is unchanged and we remain focused on delivering the first power in 2025."
Greenpeace UK chief scientist Dr Doug Parr said:
The new Hinkley nuclear plant looked like a bad idea when it was first proposed, and it's got worse ever since.
New offshore wind now costs less than half as much as Hinkley, and it might get even cheaper by the time the much-delayed reactors crank into action.
It's become overwhelmingly clear that a renewable energy system based on offshore wind and other renewables is the cheapest, fastest and most reliable way to cut carbon emissions. Ministers should heed the lesson from the Hinkley debacle and never make the same mistake again.
– DR DOUG PARR
The GMB union say the key message is that the power station is still on schedule.Justin Bowden, national officer of the GMB union, said:
The important message from today's announcement is Hinkley Point is still on schedule to be generating desperately-needed electricity by 2025.
If we are to have any chance of meeting a net zero carbon emissions target by 2050, never mind sooner, Britain leads at least six new nuclear power stations and all the ultra-low carbon electricity they produce, regardless of the weather, alongside green hydrogen gas and intermittent wind and solar as part of a balanced energy mix.
– JUSTIN BOWDEN
Stop Hinkley spokesperson Allan Jeffery said:
This project would be rapidly becoming an enormous joke if it wasn’t such a tragedy for those of us who have to live next to it.
Why anybody in Government ever thought EDF was capable of building it on time and budget after the disasters of Flamanville and Olkiluoto will remain a mystery. It must now surely be time to scrap this project. Despite having to pay cancellation fees consumers could still save around £50bn.
The cost of electricity from Hinkley Point C will now have reached around £106/MWh compared to less than £40/MWh for new offshore wind power.
