Scientists have found that an underwater acoustic deterrent system, informally called a 'fish disco', could prevent 90% of fish from being sucked into the cooling intake pipes of the Hinkley Point C nuclear reactor in Somerset. The system, which uses over 300 underwater speakers to emit sound pulses, is part of a £700m environmental protection plan by developer EDF Energy.
Research commissioned by EDF from Swansea University showed that the acoustic deterrent repelled the 'vast majority' of tagged fish. During tests, only one of the tagged twaite shad fish came within 30 metres of the intake pipes when the speakers were active, compared to 14 without the system. The full solution, costing 1.5% of the £46bn project, is expected to save about 44 tonnes of fish annually—equivalent to the catch of a small fishing vessel.
EDF had previously argued against the requirement, suggesting salt marsh creation instead. However, the company now says the system works better than hoped, allowing it to meet planning obligations without needing 900 acres of compensatory salt marsh. The system also includes special intake pipe mouths to slow water suction and a fish recovery system for any fish drawn in.
Good news for salmon populations: the study found that migrating Atlantic salmon generally use the main channel of the River Severn, well away from the intakes. Only two tagged salmon were detected within 1km of the intakes over two years. Dr David Clarke of Swansea University said the results are 'very encouraging', while Chris Fayers, head of environment at Hinkley Point C, noted the system means the plant can generate reliable low-carbon electricity without additional environmental compensation.
The research will be submitted for regulatory approval by the Marine Management Organisation later this year. Under its subsidy contract, EDF will absorb the extra cost rather than pass it to household bills.
