Rotor Layer Research Articles

Large-eddy simulation of non-isothermal flow and heat transfer in an enclosed rotor–stator cavity

This paper presents a numerical study of non-isothermal flow and heat transfer in an enclosed rotor–stator disk cavity. Wall-resolved large-eddy simulation is implemented with attention focused on the Reynolds number effect (Reϕ=105 and 5×105) and non-isothermal effects, including different thermal Rossby numbers (βΔT=0.05–0.25) and heat convection types (axial heat convection, axial and radial heat convection). Verification and validation are implemented by comparing with available experimental data and examining the resolution of the present LES. Although the Batchelor flow type is unchanged, the non-isothermal effect is found to be responsible for the acceleration of flow in both disk boundary layers and cavity core. Temperature in the cavity is negatively correlated with the Rayleigh number. The radial inward temperature gradient is found to be responsible for destabilizing the flow near the cylinders, due to the effect of centrifugal buoyant force. Transition from laminar to turbulent is shown in the rotor boundary layer for Reϕ=5×105 conditions. The non-isothermal effect increases flow unsteadiness in both rotor and stator boundary layers, but it has little to no effect on the transition position, as well as the kinematic and thermal boundary layer thicknesses, which are mainly controlled by Reϕ. Spectral proper orthogonal decomposition is implemented to explore the Reynolds number effect. Analyzing the most energetic mode and its energy spectra provides some insights into the understanding of non-isothermal rotor–stator disk cavity flows.

Wind Fields in Category 1–3 Tropical Cyclones Are Not Fully Represented in Wind Turbine Design Standards

AbstractOffshore wind energy deployment in the U.S. is expected to increase in the years to come, with proposed wind farm sites located in regions with high risk for tropical cyclones. Yet, the wind turbine design criteria outlined by the International Electrotechnical Commission for extreme events may not account for wind field characteristics unique to tropical cyclones. To evaluate if current design standards capture the extreme conditions of these storms, we perform idealized large‐eddy simulations of three tropical cyclones (one Category 1, one Category 2, and one Category 3 storms) using the Weather Research and Forecasting model. Wind conditions near the eyewall of Cat‐1, Cat‐2, and Cat‐3 storms can exceed current design standards for offshore wind turbines. Winds at 90 m can be faster than outlined in the design criteria for Class I and Class T turbines for 50‐year recurrence periods. Wind speed shear across the turbine rotor layer is also larger than assumed in design specifications. Moreover, vertical variations in wind direction across the turbine rotor layer are large for tropical cyclones of all intensity levels, suggesting design standards should include veer, which can amplify loads in wind turbines. The existence of hurricane wind field characteristics that are not represented in design standards does not imply that damage or failure will certainly occur. Engineering safety factors incorporated in the design of the turbine's blades and structural components may prevent damage from occurring.

Effect of Pole Head Profile on Torque Performance of a Disc-Type Multipole Magnetorheological Brake

A magnetorheological brake (MRB) works on the shearing effect of MR fluid in the magnetic field to develop resistance between the stator and the rotor, which are relative moving surfaces. Researchers achieved high torque volume ratios in magnetorheological fluid braking systems by adding multiple layers and using multipole approaches. Even though several designs already exist, there is a need for innovative ideas and advanced structures of MRBs for practical engineering applications. The number of magnetic poles, pole geometry and placement have a significant effect on the performance of multipole MR brakes. This research focused on the effect of the pole head geometry in a multipole dual disc compact MR brake to understand the relationship between the geometry and its magnetic flux flow. The magnetic field generated by the electromagnetic coil’s orthogonal travel through pole heads, rotor and MR fluid layers results in friction to fulfill the action of braking that achieves maximum brake torque. This flow depends on the magnetic pole head area and corresponding core dimensions. This study considered polygon, square, hexagon, trapezoid and ellipse pole head profiles in place of the conventional circular pole and the best possible core dimensions were used for each geometry. To study the brake’s performance, COMSOL Multiphysics software (version 5.5) commonly used for 3D electromagnetic modeling was used to simulate and examine the magnetic flux intensity for various pole head configurations. Results indicate an improvement compared to previous works, considering the same dimensional limitations and the flux leakage between the adjacent poles being much less. The hexagonal and elliptical pole heads had better magnetic field area, magnetic intensity distribution and higher magnetic flux lines piercing through the MR fluid perpendicularly than the circular and square pole heads. An increment of 3.88% for braking torque performance was obtained, and the braking torque was significantly enhanced.

