Skill and Potential Economic Value of Forecasts of Ice Accretion on Wind Turbines

2020 ◽  
Vol 59 (11) ◽  
pp. 1845-1864
Author(s):  
Lukas Strauss ◽  
Stefano Serafin ◽  
Manfred Dorninger
Keyword(s):  
High Resolution ◽  
Wind Turbines ◽  
Low Cost ◽  
Turbine Blades ◽  
Economic Value ◽  
Wind Farms ◽  
Model Verification ◽  
Limited Area ◽  
Ice Accretion ◽  
Probabilistic Forecasts

AbstractIn this paper, a verification study of the skill and potential economic value of forecasts of ice accretion on wind turbines is presented. The phase of active ice formation on turbine blades has been associated with the strongest wind power production losses in cold climates; however, skillful icing forecasts could permit taking protective measures using anti-icing systems. Coarse- and high-resolution forecasts for the range up to day 3 from global (IFS and GFS) and limited-area (WRF) models are coupled to the Makkonen icing model. Surface and upper-air observations and icing measurements at turbine hub height at two wind farms in central Europe are used for model verification over two winters. Two case studies contrasting a correct and an incorrect forecast highlight the difficulty of correctly predicting individual icing events. A meaningful assessment of model skill is possible only after bias correction of icing-related parameters and selection of model-dependent optimal thresholds for ice growth rate. The skill of bias-corrected forecasts of freezing and humid conditions is virtually identical for all models. Hourly forecasts of active ice accretion generally show limited skill; however, results strongly suggest the superiority of high-resolution WRF forecasts relative to other model variants. Predictions of the occurrence of icing within a period of 6 h are found to have substantially better accuracy. Probabilistic forecasts of icing that are based on gridpoint neighborhood ensembles show slightly higher potential economic value than forecasts that are based on individual gridpoint values, in particular at low cost-loss ratios, that is, when anti-icing measures are comparatively inexpensive.

scholarly journals Review of Wind Turbine Icing Modelling Approaches

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5207 ◽  
Author(s):  
Fahed Martini ◽  
Leidy Tatiana Contreras Montoya ◽  
Adrian Ilinca
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Low Cost ◽  
Turbine Blades ◽  
Experimental Tests ◽  
Ice Accretion ◽  
Wind Turbine Blades ◽  
Additional Section ◽  
Research Findings

When operating in cold climates, wind turbines are vulnerable to ice accretion. The main impact of icing on wind turbines is the power losses due to geometric deformation of the iced airfoils of the blades. Significant energy losses during the wind farm lifetime must be estimated and mitigated. Finding solutions for icing calls on several areas of knowledge. Modelling and simulation as an alternative to experimental tests are primary techniques used to account for ice accretion because of their low cost and effectiveness. Several studies have been conducted to replicate ice growth on wind turbine blades using Computational Fluid Dynamics (CFD) during the last decade. While inflight icing research is well developed and well documented, wind turbine icing is still in development and has its peculiarities. This paper surveys and discusses the models, approaches and methods used in ice accretion modelling in view of their application in wind energy while summarizing the recent research findings in Surface Roughness modelling and Droplets Trajectory modelling. An An additional section discusses research on the modelling of electro-thermal icing protection systems. This paper aims to guide researchers in wind engineering to the appropriate approaches, references and tools needed to conduct reliable icing modelling for wind turbines.

Reliability, Availability, Maintainability (RAM) for Wind Turbines

2017 ◽  
Author(s):  
Nikhil Kumar ◽  
David Rogers ◽  
Thomas D. Burnett ◽  
Eric Sullivan ◽  
Martin Gascon
Keyword(s):  
Wind Turbines ◽  
Low Cost ◽  
Rapid Development ◽  
Turbine Blades ◽  
Wind Farms ◽  
Cost Effective ◽  
Wind Turbine Blades ◽  
Unique Challenge ◽  
Operational Risks ◽  
Reliability And Availability

Wind based electric generation is one of the fastest growing energy sources in the world. With rapid development of wind farms, many challenges have emerged with respect to the reliability and availability of the in-service equipment. Additionally, with increasing size of wind turbine blades, both onshore and offshore, the serviceability and maintainability of the equipment poses its own unique challenge. There is also an inherent risk from the economics of energy production, which dictates that low-cost manufacturing methods are employed to produce cost-effective machines. In our experience, there are additional risks associated with supply chains and limited availability and understanding of damage mechanisms and reliability data of the myriad manufacturers and models of turbines, blade design and associated equipment. Failure of different components results in different outage times and therefore impact operational and maintenance (O&M) costs in different ways. Achieving high availability targets requires a robust O&M plan. The authors will highlight operational risks of large wind turbines and methodologies to improve reliability and availability for wind farms.

