A solution in support for offshore wind Henrik Lundorf Nielsen April 2013
The Evolution of Innovative yet years of experience: 1997 TekNord 1999 MIG Business Development 2002 Prototype 1 2001 MBD Offshore Power R&D of Bucket Foundation 2005 Prototype 2 2009 Prototype 3 2011: Press Release August 2011: Fred. Olsen United AS, which is owned 50/50 by Bonheur ASA and Ganger Rolf ASA, has acquired 60% of Danish company Universal Foundation A/S Other shareholders: DONG, Aalborg Universitet, Novasion
Fred. Olsen United Project management Secures a seamless interface and serves as single-point of contact Universal Foundation Harland and Wolff Fred. Olsen Windcarrier Natural Power - SeaRoc Global Wind Service Design of support structure Specialist in engineering and subseabed installation Foundation structure manufacture at their shipyard in Belfast Marine operations of structures to final site Supply and installation of met-mast structures and equipment HSEQ services Installation of wind turbines Service & maintenance Fibre repair Commissioning
Stepping up the Technology Readiness Ladder Targeting a 2015/16 contract 2016 Execution of WF Project 2015 - Wind Farm Contract - Commercially Ready 2014 WTG foundation - Field proven - TRL 7 2013-14 Trial installations - Carbon Trust TRL 5 and 6 2012-13 Met Mast Foundations Dogger Bank, Firth of Forth TRL 4 and 5 2002 11 R&D Technology Readiness Level, TRL 0 to 3
A Fred. Olsen related company Is the Bucket an Opportunity for Near Offshore sites in Denmark? Question is: Does the Suction Bucket work at a given site?
How does it work Installation? The Universal Foundation Suction Bucket is a Suction Installed CAisson SICA All in one Substructure and Foundation unit as support for offshore installations, i.e. met masts, wind turbines, sub stations... Suction is applied during installation water evacuation Suction is NOT maintained during operation Once installed the SICA is a Gravity Foundation 1: Evacuation of water creates downward force limited by the water column 2: Flow around skirt reduces effective stresses in soil thereby reducing resistance
How does it work Installation?
How does it work In Operation? Once installed the SICA is a Gravity Foundation Failure mode is overturning V H M Point of rotation
Where does it work? Installability & Capability under which conditions? Design Drivers: Geology Met Ocean conditions Superstructure (Wind Turbine)
Main Driver Type Family Grade Penetrability Capacity Soft Firm Clay Stiff Very Stiff Hard Silt Tansition from Clay to Sand Very Loose Soil Loose Sand Medium Dense Geology Dense Very Dense Clay - Sand - Clay Layered Soils Sand - Clay - Sand Glacial Till Stiff - Hard Organic Soil Igneous Magma (Granite, Basalt) Rock Sedimentary Lithification (Limestone, Sandstone...) Metamorphic Recrystallization (Slate, Gneiss) Remark: In Clay due to low permeability flow around skirt is prevented. Penetration resistance shall be overcome by vertical downward force (Water column). Experience in Clay is limited,- i.e. Carbon Trust Trial Installation Scheme! 3 Internal Bulkheads to allow additional down force
Main Driver Type Family Grade Penetrability Capacity Soft Firm Clay Stiff Very Stiff Hard Silt Tansition from Clay to Sand Very Loose Soil Loose Sand Medium Dense Geology Dense Very Dense Clay - Sand - Clay Layered Soils Sand - Clay - Sand Glacial Till Stiff - Hard Organic Soil Igneous Magma (Granite, Basalt) Rock Sedimentary Lithification (Limestone, Sandstone...) Metamorphic Recrystallization (Slate, Gneiss) Remark: In Clay due to low permeability flow around skirt is prevented. Penetration resistance shall be overcome by vertical downward force (Water column). Experience in Clay is limited,- i.e. Carbon Trust Trial Installation Scheme! 3 Internal Bulkheads to allow additional down force
