UK Gov’t Takes Action to Curb Underwater Noise in Offshore Wind Development

January 23, 2025, by Adnan Memija

The UK Department for Environment, Food & Rural Affairs (Defra) has unveiled new measures to minimise underwater noise levels during the construction of offshore wind projects.

As part of the government’s Plan for Change, the measures should reduce noise levels in the sea to allow new offshore wind projects to be built at pace, particularly in sensitive areas.

The government has partnered with The Crown Estate’s Offshore Wind Evidence and Change programme and explosives and offshore wind industry representatives to test and develop new, quieter technologies for bomb clearance and pilot proposed noise limits during offshore wind construction.

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Over 300,000 pieces of unexploded ordnance from the First and Second World Wars are said to sit on the UK seabed and, if encountered, must be cleared during the construction of offshore wind farms.

Operators are expected to use low-noise disposal methods to clear such ordnance by default, with noisy high-order detonations considered a last resort and restricted to extraordinary circumstances only, said Defra.

Developers will also be required to demonstrate they have made clear efforts to reduce underwater noise during the installation of offshore wind turbines, according to Defra. This will be followed by a public consultation on setting a future noise limit for offshore wind construction.

“As we expand offshore wind to make Britain a clean energy superpower through our Plan for Change, we need to protect the vulnerable animals of our seas. These new measures support the construction of offshore wind that the UK needs, while making sensible changes to stop needless harm to underwater life,” said Marine Minister Emma Hardy.

As well as minimising the effects of loud explosions and pile driving on vulnerable marine species and commercially valuable fish stocks, the measures will prevent construction delays caused by breaches in noise thresholds, said Defra.

“As UK seas get busier, it’s only right that all efforts are taken to limit unnecessary harmful underwater noise pollution. That’s why for many years The Wildlife Trusts have worked closely with government and statutory nature advisors, alongside regulators and industry, to find practical solutions to reduce the impact of this pollution on marine life,” said Christina Platt, marine planning officer at The Wildlife Trusts.

“Not only do we welcome Defra’s new policy on underwater noise, but see the new approach as vital given the increasing pressures our marine wildlife faces.”

In September 2024, Netherlands-headquartered IQIP put its newly developed piling technique in action, which the company said allows for the noise-compliant installation of even the largest monopiles.

The method utilises a large water tank as a drop weight. The tank, containing up to 1,700 tonnes of seawater, is raised by hydraulic cylinders and released from the drop height setpoint. The water tank falls onto buffer cylinders, which transmit the impact force to the pile, dampening it to extend the impact time.