As wind turbines increase in size and scale, so do their deadliness to wildlife and hazards to human health.
Today’s modern wind turbines now soar to heights of up to over 200 meters, can have outputs of well over 5 MW, and blade tip speeds of over 300 kilometers per hour, thus making them especially lethal to avian wildlife, and hazardous for human health through infrasound.
Source: academia.eu, Erin F. Baerwald et al.
21,000 square meters of “swept area” of annihilation
To give an idea of their scale, Danish company Vestas, for example, offers an 8-MW offshore turbine with a total height of 220 meters that is equipped with a monster rotor diameter of 164 meters. The result: horrendous blade speeds and pressure gradients. Flying wildlife stand no chance. Worse is the growing size of the hazardous swept area.
Vestas boasts that its V164-8.0 MW® turbine has a swept area of more than 21,000 square meters, which is “equivalent to almost three football pitches“. Vestas bellows: “When it comes to profitability, the bigger the swept area the bigger the revenue.”
Unfortunately for birds and other wildlife it is also: The bigger the swept area, also the bigger the wildlife annihilation area. But wildlife be damned.
Huge number of fatalities
Wildlife fatalities from wind turbines are poorly documented and mostly unknown. Estimates are on the low side and thought to be much higher, as the industry attempts to play down their real danger.
Birds, bats and other animals can be killed by turbines in any one of three ways: 1) through loss of their habitat due to the disruption of a vast installation area, 2) direct impact with high speed moving blades (birds) and 3) from barotrauma, where bats are the primary victims.
The most sinister of the three is barotrauma, which is a common way bats are killed by wind turbines.
Study shows mayhem
An article published at academia.edu by Erin F. Baerwald et al of the University of Calgary confirms the violent deaths that bats suffer from wind turbines. Bats do not even need to come into contact with the moving blades. It is enough for them to be close to the end of a moving blade to become victims of barotrauma. As the turbine’s blade slices by at 300 km/hr, the negative pressure in the blade’s wake causes the air in the bats’ lungs to expand and incur lethal injury.
Barotrauma typically occurs when an organism is exposed to a significant change in ambient pressure, such as when a scuba diver, a free-diver or an airplane passenger ascends or descends, or during uncontrolled decompression of a pressure vessel.
The academia.edu article writes:
The decompression hypothesis proposes bats are killed by barotrauma caused by rapid pressure reduction near moving turbine blades [1,4,5]. Barotrauma involves tissue damage to air-containing structures caused by rapid or excessive pressure change; pulmonary barotrauma is lung damage due to expansion of air in the lungs that is not accommodated by exhalation.”
Moving turbine blades create zones of low pressure as the air ﬂows over them. Animals entering these sudden low pressure zones may suffer barotrauma; academia.edu article writes:
Pressure differences as small as 4.4 kPa are lethal to Norway rats Rattus norvegicus) . The greatest pressure differential at wind turbines occurs in the blade tip vortices which, as with airplane wings, are shed downwind from the tips of the moving blades . The pressure drop in the vortex increases with tip speed, which in modern turbines turning at top speed varies from 55 to 80 m/s. This results in pressure drops in the range of 5–10 kPa (P. Moriarty, personal communication), levels sufﬁcient to cause serious damage to various mammals .” […]
Even if echolocation allows bats to detect and avoid turbine blades, they may be incapacitated or killed by internal injuries caused by rapid pressure reductions they cannot detect.”
188 dead bats examined
Baerwald and her team examined 188 dead bats killed by a wind turbine facility in southwestern Alberta:
Of 188 bats killed at turbines the previous night, 87 had no external injury that would have been fatal, for example broken wings or lacerations (Table 1). Of 75 fresh bats we necropsied in the ﬁeld, 32 had obvious external injuries, but 69 had haemorrhaging in the thoracic and/or abdominal cavities (Table 1). Twenty-six (34%) individuals had internal haemorrhaging and external injuries, whereas 43 (57%) had internal haemorrhaging but no external injuries. Only six (8%) bats had an external injury but no internal haemorrhaging.
Among 18 carcasses examined with a dissecting microscope, ten had traumatic injuries. Eleven bats had a haemothorax, seven of which could not be explained by a traumatic event. Ten bats had small bullae — air-ﬁlled bubbles caused by rupture of alveolar walls — visible on the lung surface (Figure 1A). All 17 bats examined histologically had lesions in the lungs consistent with barotrauma (Table 1), with pulmonary haemorrhage, congestion, edema, lung collapse and bullae being present in various proportions (Figure 1). In 15 (88%), the main lesion was pulmonary haemorrhage, which in most cases was most severe around the bronchi and large vessels.”
In summary, the wind turbines are extremely lethal to wildlife on a scale so horrendous and embarrassing that it is being kept out of the public’s eye. What’s worse is that these turbines, and the growing swept areas of annihilation they bring with them, have been installed by the thousands and plans are being made to install many thousands more – many in natural areas. Wildlife will have no chance.
This is all endorsed by Greenpeace and the WWF.