17/04/2008Presentation name1Risø DTU, Technical University of Denmark Technology developments and R&D landscape: Research overview from Risø Peter Hauge Madsen Wind Energy Division, Risø DTU The Technical University of Denmark Presented at EU offshore wind industry - a Carbon Trust/EWEA event

17/04/2008Presentation name2Risø DTU, Technical University of Denmark Wind Energy Division - Risø DTU Technical University of Denmark Windpower Meteorology Aeroelastic design methods Wind Turbine Structures Offshore Wind Energy Remote sensing & Measurements Windpower control & integration Certification Scheme

17/04/2008Presentation name3Risø DTU, Technical University of Denmark ”Wind Energy Roadmap” in the EC Communication of Financing Low Carbon Technologies. TPWind priorities : Development and testing of new structures Automation (industry- wide study) Technology transfer from oil & Gas

17/04/2008Presentation name4Risø DTU, Technical University of Denmark Research, development and demonstration challenges – Danish MEGAVIND strategy Target to make offshore wind power competitive with conventional coal- fired power by 2020 (50 % reduction in cost).

17/04/2008Presentation name5Risø DTU, Technical University of Denmark EERA JP on Wind Energy

17/04/2008Presentation name6Risø DTU, Technical University of Denmark EERA JP on Wind Energy

17/04/2008Presentation name7Risø DTU, Technical University of Denmark EERA JPWE EERA JP on Wind Energy

17/04/2008Presentation name8Risø DTU, Technical University of Denmark Wind Energy Division - Risø DTU Technical University of Denmark Offshore Wind Energy DTU MEK DTU IMM DTU BYG

17/04/2008Presentation name9Risø DTU, Technical University of Denmark Risø DTU – Offshore Wind Energy R&D priorities Marine wind, wave and current conditions –Characterize the geophysical processes,estimate local conditions and develop design basis Wakes in offshore wind turbine farms –Characterize and model wakes (performance and loads) in relation to interaction between turbines, between farms and large scale climate effects Installation and maintenance –Methods, models and tools to support installation and maintenance incl. Wind wave prediction, remedial and preventive maintenance and condition monitoring Integrated design tools –Integrated aero-hydro-servo-elastic tools incl. wave loads,soil-structure and fluid-structure interaction Offshore wind integration –Models and tools for design and control of offshore grid and clusters New concepts

17/04/2008Presentation name10Risø DTU, Technical University of Denmark Offshore Wind Conditions Ocean winds Lidar observations and modelling Wind resource mapping using satellite data Mesoscale modelling Meteorological mast observations Wind farms shadow effect Satellite observations Lidar wind data and model from Horn’s Reef offshore Satellite winds showing the wake at Horn Reef wind farm. Mean wind speed map using satellite Envisat ASAR.

17/04/2008Presentation name11Risø DTU, Technical University of Denmark Horns Rev offshore site Courtesy: DONG Energy and Alfredo Peña, Risø DTU

17/04/2008Presentation name12Risø DTU, Technical University of Denmark Wind loads dominated by wake effects CFD – Large eddy simulation

17/04/2008Presentation name13Risø DTU, Technical University of Denmark Fuga – a new, linearized wake model Solves linearised RANS equations Closure: mixing length, k-  or ’simple’ ( t =  u * z) Fast, mixed-spectral solver using pre-calculated look-up tables (LUTs) No computational grid, no numerical diffusion, no spurious mean pressure gradients Integration with WAsP: import of wind climate and turbine data times faster than conventional CFD!

17/04/2008Presentation name14Risø DTU, Technical University of Denmark User friendly GUI

17/04/2008Presentation name15Risø DTU, Technical University of Denmark Validation: Horns Rev I. Simple closure: t =  u * z No adjustable parameters!

17/04/2008Presentation name16Risø DTU, Technical University of Denmark Validation: Nysted. Simple closure: t =  u * z

17/04/2008Presentation name17Risø DTU, Technical University of Denmark Downwind Speed Recovery FUGA - predicts a much ”slower” speed recovery than standard wake models. For HR rec.distance is about 16 km; somewhat slower than observed 4) Normalized wind speed through the wind farm and behind the wind farm compared to measurements at Horns rev. Full curves are canopy-CFD-model predictions. _______________________________________________________________________________________ 4) R.J.Barthelmie et al., ” Flow and wakes in large wind farms: Final report for UpWind WP8”. Risø-R1765(EN) (2011).

