17/04/2008Presentation name1Risø DTU, Technical University of Denmark Technology developments and...

17/04/2008Presentation name1 Risø 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


Wind Energy Division - Risø DTUTechnical University of Denmark

• Windpower Meteorology

• Aeroelastic design methods

• Wind Turbine Structures

• Offshore Wind Energy

• Remote sensing & Measurements

• Windpower control & integration

• Certification Scheme

WIND ENERGYDIVISION

EDUCATION

WindTurbines

Wind EnergySystems

AeroelasticDesign

Test &Measurement

Meteorology

INTERNATIONALCONSULTING


”Wind Energy Roadmap” in the EC Communication of Financing Low Carbon Technologies.

TPWind priorities 2010-2012:

•Development and testing of new structures

•Automation (industry-wide study)

•Technology transfer from oil & Gas


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).


EERA JP on Wind Energy


EERA JPWEEERA JP on Wind Energy


Wind Energy Division - Risø DTUTechnical University of Denmark

WIND ENERGYDIVISION

EDUCATION

WindTurbines

Wind EnergySystems

AeroelasticDesign

Test &Measurement

Meteorology

INTERNATIONALCONSULTING

Offshore Wind Energy

DTU MEK

DTU IMM

DTU BYG


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

0

100

200

300

400

500

600

700

800

Time

Po

we

r (M

W)

HRBHRAHR2HR1

28/1-2000 29/1-2000 30/1-2000 31/1-2000 1/2-2000


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 andmodel from Horn’sReef offshore

Satellite windsshowing thewake at HornReef wind farm.Mean windspeed map usingsatellite EnvisatASAR.


Horns Rev offshore site

Courtesy: DONG Energy

and Alfredo Peña, Risø DTU


Wind loads dominated by wake effects

CFD – Large eddy simulation


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.

• 105 times faster than conventional CFD!


User friendly GUI


Validation: Horns Rev I.

Simple closure: t=u*z

No adjustable parameters!


Validation: Nysted.

Simple closure: t=u*z


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).


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

s u b - s t r u c t u r e

p i l e

f o u n d a t i o n

p i l e

p l a t f o r m

t o w e r t o w e r

s u b - s t r u c t u r e

sea floor

s u p p o r t s t r u c t u r e

rotor-nacelle assembly

seabed

water level


Standards for Offshore Wind Turbines

•Onshore wind turbines– IEC 61400-1, Edition 3

•Offshore wind turbines– IEC 61400-3– 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)


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


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


Benefits from the project and its need1. 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


DEEPWIND – New EU Funded Program

Vertical axis wind turbine

Bottom mounted generator for weight savings


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


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


•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


Thank you for your attention

17/04/2008Presentation name1Risø DTU, Technical University of Denmark Technology developments and...

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