Removal of Hinkley Point C’s Acoustic Fish Deterrent System
What is being proposed?
Hinkley Point C has a range of measures to help protect fish from the plant’s cooling water system. They include a fish recovery and return system and special water intakes designed to reduce the number of fish entering the intakes compared with older power stations.
As part of a set of fish protection measures, an acoustic fish deterrent system was also proposed within the station’s original planning application. The deterrent would use underwater sound to cause some species of fish to swim away from the intakes.
As part of this application, 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. Hinkley Point C will be the first to include any fish protection measures at all.
Why the change?
1. Environmental
Evidence provided by our advisors - marine and freshwater science experts, Cefas, shows that the change would have limited effects on protected fish species in the area. The number of fish potentially harmed per year is relatively low and around that of a small fishing vessel.
The acoustic fish deterrent would use 288 speakers to make noise louder than a jumbo jet 24-hours a day for 60 years. Its impact on porpoises, seals, whales, and other species is unknown.
2. Safety
The Bristol Channel has poor underwater visibility and one of the highest tidal ranges in the world. Safely installing and maintaining dozens of sound projectors underwater, two miles offshore, is dangerous and would pose unacceptable risks to divers for 60 years.
Assessing the impact of the change
Marine and freshwater science experts, Cefas have considered the impact of Hinkley Point C on fish stocks in the Bristol Channel without an acoustic fish deterrent system installed. The detailed work concluded that the removal of the acoustic fish deterrent would have limited effects on protected fish species in the area.
In the natural environment, very large numbers of fish are eaten by other fish, marine birds and porpoises. This mortality is typically 10% to 20% of the adult population per year for longer-lived species and 60% or more for shorter living species. Fishing can also sustainably take at least 10% to 20% of the adult population every year without affecting a species' ability to reproduce and maintain their population levels. For many species, higher levels of fishing is also sustainable.
In comparison, the total amount of all fish estimated to be harmed without the Acoustic Fish Deterrent has been predicted by Cefas to be in the range of 18 to 46 tonnes in a year – less than the annual catch of one small fishing vessel.
Although the impact on fish populations is limited, we are proposing compensation measures and enhancements for the wider environment. This change provides a more natural, long-term solution that does not risk the lives of divers.
Additional fish protection measures
Many power stations have taken cooling water from the Bristol Channel in the past. 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.
Further information
Further information on the proposal to remove the requirement to install and acoustic fish deterrent can be found within the consultation overview document and supporting technical reports which are available on the consultation homepage.
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).
For EDF's 24/7 media enquiry line call 01452 652233.