Courtney, Michael

Lindelöw, Per Jonas Petter

Online Research Database In Technology

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Downloaded from orbit.dtu.dk on: Dec 17, 2017From Prototype to StandardizationFive years of LIDAR Anemometry in the Wind Energy IndustryLindelöw, Per Jonas Petter; Courtney, MichaelPublished in:Conference ProceedingsPublication date:2009Link back to DTU OrbitCitation (APA):Lindelöw, P. J. P., & Courtney, M. (2009). From Prototype to Standardization: Five years of LIDAR Anemometryin the Wind Energy Industry. In Conference Proceedings (pp. 255-258)Five Years of Lidar Anemometry in the Wind Energy Industry- From Prototype to IEC standardPetter Lindelöw-MarsdenRisø DTURenewable Energy LabDenmarkpetter.lindeloew@risoe.dkRisø DTU, Technical University of Denmark2Outline• Wind Measurements in Wind Energy• Commercially available systems• The market• State of the art• ChallengesRisø DTU, Technical University of Denmark3Wind in Wind Energy• 10 minute average horizontal wind speed, U• 10 minute average wind direction• Turbulence (STDEV in 10 min at 10 Hz)• Flow angles• 50 year wind• For a few months to +1 year• Offshore, forests, ridges etc• High availability (>90%) Risø DTU, Technical University of Denmark4Wind in Wind Energy• Today at hub height,  ~ 60-110 m• Future over rotor area i.e. from 40 to 200 m.~ 100 mwind speedheightRisø DTU, Technical University of Denmark5Power Performance• Measurement of the 10 minute averaged power as a function of the 10 minute wind.Simplified : Power = C · ( wind speed )3In practice : 1% in m/s  0 – 3% in W  0 – 3% error in predicted moneyAt hub height ±2.5%2-4 rotor diameters2.5D recommendedBoth turbine and wind sensor undisturbed by wakes.Risø DTU, Technical University of Denmark6Power PerformanceWhenR&D, turbine optimisationTurbine specification (comparison between brands, prediction of production)Acceptance tests once built+ 180 h for completed test. Free sectors + ~ 4 to 16 m/s wind speeds.  1-2 months in practice.A lot of money available at this stage, penalties are high for failed acceptance testsDemand on sensor Cup anemometer better than class 1.7 AStandard uncertainty : < 0.05 m/s + 0.005*UCalibration before and afterWind vane, ± 5° in wind direction± 2.5% from hub heighthRisø DTU, Technical University of Denmark7Power PerformanceChallenges• Accuracy, less than ± 0.1 m/s in offset and ± 1%, for stand alone option• ± 1% of hub height vs sample volume FWHM 20 m• Low standard deviation• Traceability• All beams in free wind (narrow cone angles?)Lidar anemometer opportunities1 Realistic measurement to tip of bladeMore repeatable power performance testsIEC standard 61400-12-1 under revision• Screening of atypical shear and veer• Normalisation for power law shear, i.e. Ueq• Stand alone lidar.2 Redeployable sensorMore turbines tested• In big farms sometimes only 5% of the turbines are tested.Risø DTU, Technical University of Denmark8Wind Resource Assessment• To obtain building permits and bank loans> 1 yearBuilding permit for mastlong term data serie close bycorrelate and predict+ + +Fitted Weibull distributionand wind direction roseRisø DTU, Technical University of Denmark9Wind Resource Assessment+ +Annual Energy Production EstimateGWh/yearWind climateRisø DTU, Technical University of Denmark10US (113 years) 90%US 2007 (40 years) 89%Under performance or over estimation ?Not due to 3% sensor errorWind Resource AssessmentEuropean wind resource map with a 3% margin.The cost, including measurement campaigns between 2009 and 2015, estimated to 175M€.Risø DTU, Technical University of Denmark11Wind Resource AssessmentNo standard but ”bankability”€ 15 000 in consultancy cost per 2 MW turbine1MW rated power costs 1.5M€Opportunities1 No building permitsFaster start, longer measurement series2 Always at hub heightReduce bias and STDEV in AEP estimates3 Shear and veer data over rotor plane (in