Investigating the physical mechanisms that modify wind plant blockage in stable boundary layers

Abstract. Wind plants slow down the approaching wind, a phenomenon known as blockage. Wind plant blockage undermines turbine performance for front-row turbines and potentially for turbines deeper into the array. We use large-eddy simulations to characterize blockage upstream of a finite-size wind plant in flat terrain for different atmospheric stability conditions and investigate the physical mechanisms modifying the flow upstream of the turbines. To examine the influence of atmospheric stability, we compare simulations of two stably stratified boundary layers using the Weather Research and Forecasting model in large-eddy simulation mode, representing wind turbines using the generalized actuator disk approach. For a wind plant, a faster cooling rate at the surface, which produces stronger stably stratified flow in the boundary layer, amplifies blockage. As a novelty, we investigate the physical mechanisms amplifying blockage by evaluating the different terms in the momentum conservation equation within the turbine rotor layer. The velocity deceleration upstream of a wind plant is caused by an adverse pressure gradient and momentum advection out of the turbine rotor layer. The cumulative deceleration of the flow upstream of the front-row turbines instigates vertical motions. The horizontal flow is diverted vertically, reducing momentum availability in the turbine rotor layer. Although the adverse pressure gradient upstream of the wind plant remains unchanged with atmospheric stability, vertical advection of horizontal momentum is amplified in the more strongly stable boundary layer, mainly by larger shear of the horizontal velocity, thus increasing the blockage effect.

Offshore reanalysis wind speed assessment across the wind turbine rotor layer off the United States Pacific coast

Abstract. The California Pacific coast is characterized by considerable wind resource and areas of dense population, propelling interest in offshore wind energy as the United States moves toward a sustainable and decarbonized energy future. Reanalysis models continue to serve the wind energy community in a multitude of ways, and the need for validation in locations where observations have been historically limited, such as offshore environments, is strong. The U.S. Department of Energy (DOE) owns two lidar buoys that collect wind speed observations across the wind turbine rotor layer along with meteorological and oceanographic data near the surface to characterize the wind resource. Lidar buoy data collected from recent deployments off the northern California coast near Humboldt County and the central California coast near Morro Bay allow for validation of commonly used reanalysis products. In this article, wind speeds from the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2), the Climate Forecast System version 2 (CFSv2), the North American Regional Reanalysis (NARR), the European Centre for Medium-Range Weather Forecasts Reanalysis version 5 (ERA5), and the analysis system of the Rapid Refresh (RAP) are validated at heights within the wind turbine rotor layer ranging from 50 to 100 m. The validation results offer guidance on the performance and uncertainty associated with utilizing reanalyses for offshore wind resource characterization, providing the offshore wind energy community with information on the conditions that lead to reanalysis error. At both California coast locations, the reanalyses tend to underestimate the observed rotor-level wind resource. Occasions of large reanalysis error occur in conjunction with stable atmospheric conditions, wind speeds associated with peak turbine power production (> 10 m s−1), and mischaracterization of the diurnal wind speed cycle in summer months.

Spatiotemporal observations of nocturnal low-level jets and impacts on wind power production

Abstract. A challenge of an energy system that nowadays more strongly depends on wind power generation is the spatial and temporal variability in winds. Nocturnal low-level jets (NLLJs) are typical wind phenomena defined as a maximum in the vertical profile of the horizontal wind speed. A NLLJ has typical core heights of 50–500 m a.g.l. (above ground level), which is in the height range of most modern wind turbines. This study presents NLLJ analyses based on new observations from Doppler wind lidars. The aim is to characterize the temporal and spatial variability in NLLJs on the mesoscale and to quantify their impacts on wind power generation. The data were collected during the Field Experiment on Submesoscale Spatio-Temporal Variability (FESSTVaL) campaign from June to August 2020 in Lindenberg and Falkenberg (Germany), located at about 6 km from each other. Both sites have seen NLLJs in about 70 % of the nights with half of them lasting for more than 3 h. Events longer than 6 h occurred more often simultaneously at both sites than shorter events, indicating the mesoscale character of very long NLLJs. Very short NLLJs of less than 1 h occurred more often in Lindenberg than Falkenberg, indicating more local influences on the wind profile. We discussed different meteorological mechanisms for NLLJ formation and linked NLLJ occurrences to synoptic weather patterns. There were positive and negative impacts of NLLJs on wind power that we quantified based on the observational data. NLLJs increased the mean power production by up to 80 % and were responsible for about 25 % of the power potential during the campaign. However, the stronger shear in the rotor layer during NLLJs can also have negative impacts. The impacts of NLLJs on wind power production depended on the relative height between the wind turbine and the core of the NLLJ. For instance, the mean increase in the estimated power production during NLLJ events was about 30 % higher for a turbine at 135 m a.g.l. compared to one at 94 m a.g.l. Our results imply that long NLLJs have an overall stronger impact on the total power production, while short events are primarily relevant as drivers for power ramps.

