On 7th July, the meteorological mast, supported by a Mono Bucket foundation, at the Horns Rev 2 wind farm, Denmark, was successfully decommissioned. The met. mast was no longer required at the Horns Rev 2 wind farm by the current owner Dong Energy.
The Mono Bucket was one of the very first to be employed and has been in situ for 6 years, having been installed in March 2009. The weight of the foundation is 165t with a total height of 38meters. It was installed to within 0.1 degree of true vertical and with a 0.6m stick-up.
The Mono Bucket has been completely removed from the site by DBB Jack-Up Services by reversing the suction process. By applying pressure into the Mono Bucket the foundation was lifted from the seabed, leaving it unmarked.
Universal Foundation’s Head of Business Development, Kristian Jacobsen said: “Since 2009 the project has served as a key showcase to Universal Foundation and proved the feasibility of the Mono Bucket in an offshore working environment. The installation itself was innovative in the sense that the foundation was floated to the site by means of two simple tug boats, installation was quick and during operations the Mono Bucket required no scour protection proving that our system works. We are now delighted to add a successful decommissioning of the foundation to the project results. This is yet another testimony to the feasibility and flexibility of the Mono Bucket and suction technology in offshore wind”.
For DBB Jack-Up Services this was an important step in expanding into offshore wind decommissioning: “Combined with the experience and skills of the DBB Jack-Up project organisation, our crew and jack-up vessels have once again completed a very challenging decommissioning task” says Ole Jacob W. Nielsen, Chief Commercial Officer of DBB Jack-Up Services A/S, and continues: “In the race for cost-reduction we need to allow ourselves to step off the beaten track to test innovative solutions like the Mono Bucket foundation.”
The Mono Bucket has recently been chosen to support 6 3MW turbines at the Icebreaker project in the United States.
Image courtesy of DBB Jack-Up Services A/S