Hornsea 3 Offshore Windpark
In the most recent phase of the Hornsea 3 Offshore Windfarm AMS Trenchless were again contracted by Orsted to install the landfall drills.
In the most recent phase of the Hornsea 3 Offshore Windfarm AMS Trenchless were again contracted by Orsted to install the landfall drills within this phase, continuing the long-standing relationship which has seen AMS deliver the landfall drills on Hornsea 1, Hornsea 2 and now Hornsea 3, with this being the largest and most technically challenging scheme delivered by AMS to date.
Hornsea 3 located in the North Sea
Hornsea 3 will be located in the North Sea, approximately 120 km off the Norfolk coast and 160 km off the Yorkshire coast. The windfarm will consist of 197 offshore wind turbines constructed within an area of approximately 696km2.
Once completed, the wind farm will be capable of generating at least 2.9 GW of green electricity, enough to power more than 3 million homes.
Acting as Principal Contractor for the landfall operations, the scope of the installation works initially commenced with 4nr 830m drills, however due to anomalies picked up during pre-construction surveys the length was increased to 950m each.
HDD-installations
Working closely with our client, AMS mobilized the HDD spread to site and in addition to this mobilized a full marine spread, consisting of support vessels, multicats and crew transfer vessels in addition to the Jack up Barge (JUB).
Provision of a stable platform at the offshore side was an integral part to the success of the scheme, AMS crew remained on board during the operations to reduce the overall number of transfers to and from shore and to mitigate against weather downtime during transfers.
On board the JUB, AMS fabricated a number of bespoke items, including outrigger chute, duct rollers, stinger and restrain mechanisms for drill pipe recovery, tooling changes and duct installation stages of the project. Full Orcaflex analysis, fabrication design and sea fastening engineering was undertaken by AMS prior to sail away.
Reducing impact on the local area was a major consideration for both Orsted and AMS, in order to remove the need for towing duct from shore to the punch out position, it was agreed that fully extruded duct would be installed on all 4 bore.
The duct was delivered in 4 complete lengths and stored within a suitably sized, protected offshore bay until the bore was ready for duct installation. Each duct was towed from storage individually, just in time for recovery to the JUB as part of the pull in operations.
When all design, fabrication, engineering and sea fastening was complete, the vessels were mobilized to the offshore punch out point. Ahead of this, AMS had already commenced piloting and were able to quickly recover the drill pipe and progress to the reaming stage of the process.
During the operations the project encountered significant and unseasonable poor weather during the summer months. To mitigate against the impact of this AMS mobilized their second 250t HDD rig to the site to enable the crew to maintain productivity as much as possible when they would have otherwise been waiting on weather.
Despite the best efforts of the client, AMS and our subcontractors, during the final drill, the decision was rightly made to winterize the project in late 2024 and return for the final drill within April 2025.
Within the initial planning stages for the return visit, with the current pressures on vessel availability it became apparent that availability was not on our side and the only option was to bring forward the mobilisation for the return visit.
Despite the reduction in time available for mobilisation activities, AMS and their subcontractors, supported by Orsted, mobilised the offshore spread ahead of the revised programme with no incidents, accidents or concerns during these operations.
The 2025 visit was completed successfully when the final duct was installed on 09 April 2025, with vessels demobilized, sea fastenings removed and all deck remediation complete within schedule.
This project was the largest undertaking for AMS and was made possible by the collaborative approach taken by Orsted at all stages of the operations. This project has allowed AMS to demonstrate our capability of delivering on the large scale, technically challenging projects Horizontal Directional Drilling installations such as the Hornsea 3 landfalls.
