Construction Works

The main offshore construction works took place during 2008 and 2009, with the majority of the activities being conducted from the Port of Mostyn.
 
In preparing for construction works, we adopted an innovative approach to contract management.  Earlier offshore wind farms had been built on turnkey Engineer, Procure, Construct (EPC) contract strategies.  In the time between these projects finishing and Rhyl Flats starting, the market for EPC contracting on offshore wind farms virtually disappeared and a decision was taken to build using a multi-contract strategy with RWE as Owner, managing the interfaces between contracts.  While this required a larger project team and longer procurement lead times, it allowed the project team to exercise greater control over construction activities.
 
Challenges
Offshore marine environments present significant challenges to the construction of a wind farm, and no lesser intense challenges were faced during the construction of Rhyl Flats.
 
By far the biggest challenge was that of the weather. Throughout the foundation and turbine construction stages, vessels were forced into shore when the North Wales coast was clipped by the tail end of tornado; and sought shelter when not one by two cyclones caused deterioration in weather and subsequent sailing conditions. During at least one summer month in 2009, adverse weather conditions resulted in just 9 working days.
 
Construction works also had to confirm to strict environmental constraints, which limited particularly any noise-intensive activities to a small working window of between April and September, to avoid impacting on the nesting habits of the Common Scoter seabird.
 
In addition, huge tidal ranges across the North Wales coast placed significant restrictions on vessel movements, while the availability and logistics of 57 separate vessels working on the project presented their own challenges. 

Summary of construction activities

  

2002

  • Erection of 74-metre meteorological mast to collect wind data.

2006

  • Seabed site investigation works carried out at prospective turbine locations.

2007/8

  • June 2007 to September 2007: phase 1 scour protection works (this involved laying graded rock on the seabed at each turbine location. Sourced from Penrhyn Slate Quarry near Bangor, Gwynedd, North Wales, the rock prevents localised erosion of the sea bed around the turbine foundations.)
  • April 2008 - October 2008: phase 2 scour protection works
  • August 2007 and October 2008: Construction of substation buildings.

2008

  • April 2008: start of foundation piling works
  • 3 May 2008: first monopile completed
  • July 2008: foundation piling complete
  • August 2008: November 2008: Export cables laid.

2009

  • 17 April 2009: Start of wind turbine erection (you can view a timelapse video of the construction of one of the Rhyl Flats turbines)
  • 21 April 2009: first turbine completed
  • May and October 2009: inter-turbine array is laid
  • 3 June 2009: Grid connection is made
  • 15 July 2009: first clean, green energy generation is exported to the electricity network
  • October 2009: final turbine constructed.

To view the more detailed accounts of construction progress of Rhyl Flats Offshore Wind Farm, please use the construction diary archive link.