Blyth Demonstrator
Turbine foundations
pleased that Flumill and Subsea 7 have signed a letter of intent that sets the framework for a close cooperation”, says Anders Holm, Managing Director of Flumill AS. The power from tidal water will drive the screwdrivers with two opposite rotating helixes. The turbines have lower end generators and they are attached to a foundation on the seabed. The buoyancy system allows the turbines to flow with the tide to an operating angle of between 25 and 60 deg.
The first turbine foundations for the Blyth Offshore Demonstrator Wind Farm development have been making their journey up the River Tyne en route to their final destination. The project will see five wind turbines with a total generating capacity of 41.5MW installed around 6.5km off the Blyth coast. Concrete gravity based foundations (GBFs) form part of the project and are being installed using a new ‘float and submerge’ method – the first time this method has been used for offshore wind turbines. Designed and built by Royal BAM Group in the Neptune dry dock on the Tyne, the GBFs are being floated into position at sea and submerged onto the seabed to provide the support structures that act as the foundations for the installation of the wind turbines. Each GBF is made up of more than 1800m3 of concrete and weighs over 15 000t when fully installed on the seabed. The structures have a total height of around 60m from the base to the access platform. The GBFs have been constructed at the Neptune dry dock over the past 12 months by BAM Nuttall and these structures will be floated down the river to the Port of Tyne, where extra ballast will be added ahead of their ‘tow-out’ to the offshore wind farm site.
l The GBF has been fitted with a groundbreaking sensor system designed by the Offshore Renewable Energy (ORE) Catapult. This is the first time that sensors have been installed in a gravity-based foundation and used to analyse the performance of the foundations in the challenging conditions they will be exposed to in the real-world. The data collected from the sensors will be synchronised with ORE Catapult’s met mast, located three nautical miles off the Blyth coast.
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The sensor system, installed on two of the five foundations, is part of the Demowind-funded FS Found project, in which ORE Catapult is partnering with EDF ER and Royal BAM Group to demonstrate and validate the new ‘float and submerge’ GBFs at the design, manufacture and installation stages. Jonathan Hughes, ORE Catapult’s Technical Lead on FS Found, said: “Float and submerge gravity-based foundations have the potential to be deployed without the need for expensive installation or heavy lift vessels. “Incorporating a condition monitoring system into this first demonstration of this new technology will help the industry to improve design optimisation and reduce costs, helping to make GBFs commercially viable as a foundation solution.”
UT2 Issue 4 July August 2017