The owner of the Hinkley Point nuclear power station has defended its plan to build a new plant at the Somerset site.
incent de Rivaz, chief executive of France's EDF Energy, told the BBC the project was not too expensive.
He said power from nuclear plants such as Hinkley Point C would cut customer bills by at least 10% by 2026.
The project has come under fire for both its £24.5bn cost and delays to investment decisions and the timetable for building.
The original plan was for it to start generating electricity by 2023.
There is still no start date for the new facility, which will be built next to two existing generation plants at Bridgewater in Somerset.
Three days ago, the chancellor, George Osborne, who is visiting China, secured investment from the Chinese by guaranteeing a £2bn deal under which China will invest in Hinkley Point.
The deal will be signed next month during the Chinese president's State visit to the UK.
Volatility Another controversial issue is a government guarantee that EDF will receive £92 per megawatt hour, twice the current wholesale price for power.
EDF said it needed that because the price of energy would be much higher in the future: "You cannot compare the price in the next decade with the price of today, which is being depressed by the current low price of gas. We have to protect our self against volatility."
Mr de Rivaz said it was a similar situation to a consumer replacing their car with a new one, "more expensive but you will get a much better car".
He rebuffed suggestions that building gas power plants would be more cost effective, saying that would mean the UK importing billions of dollars of gas from elsewhere, putting the country at the mercy of geopolitics.
Partners Meanwhile, EDF announced that the engineering firm Rolls-Royce would take a big share of £100m worth of contracts to supply the new nuclear power plant at Hinkley Point.
EDF, the French firm in charge of the project, has selected Rolls-Royce to supply heat exchangers worth £25m.
In partnership with Nuvia, Rolls-Royce will also supply systems to treat nuclear waste in a contract worth £75m.
The contracts awarded to Rolls-Royce and Nuvia are subject to the final investment decision from EDF and the new timetable for its construction.
Mr de Rivaz said: "Hinkley Point C offers the UK a tremendous opportunity to boost employment and skills in the crucial manufacturing and construction sectors, as well as leading the revitalisation of the new nuclear programme."