ScottishPower Renewables has achieved a global engineering first – completing a record-breaking subsea drilling and duct pull-in operation at its £4 billion East Anglia TWO offshore windfarm.
The construction milestone saw the installation of the two cable ducts that will provide a protected pathway for the high-voltage export cables that will carry the clean, green electricity from the 960MW windfarm to shore.
Installed using Horizontal Directional Drilling (HDD) to safely drill beneath the Suffolk coastline and seabed, the specialist engineering operation involved the world’s longest continuous single sections of extruded polyethylene (PE) ducts.
At just under 1,800 metres long and 800mm in diameter, the giant ducts form the largest electricity transmission landfall of its kind in the UK, based on the combination of these two dimensions.
The length equals the distance of the historic Royal Mile in Edinburgh (from Edinburgh Castle to Holyrood Palace) or the stretch of the River Thames from the London Eye to the Tate Modern.
Ross Ovens, ScottishPower Renewables’ Managing Director for Offshore said, “The completion of this colossal HDD, which is three times the length of our other East Anglia projects, is a huge achievement – quite literally – and a major milestone as we progress construction of our third windfarm in the region. Our priority is always to deliver our clean energy projects, and all the benefits they bring, in a responsible and sensitive way that is mindful of the environment and the people around us.
“Landfall works are known to be one of the most technically challenging aspects of building an offshore windfarm, but thanks to precision planning and a great partnership with our principal contactor OCU Group and duct manufacturer Pipelife, this programme has well and truly hit the mark – breaking UK and world records in the process. It’s incredible.”
HDD is a complex engineering solution that goes deep beneath the ground to create an underground bore without the need to dig up beaches, dunes, cliffs or coastal habitats, minimising any disruption to the environment and sensitive landscapes. It’s completed using rigs working onshore and offshore simultaneously.
The HDD works are part of the East Anglia TWO civil engineering programme being carried out by principal contractor OCU Group, with support from its subsidiary Peter McCormack & Sons. The contract is supporting more than 80 jobs during construction.
Mike McNulty, HDD Director at OCU Group, said, “Delivering a landfall HDD of this scale is an exceptional engineering achievement, demanding meticulous planning, technical expertise and close collaboration. Successfully installing the first 1,800-metre, 800mm diameter PE pipe in a single continuous section is testament to the skill and commitment of everyone involved.
“We’re incredibly proud to be working alongside ScottishPower Renewables and our project partners to deliver this critical infrastructure for East Anglia TWO. This milestone demonstrates what can be achieved through specialist engineering, strong partnerships and a shared commitment to delivering major energy infrastructure responsibly.”
The 1800m x 800mm pipes were manufactured by Pipelife.
Project Manager in Pipelife Norway, Martin Myhre, said, “At 1,793 meters, this is the longest pipe Pipelife Norway has ever manufactured, making it a significant milestone for us. Producing the pipe through continuous extrusion meant we could manufacture it as one uninterrupted length, without the need for welding. This eliminates welded joints, resulting in a more robust and reliable solution for this demanding application.
“The pipe’s journey was also quite extraordinary. After being manufactured at our facility in Stathelle, Norway, it was transported all the way to Thorpeness in England by tow. A project of this scale takes close collaboration and careful planning throughout the entire supply chain, and we are very proud to have contributed to this record-breaking achievement.”
The first of the windfarm’s export cables is expected to be installed in summer 2027, with the windfarm working towards commercial operation in late 2028.
East Anglia TWO will be located in the southern North Sea around 33km from the Suffolk coast at its nearest point off Southwold and 37km from Lowestoft. It will have an operational capacity of up to 960MW – enough to power the equivalent of almost one million homes with homegrown clean, green electricity.
To date, the project has injected more than £1.5 billion into the UK supply chain.