Improvement of wind power prediction from meteorological characterization with machine learning models

To mitigate uncertainties in wind resource assessments and to improve the estimation of energy production of a wind project, this work uses a decision tree machine learning model to assess the effectiveness of hub-height wind speed, rotor-equivalent wind speed, and lapse rate as variables in power prediction. Atmospheric data is used to train regression trees and correlate the power outputs to wind profiles and meteorological characteristics to be able to predict power responses according to physical patterns. The decision tree model was trained for four vertical wind profile classifications to showcase the need for multiple calculations of wind speed at various levels of the rotor layer. Results indicate that when compared to traditional power curve methods, the decision tree combining rotor-equivalent wind speed and lapse rate improves prediction accuracy by 22% for the given data-set, while also proving to be the most effective method in power prediction for all classified vertical wind profile types. Models incorporating lapse rate into predictions performed better than those without it, showing the importance of considering atmospheric criteria in wind power prediction analyses.

Configuration of Statistical Postprocessing Techniques for Improved Low-Level Wind Speed Forecasts in West Texas

Abstract The wind energy industry needs accurate forecasts of wind speeds at turbine hub height and in the rotor layer to accurately predict power output from a wind farm. Current numerical weather prediction (NWP) models struggle to accurately predict low-level winds, partially due to systematic errors within the models due to deficiencies in physics parameterization schemes. These types of errors are addressed in this study with two statistical postprocessing techniques—model output statistics (MOS) and the analog ensemble (AnEn)—to understand the value of each technique in improving rotor-layer wind forecasts. This study is unique in that it compares the techniques using a sonic detection and ranging (SODAR) wind speed dataset that spans the entire turbine rotor layer. This study uses reforecasts from the Weather Research and Forecasting (WRF) Model and observations in west Texas over periods of up to two years to examine the skill added to forecasts when applying both MOS and the AnEn. Different aspects of the techniques are tested, including model horizontal and vertical resolution, number of predictors, and training set length. Both MOS and the AnEn are applied to several levels representing heights in the turbine rotor layer (40, 60, 80, 100, and 120 m). This study demonstrates the degree of improvement that different configurations of each technique provides to raw WRF forecasts, to help guide their use for low-level wind speed forecasts. It was found that both AnEn and MOS show significant improvement over the raw WRF forecasts, but the two methods do not differ significantly from each other.

Influence of Magnetic and Nonmagnetic Layers in an Axially Laminated Anisotropic Rotor of a High-Speed Synchronous Reluctance Motor Including Manufacturing Aspects

The impact of the thickness of the magnetic and nonmagnetic layers in an axially laminated anisotropic (ALA) rotor in a synchronous reluctance motor (SynRM) aimed at high-speed applications was studied. Considering possible manufacturing issues, the layers are desired to be thick rather than thin. At the same time, the layer thickness is related to the electromagnetic capabilities of the ALASynRM. In the study, a 12 kW ALASynRM was considered. As a reference, a 12 kW IM with a smooth solid rotor with copper end rings was used for comparison with the designed ALASynRM. The manufacturing procedures of an ALA rotor with certain materials were verified in practice. Strength tests of the samples were implemented showing the suitability of the selected materials for application in the prototype. In the electromagnetic design, the thickness of the ALA rotor layers has shown to have a significant impact on the rotor eddy current losses. The stator iron losses and the winding Joule losses also depend on the rotor design. Torque ripple is considerably affected by the thickness of the rotor layers and their position in relation to the stator slots.

The Effects of Wind Veer During the Morning and Evening Transitions

Direction and speed wind shear modify turbine performance by changing inflow conditions on turbine blades. Using observations from the 2013 CWEX campaign, we found the daily atmospheric boundary layer transitions (morning and evening) match periods of high electricity demand for a wind farm in central Iowa. Power production during these periods was undermined for large direction shear and low speed shear scenarios. The morning transition displayed larger direction shear over the rotor layer for most wind speeds compared to the evening period. This resulted in lower turbine performance for the morning compared to the evening and whole day. This study shows that the combined effect of direction and speed shear is affecting turbine operation during high electricity demand times of day, predominantly during the morning at this wind farm.

