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Case file

DOCKING STATION Investment in the Port of Mostyn means that the facility can continue to operate as a maintenance base now that the plant is fully operational

YELLOW HUB MARINE Transition pieces connect the turbines to the foundation piles. Each 22m section weighs 200 tonnes and provides the means of access to the structure

IMAGES ALAMY

CONVENIENCE SHORE Ensuring that the onshore facilities had enough space for storing equipment and components translated into valuable time savings once work began out at sea

to onshore wind projects. Turbines can be a lot taller out at sea than onshore, enabling their operators to capture the energy from stronger winds circulating at high altitudes. But building eight miles off the north Wales coast is inevitably more challenging than on land. Each of the turbines at Gwynt y Môr required its own foundations. These consist of two components: a long steel tube called a monopile, and a transition piece to enable its connection to the turbine. Before the monopiles could even be installed, stones had to be laid down to prevent the surrounding seabed from being eroded. Each of the piles measures up to 64m long and 6m wide. The heaviest weigh 708 tonnes, making them some of the largest ever used in a wind farm. The huge tubes were hammered into the seabed by the Friedrich Ernestine, a 100m-long and 49mwide vessel built and designed by RWE specifically to install offshore wind turbines. The yellow transition piece was then fitted on to the monopile, followed by the turbine.

The project also required its own substantial infrastructure, including new substations both on and offshore. To accommodate the former required diverting a 650m stretch of gas pipeline. Although the scale and complexity of the offshore work may be jaw dropping, the successful delivery of the project relied on minimising the amount of work that had to be done out at sea. The need for careful preparation meant that it took four years from when consent was granted for the wind farm in 2008 before work even began offshore. During this time, several back-up facilities were built onshore to support the project, among them a £3m operational centre at Port of Mostyn. This was sited close to a 10-berth pontoon, built by BAM Nutall, from which the technicians and other support staff sailed out to the offshore construction site. Neal Green MRICS, director of Londonbased building consultant Macegreen, put the specification together for the onshore

facilities, before the project was handed over to contractor Pochin, which carried out construction on a design-and-build basis. As Green explains, every minute that the wind farm’s engineers were waiting to get on a boat burnt a hole in RWE’s pockets:“It’s important to get everybody out on a boat. The design of the building had to be carefully considered so that everybody could arrive in shifts, get briefed, get tools and equipment, jump on a boat and head straight out.” In addition, the onshore site had to be large enough to provide plenty of outside space for storing equipment and the huge turbine components. Getting these facilities right meant that the process for installing the turbines at Gwynt y Môr proved much less time-consuming than RWE’s previous, smaller project at nearby Rhyl Flats. Now that construction work is over, the Port of Mostyn facility will continue in use as the base for operating and maintaining the wind farm, helping to deliver a new age of sustainable energy. n

FEBRUA RY 2016_MODUS 43

RICS Modus, Global edition — February 2016  

#RICSModus, February 2016 — the CONNECTED issue. We live in a connected society. Every aspect of our lives is now – to some degree – influen...

RICS Modus, Global edition — February 2016  

#RICSModus, February 2016 — the CONNECTED issue. We live in a connected society. Every aspect of our lives is now – to some degree – influen...