What is being proposed?

As part of its planning application, Hinkley Point C proposed a range of measures to protect fish from the plant’s cooling water system.

These include a fish return system, intakes designed to reduce the number of fish entering the intakes compared with older power stations and an acoustic fish deterrent. The deterrent uses underwater sound to cause some species of fish to swim away from the intakes.

Hinkley Point C will install the first two measures but is proposing not to install an acoustic fish deterrent and is asking people for their views in a consultation. The relevant authorities will consider the public’s views when deciding if this proposal is appropriate.

Cooling water pipe segments

On 15 March 2019, the Environment Agency launched its consultation relating to the removal of the acoustic fish deterrent at Hinkley Point C. It will consult on EDF Energy’s application to vary the environmental permit that it previously issued to Hinkley Point C.

Separately, EDF Energy will conduct its own consultation from 2 April to 4 June 2019. This consultation relates to changing the Development Consent Order, which was granted by the Secretary of State in 2013. More information will be available on this page in the coming weeks.

Why the change?

  1. A detailed independent study has shown that the power station will have negligible impact on the fish populations in the Bristol Channel and beyond, with the two planned fish protection measures in place.

  2. Installing and maintaining dozens of sound projectors underwater two miles offshore is dangerous and poses risks to divers that are unacceptable to Hinkley Point C. There is poor visibility and one of the highest tidal ranges in the world. That danger cannot be justified for a system that will have almost no benefit.

  3. Many power stations have taken cooling water from the Bristol Channel in the past with no detrimental impact on fish populations. Hinkley Point C will be the first to include fish protection measures. 

What evidence is there to support the proposal?

Hinkley Point C asked the Government’s independent expert body Cefas to use the latest data to look at the impact of the power station on fish stocks in the Bristol Channel. The detailed work concluded that the power station’s predicted impact was “negligible”.

Power stations need cooling water to generate electricity. The water taken from the Bristol Channel by Hinkley Point C will contain fish. Fisheries scientists predicted the percentage of adult fish stocks taken each year by the power station, just as they would for commercial fishing.

Very large numbers of fish are eaten by other fish, marine birds and porpoises. This natural mortality is typically 10 to 20% of the adult population per year for longer-lived species but 60% or more for shorter-lived shoaling species. Fishing can sustainably take at least 20% of the adult population every year without affecting the species' ability to reproduce and maintain their population levels. For many species higher levels of fishing are sustainable.

The worst case predicted effect of Hinkley Point C with the planned two fish protection measures in place varies by species, from a maximum of 0.2% to less than 0.001% per year. Cefas concluded that this level is negligible compared with natural mortality and fishing. The predicted levels will have no effect on the sustainability of each species nor on the predators that rely on the fish to survive.

Power stations around the Bristol Channel have taken water for decades – all with no fish protection measures. When Hinkley Point C comes into operation water use will be no higher than the late 1990s and, for the first time, fish protection measures will be in place.

Engineering studies have shown that installing and maintaining 288 sound projectors underwater would present risks to divers and offshore workers which are unacceptable to Hinkley Point C. The area has the third highest tidal range in the world with fast flowing water and poor visibility. Flow peaks at around 1.8m per second and tidal height varies by more than 10 metres between low and high tide.  

What are the other measures in place?

The cooling water intake design includes a fish return system (shown below) and low velocity side entry water intakes. The low velocity side entry intakes reduce the speed of the water being taken into the cooling pipes and are installed sideways to the tidal flow. This reduces the risk of fish entering the pipes. In addition, filtration systems called drum screens and band screens will be fitted in front of the cooling water pumps to protect the power station from clogging with seaweed or marine debris. These have been designed to carefully transfer fish to the return system and back to sea.