future standard ?)Less uncertainty in investment4 Redeployable sensorVerification of flow modelsChallenges• Really a need in flat terrain• Reliabilty (+ 1 year measurements)• Traceable accuracy• Availability (> 90%, not correlated with wind speed)Risø DTU, Technical University of Denmark12Turbine control – Yaw• Optimised power when the turbine faces the windYaw error : Power * cos2(θ)Wind direction variability in a flat siteWind direction measured on turbine.Turbine yaws a few times every 10 min to keep aligned with wind direction.Forecasts of wind direction can help the control rutines.Wind direction variability at 100 m010020030040050060070080090010000.21.22.23.24.25.26.27.28.29.210.211.212.213.214.2MoreSTDEV in 10 min wind directionFrequency MEAN =3.6°Catch the wind :      ”10% more power”Risø : ”1-2 % more power”Risø DTU, Technical University of Denmark13Turbine control – Anti Yaw LIDARAnti Yaw Lidar• Few hundred meters upwind• Accuracy better than 3 degreesChallengeHow to avoid to misinterpretate turbulence?Risø DTU, Technical University of Denmark14Turbine control – pitch and flapsPitch control:• Collective pitch• Individual pitch• Reduce loads 20-30%• Improve power production• Similar to the anti yaw lidar but also above and below hubFlaps:• Reduce loads• Improve power productionFlap input• Angle of attack• > 2 sensors per wing• 5 m aheadRisø DTU, Technical University of Denmark15Outline• Wind measurements in Wind Energy• Commercially available systems• The market• State of the art• Challenges• ConclusionsRisø DTU, Technical University of Denmark16Zephir – Natural Power Consultants• Continuous Wave• Variable focus setting• VAD Scan 50 points, rotating wedge• 60° elevation angle• Cloud correction algorithm• CE marked – eyesafe IEC 60825-1• 1.56 µm fiber laser• 1 W output power• 7 cm diameter lens• No offset on LO• RIN and not head or tail wind• One LOS every 20 ms• Frequency resolution 200 kHz• Measures to 200 m in good conditions• Minimum range 10 m• 5 heights sequentially• 3 sec per height, 1 sec to change• about 30 measurements at one height  in 10 min• € 125.000Risø DTU, Technical University of Denmark17WindCube – Léosphère• Range gated• Fixed focus at ~100 m• 4 directions, 90° start-stop wedge• 60° elevation angle• eyesafe IEC 60825-1• 1.54 µm• 200 ns pulse• 10 µJ• 20 kHz• 500 ms to get one LOS velocity• 10000 averages per LOS• 5 cm diameter lens• Offset on LO• Frequency resolution 5 MHz• Measures to 200 m in good conditions• Minimum range 40 m• 10 heights in parallel• 4 sec per full revolution• about 600 measurements in 10 min (125 completely uncorrelated)• € 150.000Risø DTU, Technical University of Denmark18Galion – Sgurr Energy• Range gated• Collimated• two axis scanner head• eyesafe IEC 60825-1• 9 month warranty• 1.54 µm• 180 ns pulse• 10 µJ• 20 kHz• 50 mm aperture• Offset on LO• Measures to 200 m in good conditions• 20 sec per full revolution• 30 uncorrelated meas in 10 min (in 4 direction mode)• + 30 vertical meas• € 150.000Risø DTU, Technical University of Denmark19Vindicator – Catch The Wind• Range gated• Three telescopes• No moving parts• Turbine mounted• 200 ns pulse• Measures to 300 m in good conditions• Aim price $125.000Risø DTU, Technical University of Denmark20Competing technologiesTowersTilt up tower: 1 week assembly € 16.000 + 500 per sensorSODAR3 * Cheaper : $ 40.000 (Lidar € 100.000 -150.000) 5 * Less accurate : σ ~ 0.5 m/s (Windcube σ < 0.1 m/s)beam bending and low availability at high wind speed0.1 * power consumption : 10 W (LIDAR> 100 W)max 70 m100 m tower: < €150.000 (Offshore, ·3) 3 months for permit + construction= 1.5Risø DTU, Technical University of Denmark21Outline• Wind measurement in Wind Energy• Commercially available systems• The market• State of the art• Challenges• ConclusionRisø DTU, Technical University of Denmark22Lidar marketEstimated cumulative sold lidars:Zephir ~ 60 systems soldWindCube ~ 50 systemsVindicator and Galion < 10 systems2010 : 75 LIDAR = 10 M€Lidar market010203040506070802002 2004 2006 2008 2010 2012YearSold units Sold LIDAR anemometersGlobal annual installedwind enregy [GW]Risø DTU, Technical University of Denmark23Outline• Wind measurement in Wind Energy• Commercially available systems • The market• State of the art• Challenges• ConclusionTesting of LIDAR anemometers in HøvsøreHøvsøre Large Wind Turbin Test Facility• West coast of Denmark, flat terrain, wide range of horisontally homogeneous wind speed.