17/04/2008Presentation name18Risø DTU, Technical University of Denmark Design of offshore wind turbines –Offshore wind turbines are not onshore wind turbines! hydrodynamic loads, sea ice, long periods at standby –Offshore wind turbines are not oil rigs! wind loads, shallow water, dynamics, unmanned –Marriage of expertise from wind power and offshore engineering industries –Technology Risks Improve confidence with which offshore wind farms can be financed and implemented

17/04/2008Presentation name19Risø DTU, Technical University of Denmark Standards for Offshore Wind Turbines Onshore wind turbines –IEC , Edition 3 Offshore wind turbines –IEC –GL Regulations for Offshore WECS, 1995 –DNV, Design of Offshore Wind Turbine Structures, OS-J101, 2007 –GL Wind, Guideline for the Certification of Offshore Wind Turbines, 2005 Offshore structures – petroleum and natural gas industries –ISO 19900, General Requirements for Offshore Structures, 2002 –ISO 19901, Specific Requirements for Offshore Structures, 2003 –ISO 19902, Fixed Steel Offshore Structures, 2004 (DIS) –ISO 19903, Fixed Concrete Offshore Structures, 2004 (DIS)

17/04/2008Presentation name20Risø DTU, Technical University of Denmark Walney Offshore Wind Farm Project 1.Large offshore wind farm being constructed by DONG energy with ~50 machines in phase 1 2.Siemens 3.6MW machines with monopile foundations 3.Average HH wind speed: 9.3 m/sec 4.Water depth 19m –28 m Objectives 1.Database of loads measurements with correlated wind and wave data 2.Assessment of uncertainty in loads simulations to provide improved structural reliability. 3.Recommendations to international wind turbine standards on offshore turbine design. Partners: Risø DTU, DONG, Siemens

17/04/2008Presentation name21Risø DTU, Technical University of Denmark EUDP Walney Offshore Wind Farm Project Measurements: Nacelle mounted LIDAR measuring wind speed at 2.5 rotor diameter in front of turbine. Wave and current measurements near foundation

17/04/2008Presentation name22Risø DTU, Technical University of Denmark Benefits from the project and its need 1.Maturity of loads prediction on offshore wind turbines, both on the support structure, as well as rotor nacelle. Provides offshore turbine loads data for research purposes. Provides for correlated wind and wave measurements for each load data point. One of the very few nacelle mounted LIDARs for offshore wind turbines with accurate wind measurements 2.Cost effective foundations. –Improved accuracy for site specific loads prediction –Estimation of damping of the structure to mitigate fatigue and extreme loads 3.Long term loads on the foundations –Fatigue and ultimate strength requirement evaluations –Enables improved life prediction

17/04/2008Presentation name23Risø DTU, Technical University of Denmark DEEPWIND – New EU Funded Program Vertical axis wind turbine Bottom mounted generator for weight savings

17/04/2008Presentation name24Risø DTU, Technical University of Denmark Mooring point Wave energy conversion device 3x GAIA 11kW. Downwind, Free yaw and teetering Grid connection point PSO project, measurements and modeling: DONG, FPP, DHI and Risø DTU Combined floating wind- and wave energy converter – Poseidon Experiment

17/04/2008Presentation name25Risø DTU, Technical University of Denmark Poseidon: Modeling Challenges Risø Hawc2 Overview Three rotors in one simulation –Structural modeling already possible in the multi-body formulation –Aerodynamic model updated to handle this Wake from upwind rotors –Already possible with the dynamic wake meandering model in HAWC2 Large water surface area Full coupled HAWC2-WAMSIM simulations HAWC2 validated aeroelastic code WAMSIM validated radiation/diffraction code for dynamic of floating structures from DHI WAMSIM recode to HAWC2 dll-interface format Ordinary HAWC2 turbine model Ordinary WAMSIM model Full system solved by HAWC2

17/04/2008Presentation name26Risø DTU, Technical University of Denmark The development of offshore wind energy depends not only on industrial development and demonstration –but also on medium to long term research Site conditions very complex – the site specific design conditions are derived in an ad-hoc and pragmatic way Integrated design tools exist but are primarily used to demonstrate conservatism of approach Limited validation of design loads and response Deep water (> 30 m) is a challenge Deep water concepts under way Offshore wind is just at the beginning – all options are open Conclusions

17/04/2008Presentation name27Risø DTU, Technical University of Denmark Thank you for your attention