Revised planning consent and the consultation process

Hinkley Point C will be making applications to relevant regulators to remove the requirement to install the acoustic fish deterrent system. Three separate applications will be made:

  • Development Consent Order (DCO): Application to the Secretary of State for a material change to the DCO
  • Environmental Permit variation: Application to the Environment Agency
  • Marine Licence variation: Application to the Marine Management Organisation


In advance of submitting an application to change the DCO, Hinkley Point C will carry out a consultation with interested groups on the proposals. The consultation is planned to begin 2 April running until 4 June 2019 and all information, including the Cefas report, will be available here. The Environment Agency is carrying out its own consultation on our application to vary the permit, click here to take part.

Frequently asked questions

What is Hinkley Point C doing?

Hinkley Point C is making applications to relevant regulators to remove the requirement to install an acoustic fish deterrent (AFD) system. Requirements relating to the deterrent are set out in the Hinkley Point C Development Consent Order (DCO), water discharge activity environmental permit and marine license. Three separate applications will be needed:

  1. DCO: Application to the Secretary of State for a material change to the DCO
  2. Environmental Permit variation: Application to the Environment Agency
  3. Marine Licence variation: Application to the Marine Management Organisation

What is an acoustic fish deterrent?

The deterrent uses sound to deter certain groups of fish (i.e. those with well-developed hearing) from the cooling water intakes. Only sprat and herring of the most common fish in the Bristol Channel have good hearing and they are abundant and not commercially fished. The deterrent is less effective for fish with less developed hearing and ineffective for some species.

What does the new study show?

Hinkley Point C commissioned an environmental study from the Government’s independent expert body, the Centre for Environment, Fisheries and Aquaculture Science. It evaluated new and previous data to consider the impacts on fish species assuming the deterrent is removed. This work concludes that the power station would have negligible impacts on fish stocks.

The worst case predicted effect of Hinkley Point C with the planned 2 fish protection measures varies by species from a maximum of 0.2% to less than 0.001% per year.

The impact of the power station is tiny in comparison to the impact of commercial fishing.

Why did EDF Energy propose the system in the first place?

It was regarded as emerging best practice when the plans were drafted. Now that more detailed design has been undertaken Hinkley Point C has concluded that the deterrent does not provide significant benefit and that its installation and on-going maintenance poses unacceptable safety risks to divers and workers.

Why did you commission the study?

Hinkley Point C wanted to understand the impact of the power station on fish stocks without an acoustic fish deterrent. We knew that there was new data available six years on from the planning application. We believe in a science-based approach and asked Cefas to look at the science to assess the impact of the power station.

Can I see the report?

Yes, the report will be published as part of the consultation.

What is the danger to workers?

Further detailed design work has concluded that the safety risk to workers is unacceptable to the Hinkley Point C project – especially given the minimal benefit provided by the acoustic fish deterrent.

Visibility in the muddy water is zero, tidal flow peaks at around 1.8 metres per second and tidal height varies by more than 10 metres between low and high tide. Maintenance by divers is really only achievable around slack water for 30 minutes. 

The system would be extremely complex to construct and maintain with offshore operations restricted to narrow tidal windows and subject to lengthy periods of interruption by weather. The fish recovery and return system and low velocity side entrance intake head structure have been successfully incorporated into the design and will be built.

What fish protection measures will be built?

Hinkley Point C will be the first power station in the Bristol Channel to have fish protection measures. The cooling water system includes low velocity side entry water intakes designed to minimise the number of fish taken into the system and a fish return system.

The Hinkley Point C cooling water intake system will take seawater direct from Bristol Channel before returning that same water back into the sea. Water will be taken through intake heads and tunnels 3.3km from the shore at a depth of 20m below the seabed. Four intake heads and two tunnels are proposed. Once at the shore the water will go through a filtration system of coarse and fine mesh screens in a cooling water pumphouse. Fish will be returned to the sea via a fish return system.

Will all fish survive going through the cooling pipes?

All power station cooling systems using river or sea water have an impact on fish. Even with measures to protect fish, not all will survive the passage through the cooling tunnels. The fish return system is effective for more robust species.

The total amount of fish taken will be around 56 tonnes compared with 650,000 tonnes commercially fished in the UK each year by over 6,000 boats. So our impact will be equivalent to about a small trawler's catch per year.

