The next generation offshore wind foundation from Universal Foundation has recently completed a trial installation campaign across three major offshore wind sites in the UK North Sea, as part of the Carbon Trust’s Offshore Wind Accelerator (OWA) programme.
The project was managed by Statoil and delivered by Universal Foundation, in partnership with the Carbon Trust, Statkraft, EON and DONG Energy, in close co-operation with Aalborg University. It also received funding from EUDP, the Danish Energy Agency.
The trial installation was conducted to run a series of tests with a scaled down Universal Foundation design, as well as a “standard” suction anchor for benchmarking and referencing. It focused on penetration ability, verticality, water injection impact on soil plug, forces and stress in skirt structure and internal soil levelling capability. Installation was completed across a range of challenging soil conditions including soft clay,moraine clay, boulder bank clay – with sand spikes and layers, clay crust, sand and silt.
Fred. Olsen Windcarrier’s installation vessel Brave Tern departed from Frederikshavn on the 5th September 2014 to mark the start of the campaign. On deck were two suction foundation structures – one Universal Foundation structure measuring 8m in diameter with a 6m skirt and a reference structure of 4m diameter with 6m skirt. Within the 24-day campaign, 28 suction installations were achieved between the two structures.
“We are delighted with the progress of the project and now follows an equally important period of data analysis with results expected early 2015 to conclude the project”, said Lars Kjuul Kristensen, project manager from Universal Foundation.
“The structures were successfully installed and retrieved in some of the most challenging soil conditions experienced by the participating developers. The Universal Foundation bucket achieved full penetration with 0.1 degree inclination or less, and the functionality of the internal top soil levelling system has been proven. This marks a major step forward in the de-risking of suction technology.”
It marks a milestone in the development of the Universal Foundation and follows on from last year’s successful installation at Dogger Bank, a major Round 3 offshore wind site, where Universal Foundations support two meteorological masts. In addition, an offshore met mast foundation was installed at Horns Rev 2 in Denmark in 2009 and a 3MW turbine on a Universal Foundation has been fully operational in Frederikshavn for 12 years.
Otto Jermiin Nielsen, CEO of Universal Foundation in Denmark said, “The collaboration among the parties involved in this project was extraordinary. Through the Carbon Trust Offshore Wind Accelerator we were able to bring together the right industry players to make the trials happen, and the involvement of Aalborg University made the project set up truly unique. The ability to bring commercial and scientific interests together is the trademark of this project. The results will impact the wind industry for years to come and will be the basis for further important research.”
Jan Matthiesen, Director of Innovation at the Carbon Trust commented, “The results from this latest trial further establish Universal Foundation suction bucket as a promising structure that could be a real game changer for the industry. We have backed the design, along with our partners in the Offshore Wind Accelerator ever since it was shortlisted from the Foundation competition in 2009. We have seen it go from concept through to a detailed de-risking process and now pleased to support this critical phase of installation testing. Universal Foundation will achieve critical cost reduction and has proven it can deliver on a number of key aspects including elimination of noise, faster, easier installation, and now has achieved a big leap forward by demonstrating it can be installed successfully in testing soil conditions.”
“We are very pleased to have completed the test-program of the suction bucket trial installation project and to be able to capture valuable experience and gathered essential data for various types of soil conditions in the North Sea. We are looking forward to a thorough analysis of the results and consider these tests an important step of bringing cost effective foundation technologies further to commercial use in our future projects”, says Jan-Fredrik Stadaas, project lead and technology manager for Offshore Wind in Statoil.
Universal Foundation’s ‘suction bucket’ was one of four novel low cost foundation designs that were shortlisted following an international competition run by the Carbon Trust’s Offshore Wind Accelerator in 2009 to discover world leading innovation in this area.
Further findings from the trial installation project will be published in due course.