Resource Documents: Safety (48 items)
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Author: Palmer, William
Wind turbines are often perceived as benign. This can be attributed to the population majority dwelling in urban locations distant from most wind turbines. Society may understate the risk to individuals living near turbines due to an overstatement of the perceived benefits of turbines, and an understatement of the risk of injury from falling turbine parts, or shed ice. Flaws in risk calculation may be attributed to a less than fully developed safety culture. Indications of this are the lack of a comprehensive industry failure database, and safety limits enabling the industry growth, but not protective of the public. A comprehensive study of wind turbine failures and risks in the Canadian province of Ontario gives data to enable validation of existing failure models. Failure probabilities are calculated, to show risk on personal property, or in public spaces. Repeated failures, and inadequate safety separation show public safety is not currently assured. A method of calculating setbacks from wind turbines to mitigate public risk is shown. Wind turbines with inadequate setbacks can adversely impact public health both directly from physical risk and indirectly by irritation from loss of safe use of property. Physical public safety setbacks are separate from larger setbacks required to prevent irritation from noise and other stressors, particularly when applied to areas of learning, rest and recuperation. The insights provided by this paper can assist the industry to enhance its image and improve its operation, as well as helping regulators set safety guidelines assuring protection of the public.
William K.G. Palmer, Journal of Energy Conservation – 2018;1(1):41-78
Download original document: “Wind Turbine Public Safety Risk, Direct and Indirect Health Impacts”
Author: Sarlak, Hamid; and Sørensen, Jens
Figures 4 to 6 show the results for different-size blade pieces from different-size turbines at different wind speeds and blade tip speeds. For normal tip speeds (figs 4 and 5), the potential blade throw distance for a 2.3-MW turbine was calculated to be ~500 m (1,640 ft) and for a 5-MW turbine ~900 m (2,953 ft). At “extreme” tip speeds (fig 6) the corresponding distances were 800 m (2,625 ft) and 1500 m (4,921 ft).
[ABSTRACT] This paper aims at predicting trajectories of the detached fragments from wind turbines, in order to better quantify consequences of wind turbine failures. The trajectories of thrown objects are attained using the solution to equations of motion and rotation, with the external loads and moments obtained using blade element approach. We have extended an earlier work by taking into account dynamic stall and wind variations due to shear, and investigated different scenarios of throw including throw of the entire or a part of blade, as well as throw of accumulated ice on the blade. Trajectories are simulated for modern wind turbines ranging in size from 2 to 20 MW using upscaling laws. Extensive parametric analyses are performed against initial release angle, tip speed ratio, detachment geometry, and blade pitch setting. It is found that, while at tip speeds of about 70 m/s [157 mph] (normal operating conditions), pieces of blade (with weights in the range of approximately 7-16 ton) would be thrown out less than 700 m for the entire range of wind turbines, and turbines operating at the extreme tip speed of 150 m/s [336 mph] may be subject to blade throw of up to 2 km from the turbine. For the ice throw cases, maximum distances of approximately 100 and 600 m are obtained for standstill and normal operating conditions of the wind turbine, respectively, with the ice pieces weighing from 0.4 to 6.5 kg. The simulations can be useful for revision of wind turbine setback standards, especially when combined with risk assessment studies.
Hamid Sarlak and Jens N. Sørensen
Section of Fluid Mechanics, Department of Wind Energy, Technical University of Denmark, Lyngby, Denmark
Wind Energy 2016; 19:151–166. DOI: 10.1002/we.1828
Download original document: “Analysis of throw distances of detached objects from horizontal-axis wind turbines”
- “A method for defining wind turbine setback standards” by Jonathan Rogers, Nathan Slegers, and Mark Costello, Wind Energy 2012; 15:289–303. (463 m [1,519 ft] for a Vestas 2-MW turbine)
- “Analysis of blade fragment risk at a wind energy facility” by Scott Larwood and David Simms, Wind Energy (published online 6 April 2018). “The results showed that a setback to property lines of 2 times the overall turbine height would be acceptable. However, the setback to dwellings should probably be increased from 3 to 3.5 times the overall turbine height for an acceptable risk.”
Author: Neville, Tania
There is a growing body of information, data, opinion, litigation and complaint surrounding the proliferation of industrial wind turbine developments worldwide. Governments have been quick to adopt the purported clean energy benefits of such development but slow to advance and implement appropriate guidelines, enforcement mechanisms and a means to examine what appears to be a growing public health issue related to noise.
