Landfall works have been completed in Carnoustie in the North-East of Scotland for the Seagreen Wind Farm project – the world’s deepest and Scotland’s biggest fixed bottom offshore wind farm.
The works will allow project contractors to connect the offshore export cables to the onshore cables which will run from landfall at the Carnoustie coastline to the project’s new substation at Tealing in Angus.
The open cut trenching technique applied has enabled the installation of three ducts through the excavation of a section of the coastal flood defence system which protects the coastline from the North Sea. The coastal defence system has also now been reinstated.
The installed ducts now allow each cable to be pulled through on to land and to be jointed to the onshore cables.
Onshore Construction Project Manager, Steven Reid said:
“We are pleased to have reached another milestone in the Seagreen Project along with our contractors Nexans. It is satisfying after the significant years of work by the onshore team to get the project to this stage and we’re pleased to now be passing this over to our offshore team to use to complete the critical connections to the wind farm.
“I’d like to thank our stakeholders who have assisted us in completing these works successfully, namely Angus Council, Carnoustie Golf Links, and Marine Scotland. Naturally, we are also extremely grateful to the local community for their patience over the last year.
An explanation of the completed process
The construction process took approximately one year to complete.
The existing sand dunes were levelled and excavation work commenced of the existing revetment.
A large twin walled cofferdam was installed using steel sheet piles which were vibropiled into the ground to depths of approximately 15m. The cofferdam was installed to protect the works and staff and surrounding coastal line from the elements of the North Sea.
Three ducts were excavated into the area protected by the cofferdam.
The ducts were encased in cement bound sand and then backfilled over with stone to a level which was then suitable to start the removal of the sheet piles of the cofferdam.
As the sheet piles were removed, large boulders were used to re-construct the final layer of the coastal defence system.
The sand dunes were then reconstructed back into the original position at the top of the revetment.
The intention is for the cable pull activities to commence imminently.