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With the very real threat of climate change looming large over the horizon, nations have been increasingly looking towards renewable energy, particularly solar and wind energy as a greener alternative to the fossil burning and highly polluting conventional energy. When it comes to wind energy, not only is it an easily available renewable and non-polluting source, but it also does not entail mining of non-renewable resources from the earth which causes degradation and destruction of the environment and wilderness areas. It also operates without the need for water resources as is required for the production of other forms of conventional energy.
Wind energy is obtained by harnessing the kinetic energy of the wind to rotate the blades of the wind turbines to mechanically generate electric power. Typically, wind turbines have a tall tubular tower, with an upward rotor with blades installed on the top. This in turn is connected to a power transmission network that may be located onshore or offshore. Since the energy output is wind dependent and varies with the weather, seasons and years, wind power is generally used in conjunction with other power sources.
Threat to Birds and Bats
Global Wind Day falls on 15 June. It is a day for discovering wind, its power and possibilities it holds to change our world. Generated from a clean and renewable source, wind energy does not harm habitats like the creation of power plants. While wind turbines allow ecosystems to flourish and although animals are unaffected by them, they kill birds and bats if precautions are not taken.
The rapid expansion of wind energy generation in many parts of the world and in India has revealed that it poses threats to birds and bats. Among birds, besides soaring birds, migratory species tend to have a higher risk of collision as they migrate in large flocks, especially if the wind farms are located in the midst of their migration routes. The increasing realization in recent years that wind turbines kill birds and bats on an enormous scale has tarnished the green image of this energy sector.
Many studies throughout the world have conclusively established the threat posed by wind farms to birds and bats that get killed or injured when they collide with the windmill blades. Though the wind turbine blades appear to move very slowly, this is deceptive as the distal tips of the blades can reach a speed of more than 280 kms per hour. Raptors which soar high in the thermals, are especially susceptible to collision, as they tend to look downwards for prey or sideways during flight, and often do not notice the swift, swirling blades until it is too late. Evolution has not prepared birds to deal with the new threat of wind turbines. Moreover, the older models of wind towers offer perching sites for large raptors, and the structures also offer a favourable habitat for small prey animals like rodents which in turn lure these birds to their deaths.
Wind energy generation takes a heavy toll on migratory birds. These casualties especially occur along narrow passes on the migratory route of birds. According to the California Energy Commission, 1,300 raptors including more than a 100 Golden Eagles die every year from the wind turbines located in Altamont Pass, California, despite preventive measures that have been taken over the years. The farm, lying in the middle of an important route for birds, was notorious in the past for being one of the deadliest wind farms in the world. Another site known for the kills of migratory birds due to wind turbines is in the Strait of Gibraltar, a migration bottleneck site for birds migrating between Europe and Africa. Besides casualties of birds along migration routes and especially migration bottleneck sites, kills tend to be higher if the turbines are situated near wetlands.
A comprehensive study conducted by the Bombay Natural History Society (BNHS) and published in their journal Hornbill (April-June 2017) reveals that in general, bird collision probability depends on species, turbine height (taller, more hits), and the elevation above sea level (higher, more hits), implicating species-specific and topographic factors in collision mortality. Large birds with poor manoeuvrability, like pelicans and storks, are generally at a greater risk of colliding, as also species that habitually fly at dawn and dusk or at night as they are not likely to detect and avoid the turbines.
The BNHS study also found that other than direct kills from the rotors of turbines, wind farms also impact birds in other ways. They alter, fragment or destroy habitats, obstruct the movement of birds, while the humming noise of the rotating blades also cause disturbance, in addition to spoiling the aesthetics of landscapes in pristine areas. All these disturbances have the potential to impact bird behaviour, causing them to avoid or abandon an area, and negatively affect survival and breeding success. Additionally, since wind farms tend to be located in remote or wilderness areas, its ‘footprint’ extends to areas far beyond its confines, due to the network of power lines, towers, and other infrastructure that go hand in hand with its development. In fact, a number of studies in Europe have reported that bird densities near windmills have declined significantly while other studies suggest that wind farm development could lead to displacement of migrating and breeding waterfowl and shorebirds, probably due to the disturbance associated with wind farm construction and maintenance.
In 2018 research published in Nature Ecology & Evolution stated that an international team of scientists studied the effects of wind turbine use in the Western Ghats at Chalkewadi plateau in Satara district and compared this with their study in the Sahyadri Tiger Reserve and Koyna Wildlife Sanctuary, and found that predatory raptor birds were four times rarer in areas where wind turbines were present. They also observed in the former area an increase in fan throated lizards which were predated upon by the raptors. They therefore declared that there was a cascading effect because wind farms acted as predators harming birds at the top of the food chain and damaging the ecosystem.
In December 2021 the Government of India (GoI) sought modification of the Supreme Court April 2021 order for putting underground power transmission cables in Rajasthan and Gujarat to protect the endangered Great Indian Bustard. GoI said was not feasible because it cost Rs 12 crore per kilometre and would be a huge set back to India’s international commitment to move towards renewable energy. The area contained a very large proportion of the total solar and wind energy potential of the country. Bird Diverters as used on Gwalior-Jaipur line by the Power Grid Corporation to protect the Indian Vulture and Egyptian Vulture and in Bhuj-Banakantha line to protect Flamingos and Cranes, would be installed so that the Great Indian Bustard would not be electrocuted. Subsequently, the SC had asked a 3-member high-level committee to file a report “indicating what steps have been taken for compliance with the directions contained in the judgement of this Court”.
