scholarly journals Flight Altitudes of Raptors in Southern Africa Highlight Vulnerability of Threatened Species to Wind Turbines

2021 ◽  
Vol 9 ◽  
Author(s):  
Christopher J. W. McClure ◽  
Leah Dunn ◽  
Jennifer D. McCabe ◽  
Brian W. Rolek ◽  
André Botha ◽  
...  

Energy infrastructure, particularly for wind power, is rapidly expanding in Africa, creating the potential for conflict with at-risk wildlife populations. Raptor populations are especially susceptible to negative impacts of fatalities from wind energy because individuals tend to be long-lived and reproduce slowly. A major determinant of risk of collision between flying birds and wind turbines is the altitude above ground at which a bird flies. We examine 18,710 observations of flying raptors recorded in southern Africa and we evaluate, for 49 species, the frequency with which they were observed to fly at the general height of a wind turbine rotor-swept zone (50–150 m). Threatened species, especially vultures, were more likely to be observed at turbine height than were other species, suggesting that these raptors are most likely to be affected by wind power development across southern Africa. Our results highlight that threatened raptor species, particularly vultures, might be especially impacted by expanded wind energy infrastructure across southern Africa.

1995 ◽  
Vol 117 (3) ◽  
pp. 200-204 ◽  
Author(s):  
K. Pierce ◽  
A. C. Hansen

The Beddoes-Leishman model for unsteady aerodynamics and dynamic stall has recently been implemented in YawDyn, a rotor analysis code developed at the University of Utah for the study of yaw loads and motions of horizontal axis wind turbines. This paper presents results obtained from validation efforts for the Beddoes model. Comparisons of predicted aerodynamic force coefficients with wind tunnel data and data from the combined experiment rotor are presented. Also, yaw motion comparisons with the combined experiment rotor are presented. In general the comparisons with the measured data are good, indicating that the model is appropriate for the conditions encountered by wind turbines.


2014 ◽  
Vol 21 ◽  
pp. 78
Author(s):  
Samuel S. Webster

This paper analyzes the impact of the federal Production Tax Credit on the development of wind energy in the US. Following an analysis of the incentives these policies produce for wind energy generation and integration, this paper finds that, although the Production Tax Credit has proven effective at promoting some level of wind power development, the effectiveness of the Production Tax Credit varies by region and by itself is unlikely to achieve the deep levels of wind power penetration desired by some policymakers and the U.S. Department of Energy.


Inventions ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 59
Author(s):  
Hasanali Khojasteh ◽  
Younes Noorollahi ◽  
Mojtaba Tahani ◽  
Mehran Masdari

Nowadays, by increasing energy demand and considering the importance of environmental issues in recent decades, the use of renewable energies is expanding. Among renewable energies, wind power and its technology are growing and evolving more rapidly. Resource assessment in Iran has revealed the significant potential of wind energy around the country. To further develop wind energy in the country and create large-scale wind power plants, the consideration of distributed power generation using small wind turbines for applications in agricultural and residential use is needed. Conventional small wind turbines and small wind lens turbines have been developed in recent years. In this research project, a small wind lens turbine is designed. The advantages of this turbine are an increased production capacity and reduced cut-in speed and noise pollution. In this study, a lens (or shroud) is added to a small turbine, and the maximized annual energy production (AEP) and minimization of the levelized cost of energy (LCOE) are modeled. We applied the NSGA-II algorithm for optimization to find the best answer. The input parameters in the objective function of the AEP are cut-in, cut-out, rated speeds, scale factor, and shape factor. Additionally, the input parameters in the objective function of the LCOE are the power production, initial capital cost, annual operating expenses, and balance of energy. The results indicate that installing a wind lens turbine in Kish Island led to an LCOE decrease of 56% on average, and we can see an 83% increase in the AEP. In the Firoozkooh area, an average reduction of 59% in the LCOE and 74% increase in the AEP for a wind lens turbine is observed.


Author(s):  
Sayem Zafar ◽  
Mohamed Gadalla

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.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Dieniar N Ramadhani

Much human energy needs are obtained from fossil fuels. This fossil energy is decreasing day by day. So that the utilization of natural energy such as solar energy, water energy and wind energy is being developed. Wind energy is energy that we can find, so it is very easy to use by using a turbine as the driving force. The vertical axis wind turbine is a type of wind turbine that is easier to apply in places where wind potential is not too large. This research was conducted by means of simulation using Qblade v0.963 software by comparing the influence generated from several numbers of wind turbine rotor blades. From the simulation process, it is known that the wind turbine rotor blades with 4 blades are the wind turbines capable of producing the greatest power, which is 75 Watts at a low TSR. So that in the manufacturing process it does not require large costs, but it still has to be built rigid and solidly.