scholarly journals Wind turbine icing characteristics and icing-induced power losses to utility-scale wind turbines

2021 ◽  
Vol 118 (42) ◽  
pp. e2111461118
Author(s):  
Linyue Gao ◽  
Hui Hu
Keyword(s):  
Wind Turbines ◽  
Power Output ◽  
Turbine Blades ◽  
Digital Camera ◽  
Unmanned Aircraft ◽  
Ice Accretion ◽  
Power Losses ◽  
Field Campaign ◽  
Output Losses ◽  
Utility Scale

A field campaign was carried out to investigate ice accretion features on large turbine blades (50 m in length) and to assess power output losses of utility-scale wind turbines induced by ice accretion. After a 30-h icing incident, a high-resolution digital camera carried by an unmanned aircraft system was used to capture photographs of iced turbine blades. Based on the obtained pictures of the frozen blades, the ice layer thickness accreted along the blades’ leading edges was determined quantitatively. While ice was found to accumulate over whole blade spans, outboard blades had more ice structures, with ice layers reaching up to 0.3 m thick toward the blade tips. With the turbine operating data provided by the turbines’ supervisory control and data acquisition systems, icing-induced power output losses were investigated systematically. Despite the high wind, frozen turbines were discovered to rotate substantially slower and even shut down from time to time, resulting in up to 80% of icing-induced turbine power losses during the icing event. The research presented here is a comprehensive field campaign to characterize ice accretion features on full-scaled turbine blades and systematically analyze detrimental impacts of ice accumulation on the power generation of utility-scale wind turbines. The research findings are very useful in bridging the gaps between fundamental icing physics research carried out in highly idealized laboratory settings and the realistic icing phenomena observed on utility-scale wind turbines operating in harsh natural icing conditions.

Design and Evaluation of a Rooftop Wind Turbine Rotor With Untwisted Blades

2013 ◽  
Author(s):  
Sayem Zafar ◽  
Mohamed Gadalla
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Low Cost ◽  
Turbine Blades ◽  
Angle Of Attack ◽  
Turbine Rotor ◽  
Wind Turbine Blades ◽  
Wind Speeds ◽  
Small Wind Turbines ◽  
Wind Turbine Rotor

A small horizontal axis wind turbine rotor was designed and tested with aerodynamically efficient, economical and easy to manufacture blades. Basic blade aerodynamic analysis was conducted using commercially available software. The blade span was constrained such that the complete wind turbine can be rooftop mountable with the envisioned wind turbine height of around 8 m. The blade was designed without any taper or twist to comply with the low cost and ease of manufacturing requirements. The aerodynamic analysis suggested laminar flow airfoils to be the most efficient airfoils for such use. Using NACA 63-418 airfoil, a rectangular blade geometry was selected with chord length of 0.27[m] and span of 1.52[m]. Glass reinforced plastic was used as the blade material for low cost and favorable strength to weight ratio with a skin thickness of 1[mm]. Because of the resultant velocity changes with respect to the blade span, while the blade is rotating, an optimal installed angle of attack was to be determined. The installed angle of attack was required to produce the highest possible rotation under usual wind speeds while start at relatively low speed. Tests were conducted at multiple wind speeds with blades mounted on free rotating shaft. The turbine was tested for three different installed angles and rotational speeds were recorded. The result showed increase in rotational speed with the increase in blade angle away from the free-stream velocity direction while the start-up speeds were found to be within close range of each other. At the optimal angle was found to be 22° from the plane of rotation. The results seem very promising for a low cost small wind turbine with no twist and taper in the blade. The tests established that non-twisted wind turbine blades, when used for rooftop small wind turbines, can generate useable electrical power for domestic consumption. It also established that, for small wind turbines, non-twisted, non-tapered blades provide an economical yet productive alternative to the existing complex wind turbine blades.

Development of wireless bird collision monitoring system using 0-3 piezoelectric composite sensor on wind turbine blades

2017 ◽  
Vol 29 (17) ◽  
pp. 3426-3435
Author(s):  
Sang-Hyeon Kang ◽  
Lae-Hyong Kang
Keyword(s):  
Wind Turbine ◽  
Monitoring System ◽  
Wind Turbines ◽  
Turbine Blades ◽  
Wind Farms ◽  
Clean Energy ◽  
Piezoelectric Composite ◽  
Collision Rate ◽  
Wind Turbine Blades ◽  
The Impact

