|Date||30 December 2014|
|Location||Viewed from Welsh Mountain Zoo, Colwyn Bay||SH 83619 78854; 53.29380°N, 3.74753°W|
RWE Innogy UK owns and operates three adjacent offshore wind farms in Liverpool Bay off the North Wales coast: North Hoyle, Rhyl Flats, and Gwynt y Mor.
The oldest of the three, North Hoyle, covers an area of 4 sq miles, is located 4 miles from shore and was constructed in 2003. It was the UK’s first major offshore wind farm and comprises 30 2 MW turbines (total installed capacity 60 MW), each with a maximum height of 107 m above mean sea level.
Construction of Rhyl Flats started in 2008 and its 25 3.6 MW turbines (total installed capacity 90 MW) became fully operational in 2009. The farm has an area of 4 sq miles and is 5 miles from the coast. The maximum height to the top of the rotor blades is 134 m above mean sea level.
Planning permission for the 31 sq mile Gwynt y Mor wind farm, located 8 miles from shore, was granted in 2008 and construction started in 2012. This £2 billion wind farm comprises 160 Siemens 3.6 MW turbines, each with a maximum height of 150 m above mean sea level, giving the facility a total installed capacity of 576 MW, enough to power the equivalent of 400,000 homes. Gwynt y Mor has an expected lifetime of 25 years and is currently the world’s second largest offshore wind farm. The first electricity was generated from the site in September 2013 and the last of the turbines was installed in July 2014. Half of the turbines had been commissioned and were operational by September 2014 and the overall construction phase was completed in November 2014 when the final cabling work was finished. Final commissioning of the farm was originally planned for late summer 2014 and is expected in 2015. Three unexploded WWII bombs were discovered on the seabed during construction of the farm, an incident that is said not to be uncommon when undertaking operations of this nature.
The turbine generators are on a 33 kV network and the voltage is transformed on two offshore substations to 132 kV for transmission to the new onshore substation at St Asaph. The 1,500-tonne offshore substations were designed and manufactured by Siemens (Manchester) and Harland and Wolff in Belfast. The power cables were laid and buried by Reef Subsea using a 36-tonne submarine plough. The turbine foundations were pre-assembled at a construction facility set up in part of Cammell Laird’s 52-hectare shipyard in Birkenhead, whilst turbine installation was carried out from a new operations and maintenance base built at the Port of Mostyn.