Main Driver Type Family Grade Penetrability Capacity 0-10 m 10-20 m Bathymetry Water Depth 20-30 m Met Ocen 30-40 m >40-50m Waves Dynamics T < f0 (system) T = f0 (system) T > f0 (system) Remark: Water column defines downward force Dynamic effect gradually governs Wave load takes dominance over turbine loads
Main Driver Type Family Grade Penetrability Capacity 0-10 m 10-20 m Bathymetry Water Depth 20-30 m Met Ocen 30-40 m >40-50m Waves Dynamics T < f0 (system) T = f0 (system) T > f0 (system) Remark: Water column defines downward force Dynamic effect gradually governs Wave load takes dominance over turbine loads Load Response Amplification
Main Driver Type Family Grade Capacity 3 MW 4 MW 5 MW MW nameplate 25 to 45 m WD 6 MW 7 MW 8 MW System f0 below Allowable frequency interval System f0 within System f0 above Wind Turbine Remark: Threshold of structure tonnage = app. 1200 tonnes (Green colour). Very dependent on installation vessel crane capacity & method Integrated design WTG <> Substructure will accommodate for for correct system f 0
Main Driver Type Family Grade Capacity 3 MW 4 MW 5 MW MW nameplate 25 to 45 m WD 6 MW 7 MW 8 MW System f0 below Allowable frequency interval System f0 within System f0 above Wind Turbine Remark: Threshold of structure tonnage = app. 1200 tonnes (Green colour). Very dependent on installation vessel crane capacity & method Integrated design WTG <> Substructure will accommodate for for correct system f 0
Wind Turbine: Case study... Fine tuning system f 0 to avoid resonance = load amplification Typical deflection shapes for first few modes and load amplification as fuction of damping... Typical damping estimate = 10 15% (soil contribution 2% - 4%) => H(f) = 3 to 4 Note: This affects SLS and FLS load cases only
Typical WTG ranges The Bucket = MP like shaft but stiffer however not as stiff as Jacket... Can be tailored by tapered shaft, lid design... System f 0 depends on Nacelle/Rotor Mass, Tower, Water Depth... Narrow feasible frequency band here soft - hard f 0 It calls for Integrated design load loop iteration Trade off to find the cost optimal solution
Then lets assume we got the integrated design right what value proposition is to be expected: Simplified ULS perspective: 1000 900 ULS moment as function of Rotordiameter ULS Overturning Moment MNm 800 700 600 500 400 300 200 100 Wave & WTG WTG 30 m Mudline 40 m Mudline 25 m Mudline Lineær (Tower bottom extreme bending moment) 0 60 80 100 120 140 160 180 200 Rotor Diameter
Simplified ULS perspective - continued: Suction Bucket Tonnage as function of Mudline Resulting Moment Universal Foundation Suction Bucket tons 1600 1400 1200 1000 800 600 400 200 0 0 100 200 300 400 500 600 700 800 900 Resulting moment @ mudline ULS, MNm
The Cost perspective To say something clever on Cost level would need a specific project estimate Significant contribution to shorten Project Schedule LCoE is reduced significantly 100% 90% 80% 100% 96% Cost per unit Index 70% 60% 50% 72% 69% 60% 57% 40% 30% 20% 0 10 20 30 40 50 Nos of Structures 31%
In conclusion: The Bucket will be a feasible support structure given the right soils and Met Ocean conditions Tonnage: Site Specific Design required At a cost of - too early to say All to be confirmed. i.e we need: Geotechnical info Met Ocean info WTG-Support Structure - integrated design initiated - Design Basis - Load Loop Iteration - Detailed design / Interface concept
Feasibility Assessment - A solution for the ALSTOM Hal150 @ Belwind II? Dogger Bank Campaign February 2013
Dogger Bank Met Mast East - SCADA screen dump... Penetration: Duration: Verticality: 7.31 m 6 hrs 46 min 0,09 degrees Expanding this to full scale project the positive impact on project schedule is huge!!
Thank you!