Proposed change to fish protection measures at Hinkley Point C

What is being proposed?

Hinkley Point C has a range of measures to help protect fish from the plant’s cooling water system. These include a fish recovery and return system and special water intakes designed to reduce the number of fish entering the intakes.

An acoustic fish deterrent system was also proposed which would use underwater sound to cause some species of fish to swim away from the intakes.

We are proposing to install the first two fish protection measures but make a change to remove the inclusion of an acoustic fish deterrent system. Many power stations have taken cooling water from the Bristol Channel in the past with no detrimental impact on fish populations and Hinkley Point C will be the first to include any fish protection measures at all.

Watch video: Proposed change to fish protection plans at Hinkley Point C

We are working with the Environment Agency, Natural England and Natural Resources Wales to develop a proportionate and robust compensation package to mitigate any impact of the removal of the acoustic fish deterrent system. Alongside working on compensation, we are seeking a permit variation to avoid duplicate regulation, which will be consulted on by the Environment Agency.

The proposed changes and mitigation measures will form part of a formal application and public consultation later in 2023.

Why the change?

  1. Evidence provided by the governments marine and freshwater science experts, Cefas, shows that the change would have very little effect on protected fish species in the area. The amount of fish killed per year could be equated to the annual catch of a small fishing vessel.
  2. Installing and maintaining dozens of sound projectors underwater two miles offshore is dangerous and poses risks to divers that are unacceptable. The Bristol Channel has poor underwater visibility and one of the highest tidal ranges in the world. Operating a system with negligible benefit would place a burden on future operators and endanger the lives of workers for decades to come.
  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 removal of the acoustic fish deterrent would have very little effect on protected fish species in the area.

 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 around 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 0.4% to less than 0.002% per year.  To put this into context, the total amount of fish estimated to be killed by the operation of HPC without the AFD system has been predicted by Cefas to be around 56 tonnes in a year - about the same as would be caught by one small fishing vessel.

Engineering studies have shown that installing and maintaining sound projectors underwater would present risks to divers and offshore workers which, given the minimal benefits to fish species, 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?

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 any fish protection measures at all.

Even without an acoustic fish deterrent, Hinkley Point C’s water intake system will include a fish recovery and return system and specially designed low velocity, side entry water intake heads.

The design of the intake heads reduces the speed of the water being taken into the cooling pipes and are installed sideways to the tidal flow seen in the Severn Estuary. 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.

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.

Technical documents

Documents relating to the consultation are set out below. These consist of a Consultation Overview Document and a further eight documents providing more detailed environmental and technical information.

Consultation Overview Document

Full document title: Consultation Overview Document

Purpose of the document: Provides an overview of what is being proposed and gives details on how to respond and where to view the supporting documents to the consultation.

Document number: 100195841

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Updated Environmental Statement

Full document title: Updated Environmental Statement

Purpose of the document: This document provides an assessment of the likely significant effects arising from the proposed change (not installing an acoustic fish deterrent system). It updates the assessment submitted with the original Development Consent Order application. It confirms that no significant environmental effects will be caused. It is prepared in accordance with the Infrastructure Planning (Environmental Impact Assessment) Regulations 2017.

Document number: NNB-308-REP-000723

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Updated HRA Report

Full document title: Updated Report to Inform the Habitats Regulations Assessment

Purpose of the document: This document provides an update to the Habitats Regulations Assessment Report submitted with the original Development Consent Order application. It includes updated information, which confirms that the proposed change (not installing an acoustic fish deterrent system) will not have an adverse effect on the integrity of sites protected by the Conservation of Habitats and Species Regulations 2017 (Habitats Regulations). It is prepared in accordance with the Habitats Regulations.

Document number: NNB-308-REP-000722

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Updated WFD Report

Full document title: Updated Water Framework Directive Compliance Assessment

Purpose of the document: This document assesses the proposed fish protection measures (without an acoustic fish deterrent system) and confirms that the design will continue to comply with the requirements of the Water Framework Directive.