Synchronous Reluctance Motors With an Axially Laminated Anisotropic Rotor as an Alternative in High-Speed Applications

The performance capabilities of an axially laminated anisotropic rotor (ALA) in a high-speed synchronous reluctance motor (SynRM) were studied. A 12 kW ALASynRM was designed as an alternative to a high-speed induction motor (IM) with a solid rotor. The electromagnetic design was implemented taking into account possible issues related to the new manufacturing methods, which require thicker rotor layers than in a typical ALA. The ALASynRM shows a higher efficiency than the corresponding IM with a smooth or slitted solid rotor equipped with copper end rings. To verify the design method, a prototype IM with a smooth solid rotor was built and tested. In the analysis, it was found that, similar to IMs, in an ALASynRM a considerable part of losses takes place in the rotor despite the absence of slip-related losses in the SynRM. The distribution of eddy current losses in the ALA rotor is significantly uneven. The torque ripple in the ALASynRM is considerably larger than the corresponding ripple in IMs.

Spatial Variability of Winds and HRRR–NCEP Model Error Statistics at Three Doppler-Lidar Sites in the Wind-Energy Generation Region of the Columbia River Basin

AbstractAnnually and seasonally averaged wind profiles from three Doppler lidars were obtained from sites in the Columbia River basin of east-central Oregon and Washington, a major region of wind-energy production, for the Second Wind Forecast Improvement Project (WFIP2) experiment. The profile data are used to quantify the spatial variability of wind flows in this area of complex terrain, to assess the HRRR–NCEP model’s ability to capture spatial and temporal variability of wind profiles, and to evaluate model errors. Annually averaged measured wind speed differences over the 70-km extent of the lidar measurements reached 1 m s−1 within the wind-turbine rotor layer, and 2 m s−1 for 200–500 m AGL. Stronger wind speeds in the lowest 500 m occurred at sites higher in elevation, farther from the river, and farther west—closer to the Cascade Mountain barrier. Validating against the lidar data, the HRRR model underestimated strong wind speeds (>12 m s−1) and, consequently, their frequency of occurrence, especially at the two lowest-elevation sites, producing annual low biases in rotor-layer wind speed of 0.5 m s−1. The RMSE between measured and modeled winds at all sites was about 3 m s−1 and did not degrade significantly with forecast lead time. The nature of the model errors was different for different seasons. Moreover, although the three sites were located in the same basin terrain, the nature of the model errors was different at each site. Thus, if only one of the sites had been instrumented, different conclusions would have been drawn as to the major sources of model error, depending on where the measurements were made.

The effect of surface roughness on rotor-stator cavity flows

We are concerned with the CFD simulation of annular rotor-stator cavities using the general purpose second-order finite volume method (FVM) solver OpenFOAM® and Large Eddy Simulation (LES) methods. Simulations of cavities with smooth surfaces are conducted at various Reynolds numbers, and the properties of the mean turbulent flows are validated against experimental and numerical data available in the literature. Comparisons show that second-order accurate FVM approaches can produce high-fidelity simulations of rotor-stator cavities to an acceptable accuracy and are therefore a viable alternative to the computationally intensive high-order methods. Our validated second-order FVM model is then combined with the parametric force approach of Busse and Sandham [“Parametric forcing approach to rough-wall turbulent channel flow,” J. Fluid Mech. 712, 169–202 (2012)] to simulate cavities with a rough rotor surface. Detailed flow visualisations suggest that roughness-induced disturbances propagate in the downstream direction of the rotor flow toward the outer wall of the cavity. The outer wall subsequently provides a passage to transport said roughness effects from the rough rotor layer to the smooth stator layer. We demonstrate that rotor-stator cavity flows are sensitive to even small roughness levels on the rotor surface alone.