Over the past several decades, wind turbines have been established as one of the promising renewable energy systems for safe and clean energy collection. In order to collect more energy efficiently, the size of wind turbines has been increased and many wind farms have been constructed. Wind farms generate lots of energy, but they cause several side effects, such as noise and a threat to wildlife. It is reported that the bird collision rate of a wind turbine ranges from 0.01 to 23 annually. It is more serious in the case of rare and endangered birds. In order to monitor the effect on birds in wind farms, researchers have developed remote sensing technology for a detection apparatus using heat and radar. In addition, paint color and other variables have been studied regarding their effects on the collision rate. However, the existing methods are passive ways to prevent bird collision or just monitor bird conditions. Therefore, in this study, we propose a bird collision monitoring system that can detect where the bird collision occurred, which will aid in rescuing the birds. If the wind turbine blade has its own ability to capture an impact signal, the impact location can be easily detected, and the birds can be rescued. For this purpose, piezoelectric paint was applied to the wind turbine blades used in this study. The piezoelectric paint is also known as 0-3 piezoelectric composite, which is composed of piezoelectric particles and polymer resin. It is sensitive to high-frequency signals such as impacts, so it is suitable for monitoring bird collision signals. In order to amplify and transmit the impact signal from the rotating blade to a stationary base, a wireless transmission device using a ZigBee module and signal conditioning circuit was also installed. Through lab-scale tests, it was confirmed that this bird collision monitoring system shows a 100% bird collision detection rate.

scholarly journals Statistical Postprocessing and Multivariate Structuring of High-Resolution Ensemble Precipitation Forecasts

2018 ◽  
Vol 19 (11) ◽  
pp. 1815-1833 ◽  
Author(s):  
Chiem van Straaten ◽  
Kirien Whan ◽  
Maurice Schmeits
Keyword(s):  
High Resolution ◽  
Land Surface ◽  
Deep Convection ◽  
Winter Season ◽  
End Users ◽  
Ensemble Prediction ◽  
High Dimensional ◽  
Limited Area ◽  
Ensemble Prediction System ◽  
Probabilistic Forecasts

A comparison of statistical postprocessing methods is performed for high-resolution precipitation forecasts. We keep hydrological end users in mind and thus require that the systematic errors of probabilistic forecasts are corrected and that they show a realistic high-dimensional spatial structure. The most skillful forecasts of 3-h accumulated precipitation in 3 × 3 km2 grid cells covering the land surface of the Netherlands were made with a nonparametric method [quantile regression forests (QRF)]. A parametric alternative [zero-adjusted gamma distribution (ZAGA)] corrected the precipitation forecasts of the short-range Grand Limited Area Model Ensemble Prediction System (GLAMEPS) up to +60 h less well, particularly at high quantiles, as verified against calibrated precipitation radar observations. For the subsequent multivariate restructuring, three empirical methods, namely, ensemble copula coupling (ECC), the Schaake shuffle (SSh), and a recent minimum-divergence sophistication of the Schaake shuffle (MDSSh), were tested and verified using both the multivariate variogram skill score (VSS) and the continuous ranked probability score (CRPS), the latter after aggregating the forecasts spatially. ECC and MDSSh were more skillful than SSh in terms of the CRPS and the VSS. ECC performed somewhat worse than MDSSh for summer afternoon and evening periods, probably due to the worse representation of deep convection in the hydrostatic GLAMEPS compared to reality. Overall, the high-resolution postprocessing comparison shows that skill for local precipitation amounts improves up to the 98th percentile in both the summer and winter season and that the high-dimensional joint distribution can successfully be restructured. Forecasting products like this enable multiple end users to derive their own desired aggregations.

Unsteady Flow Analysis Around an Elliptic-Bladed Savonius-Style Wind Turbine

2014 ◽  
Author(s):  
Abhisek Banerjee ◽  
Sukanta Roy ◽  
Prasenjit Mukherjee ◽  
Ujjwal K. Saha
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Low Cost ◽  
Turbine Blades ◽  
Flow Analysis ◽  
Experimental Studies ◽  
Flow Characteristics ◽  
Small Scale ◽  
Circular Design

Although considerable progress has already been achieved in the design of wind turbines, the available technical designs are not yet adequate to develop a reliable wind energy converter especially meant for small-scale applications. The Savonius-style wind turbine appears to be particularly promising for the small-scale applications because of its design simplicity, good starting ability, insensitivity to wind directions, relatively low operating speed, low cost and easy installation. However, its efficiency is reported to be inferior as compared to other wind turbines. Aiming for that, a number of investigations have been carried out to increase the performance of this turbine with various blade shapes. In the recent past, investigations with different blade geometries show that an elliptic-bladed turbine has the potential to harness wind energy more efficiently. In view of this, the present study attempts to assess the performance of an elliptic-bladed Savonius-style wind turbine using 2D unsteady simulations. The SST k-ω turbulence model is used to simulate the airflow over the turbine blades. The power and torque coefficients are calculated at rotating conditions, and the results obtained are validated with the wind tunnel experimental data. Both the computational and experimental studies indicate a better performance with the elliptical blades. Further, the present analysis also demonstrates improved flow characteristics of the elliptic-bladed turbine over the conventional semi-circular design.

