float and submerge gbf gravity based foundation offshore windfarm wind energy blythe bam

World’s first “float and submerge” offshore windfarm

The world’s first “float and submerge” offshore wind turbine foundation has made its way up the River Tyne in England. It is the start of the Blyth Offshore Wind Demonstration Project.

The concrete gravity-based foundations (GBFs) form part of the project and are being installed using a new “float and submerge” method–a construction technique more common in the oil and gas sector. They will, if successful, help further reduce the costs of deploying offshore windfarms. The GBFs are built by the Dutch Royal BAM Group. Each GBF consists of more than 1,800 cubic metres of concrete. It weighs more than 15,000 tonnes when fully installed on the seabed. Each foundation is floated into position and then filled with water to be sunk onto a prepared gravel bed on the sea floor. They stand 60 metres tall to the access platform. The GDFs will be sunk in waters up to 40 metres deep around 5.7 kilometres off the northeast coast of England.

100 MW of power generating capacity

The first phase will have a generating capacity of 41.5 megawatts (MW). It will be able to power up to 33,000 homes when it goes live in 2018. Five of the world’s largest turbines will be used: V164-8.0 models rated at 8.3-MW each from MHI Vestas Wind Systems. A second phase will follow with the installation of up to 60 MW of generating capacity. For this phase, different turbines will be used, the model which is yet to be decided.

Over the summer, the GBFs will be placed for this float and submerge offshore windfarm. Once that is done, specialist VBMS will start laying the inter array cables that will connect the individual wind turbines. The project is owned by EDF Energies Nouvelles. However, it will be built by EDF Energy Renewables, a 50-50 joint venture between EDF Energies Nouvelles and EDF Energy.

Groundbreaking scheme

“This is the first major offshore operation on this project. Over the coming months people will be able to see the windfarm being built out at sea,” said EDF ER Chief Executive Matthieu Hue. “This groundbreaking scheme will benefit the North East of England. It will also help the UK to meet its future low-carbon electricity needs. This is the first time that this float and submerge method has been used on a windfarm project. The GBFs are held in place by gravity. This unique design reduces the need to use expensive marine equipment for the installation on the sea bed.”

Source: Industrial Info Resources – 3 August 2017

Image courtesy of Royal BAM Group