CFD analyses of liquid flow characteristics in a rotor-stator reactor

Rotor-stator reactor (RSR) is a novel device for the intensification of multiphase processes and can greatly boost mass transfer and mixing efficiency. However, due to the unique structure, the flow characteristics in the RSR is unknown and difficult to acquire by experiments. Therefore, this work employed computational fluid dynamics (CFD) technique to reveal liquid flow behaviors in an RSR for the first time. The volume of fluid (VOF) multiphase model, sliding model (SM) and standard k–ε model were used to simulate liquid flow field in a typical two-dimensional computational framework of the RSR. It was found that the droplet size and velocity in the cavity zone of the RSR were in agreement with the published data of the visual experiments. The results show that the liquid was quickly split and synchronized with the motion of the rotor layers when injected into the RSR. Two droplet formation schemes were observed in the RSR: “ligament to droplets disintegration” and “droplets disintegration”. The droplets size distribution could be well described by Rosin–Rammler model. The droplets diameter decreased but the droplet velocity increased with increasing rotational speed, while the droplets diameter increased and the droplet velocity changed little with increasing liquid inlet velocity. With the increase of the number of rotor/stator layers, droplet size decreased and velocity increased. The agreement of the experiment and simulation results indicate that the CFD technique is an effective tool to analyze the hydrodynamic characteristics of RSR.

Assessment of NWP Forecast Models in Simulating Offshore Winds through the Lower Boundary Layer by Measurements from a Ship-Based Scanning Doppler Lidar

Evaluation of model skill in predicting winds over the ocean was performed by comparing retrospective runs of numerical weather prediction (NWP) forecast models to shipborne Doppler lidar measurements in the Gulf of Maine, a potential region for U.S. coastal wind farm development. Deployed on board the NOAA R/V Ronald H. Brown during a 2004 field campaign, the high-resolution Doppler lidar (HRDL) provided accurate motion-compensated wind measurements from the water surface up through several hundred meters of the marine atmospheric boundary layer (MABL). The quality and resolution of the HRDL data allow detailed analysis of wind flow at heights within the rotor layer of modern wind turbines and data on other critical variables to be obtained, such as wind speed and direction shear, turbulence, low-level jet properties, ramp events, and many other wind-energy-relevant aspects of the flow. This study will focus on the quantitative validation of NWP models’ wind forecasts within the lower MABL by comparison with HRDL measurements. Validation of two modeling systems rerun in special configurations for these 2004 cases—the hourly updated Rapid Refresh (RAP) system and a special hourly updated version of the North American Mesoscale Forecast System [NAM Rapid Refresh (NAMRR)]—are presented. These models were run at both normal-resolution (RAP, 13 km; NAMRR, 12 km) and high-resolution versions: the NAMRR-CONUS-nest (4 km) and the High-Resolution Rapid Refresh (HRRR, 3 km). Each model was run twice: with (experimental runs) and without (control runs) assimilation of data from 11 wind profiling radars located along the U.S. East Coast. The impact of the additional assimilation of the 11 profilers was estimated by comparing HRDL data to modeled winds from both runs. The results obtained demonstrate the importance of high-resolution lidar measurements to validate NWP models and to better understand what atmospheric conditions may impact the accuracy of wind forecasts in the marine atmospheric boundary layer. Results of this research will also provide a first guess as to the uncertainties of wind resource assessment using NWP models in one of the U.S. offshore areas projected for wind plant development.

Gusts and shear within hurricane eyewalls can exceed offshore wind turbine design standards

AbstractOffshore wind energy development is underway in the U.S., with proposed sites located in hurricane‐prone regions. Turbine design criteria outlined by the International Electrotechnical Commission do not encompass the extreme wind speeds and directional shifts of hurricanes stronger than category 2. We examine a hurricane's turbulent eyewall using large‐eddy simulations with Cloud Model 1. Gusts and mean wind speeds near the eyewall of a category 5 hurricane exceed the current Class I turbine design threshold of 50 m s−1 mean wind and 70 m s−1 gusts. Largest gust factors occur at the eye‐eyewall interface. Further, shifts in wind direction suggest that turbines must rotate or yaw faster than current practice. Although current design standards omit mention of wind direction change across the rotor layer, large values (15–50°) suggest that veer should be considered.

