Ballast has won the contract from Walney (UK) Offshore Windfarms Ltd which is a joint venture between DONG Energy of Denmark and Scottish and Southern Energy.

Ballast Nedam Offshore will install the tubular steel piles which form part of the foundations.

These monopiles weigh between 800 and 1000 tons each, which makes them the heaviest monopiles ever used as the foundation for an offshore wind turbine.

Ballast will use its  heavy lift vessel Svanen, which is built to handle 8,700 tons. The Svanen will start putting the foundations in place during the second quarter of 2011.

The Svanen is currently installing 90 foundations for the Sheringham Shoal Offshore Wind Park in the United Kingdom, which lies between 17 and 23 kilometres off the coast of Sheringham.

Piling work is currently underway on Phase I at Walney where 21 monopiles have been installed in the seabed.

A project spokesman told the Enquirer: “During the winter of 2009/2010, it became clear for the offshore wind industry that the construction method, used for other offshore wind farms, of grouting transition piece and monopile together with special concrete was not as durable as expected.

“As a result of this, it was decided to adjust the foundation design at Walney 1. The adjustment consists of welding rings on the inside of the transition piece and the outside of the monopiles, also called ‘Shear keys’.

“At Walney 2, a solution has been chosen where the top of the monopiles is conically shaped. Thus, a future vertical load will squeeze the concrete together in a downward direction and prevent the transition piece from sliding down.”