Floating wind turbines: the future of wind energy? Axelle Viré Faculty of Aerospace Engineering A.C.Vire@tudelft.nl 1
Outline Trends in (offshore) wind energy Concepts of floating wind turbines Some challenges Research in the field at LR 2
Trends in (offshore) wind energy 3
Scale-up success 171 m Ø 33 m Ø A380 Airbus 126 m Ø 89 91 93 95 97 99 01 03 05 07 09 11 13 15. 3. 5 1.3 1.6 2 4.5 5 7.5 8 MW 4
How big is 8MW? 5
How big is 8MW? Samsung S7.0-171 83.5 m blade length 6
Cumulative wind power installations in Europe (GW) Wind in power 2015 European Statistics, EWEA report (Feb. 2016) 7
Cumulative wind power installations offshore in Europe (MW) The European offshore wind industry - key trends and statistics 2015, EWEA report (Feb. 2016) 8
Types of foundations Newly installed foundations in Europe in 2015 97% monopiles (385 structures) 3% jackets (12 structures) 3% In 2015, there were 3,313 foundations installed offshore in Europe 97% Monopile: www.londonarray.com (May, 2016) Jacket: Alpha Ventus, www.offshorewind.biz (May, 2016) 9
Limitations of current technology Most seas are deeper than 50 metres Existing commercial foundations are not economically viable in deep seas Source: N. Anscombe, Turbines take float, Power Engineer, Vol. 18, Issue 3 (2004) 10
Concepts of floating wind turbines 11
Main types of foundation Tension leg platform Semi-submersible Spar buoy Stability Moorings Buoyancy Ballast Assembly Dry dock Dry dock On/off-shore Installation Towing to site Towing to site Towing or not Depth 50-150 m 50-150 m 100m -? 12
Recent developments 2008 Blue H (80kW) hsp://www.bluehengineering.com/historical- development.html 13
Recent developments 2009 Hywind (2.3MW) Upcoming Hywind Scotland Pilot Park (30MW) www.statoil.com/hywindscotland Photo: Trude Refsahl/Statoil 14
Recent developments 2011 WindFloat (2MW) Upcoming WindFloat Atlan\c (25MW) hsp://www.principlepowerinc.com/en/windfloat 15
Recent developments 2011-2016 Fukushima Forward project (2MW, 5MW, 7MW) hsp://www.fukushima- forward.jp 16
And much more 17
And much more 18
Combining wind and wave energy hsp://www.floa\ngpowerplant.com 19
Floating airborne wind energy hsp://www.skysails.info/english/power 20
Some challenges 21
Some challenges Turbine Rotor-wake interactions Control systems Support structure Conservatism in the design (not cost effective) Relation between size of turbine rating Mooring lines Dynamic behaviour of moorings, esp. in shallow water Anchors and soil conditions Electrical infrastructure Dynamic power cables Operation and maintenance Harsh environmental conditions Design standards Lack of experience leads to conservative designs Modelling of the system dynamics Technologically feasible but needs to be cheaper! 22
Numerical modelling Accuracy CFD & FEM Detailed design Aero-servohydro-elastic coupling Design validation Reduced modeling Pre-design Cost 23
Research at LR 24
High-fidelity modelling of FSI Unstructured mesh fluid/ocean model (finite elements) Page 17 Imper hsp://fluidityproject.github.io 25
High-fidelity modelling of FSI 26
Applications Wind/tidal turbine modelling through actuator disks Abolghasemi et al. Simulating tidal turbines with multi-scale mesh optimisation techniques, Journal of Fluids and Structures 66:69-90 (2016) Viré et al. Towards the fully-coupled numerical modelling of floating wind turbines, Energy Procedia 35:43-51 (2013) Dynamics of a floating monopile Viré et al. Towards the fully-coupled numerical modelling of floating wind turbines, Energy Procedia 35:43-51 (2013) Aerodynamics of kite wings Rajan et al. Fluid-structure interaction of an inflatable kite wing, Airborne Wind Energy Conference (2015) Wave-structure interactions Viré et al. Application of the immersed-body method to simulate wave-structure interactions, European Journal of Mechanics B/Fluids 55:330-339 (2016) 27
Applications Wind/tidal turbine modelling through actuator disks Abolghasemi et al. Simulating tidal turbines with multi-scale mesh optimisation techniques, Journal of Fluids and Structures 66:69-90 (2016) Viré et al. Towards the fully-coupled numerical modelling of floating wind turbines, Energy Procedia 35:43-51 (2013) Dynamics of a floating monopile Viré et al. Towards the fully-coupled numerical modelling of floating wind turbines, Energy Procedia 35:43-51 (2013) Aerodynamics of kite wings Rajan et al. Fluid-structure interaction of an inflatable kite wing, Airborne Wind Energy Conference (2015) Wave-structure interactions Viré et al. Application of the immersed-body method to simulate wave-structure interactions, European Journal of Mechanics B/Fluids 55:330-339 (2016) 28
Wave-structure interactions Regular waves of steepness ak =0.01 where gk tanh(kh) =(2 T ) 2 and T =1 Intermediate water depth: h/ 0 =0.45 ( 0 =2 g/! 2 ) Inviscid flow Reference: linear wave theory (MacCamy & Fuchs, 1954) 29
Wave-structure interactions Theoretical solution Defined-body approach Immersed-body approach 1 1 0.5 0.5 η/a 0 η/a 0 0.5 0.5 1 1 0 5 10 15 20 x/h 0 5 10 15 20 x/h 30
Wave-structure interactions Irregular waves Amplitudes of the focused wave ( k p is the Jonswap peak) A sum k p =0.018 A sum k p =0.09 The amplitude is maximum at: x f = 10h and t f =7.5T Reference: second-order calculation (Sharma & Dean, 1981) 31
Wave-structure interactions Second-order solution CFD 1 1 A sum k p =0.018 A sum k p =0.09 0.5 η/a sum 0 0.5 η/a sum 0 0.5 8 9 10 11 12 t/t p 0.5 8 9 10 11 12 t/t p 32
Wave-structure interactions Without pile With defined pile With immersed pile 1 A sum k p =0.018 A sum k p =0.09 1 0.5 η/η max 0 0.5 η/η max 0 0.5 0.5 1 6 7 8 9 t/t p 1 6 7 8 9 t/t p 33
Wave-structure interaction 0.7 0.5 0.3 F body 0.1 0.7 0.6 0.5 0.4 0.3 1.4 1.6 1.8 2 2.2 2.4 0.1 0.3 Immersed body Hu et al. (num) Hu et al. (exp) 0 2 4 6 8 10 12 14 t 34
Upcoming works CFD modelling of the TetraSpar concept (Stiesdal, 2016), with Deltares and NTNU Re-design of blades for model-scale testing, with MARIN Build synergies at TU Delft and internationally on floating wind energy 35
The future of wind energy? Subsidies and costs of EU energy, Ecofys (Nov. 2014) 36
The future of wind energy? Cost comparison for a wind farm of 800 MW installed capacity Market study floa\ng wind in the Netherlands, TKI Wind Op Zee (Nov. 2015) 37
Insert a picture Thank you for your attention 38