Observing and Simulating Wind-Turbine Wakes During the Evening Transition

Wind-turbine-wake evolution during the evening transition introduces variability to wind-farm power production at a time of day typically characterized by high electricity demand. During the evening transition, the atmosphere evolves from an unstable to a stable regime, and vertical stratification of the wind profile develops as the residual planetary boundary layer decouples from the surface layer. The evolution of wind-turbine wakes during the evening transition is examined from two perspectives: wake observations from single turbines, and simulations of multiple turbine wakes using the mesoscale Weather Research and Forecasting (WRF) model. Throughout the evening transition, the wake’s wind-speed deficit and turbulence enhancement are confined within the rotor layer when the atmospheric stability changes from unstable to stable. The height variations of maximum upwind-downwind differences of wind speed and turbulence intensity gradually decrease during the evening transition. After verifying the WRF-model-simulated upwind wind speed, wind direction and turbulent kinetic energy profiles with observations, the wind-farm-scale wake evolution during the evening transition is investigated using the WRF-model wind-farm parametrization scheme. As the evening progresses, due to the presence of the wind farm, the modelled hub-height wind-speed deficit monotonically increases, the relative turbulence enhancement at hub height grows by 50%, and the downwind surface sensible heat flux increases, reducing surface cooling. Overall, the intensifying wakes from upwind turbines respond to the evolving atmospheric boundary layer during the evening transition, and undermine the power production of downwind turbines in the evening.

Properties of the offshore low level jet and rotor layer wind shear as measured by scanning Doppler Lidar

AbstractThe atmospheric flow phenomenon known as the Low Level Jet (LLJ) is an important source of wind power production in the Great Plains. However, due to the lack of measurements with the precision and vertical resolution needed, particularly at rotor heights, it is not well‐characterized or understood in offshore regions being considered for wind‐farm development.The present paper describes the properties of LLJs and wind shear through the rotor layer of a hypothetical wind turbine, as measured from a ship‐borne Doppler lidar in the Gulf of Maine in July–August 2004.LLJs, frequently observed below 600 m, were mostly during nighttime and transitional periods, but they were also were seen during some daytime hours. The presence of a LLJ significantly modified wind profiles producing vertical wind speed shear. When the wind shear was strong, the estimates of wind power based upon wind speeds measured at hub‐height could have significant errors. Additionally, the inference of hub‐height winds from near‐surface measurements may introduce further error in the wind power estimate. The lidar dataset was used to investigate the uncertainty of the simplified power‐law relation that is often employed in engineering approaches for the extrapolation of surface winds to higher elevations. The results show diurnal and spatial variations of the shear exponent empirically found from surface and hub‐height measurements.Finally, the discrepancies between wind power estimates using lidar‐measured hub‐height winds and rotor equivalent winds are discussed. Copyright © 2016 John Wiley & Sons, Ltd.

Electromagnetic Modeling and Analysis of Can Effect of a Canned Induction Electrical Machine

The can shields in airgap characterize a canned electrical machine as a hydraulic pump drive. This paper studies modeling and characterization of the can effect. To analyze electromagnetic field on can shields, followed by can loss, an analytical model is proposed. Such a model is of concentric cylindrical rotor layer structure with the slotting effect and magnetic saturation. This work is performed by comparing an ordinary induction machine with a canned version. Based on differences of airgap flux distribution, iron loss due to the can effect is analyzed. Then, the can loss and harmonics under typical operating condition are analyzed. The can loss calculation determined by magnetic saturation is discussed. Finite element method and measurement are used as reference.

Improving Maryland’s Offshore Wind Energy Resource Estimate Using Doppler Wind Lidar Technology to Assess Microtmeteorology Controls

There is enormous potential to harness the kinetic energy of offshore wind and produce power. However significant uncertainties are introduced in the offshore wind resource assessment process, due in part to limited observational networks and a poor understanding of the marine atmosphere’s complexity. Given the cubic relationship between a turbine’s power output and wind speed, a relatively small error in the wind speed estimate translates to a significant error in expected power production. The University of Maryland Baltimore County (UMBC) collected in-situ measurements offshore, within Maryland’s Wind Energy Area (WEA) from July-August 2013. This research demonstrates the ability of Doppler wind lidar technology to reduce uncertainty in estimating an offshore wind resource, compared to traditional resource assessment techniques, by providing a more accurate representation of the wind profile and associated hub-height wind speed variability. The second objective of this research is to elucidate the impact of offshore micrometeorology controls (stability, wind shear, turbulence) on a turbine’s ability to produce power.Compared to lidar measurements, power law extrapolation estimates and operational National Weather Service models underestimated hub-height wind speeds in the WEA. In addition, lidar observations suggest the frequent development of a low-level wind maximum (LLWM), with high turbinelayer wind shear and low turbulence intensity within a turbine’s rotor layer (40m-160m). Results elucidate the advantages of using Doppler wind lidar technology to improve offshore wind resource estimates and its ability to monitor under-sampled offshore meteorological controls impact on a potential turbine’s ability to produce power.