Understanding the impact of wind energy on birds and bats

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Understanding the impact of wind energy on birds and bats in South Africa
Submitted by Amanda Botes on Wed, 25/02/2015 - 09:28


The impact of wind energy developments on birds and bats has received a lot of attention around the world. Closer to home there has recently been debate around a wind farm proposed in the Lesotho Highlands and the impact this will have on the endangered Bearded Vulture. In 2011 there was also concern about the possible impact of a proposed wind turbine in Durban on a colony of Egyptian Slit-Faced bats.

Wind farms are increasing in South Africa as a result of the introduction of the Renewable Energy Independent Power Producer Procurement Programme (REIPPPP). As a result, there is an increasing need to understand the possible impacts of this type of energy on birds and bats and how best to reduce those impacts.

Wind energy and birds

“Wind energy developments negatively impact on birds in three ways. Firstly birds can collide with the actual wind towers and blades. Secondly, as the land is physically transformed for development, habitat for the birds is altered, and thirdly birds are displaced from their habitat even if much of their habitat remains intact,” explains Samantha Ralston-Paton, Renewable Energy Manager at Birdlife South Africa. Even though research done overseas indicates that more birds are killed from flying into buildings or eaten by cats, than from wind energy developments, Ralston-Paton cautions that “one cannot lump all bird species into one group, and that we need to look at which bird species are most vulnerable to wind developments. We don’t have good data yet, but some of the bird species that we predict will be impacted on by wind developments in South Africa include the Cape Vulture, the Bearded Vulture, the Black Eagle, the Blue Crane, and other raptors as well as water birds. In Lesotho, an 80 tower wind development has been proposed that could lead to the local extinction of the Bearded Vulture, as these birds regularly move through this area.”

Ralston-Paton adds that the main way to mitigate the impact of wind turbines on bird populations is to critically look at the location of the wind energy development and the individual towers. “Location is the main way to mitigate impacts, once a wind farm is built there is very little one can do. In Spain, there are examples of wind farms shutting down during high risk periods when birds are migrating. However in Spain the migrating birds move though a geographic bottleneck and the risk is limited to a short period. Lesotho is different in that the birds are likely to move though the area regularly and frequent shutdowns can result in economic losses and increase maintenance requirements. Shutting turbines down is also not one hundred percent effective and birds will still be at risk if turbines are poorly sited. Therefore if more work is done when siting a wind energy development, birds can be saved,” she explains.

Birdlife South Africa has developed a sensitivity map to show areas where wind energy developments would not be advised. This can be used by developers as a first step when they consider a location for wind development. This map is available from the Birdlife South Africa website and Ralston-Paton encourages developers to approach Birdlife South Africa for assistance in locating wind projects.

Wind energy and bats

“The most significant impact of wind farms on bats is fatality due to collision with turbine blades and/or barotrauma [due] to the difference in pressure close to the spinning blades,” says Kate MacEwan from the South African Bat Assessment Association (SABAA). “Hundreds of thousands of bats get killed from wind turbines in the USA and Canada annually, with the cumulated numbers to date, since the commencement of wind energy in the USA, being in the millions. Fatalities have been recorded already at most operating South African facilities, however, the quantities and extent need to still be verified,” says MacEwan.

“Bats are among the most overlooked, yet economically important, non-domesticated animals,” explains MacEwan. “The majority of bat species in South Africa are insectivorous and consume significant quantities of agricultural and disease causing pests. Insectivorous bats in the USA save farmers many millions of dollars in terms of reduced pesticide usage and reduced crop damage, with recent evidence pointing towards South African bats doing the same. Fruit and nectar eating bats play a vital role for many plants in terms of pollination and seed dispersal,” says MacEwan. She indicates that much can be done to reduce the impact of wind energy developments in South Africa, which includes strategic planning on an ecoregion level; monitoring pre- construction, as well as during operation; and using fatality minimisation strategies, such as time specific curtailment and blade feathering.

A collaborative effort to mitigate the impacts of wind farms in South Africa

In order to reduce the impacts of wind energy developments in South Africa on birds and bats Birdlife South Africa, the Endangered Wildlife Trust (EWT), and the SABAA, have worked closely with the South African Wind Energy Association (SAWEA). “The SAWEA is committed to working on wind project development in a sustainable manner. We are committed to working with EWT, Birdlife South Africa, and the SABAA and have an open line of communication with them. We have a professional respect for each other, which has resulted in a positive collaborative effort. Wind energy is a new industry in South Africa and there is little information on bat and bird deaths in South Africa. We are treading carefully together and learning together as we go along, about the specific impacts,” says Katherine Persson from SAWEA’s Environmental Working Group.

One of the main areas of collaboration has been on the development of best practice guidelines documents for the surveying of birds and bats pre- and post- wind farm construction in South Africa. The bird monitoring guidelines have been developed by Birdlife South Africa and the EWT, and the bat monitoring guidelines developed by the SABAA and EWT.

Both Ralston-Paton and MacEwan stated that because the wind energy industry is still new in South Africa, that monitoring of bird and bat fatalities due to wind developments is still in its infancy and that limited statistics are currently available. Ralston-Paton explains the significance of the guidelines in gathering good data, “The aim of the guidelines is to align monitoring and impact assessment methodologies with international best practice. When the first impact assessments were done for the first wind farms in South Africa, we didn’t know much. Today, these guidelines help to provide detailed guidance for specialists on how to collect pre- and post- construction data on birds. The methodology is highly detailed and is useful, as we can now achieve standardisation with regards to how sites are monitored and we can compare data across sites,” says Ralston-Paton.

During the guideline development process, SAWEA was consulted extensively to ensure that the guidelines were implementable. Persson explains, “In 2011, we started to work with Birdlife South Africa and EWT to develop a set of monitoring guidelines. There are guidelines that exist around the world, but there were none for South Africa. During this process of guideline development, we made sure that what was proposed was reasonable. Many of the wind energy professionals working in South Africa already had experience using guidelines in other countries and were able to make significant contributions to the development of the guidelines.”

Ralston-Paton adds that working together with SAWEA has resulted in positive outcomes, “We have a very good relationship with the SAWEA, and we host a forum once a year where developers are invited to discuss issues. We have found the developers to be very responsive to the guidelines and are willing to engage with us. Developers don’t want to kill birds, it’s not good for their reputation and costs,”

The way forward

Ralston-Paton explains that Birdlife South Africa is not opposed to wind energy development but that the development should be done in a way to minimise the impact on birds in South Africa, “We, as an organisation, are not against renewable energy and believe that it is the way to go when compared with coal power. However, we do need to maintain a balance and ensure that these developments are constructed in a way that minimises their impacts on birds. We realise that there will be a degree of impact and that we can’t expect zero mortalities. At the moment, there is a lack of data in South Africa on the impact of wind energy on birds, and monitoring and information sharing is critical if the industry is to develop sustainably. While large-scale wind energy facilities have their place they also have their challenges. We could be doing a lot more to support small local projects in South Africa, such as rooftop solar and energy conservation initiatives; these seem to be a more sustainable option.”