• Site equipped with rain and cloud sensors• 15 Zephirs, 15 Windcubes and 1 Gallion tested = 31 lidars • 90 months of comparison with class 1 cup anemometers @ 40-116 m (160 m)• Data from 2 other flat sites evaluatedError vs Velocity and Shear: 2-parametric linear regression0.334060.163133  7.94365x  0.0248088yWind Gradient [m/s per m] Wind velocity [m/s]ΔU=R2=Estimate 7.9 m above intended height- 2.48 % mostly due to cone anglewhere ΔU is lidar - cup [m/s]x is wind shear [m/s per m]y is wind speed [m/s]Development of Lidar anemometry2006: Zephir commercial model introduced. Hardware issues.2007: Ceilometer installed, screening on clouds: positive bias and σ reduced, availability drops.Leosphere introduces Windcube.2008: Cloud correction: availability increases. Cone angle accuracyCone angle accuracy: bias reduced.2008.5: Estimator improved: nonlinear problems solved.2009: Improved test conditions, lower RIN. Improved test conditions.Vindicator and Galion commercialStandard Deviation of Remote Sensor Error [m/s]00.10.20.30.40.50.62003 2004 2005 2006 2007 2008 2009 2010ZephirsWindCubesScintekMean Remote Sensor Error [m/s]-0.3-0.2-0.100.10.20.32003 2004 2005 2006 2007 2008 2009 2010ZephirsWindCubesScintek(flat terrain, no rain, low veer, moderate σ)0.5 0 0.5 1Lidar Errorms60 m102030400.5 0 0.5 1Sodar Errorms60 m20406080WindcubeHistograms of Remote sensor – cupat 60 m Scintek 2004ZephirZephir mean -0.08, STDEV: 0.18Scintek mean -0.08, STDEV: 0.370.5 0 0.5 1Lidar Errorms60 m50100150200250300WC mean -0.08, STDEV: 0.090.5 0 0.5 1Lidar Errorms116 m10203040WindcubeHistograms of Remote sensor – cup at 116 m ScintekZephirWC mean -0.11, STDEV: 0.10Zephir mean -0.29, STDEV: 0.39Scintek mean -0.55, STDEV: 0.530.5 0 0.5 1Sodar Errorms116 m1020304050600.5 0 0.5 1Lidar Errorms116 m50100150200250At the coast of northen Denmark, >90% availabilityA good measure of Lidar anemometry accuracyEstimation of errors for sliding time period1000 test parameters @ 100 m± 0.03 m/s ± 0.75 m± 0.3%TO CALIBRATE OR NOT TO CALIBRATE ?Risø DTU, Technical University of Denmark30Outline• Wind measurement in wind energy • Commercially available systems • The market• State of the art• Challenges• ConclusionRisø DTU, Technical University of Denmark31ChallengesTraceable AccuracyBest units probably there (flat terrain, no rain, low veer, moderate σ)Price/3Reliability*3 , i.e. much more reliableComplex terrain3 LOS in same space = 3 Lidars with good scannersPower consumption, roughly 100 W (unheated)Selfsupporting for a yearRisø DTU, Technical University of Denmark32Conclusions• A need for more and better wind measurements in the wind energy industry• Need to have in the near term- More repeatable Power Performance, new IEC standard will include lidar anemometry- Ressource assessment, at hub heigth with lidar beats lower masts, bankable at a few occasions- Turbine control, research stage• 4 commercial suppliers, 10M€ in 2010.• 0.1 m/s stdev traceable accuracy (Flat terrain, no rain, little veer, moderate turbulence) • Still key challenges to be met (complex terrain)Thank you

From Prototype to Standardization:Five years of LIDAR Anemometry in the Wind Energy Industry

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From Prototype to Standardization:Five years of LIDAR Anemometry in the Wind Energy Industry

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