Onshore works-clear.png

Onshore cable route

Cable route overview

 The onshore electrical infrastructure required to bring the electricity from the export cable landfall site and on to the national electricity transmission network consists of:

  • approximately 19km of underground electricity transmission cables

  • a new dedicated substation at Tealing (near Dundee)

  • an extension to the existing substation at Tealing

  • creation of access points during construction

  • associated ancillary works

Construction on the extension to the existing substation at Tealing began at the start of 2020 and is being managed by Scottish Hydro Electric Transmission PLC (SHE Transmission).

 

Construction of the new Seagreen substation began in March 2020 and is being managed by Seagreen Wind Energy Ltd (SWEL).

 

The construction of the underground cable route began in xxxx 2020 and is being managed by SWEL.  

 

Construction overview

The installation of the 19km of underground export cable will be undertaken by Nexans as the Principal Contractor. They are responsible for the design, supply and installation of the offshore and onshore cabling.

Construction began in xxxx 2020, with initial activities including mobilisation and the setting up of welfare facilities and the transport of plant and materials to the construction compounds along the cable route.

The contractors also created access points along the route (providing access to the work areas from the local road network).

Once access has been taken, the contractors mark out the cable route boundary with fencing in order to create a safe work zone which also ensures that farm animals and members of the public are excluded from the work area.

The activities undertaken during cable installation include:

  • Ongoing creation of temporary haul and access roads

  • Creation of temporary compounds and storage areas

  • Excavation of trenches and installation of cable ducting

  • Excavation of cable 'pits'

  • Installation of 'joint bays'

  • Laying of cable through installed ducting

  • Reinstatement of the ground once work is complete

The cable route includes the requirement to cross roads, railways and watercourses. Each of these will be crossed either by using Horizontal Directional Drilling (HDD) underneath where appropriate or the use of 'open cut' techniques where roads are trenched, ducting installed and the road reinstated again.  Where open cut is used, access will be maintained through the use of traffic management.

Seagreen strip topper.png
Seagreen strip topper white.png
Mitigation

A variety of best practice and mitigation measures will be employed to ensure that the construction of the onshore electrical infrastructure does not result in unacceptable environmental effects.  The construction work has been preceded by extensive surveys and studies and is subject to ongoing assessment.

Potential impacts will be controlled through the conditions attached to the planning permissions.

You can find out more by clicking below:

Noise, dust and air quality, traffic and transport and landscape and visual - Click here

Hydology, biodiversity and agricultural land use - Click here

Cable installation

Seagreen will have a three circuit 220kv High Voltage Alternative Current (HVAC) which means that there will be three sets of cables installed, side by side, along the entire cable route.

The majority of the cables will be directly installed in to conventional open cut trenches or in to ducts laid within trenches.  There will be three cable trenches within the working corridor.

The working corridor will be 30m wide, providing sufficient space beside the trenches for access, working space and laydown of equipment, topsoil and spoil from trench excavations.

Topsoil and vegetation will be stripped from the working area and stored to one side separately and away from watercourses or drains.  Storage times for topsoil will be kept to a minimum to prevent deterioration in its quality.

An excavator or trench digger will then be used to dig the trench which will be back filled once the cable installation is complete and the land will be restored.

Joint bays are needed to join the lengths of cable together along the route as cable lengths are restricted to allow them to be safely delivered by road.

Joint bays are simple underground concrete chambers which enclose and protect the cable joints.  The bays will be approximately 9.2m long, 2.4m wide and 2m deep.

Pulling pits are temporary excavations which are required for the pulling operations - when the cables are pulled through the installed ducting.

 

Once the pulling is complete, the pits will be reinstated back to existing ground levels.
 

Seagreen strip topper white.png
Seagreen strip topper.png
Construction overview

The installation of the 19km of underground export cable will be undertaken by Nexans as the Principal Contractor. They are responsible for the design, supply and installation of the offshore and onshore cabling.

Construction began in xxxx 2020, with initial activities including mobilisation and the setting up of welfare facilities and the transport of plant and materials to the construction compounds along the cable route.

The contractors have created access points along the route (providing access to the work areas from the local road network).

Once access has been taken, the contractors mark out the cable route boundary with fencing in order to create a safe work zone which also ensures that farm animals and members of the public are excluded from the work area.

The activities being undertaken during cable installation include:

  • Creation of temporary haul and access roads

  • Creation of temporary compounds and storage areas

  • Excavation of trenches and installation of cable ducting

  • Excavation of cable 'pits'

  • Installation of 'joint bays'

  • Laying of cable through installed ducting

  • Reinstatement of the ground once work is complete

The cable route includes the requirement to cross roads, railways and watercourses. These will be crossed either by using Horizontal Directional Drilling (HDD) underneath where appropriate or the use of 'open cut' techniques where roads are trenched, ducting installed and the road reinstated again.  Where open cut is used, vehicular access will be maintained through the use of traffic management.

Seagreen strip topper white.png
 
Cookie Settings