Ørsted contract win for Seiche

Seiche Ltd

Seiche Ltd’s specialist team of personnel and equipment have mobilised to two vessels at Ørsted’s Hornsea Two offshore wind farm site. Their purpose is to manage Ørsted’s commitment to ensure that impacts on marine mammals during the Hornsea Two wind farm construction activities are negligible.

Specialising in marine mammal monitoring and mitigation measures, the team from Seiche has been brought on board to ensure compliance with procedures that seek to minimise the effects of construction noise on the local marine population. Key species known to occur in the project area are harbour porpoise, white-beaked dolphins, minke whales as well as grey and harbour seals.

Prior to any construction activities taking place, dedicated Marine Mammal Observers (MMOs) will monitor the area for any animals that could be affected by the noise produced from pile driving.

Monitoring activities are taking place from DEME’s jack-up installation vessels during the installation of 165 monopiles, as well as Heerema’s semisubmersible crane vessel
Sleipnir during the construction of the two offshore substations. In addition to visual monitoring to ensure marine mammals are not within close proximity to piling operations, acoustic deterrent devices (ADDs) are used to deter animals from the area to protect them from harmful levels of noise.

Seiche’s team of observers and ADD Operators ensure that the Marine Mammal Mitigation Plan, which follows the government’s Joint Nature Conservation Committee’s guidance protocol, is adhered to at all times. Should a mammal be detected within the designated protection zone piling operations are delayed until the mammal leaves the area.

Based locally in East Anglia, Seiche’s Associate Director of Environmental Services Nicola Harris said: “As a company we are extremely pleased to be working with Ørsted as well as its contractors DEME and Heerema to ensure that the construction of the world’s largest wind farm can be completed without harming the marine animals off our own coast. Offshore Renewables are key to developing a greener and more sustainable future and we are proud to be working with companies like Ørsted to be a part of that achievement.”

Natalia Lopez, Senior Environment & Consents Specialist for Ørsted, said: “We adhere to a strict consenting process before any construction works commence offshore and it’s imperative that outlined procedures are fully adhered to. It’s great to be able to work alongside UK based suppliers with specialist expertise in this field so that together, we can deliver the world’s largest offshore wind farm in the most sustainable way possible.”


Hornsea Two will surpass its predecessor Hornsea One by generating 1.4 GW of clean energy, once complete in 2022. The project spans an offshore area of 462 km² and is located 89 km off the Yorkshire coast in the North Sea. It will feature 165 Siemens Gamesa 8 MW SG 8.0-167 DD turbines. It is expected to deliver 20% more annual output than those used for Hornsea One. The wind farm is on track to be fully operational in 2022, and will provide power to well over 1.3 million homes.

For more information on offshore wind farms worldwide, click here.