About offshore resource assessment with floating lidars with special respect to turbulence and extreme events

Gottschall, Julia; Wolken-Möhlmann, Gerrit; Lange, Bernhard

doi:10.1088/1742-6596/555/1/012043

Cited by 19 publications

(22 citation statements)

References 1 publication

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“…However, some FLS trial data studies included a more detailed analysis. In line with the findings from simulation studies, 28 movements of the floating platform systematically increase the TI values recorded by the floating lidar device. It depends on the used type of platform, to which extent sea motions are translated into platform motions and how severe the impact of the motions on the FLS measurements is.…”

Section: Turbulence Intensity Data From Flssupporting

confidence: 88%

“…The studies comprise computer simulations [25][26][27] and onshore measurements with a lidar device on a motion platform, i.e., a construction performing controllable motions with up to six DoF. Onshore tests were reported for a 2-DoF system next to a met mast 28 and a 6-DoF system next to a second lidar device of the same type. 29 All listed studies confirm that there is an effect of the simulated motions on the wind measurements and its magnitude depends not only on the amount and characteristics of motions that are passed through to the lidar measurement system but also on the lidar measurement principle itself, i.e., if a pulsed or cw lidar is applied.…”

Section: Challenges To Floating Lidarsmentioning

confidence: 99%

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Floating lidar as an advanced offshore wind speed measurement technique: current technology status and gap analysis in regard to full maturity

Gottschall

Gribben²,

Stein

et al. 2017

WIREs Energy & Environment

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Floating lidar was introduced in 2009 as an offshore wind measurement technology focusing on the specific needs of the wind industry with regard to wind resource assessment applications. Floating lidar systems (FLS) are meant to replace an offshore met mast, being significantly cheaper and saving an essential part of project upfront investment costs. But at the same time, they need to overcome particular challenges—these are (1) the movement of the sea imparting motion on the buoy and the lidar, and the subsequent challenge of maintaining wind speed and direction accuracy, and (2) the remoteness of the deployed system in an extremely challenging environment necessitating robust, autonomous and reliable operation of measurement, power supply, data logging, and communication systems. The issue of motion influences was investigated in a number of studies and is to be checked and monitored in offshore trials of individual FLS realizations. In trials to date, such influences have been demonstrated to be negligibly or manageably small with the application of motion reduction or compensation strategies. Thereby, it is possible to achieve accurate wind measurement data from FLS. The second kind of challenge is tackled by implementing a sufficiently robust and reliable FLS design. Recommended practices collected by a working group within the International Energy Agency (IEA) Wind Task 32 and within the UK offshore wind accelerator program offer guidance for FLS design and configuration, and furthermore set requirements for trialing the system types and individual devices in representative offshore conditions. WIREs Energy Environ 2017, 6:e250. doi: 10.1002/wene.250 This article is categorized under: Wind Power > Science and Materials Wind Power > Climate and Environment

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Section: Turbulence Intensity Data From Flssupporting

confidence: 88%

Section: Challenges To Floating Lidarsmentioning

confidence: 99%

Floating lidar as an advanced offshore wind speed measurement technique: current technology status and gap analysis in regard to full maturity

Gottschall

Gribben²,

Stein

et al. 2017

WIREs Energy & Environment

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“…The increasing use of floating lidar systems in the offshore wind energy sector motivates the need to assess and compensate the effect of motion on floating lidar measurements [34,35]. It has been shown that both the static [36] and dynamic tilt [37][38][39][40] of the lidar instrument induce errors in the retrieved horizontal wind speed (HWS).…”