Author(s):  
Youjin Kim ◽  
Ali Al-Abadi ◽  
Antonio Delgado

This study introduces strategic methods for improving the aerodynamic performance of wind turbines. It was completed by combining different optimization methods for each part of the wind turbine rotor. The chord length and pitch angle are optimized by a torque-matched method (TMASO), whereas the airfoil shape is optimized by the genetic algorithm (GA). The TMASO is implemented to produce an improved design of a reference turbine (NREL UAE Phase V). The GA is operated to generate a novel airfoil design that is evaluated by automatic interfacing for the highest gliding ratio (GR). The adopted method produces an optimized wind turbine with an 11% increase of power coefficient (Cp) with 30% less of the corresponding tip speed ratio (TSR). Furthermore, the optimized wind turbine shows reduced tip loss effect.


Author(s):  
B K Kirke

Improvements in technology have reduced the unit cost of wind–electric power systems by almost an order of magnitude since 1981, and installed wind power capacity is growing rapidly world-wide. Paradoxically, the use of wind-powered pumping systems, formerly the major application of wind power, is declining and little progress has been made towards the direct application of wind power to drive other mechanical loads such as aerators and compressors for heat pumps, despite huge potential markets in areas remote from electricity grids. A major reason for this failure to apply improved wind turbine technology to non-electrical loads is low system efficiency resulting from poor torque matching between the wind turbine rotor and the load. Methods of improving system efficiency are reviewed, including load-disengaging devices to permit easy starting and a simple mechanical control system for a variable ratio drive which would ensure that any wind turbine driving any load will operate near peak efficiency over the full operating range from cut-in to governing. The latter system could improve average system efficiency by a factor of 3 to 8 and has the further advantage that it can provide starting torque and can actuate overspeed control for Darrieus vertical axis wind turbines and low-solidity horizontal axis wind turbines.


Rangifer ◽  
2004 ◽  
Vol 24 (2) ◽  
pp. 55-66 ◽  
Author(s):  
Kjetil Flydal ◽  
Sindre Eftestøl ◽  
Eigil Reimers ◽  
Jonathan E. Colman

In recent decades, industrial developments have expanded into reindeer ranges in the arctic and adjacent higher latitudes in search for energy, minerals, timber and other resources. Several wind turbine parks are under planning in reindeer ranges in Norway, and there is concern about possible negative effects on behaviour and area use of wild and semi-domestic reindeer. We tested whether a wind turbine and its rotor movement had any effect on area use, activity changes, vigilance bouts, and restless behaviour like running, walking, and standing for enclosed semi-domestic reindeer. Five different groups of reindeer in a 450 m long, 8 hectare, enclosure close to a wind turbine were manipulated by turning the wind turbine rotor on and off, and compared with reindeer in a control enclosure without wind turbine exposure. When exposed to rotor movement, two groups used locations farther from the wind turbine, two groups showed no shift, while one group moved closer to the wind turbine. The reindeer showed no systematic differences in the measured behaviour patterns between the two enclosures that could indicate fright or stress as a consequence of the wind turbine or rotor movement. We conclude that semi-domestic reindeer in an enclosure showed no negative behavioural response and little or no aversion towards a wind turbine. The possibility of rapid habituation in a small enclosure with continuous wind turbine exposure suggests that effects on area use should be studied at a larger scale or with free-ranging reindeer.Abstract in Norwegian / Sammendrag:I løpet av de senere tiår har industriell utbygging til utnytting av energi, mineraler, tømmer og andre ressurser ekspandert inn i reinens beiteområder i nordområdene. Flere vindmølleparker er under planlegging i norske reinbeiteområder, og det spekuleres i mulige konsekvenser av disse på atferd og arealbruk hos villrein og tamrein. Vi testet om en vindmølle og dens rotorbevegelse hadde noen effekt på arealbruk, aktivitetsskifter, vaktsomhetsatferd, og rastløshetsatferd i form av løp, gange og ståing for tamrein i innhegning. I en 450 m lang innhegning på 8 hektar som var plassert tett opp til en vindmølle, ble fem forskjellig grupper av reinsdyr manipulert ved å slå vindmøllerotoren av og på. Reinsdyrene i innhegningen ved vindmøllen ble sammenlignet med reinsdyr i en kontrollinnhegning som var uten påvirkning fra vindmøller. Når reinsdyrene ble utsatt for vindmøllerotoren i bevegelse, viste to grupper av dyr et skifte i arealbruk til områder av innhegningen som var lenger unna møllen, to grupper av dyr viste ikke noe skifte i arealbruk, mens en gruppe dyr beveget seg nærmere vindmøllen. Sammenligning av atferden hos reinsdyrene i vindmølleinnhegningen og kontrollinnhegningen viste ingen systematisk forskjell som kunne indikere frykt eller stress som en effekt av vindmøllen eller rotorbevegelsen. Vi konkluderer med at tamrein i innhegning ikke viser negative atferdsresponser og viser lite eller ingen reduksjon i arealbruken tett opp til en vindmølle. Muligheten for at det skjer en rask tilvenning i en liten innhegning der dyrene er i kontinuerlig påvirkning av vindmøllen betyr at effekter på arealbruk bør studeres i et større arealperspektiv eller på frittgående rein.


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