scholarly journals Weather response to a large wind turbine array

2010 ◽  
Vol 10 (2) ◽  
pp. 769-775 ◽  
Author(s):  
D. B. Barrie ◽  
D. B. Kirk-Davidoff
Keyword(s):  
Surface Roughness ◽  
Wind Turbines ◽  
General Circulation ◽  
Wind Farm ◽  
Turbine Blades ◽  
Circulation Model ◽  
Wind Farms ◽  
The North ◽  
Roughness Elements ◽  
Electrical Generation

Abstract. Electrical generation by wind turbines is increasing rapidly, and has been projected to satisfy 15% of world electric demand by 2030. The extensive installation of wind farms would alter surface roughness and significantly impact the atmospheric circulation due to the additional surface roughness forcing. This forcing could be changed deliberately by adjusting the attitude of the turbine blades with respect to the wind, which would enable the "management" of a large array of wind turbines. Using a General Circulation Model (GCM), we represent a continent-scale wind farm as a distributed array of surface roughness elements. Here we show that initial disturbances caused by a step change in roughness grow within four and a half days such that the flow is altered at synoptic scales. The growth rate of the induced perturbations is largest in regions of high atmospheric instability. For a roughness change imposed over North America, the induced perturbations involve substantial changes in the track and development of cyclones over the North Atlantic, and the magnitude of the perturbations rises above the level of forecast uncertainty.

scholarly journals Modified Power Curves for Prediction of Power Output of Wind Farms

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1805 ◽  
Author(s):  
Mohsen Vahidzadeh ◽  
Corey D. Markfort
Keyword(s):  
High Resolution ◽  
Wind Speed ◽  
Wind Turbines ◽  
Power Output ◽  
Wind Farm ◽  
Sonic Anemometer ◽  
Wind Farms ◽  
Operating Conditions ◽  
Horizontal Axis Wind Turbine ◽  
Power Curves

Power curves are used to model power generation of wind turbines, which in turn is used for wind energy assessment and forecasting total wind farm power output of operating wind farms. Power curves are based on ideal uniform inflow conditions, however, as wind turbines are installed in regions of heterogeneous and complex terrain, the effect of non-ideal operating conditions resulting in variability of the inflow must be considered. We propose an approach to include turbulence, yaw error, air density, wind veer and shear in the prediction of turbine power by using high resolution wind measurements. In this study, two modified power curves using standard ten-minute wind speed and high resolution one-second data along with a derived power surface were tested and compared to the standard operating curve for a 2.5 MW horizontal axis wind turbine. Data from supervisory control and data acquisition (SCADA) system along with wind speed measurements from a nacelle-mounted sonic anemometer and wind speed measurements from a nearby meteorological tower are used in the models. The results show that all of the proposed models perform better than the standard power curve while the power surface results in the most accurate power prediction.

scholarly journals An Aero-acoustic Noise Distribution Prediction Methodology for Offshore Wind Farms

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 18 ◽  
Author(s):  
Jiufa Cao ◽  
Weijun Zhu ◽  
Xinbo Wu ◽  
Tongguang Wang ◽  
Haoran Xu
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Noise Source ◽  
Acoustic Noise ◽  
Turbine Blades ◽  
Wind Farms ◽  
Noise Generation ◽  
Human Beings ◽  
Wind Turbine Noise

Recently attention has been paid to wind farm noise due to its negative health impact, not only on human beings, but also to marine and terrestrial organisms. The current work proposes a numerical methodology to generate a numerical noise map for a given wind farm. Noise generation from single wind turbines as well as wind farms has its basis in the nature of aerodynamics, caused by the interactions between the incoming turbulent flow and the wind turbine blades. Hence, understanding the mechanisms of airfoil noise generation, demands access to sophisticated numerical tools. The processes of modeling wind farm noise include three steps: (1) The whole wind farm velocity distributions are modelled with an improved Jensen’s wake model; (2) The individual wind turbine’s noise is simulated by a semi-empirical wind turbine noise source model; (3) Propagations of noise from all wind turbines are carried out by solving the parabolic wave equation. In the paper, the wind farm wake effect from the Horns Rev wind farm is studied. Based on the resulted wind speed distributions in the wind farm, the wind turbine noise source and its propagation are simulated for the whole wind farm.

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