On 7 July, DBB Jack-Up successfully decommissioned the meteorological mast and Mono Bucket foundation at the Horns Rev 2 offshore wind farm in Denmark. The met mast was no longer required at the Horns Rev 2 wind farm by the current owner Dong Energy.
The Mono Bucket was installed in March 2009 and has been in situ for six years. The weight of the foundation is 165 tons with a total height of 38 metres.
The Mono Bucket was completely removed from the site by reversing the suction process. By applying pressure into the Mono Bucket, the foundation was lifted from the seabed, leaving it unmarked.
For DBB Jack-Up 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 reductions, we need to allow ourselves to step off the beaten track to test innovative solutions like the Mono Bucket foundation.”
Kristian Jacobsen, Head of Business Development of Universal Foundation – the supplier of the Mono Bucket foundation – 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 tugboats, installation was quick and during operations, the Mono Bucket required no scour protection proving that the 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”.
The offshore wind decommissioning market is expected to grow significantly as met masts, foundations and wind turbines reach the end of their lives. Some wind farms will be repowered by new turbines which will be installed on the existing foundations whereas other wind farms will be fully decommissioned.