Jacket foundation placed and secured for the Walney 2 offshore transformer

 

In a gigantic lifting operation, the jacket for the Walney 2 offshore substation was placed on the night of Tuesday 5 May 2011. Once again the heavy lift barge Rambiz entered the scene and lifted the 1,100 tonnes heavy jacket into its final position in the Irish Sea.

 
The offshore substation left Aalborg in
Denmark 26 April.

In order to keep the jacket placed in its position, four 60-metre long steel piles were placed in the corners of the jacket. After a thorough process, where the jacket was vertically levelled, the jacket and piles were grouted together.
The grouting needs some 24 hours to harden up before the jacket can carry the load of the top section, and since then the weather hasn't been favourable for the lifting of the top section.

 
Both the top section and Rambiz are awaiting a suitable weather window in the area for the final lift.

Export cable for Walney 2
At Cleveleys near Blackpool, the Stemat Spirit cable barge arrived just off shore in the afternoon of Saturday 7 May. It beached in the early hours of Sunday 8 May in the morning, waiting for very low tide. At about 9 a.m., the process of pulling the cable from the spool on board the barge began.



Up till now, Stemat Spirit has managed to lay 7 kilometres of the 29-kilometre long submarine cable, running half the 44-kilometre long distance from the offshore substation in Walney 2 to the onshore substation at Cleveleys. The first section of the export cable will be laid from the shore of Cleveleys and onwards the site.



The second section of the export cable will be laid by the installation vessel Giulio Verne, starting from the offshore substation and onwards the shore. Where the two cables meet, they will be taken out of the water and connected and thereafter lowered to the seabed and buried.

As for the Walney 1, the export cable is a single-wire armoured three-core 132kV cable complete with a 48-core fibre optic cable. The cable will be laid approximately 2 metres below the seabed during the cable installation process.

 
The blue line marks the export cable for Walney 1 and the red line marks the export cable for Walney 2.

At Cleveleys, 5 kilometres off the coastline, some 35 workers are working hard to finish the offshore substation before August and well in time to receive the first power from Walney 2. The civil works are almost completed, and the technical installations in the onshore substation have begun.

Ready for turbine installation in Mostyn
In the harbour of Mostyn, the first two wind turbines for Walney 2 have been loaded onto Kraken, and she is awaiting better wind conditions before leaving for the Walney 2 site.

 
Lifting the nacelle onboard Kraken at Mostyn.

Also in the harbour in Mostyn, the installation vessel Leviathan is awaiting Kraken's departure before it can take its position and load the next two turbines for Walney 2; the two vessels are sharing the same loading facilities in Mostyn.

Installation of the 51 turbines is planned to take half the time it took to install the turbines for Walney 1. This will load the infrastructure in the harbours of Mostyn and Barrow and be vital to in order plan the installation sequences carefully and secure the logistics.



Robust logistics needed to secure the intense installation process
The foundation installation has had a good start, and the installation vessels Svanen and Goliath have already managed to place 20 monopiles and 11 transition pieces in Walney 2.

 
Walney project manager Jens Hansen.

However, for the last almost two weeks, the installation has been influenced by unfavourable weather conditions, but despite the wind, there have been minor weather windows when it has been possible to work offshore.

 
Svanen at work with a monopile.

Due to the excellent start of the foundation activities, the logistical setup has been upgraded, and an additional barge was put into service in order to secure sufficient supplies of transition pieces from Germany.

 
20 monopiles and  11 transition pieces has been placed in Walney 2.

At the same time, all array cables for Walney 2 have arrived on the site in Barrow and are now tested after the transport. 

45 turbines in Walney 1 have generated the first power
The commissioning of the 51 turbines in Walney 1 is peaking. All array cables in Walney 1 are energised, and some 45 turbines have generated the first power.

Sea Spirit has replaced Wind Ambition
The accommodation vessel Sea Spirit has replaced Wind Ambition as base for the Siemens technicians during the commissioning of the turbines. Sea Spirit is a floating hotel which can accommodate 120 people. Sea Spirit is 15.3 metres wide and 90.6 metres long.