Sizewell C and the environment

Sizewell C will have no impact whatsoever on the supply of water to homes and businesses in East Suffolk.

Sizewell C has a clear plan for providing all the water the project needs during construction. 

In the first 9-12 months of construction, water will be supplied to site using water tankers. After that, water will be supplied using a desalination plant which will draw its water from the North Sea. Northumbrian Water has committed to providing a permanent supply to the project and is aiming for this to be in place by the late 2020s. Should this not become available until later, the desalination plant could continue to operate throughout the construction phase.

Our original proposals did not envisage the need for a desalination plant. We have been consulting with the water utilities for some time and our original planning application set out plans to supply the project using a permanent water main.  

Towards the end of the planning process, Northumbrian Water indicated there was a risk that the mains supply might not be able to provide the full amount of drinking water needed in the early years of construction. To make sure there is no risk to the local supply and to ensure the project has adequate water, we have decided to use desalinated water from the sea.

The change in advice from Northumbrian Water came towards the end of the examination of our planning application. It was important that we listened to this new information and adapted our plans accordingly.

No. We have agreed to cap the number of HGVs to and from the main development site each day. HGV movements will be strictly monitored to make sure the total number of journeys remains within agreed limits. We will accommodate the journeys made by the water tankers by rescheduling other deliveries to the site.

The assessment that we submitted as part of our planning application, which was based on a set of worst-case assumptions, showed that the desalination plant would have a negligible impact on the project’s overall emissions.

Northumbrian Water have confirmed their commitment to supplying Sizewell C’s long-term requirements for drinking water. While this will not come from a transfer main, good progress is being made to identify other options and these are now being considered. These include a water transfer system, larger local desalination and new reservoir infrastructure. 

NB: Cooling water used for generating electricity is provided through the power station’s own sea-water intake system.

Desalination plants supply several nuclear power projects globally but it is not an option we are considering for Sizewell C. We are confident that Northumbrian Water will be able to meet the project’s long-term water needs through the sources that it is in the process of identifying. Any proposal to use a permanent desalination plant during the operational phase would require further detailed assessments.

The land to the north of Sizewell B was identified as a suitable site for a new nuclear power station by the Government over a decade ago. 

Electricity has been safely produced from nuclear power at Sizewell for over half a century. Siting Sizewell C next to Sizewell B reduces the environmental impact from construction and the site can benefit from nuclear licencing and a grid connection. 

All nuclear plants in the UK are located near the sea so that water can be used in the power station cooling system.

No. Extensive investigations have been undertaken by experts to establish that the Sizewell C site is stable.

Parts of the Suffolk coastline are experiencing erosion, but Sizewell is located on a more stable section of land, between two hard points and the offshore bank of sediment known as the ‘Dunwich - Sizewell Bank’. 

Sizewell A has stood on the same part of coastline since 1966 and Sizewell B has operated since 1995. In more than half a century, neither of those power stations has seen any flooding or significant coastal erosion. 

The Government’s Centre for Environment, Fisheries and Aquaculture Science (CEFAS) is based in nearby Lowestoft and has comprehensive data for coastal change on the East Coast going back to the 1800s. The data show that this part of the coast has been very stable.

No. Sizewell C will be built on a platform standing approximately 7 metres above today’s mean sea level and will be protected by a sea defence structure that will be more than 14 metres above mean sea level. These and many other measures incorporated into the design of the power station will protect it from the sea.  

The sea defence will be adaptable and could be raised in future if sea level rise turns out be greater than current predictions. Based on current forecasts, any adaptation would not be needed until 2140 and only under the most extreme climate change scenario. 

We have performed thousands of hours of flood risk modelling using the highest plausible estimates for sea level rise in the Sizewell area. Our assessments show that the power station and access road will be built to withstand a 1-in-10,000-year storm and 1-in-100,000-year surge events.   

Although extreme storm events could result in some sea water coming over the sea defence and pooling around the site, it would drain away in a matter of hours. This is predicted, planned for, and reflected in the design of the entire Sizewell C site. 

Drones are flown over the Sizewell beach each month and photograph every 3cm square of the coastline, producing 3D maps of any changes. Radar and tide gauges will also allow us to monitor sea conditions and levels at Sizewell throughout the lifetime of the power station. If there are any unexpected developments, we will take action to address them.

Read the 2021 Sizewell Coastal Defences report here and the draft Coastal Processes Monitoring and Mitigation Plan (CPMMP) here.

Sizewell C will not have a significant effect on fish populations. Sea water is needed to operate the cooling system of the power station, but a fish return system and specially designed heads on the sea intake pipes will minimise the impact on fish.

Government scientists at CEFAS say there is no scientific evidence that the rates of impingement at Sizewell C will have a significant effect on population sizes.

Fish populations produce vast numbers of young each year. The species which will be most affected by the power station will be sprat and herring but the losses are expected to be just 0.01% of the adult population each year. That’s a tiny fraction of the population size and of the natural variation in the numbers of adult fish from year to year.