Document number: NNB-308-REP-000725

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Eels Report

Full document title: Implications for Compliance with the Eels Regulations

Purpose of the document: This document assesses the suitability of the proposed fish protection measures (without an acoustic fish deterrent system) on the basis of compliance with the Eels (England and Wales) Regulations 2009 and Eel Management Plans.

Document number: NNB-308-REP-000746

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Cefas TR456 Report

Full document title: Revised Predictions of Impingement Effects at Hinkley Point C – 2018 Edition 2 (Cefas)

Purpose of the document: This report underpins the above assessments and reports. It provides revised predictions of impingement arising from fish being entrapped in the cooling water system. This includes an updated baseline, taking into consideration newly available data, information and analysis techniques.

Document number: HPC-DEV024-XXX-000-RET-100031

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AFD Optioneering Report

Full document title: Summary of Engineering Optioneering Process 2019

Purpose of the document: This report provides details of the engineering and design process undertaken to identify a suitable acoustic fish deterrent system. It includes an appendix containing an independent review of the health and safety studies and risk analysis undertaken to support the optioneering and design processes for an acoustic fish deterrent system: Bureau Veritas (2018) Acoustic Fish Deterrent Health and Safety Review. 

Document number: NNB-301-REP-000710

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CW1 Report

Full document title: Hinkley Point C Cooling Water Infrastructure Fish Protection Measures: Report to Discharge DCO Requirement CW1 (Paragraph 1) and Marine Licence Condition 5.2.31

Purpose of the document: This report provides details of the cooling water system design as approved by the Marine Management Organisation, particularly the mitigation measures of the fish recovery and return system and intake head design which have been assessed in the Updated Environmental Statement.

Document number: NNB-209-REP-0001030

View document

Frequently Asked Questions

Frequently asked questions

What is an acoustic fish deterrent?

An acoustic fish 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 are you planning on changing?

Evidence provided by the governments marine and freshwater science experts, Cefas, shows that the operation of an acoustic fish deterrent system would have very little effect on protected fish species in the Severn Estuary. The number of fish killed per year could be equated to that of a small fishing vessel.

Installing and maintaining dozens of sound projectors underwater two miles offshore is also dangerous and poses risks to divers that are unacceptable. The Bristol Channel has poor underwater visibility and one of the highest tidal ranges in the world. 

As a result of these reasons, we have decided that it would not be appropriate to install an acoustic fish deterrent. Operating a system with negligible benefit for the environment would place a burden on future operators and endanger the lives of workers for decades to come.

What will be the impact of the change?

Hinkley Point C, like all power stations, needs cooling water to generate electricity. The government’s marine and freshwater science experts, Cefas, 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 10% to 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 0.4% to less than 0.02% per year. To put this into context, the total amount of fish estimated to be killed by the operation of HPC without the AFD system has been predicted by Cefas to be around 56 tonnes in a year - about the same as would be caught by one small fishing vessel.

Cefas concluded the predicted levels would have no effect on the sustainability of each species nor on the predators that rely on the fish to survive.

I have seen reports of billions of fish being killed – is this true?

No - the total amount of fish estimated to be killed by the operation of HPC without the AFD system has been predicted by Cefas to be around 56 tonnes in a year - about the same as the annual catch of one small fishing vessel.

Cefas concluded that this level limited 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.

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.

Do other power stations use AFD technology?

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 any fish protection measures at all.

Some power stations have experimented with the use of acoustic fish deterrent systems in the past but there has been no use of long-term permanent systems.

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

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

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 installed. 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. 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.

What are the next steps?

We are now working with the Environment Agency, Natural England and Natural Resources Wales to develop a proportionate and robust compensation package to mitigate any impact of the removal of the acoustic fish deterrent system.

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 water intake structuresare about 10km from the main channel and are near the bottom.

Contact us

The best way to contact us about Hinkley Point C is by completing our online enquiry form. You can also call us on 0333 009 7070 (24 hour free phone number).

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