Bam is to design, make and install five massive gravity base foundations for wind turbines – the first of its kind ever built.
Each unit will be a combined concrete and steel structure, going 40m below water, with an overall height of 60m. The diameter of each base will be 30m and they will weigh 13,000t.
The bases will provide the foundations for wind turbines of 41.5MW in capacity off the Northumberland coast. Bam has been commissioned to build the bases by EDF Energy Renewables via SPV Blyth Offshore Demonstrator.
Construction work for the wind farm has begun onshore and offshore work will start in 2017 to install the turbines. The power generated by the wind farm will be supplied to an electricity substation at Blyth which will be built by Balfour Beatty, for transmission to the National Grid.
The concrete base project is designed to be a demonstration to show how they can work in future offshore wind farms. Each foundation will use self-installing technology, which has been designed by Bam and described by EDF as a ‘float and sink’ method. When ready, they will be floated and sunk in position using tugs.
The concrete base project is being delivered by a combination of Bam Nuttall, Bam Infra and Bam Infraconsult. The bases will be made by Shepherd Offshore in Newcastle on the River Tyne at its Neptune Energy Park.
“This is a very significant milestone not just for Bam but for the wider offshore wind sector. An opportunity to demonstrate the potential for self-installing concrete gravity bases to provide economic foundations for large wind turbines in deeper water,” said Bam Nuttall’s head of civil engineering Malcolm Corlett.
“Following five years of intensive work refining our design and method of construction we now have a live project to demonstrate our technology and bring new skills and opportunity to the North East of England.”
The project is due for completion in summer 2017.