Section: Introductionmentioning

confidence: 99%

Estimation of the Motion-Induced Horizontal-Wind-Speed Standard Deviation in an Offshore Doppler Lidar

et al. 2018

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This work presents a new methodology to estimate the motion-induced standard deviation and related turbulence intensity on the retrieved horizontal wind speed by means of the velocity-azimuth-display algorithm applied to the conical scanning pattern of a floating Doppler lidar. The method considers a ZephIR™300 continuous-wave focusable Doppler lidar and does not require access to individual line-of-sight radial-wind information along the scanning pattern. The method combines a software-based velocity-azimuth-display and motion simulator and a statistical recursive procedure to estimate the horizontal wind speed standard deviation—as a well as the turbulence intensity—due to floating lidar buoy motion. The motion-induced error is estimated from the simulator’s side by using basic motional parameters, namely, roll/pitch angular amplitude and period of the floating lidar buoy, as well as reference wind speed and direction measurements at the study height. The impact of buoy motion on the retrieved wind speed and related standard deviation is compared against a reference sonic anemometer and a reference fixed lidar over a 60-day period at the IJmuiden test site (the Netherlands). Individual case examples and an analysis of the overall campaign are presented. After the correction, the mean deviation in the horizontal wind speed standard deviation between the reference and the floating lidar was improved by about 70%, from 0.14 m/s (uncorrected) to −0.04 m/s (corrected), which makes evident the goodness of the method. Equivalently, the error on the estimated turbulence intensity (3–20 m/s range) reduced from 38% (uncorrected) to 4% (corrected).

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“…In another case, Gottschall found that measurements from a LiDAR mounted to a met mast agreed with a separate LiDAR mounted on a controlled motion platform but showed increased turbulence and data variability. However, with the use of software to compensate for motions, this effect can be mitigated . Validation of floating LiDARs has progressed as well.…”

Section: Introductionmentioning

confidence: 99%

“…However, with the use of software to compensate for motions, this effect can be mitigated. 10 Validation of floating LiDARs has progressed as well. For example, a 10-day study between a floating LiDAR and land-based LiDAR was performed by the Taiwan Ocean Research Institute.…”

Section: Introductionmentioning

confidence: 99%

Validation of the first LiDAR wind resource assessment buoy system offshore the Northeast United States

Viselli

Filippelli²,

Pettigrew

et al. 2019

Wind Energy

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The US offshore wind industry is maturing with several projects in various stages of development. These projects require site wind and environmental data before and during operation. Conventional techniques such as fixed‐bottom meteorological towers present economical and permitting challenges for the US. Floating Light Detection and Ranging (LiDAR) buoys offer significant advantages including reduced costs, less permitting, and reusability. This paper presents the validation of the first floating LiDAR buoy in Northeast US waters. The buoy, named DeepCLiDAR, includes a LiDAR, ecological monitoring sensors, and metocean sensors. A three‐phase LiDAR validation plan was executed, and its results are presented. The objective of the validation plan was to verify the accuracy of measurements made by the LiDAR buoy in wave environments against an unmoving reference wind measurement. Due to a lack of reference met masts, the use of a LiDAR on land as a baseline reference was implemented for validation. Comparison to a reference LiDAR instead of a traditional meteorological tower was a unique approach required in the Northeast US waters due to the absence of a reference fixed‐bottom meteorological tower in the region at the time of this study. The testing included a comparison of wind speed measurements made by the buoy deployed 15 km offshore from the mainland and a land‐based reference LiDAR located on a nearby island. This paper presents the methodology and results of this program, which indicate favorable agreement. This was the first such validation program in the Northeast USA which is now seeing rapid development of offshore wind.

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About offshore resource assessment with floating lidars with special respect to turbulence and extreme events

Cited by 19 publications

References 1 publication

Floating lidar as an advanced offshore wind speed measurement technique: current technology status and gap analysis in regard to full maturity

Floating lidar as an advanced offshore wind speed measurement technique: current technology status and gap analysis in regard to full maturity

Estimation of the Motion-Induced Horizontal-Wind-Speed Standard Deviation in an Offshore Doppler Lidar

Validation of the first LiDAR wind resource assessment buoy system offshore the Northeast United States

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