Hornsea 2 Offshore Wind Farm
Hornsea 2 is currently the world’s largest offshore wind farm (VolkerFitzpatrick is currently working on Hornsea 3), and the second offshore wind farm within this zone of the North Sea. It has a total capacity of 1,386MW, capable of supplying clean electricity to 1.3 million UK homes. The wind farm is located 89km off the Yorkshire coast, with an export cable coming ashore near North Cotes in Lincolnshire.
The project
VolkerFitzpatrick's sister business VolkerStevin, completed all the civils works associated with the 38km onshore cable route. This included installing underground circuits within a 40m-wide construction corridor, consisting of three 220kV export cables and fibre optics. The cables will carry electricity from the newly constructed Hornsea 2 substation to National Grid’s North Killingholme substation.
A 38km geotextile and geogrid haul road was needed to access the works. Engineers and temporary works specialists revisited the original plans and managed to reduce the length to 18km, eliminating 52,800 tonnes of 6F5 stone and more than 5,000 wagon movements. Working with suppliers, they devised a safer, more efficient way to lay the geotextile and geogrid. Our ‘sledge’ rolled the material out 40 percent more quickly whilst eliminating 95 percent of manual handling and people-plant interfaces – both key safety considerations.
VolkerFitzpatrick is currently working on Hornsea 3.
The process
The team continuously improved its methodology, laying 360km of cable in total, at a rate of up to 1km/day. Following a review of the retaining walls for ditch crossings, they switched from the dusty operation of stockpiling limestone bulk bags to using prefilled, palletised 1000kg bulk bags. This increased the task’s productivity by 40 percent.
They also carried out 13.5km of horizontal directional drills across 62 locations, including crossing two railway lines, and designed and constructed 23 triple joint bays. We achieved 100 percent HV, LV and fibre test pass rates.
On completion of the onshore cable installation element, Luke Bridgman, deputy director for Hornsea 2 at Ørsted, said: “Our teams have persevered relentlessly throughout the pandemic, for which we are deeply thankful. They have maintained a clear focus on collaborative behaviours, ensuring that the works were delivered with the highest standards of safety and within the original project programme.”
“It has been a difficult year to deliver a project of this scale but VolkerInfra has been a great partner to tackle this challenge with."
David Morgan Senior project lead at Ørsted
