Construction milestone for pioneering offshore windfarm

In a world first, the five gravity base foundations, designed and built by Royal BAM Group, were installed using a new ‘float and submerge’ method. The gravity bases were built in the Neptune dry dock of the Tyne before being floated into position off the coast of Northumberland and submerged onto the seabed and further ballasted to provide the support structures that act as the foundations for the turbines.

This pioneering work, completed by BAM, is a huge milestone for the Blyth Offshore Demonstrator Wind Farm, which is being delivered by EDF Energy Renewables after they took over responsibility for the scheme from Narec (now ORE Catapult) in October 2014.

BAM Nuttall Regional Director, Gareth Farrier, said: ‘This is a significant milestone in both the construction of the Blyth project and in the development of the BAM gravity base foundation. I would like to express my own and BAM’s appreciation for the hard work and professionalism of the BAM and Strukton marine teams in successfully completing the world’s first float and submerge installation for wind farm foundations.’

Following the successful installation of the gravity based foundations cable laying works, carried out by VBMS, are now underway.

Around 11 kilometres of buried 66Kv offshore cables will connect the individual turbines and bring the electricity onshore, where a further 1.5 kilometres of onshore cable will link directly to a new substation built on part of the site of the former Blyth power station.

The installation of five MHI Vestas V164 turbines will begin in mid-September with the first power expected to be generated later this year. When complete, the turbines will have the largest power rating of any offshore windfarm.

EDF Energy Renewables Director of Operations, Don Mackay, said: ‘This is an important milestone in a ground-breaking project. It incorporates several new and innovative features as part of its role in testing and proving new and emerging offshore installation methods and technologies. In addition the windfarm will benefit the local community and help the country to meet its low-carbon energy needs. The demonstration scheme will set a new technology benchmark for other similar offshore wind developments around the country.’

Installed around 6.5km off the coast of Blyth, the turbines have a total generating capacity of 41.5MW and once operational will produce enough low carbon electricity to power around 34,000 homes. *

Wholly owned by EDF Energies Nouvelles, the Blyth Offshore Demonstrator project is being built by EDF Energy Renewables, a 50-50 UK joint venture between EDF Energies Nouvelles and EDF Energy. The wind farm will be EDF Energy Renewables’ second offshore wind farm construction following the Teesside wind farm off the North East coast at Redcar.

*41.5MW installed x 0.369 offshore average load factor (a) x 8760 hours, divided by 3.938MWh annual domestic energy consumption per home(b)

(a) Digest of United Kingdom energy statistics 2016, DBEIS, July 2016.

(b) Energy consumption in the UK, DBEIS, November 2016.

Blyth Offshore Demonstrator Wind Farm – key facts:

• The Blyth Offshore Demonstrator project will produce enough low-carbon electricity to power approximately 34,000 UK households
• It will save around 57,600 tonnes of CO2 emissions each year
• It will be the first offshore wind project to connect using 66kv rated cables
• It will be the first time that a “float and submerge” gravity based foundation is used for offshore wind turbines
• Each gravity based foundation will weigh more than 15,000 tonnes when fully installed
• 8.0MW wind turbines with a power mode uprating them to 8.3MW will be installed
• Each GBF is made up of more than 1,800m3 of concrete and weighs over 15,000 tonnes when fully installed on the seabed. The structures have a total height of around 60 metres from the base to the access platform