BWC feels that there needs to be a balance between the two, one can not risk harming birds, bats, and indirectly other lives (whether endangered or not) for the sake of renewable energy.
In January 2023 a government order sent for the first time a target to auction 8GW of wind power projects every year until the end of 2030 to boost the country’s renewable energy capacity. Union Ministry of New and Renewable Energy data showed that India had a wind power capacity of 410 GW, but installed capacity as on 31 December 2022 was just 42 GW. |
Wind Energy in India
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Since wind farms have the tag of ‘green’ energy, the Indian government provides tax incentives and benefits for the setting up of wind farms with the broad aim of developing and deploying renewable energy to supplement the energy requirements of India. Today, wind power accounts for nearly 9% of India’s total installed power generation capacity, and the country is placed fifth in the global scenario.
Cases of bird kills from windmills, involving resident and migratory species are getting reported more frequently in India with the increase in the number of birdwatchers. Birders have reported bird deaths in the Thar Desert in Rajasthan and the Rann of Kutch in Gujarat. Data is also being obtained from a few Environmental Impact Assessment (EIA) studies, but these are of limited use as the rapid biodiversity inventories are undertaken to obtain sanction for the setting up of power plants. Though the Ministry of Environment, Forest & Climate Change is aware that migratory birds are especially prone to windmill hits, EIA reports try to get around this by using terms like ‘not even close proximity’ and ‘safe distance’ to claim that migratory birds would not be affected, ignoring the fact that birds may not stick to the exact same route each year – the distribution of rainfall in the Indian subcontinent being an important factor in the routes chosen.
Wind farms are bad for birds but a study has found that black-naped hare actually prefer living on them because they are clever enough to have realised that their predators keep away from the area! |
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How Green is Wind Energy?
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Mining iron ore causes forest encroachment and wildlife habitat destruction apart from requiring energy for mining. As per the US Geological Survey, one megawatt of wind capacity requires on average about 100 tonnes of steel, 400 tonnes of concrete, 6.8 tonnes of fibreglass, besides copper and cast iron. Wind turbines kill an estimated 1,40,000 to 3,28,000 birds each year in North America alone.
As for India, very few in-depth long term studies have been conducted to estimate the bird kills every year attributable to wind farms.
A study in Gujarat in 2012 by scientists from the Salim Ali Centre for Ornithology and Natural History, Coimbatore, (Scientific Journal of Environmental Sciences, 2012) has established a definite link between avian fatalities and wind farms. In India, several wind farms are already operational and many more are under construction. Often, suitable areas tend to occur offshore or onshore in coastal areas, on ridges and mountains, in agricultural areas and open grasslands, many of which are sensitive habitats for different bird species. This highlights the importance of assessing the effects of wind energy projects before clearance is given by the government. It should be noted that even low levels of mortality may be disastrous for long lived species with low productivity and slow maturation rates, as in the case of critically endangered species like the Great Indian Bustard with a recorded population of less than 300 individuals. In September 2017 a young female crashed into a 33 KV transmission line connected to wind turbines in Naliya on the edge of the Lala Bustard Sanctuary.
In 2019 researchers were invited to two wind farm owners – one in Samakhiali in Kutch, Gujarat and the other in Harapanahalli, Davangere, Karnataka – to investigate bird mortalities in their farms. The study found 47 carcasses of birds belonging to 11 species in Samakhiali. In Harapanahalli 7 birds belonging to 3 species were found. Their research indicated approximately 0.5 death per turbine which they felt may be an underestimation as only collision death were recorded at 40-day intervals.
In 2019 taking a serious note of alarming extinction of two Indian birds namely Great Indian Bustard and Lesser Florican, the Supreme Court of India constituted a High Powered Committee to urgently frame and implement an Emergency Response Plan for protection of these species. The two main steps suggested were as follows:
1. Urgent dismantling and under-grounding of power lines and wind turbines.
2. Immediate embargo on any upcoming wind, solar power projects, and power lines in and around critical habitats.
Can we consider an energy source as ‘green energy’ if it kills hundreds of thousands of birds each year, and has the potential to contribute to making rare species extinct? This is a serious point which needs to be pondered over.
There are, however, some promising developments which could help lift the dark shadow cast on wind energy. One is a bladeless wind turbine under development by Vortex Bladeless, a Spanish company and another by Saphon Energy, a Tunisian company, whose turbine design is inspired by the ships of ancient Carthage, which they claim is quieter, safer and more efficient, and capable of capturing twice as much wind energy.
More attention to making the turbines ‘bird safe’ and care in the location of wind farms would help in avoiding or minimizing bird fatalities. Wind farms need to be in safe locations, have ultrasonic “boom boxes”, be painted purple, and install GPS to enable the turbines to be shut off when a flock is flying through. To minimise danger to flying birds it has also been suggested that scarecrows be installed near windmills.
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| Page last updated on 11/05/23 |
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