The Sizewell C is a 3.3GW nuclear power project proposed to be developed near the Sizewell A and B nuclear power plant (NPP) sites in Sizewell, on the Suffolk coast, in the East of England, UK.

The twin-reactor facility is proposed to be built and operated through a joint investment partnership between France’s state-owned EDF Energy (80%) and China General Nuclear Power Corporation (CGN, 20%).

EDF and its Chinese partner CGN are also building the Hinkley Point C nuclear plant in Somerset, which is the UK’s first new nuclear power project to be implemented in the last 25 years. Sizewell C is the next project to have progressed in the country after the currently under construction identically-designed Hinkley Point C, as the funding problems have pulled other proposed nuclear developments including Moorside and Wylfa Newydd to an apparent halt.

EDF submitted a planning application for the Sizewell C nuclear power plant (NPP) to the UK government in May 2020 and expects the Planning Inspectorate to take a final decision regarding the development consent order (DCO) for the project by 2021.

If approved, the construction on the £16bn ($21bn) project is expected to be started in 2022 with commissioning expected in the early 2030s.

The Sizewell C NPP is expected to generate enough baseload electricity for approximately six million UK households and offset up to nine million tonnes (Mt) of CO2 emissions a year.

The plant is estimated to account for approximately 7% of the UK’s electricity supply, while the combined electricity generation with the existing Sizewell B facility is estimated to meet approximately one-tenth of the UK’s total energy requirements.

Location and site details 

The Sizewell C nuclear power station is proposed to be developed on a 32-ha site located north of the Sizewell B nuclear power station. The plant site will be protected by sea defense and a beach landing facility.

Sizewell is one of the oldest nuclear power generation sites in the UK. The Sizewell A power station operated almost for four decades at the site before it was permanently retired for decommissioning in December 2006.

The Sizewell C project development background

EDF acquired British Energy, the previous owner of the Sizewell power station, in 2009. The UK government announced Sizewell as a suitable site for a new nuclear power plant construction in November 2009.

The public consultation for the proposed project was initiated in November 2012 and CGN signed a strategic investment agreement with EDF Energy for the development of Sizewell C in September 2016.

The fourth and the last consultation stage for the project was concluded in September 2019 and EDF submitted an application for DCO to the Planning Inspectorate in May 2020.

Sizewell C is being projected to provide a boost to the UK economy post the Covid-19 pandemic, as the project is estimated to create approximately 25,000 construction jobs and 1,000 apprenticeships, and the UK firms are proposed to account for up to 70% of the total construction value.

Sizewell C nuclear power station make-up

The Sizewell C facility will be equipped with two European pressurised reactor (EPR) units of 1,670MW capacity each.

Each generating unit will comprise a nuclear island housing the reactor, fuel and the safeguard buildings, and a conventional island housing the turbine hall, as well as electrical and ancillary buildings.

The power station will use a cooling water system along with combined drainage outfall in the North Sea.

The other facilities at the project site will include interim storage facilities for spent fuel and other radioactive wastes. 

Power evacuation

The electricity generated by the Sizewell C facility will be evacuated through a 400kV overhead transmission line with four or five pylons connected to a new National Grid 400kV substation proposed adjacent to the existing National Grid substation for Sizewell B.

Contractors involved 

Atkins, a subsidiary of SNC-Lavalin, in July 2019, was awarded a £5mn ($6.2m) contract to provide the basic design for the preparatory works required for the site development involving civil and marine construction works.

Quod, a London-based consultancy provided strategic planning and socio-economic advisory services to EDF on the planning application for Sizewell C.

Sizewell A and B nuclear power plants

Sizewell A comprises two Magnox gas-cooled reactors of 210MW net electricity capacity each. The construction of the plant was started in 1961 while commissioning took place in 1966.

The Sizewell A reactors were permanently shut down for decommissioning in 2006 after generating approximately 110TWh of electricity during its 40 years of operation.

Sizewell B is a single pressurised water reactor (PWR) unit of 1,198MW net electricity capacity commissioned in February 1995.