Onshore construction update - February 2019
The new onshore substation is located in Burstall, near Bramford.
The substation building is now complete, with commissioning activities and testing underway. All components for the substation are now in position and Internal high voltage cabling installation has begun. Landscaping of the surrounding area has also commenced.
Connecting ductwork between the new substation and the existing National Grid facility is approaching completion. Once finished, this will connect the offshore wind turbines into the National Grid.
Open cut works
The majority of the onshore cable route runs through farmland and has been installed by digging a trench and laying ducts to house the cables. The cables will then be pulled through at a later date. Open cut works have been undertaken by J Murphy and are nearly complete. J Murphy will remain with the project during the cable pulling phase to undertake any amends to the ducts.
Horizontal Direct Drilling (HDD)
Occasionally the cable route must go under a major transport network or natural obstacle, where it is not possible to use open trench methods. In these locations the ducting has been installed using Horizontal Direct Drilling (HDD) or auger bore techniques. HDD is a trenchless method, used to install ducts beneath the ground, through which the power cables for East Anglia ONE will later be pulled. Our contractor is Volker Infra.
HDD requires two working areas either side of the drill:
- The rig side, where the drill rig is located and where the drill commences.
- The pipe side, from which to exit the drill. A pipe (ducting for the cable) is then pulled back through the drilled hole.
All HDD work associated with EA1 is complete. The only remaining activity is at our landfall site at Bawdsey, where the an EA3 duct needs to be pulled back through the drilled hole and calibrated. This is expected to finish in early 2019.
Our cable installation contractor Prysmian has started pulling the EA ONE power cables through the pre-installed cable ducts. The cables are being installed in sections and will be joined together every 2km at an underground Joint bay. Construction of the joint bays is complete and we have pulled nine out of eighteen cable sections.
Delivery of the cables on large drums will involve the use of abnormal load vehicles. Once delivery is made to a Construction Compound, onward delivery to the construction area will be made along our temporary haul road within the construction corridor.
The pre-construction phase involved fencing off the construction corridor and building the haul road. Ongoing maintenance works related to this package will occasionally be required.
Once construction of the onshore substation and cable route are concluded and connected to the off-shore windfarm, testing and commissioning will take place. On completion, the stockpiles of earth can be returned, the haul road and other temporary measures will be removed and the land reinstated.
East Anglia ONE is expected to be fully operational in 2020.