This paper reviews case law to date and current health and independent noise data that indicate litigation in common law for private nuisance and negligence may succeed based on the common complaints associated with living near industrial wind turbines, that is, noise, health problems and property devaluation.
Planning and guidelines in relation to these developments now offer certainty to developers but have reduced the input of locals and local government. It is considered that the global view cannot override well established common law principles and that those impacted by these developments locally, should be able to seek redress in the courts.
Government responses to global problems should not result in harm or damage to individuals or small communities.
Download original document: “Industrial wind energy: When planning & guidelines fail the locals; Is common law an instrument to protect neighbours? A discussion on nuisance and negligence actions relating to noise and health”
Author: Wiser, Ryan; Yang, Zhenbin; et al.
[section 220.127.116.11 (pp. 575-576), “Wind Energy,” IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation, 2011]
A variety of proximal ‘nuisance’ effects are also sometimes raised with respect to wind energy development, the most prominent of which is noise. Noise from wind turbines can be a problem, especially for those living within close range. Possible impacts can be characterized as both audible and sub-audible (i.e., infrasound). There are claims that sub-audible sound, that is, below the nominal audible frequency range, may cause health effects (Alves-Pereira and Branco, 2007), but a variety of studies (Jakobsen, 2005; Leventhall, 2006) and government reports (e.g., FANM, 2005; MDOH, 2009; CMOH, 2010; NHMRC, 2010) have not found sufficient evidence to support those claims to this point. Regarding audible noise from turbines, environmental noise guidelines (EPA, 1974, 1978; WHO, 1999, 2009) are generally believed to be sufficient to ensure that direct physiological health effects (e.g., hearing loss) are avoided (McCunney and Meyer, 2007). Some nearby residents, however, do experience annoyance from wind turbine sound (Pedersen and Waye, 2007, 2008; Pedersen et al., 2010), which can impact sleep patterns and well-being. This annoyance is correlated with acoustic factors (e.g., sound levels and characteristics) and also with non-acoustic factors (e.g., visibility of, or attitudes towards, the turbines) (Pedersen and Waye, 2007, 2008; Pedersen et al., 2010). Concerns about noise emissions may be especially great when hub-height wind speeds are high, but ground-level speeds are low (i.e., conditions of high wind shear). Under such conditions, the lack of wind-induced background noise at ground level coupled with higher sound levels from the turbines has been linked to increased audibility and in some cases annoyance (van den Berg, 2004, 2005, 2008; Prospathopoulos and Voutsinas, 2005).
Significant efforts have been made to reduce the sound levels emitted by wind turbines. As a result, mechanical sounds from modern turbines (e.g., gearboxes and generators) have been substantially reduced. Aeroacoustic noise is now the dominant concern (Wagner et al., 1996), and some of the specific aeroacoustic characteristics of wind turbines (e.g., van den Berg, 2005) have been found to be particularly detectable (Fastl and Zwicker, 2007) and annoying (Bradley, 1994; Bengtsson et al., 2009). Reducing aeroacoustic noise can be most easily accomplished by reducing blade speed, but different tip shapes and airfoil designs have also been explored (Migliore and Oerlemans, 2004; Lutz et al., 2007). In addition, the predictive models and environmental regulations used to manage these impacts have improved to some degree. Specifically, in some jurisdictions, both the wind shear and maximum sound power levels under all operating conditions are taken into account when establishing regulations (Bastasch et al., 2006). Absolute maximum sound levels during the day (e.g., 55 A-weighted decibels, dBA) and night (e.g., 45 dBA) can also be coupled with maximum levels that are set relative to pre-existing background sound levels (Bastasch et al., 2006). In other jurisdictions, simpler and cruder setbacks mandate a minimum distance between turbines and other structures (MOE, 2009). Despite these efforts, concerns about noise impacts remain a barrier to wind energy deployment in some areas.
In addition to sound impacts, rotating turbine blades can also cast moving shadows (i.e., shadow flicker), which may be annoying to residents living close to wind turbines. Turbines can be sited to minimize these concerns, or the operation of wind turbines can be stopped during acute periods (Hohmeyer et al., 2005). Finally, wind turbines can shed parts of or whole blades as a result of an accident or icing (or more broadly, blades can shed built-up ice, or turbines could collapse entirely). Wind energy technology certification standards are aimed at reducing such accidents (see Section 7.3.2), and setback requirements further reduce the remaining risks. In practice, fatalities and injuries have been rare (see Chapter 9 for a comparison of accident risks among energy generation technologies).