What fish live in the Bristol Channel?

Typically, there are between seven and ten species that make up 95% of the fish found around Hinkley Point: European sprat, herring, whiting, sole, cod, thin-lipped grey mullet, flounder and 5 bearded rockling. Of these species only sprat and herring have good hearing, the others have average to poor hearing and are therefore less likely to respond to sound deterrents. Twenty fish species were included in the comprehensive assessment undertaken by Cefas. 

What about salmon and sea trout?

These migratory species do use the Severn Estuary but primarily use the main channel of the estuary they also swim near to the surface. They are not expected to be affected in any significant numbers as the future intakes are about 10km from the main channel and are near the bottom.

Do any other power stations use acoustic fish deterrents?

There are examples of AFD systems being used at UK power stations, there are no examples of such a system being installed in an offshore environment or in conditions as harsh as those encountered in the Bristol Channel.

What is a material change to a Development Consent Order?

There is no set definition of what constitutes a material or non-material change although there is some Government guidance on suggested circumstances. We intend to submit an update to the Environmental Impact Assessment and updated information to inform a Habitats Regulations Assessment focusing on the removal of the AFD. This will be based on updated information and data since the DCO in 2013. As these assessments are being prepared to be submitted, we are adopting a precautionary approach by treating the change as material.

An application for a material change is decided by the Secretary of State for Business, Energy and Industrial Strategy.

Who are you consulting with?

Hinkley Point C has an independently chaired Marine Technical Forum, made up of the Environment Agency, Marine Management Organisation, Natural England, Natural Resource Wales and the Devon & Severn Inshore Fisheries Conservation Authority.

There will be a pre-application consultation period in which statutory and non-statutory consultees will be consulted. Notices are being published in appropriate newspapers, Lloyds List, London Gazette and relevant fishing journal. The Environment Agency and the Marine Management Organisation will carry out separate consultations on our respective applications to them.

Are you doing any public events?

All the information will be publicly available on this page. We will be updating the Hinkley Point C community forum on the consultation and holding events for the public to talk to our experts.

When do you propose to consult?

We are proposing to start formal consultation 2 April running until 4 June 2019.

What is the process once an application has been submitted?

Once an application has been made we will notify consultees and publish notice of the application. There will then be a 28-day period within which representations can be made to the Secretary of State. The Secretary of State will consider whether to hold an examination prior to determination of the application and will take all relevant representations into account prior to making any decision.

Respecting the environment

Hinkley Point C’s low carbon electricity will play a critical role in the fight against climate change as Britain moves away from fossil fuels. The power station is also being built with environmental protection in mind.

We employ environmental experts, including ecologists and marine biologists to ensure we manage our environmental footprint carefully. We’ve planted 20,000 trees around the site, we’ve replaced habitats and homes for protected species like bats, newts and badgers and created wildflower meadows specifically for wildlife foraging.

Much of our environmental work is done outside of our site in partnership with environmental organisations like the Quantock Area of Outstanding Natural Beauty, who’ve planted more than a mile of new hedgerows, ponds have been restored, and more than eight acres of new wildflower meadows have been sown via our Quantock Landscape Development Fund.

Somerset Wildlife Trust’s warden helps us manage our own nature reserve at the Hinkley Point site and they are running a Brilliant Coast campaign to promote and protect coastal wildlife with investment from our Community Fund. We also work closely with organisations like the Wildfowl and Wetlands Trust that manage the nearby reserve at Steart Marshes, adding to the understanding of the ecologically rich habitats around Hinkley Point.

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Contact us

The best way to contact us is by completing our online enquiry form.

Call us on 0333 009 7070 (24 hour free phone number).

Stop by our visitor centre in the Angel Place Shopping Centre, Bridgwater, TA6 3TQ. We are open from 9am-4pm Monday to Friday and 9am-1pm on Saturday.

Write to us at: Hinkley Point Visitor Centre, Angel Place Shopping Centre, Bridgwater, TA6 3TQ

For media enquiries, email media@edfenergy.com.