How the wind power industry works with the bird community

Richard Foote

Wind power firms need a wide array of specialised knowledge to measure the environmental impact of their turbines. Richard Foote finds out how companies are working with ornithologists to plan wind farms around bird flight patterns and migratory routes.

The wind power industry looks set for a boom following the agreement of the EU's 2009 Renewable Energy Strategy and the introduction of a more sympathetic planning act last year. But the picture across Europe remains inconsistent; although many countries are building wind farms capable of generating hundreds of megawatts of power – in Denmark, nearly one fifth of stationary electricity production is already powered by wind – in the UK only 1.8% of energy has its roots in wind.

If the EU is to meet its binding target of generating one fifth of all energy from renewable sources by 2020, it will need a major turbine revolution and a massive building strategy. Unfortunately, the wind turbines themselves remain a source of controversy – often for aesthetic reasons – and their installation and presence can have an impact on surrounding ecosystems and wildlife. They have been accused in the shrinking of local bat populations for example.

As a result, wind power companies need to take into account a variety of ecological issues in the planning and building stages of wind farms, following highly specialised advice from experts in fields such as meteorology, noise reduction and even ornithology.

According to Simon Pickering of RenewableUK – formerly the British Wind Energy Association (BWEA), the risk to birds from wind farms falls into two categories: the risk of mortality and the risk of disturbance. Apart from the obvious dangers of a bird hitting a spinning turbine, there are several other impacts to consider.

Working in partnership with ornithologists

Turbines can, for example, create a physical barrier effect that denies birds access to their natural feeding grounds and roosting locations. On a migratory route, birds may have to swing round the wind farm and deviate from their usual route, increasing energy expenditure and reducing survival rates.

Pickering says developers can ensure their wind farm projects stay on track and are granted planning permission by performing all the requisite environmental studies in advance. “Ornithological studies are now a crucial part of the environmental assessment of any wind farm development,” says Pickering. “Get the wind farms in the right places and show that they are not producing electricity at the cost of wildlife.”

A number of wind farm companies have been working successfully with avian specialists on an assessment process based on simple observation and analysis. The main method used for assessing wind farm sites is a vantage point survey, the number of which varies widely from location to location. A good ornithologist is able to recognise around 500 different bird species from their appearance, call and behaviour.

“Where possible, we try to visit the site at the tender phase to identify how many vantage points we should include in a proposal,” says Mark Gash, a Senior Consultant in RSK Carter Ecological's four-strong ornithology team. “This is a unique way of tendering and it gives developers confidence that the ornithological study we produce will be robust and will highlight any potential issues.”

Vantage points are selected from the outside looking into the site – based on its size and topography – to obtain a comprehensive view across the whole of the development area. Birds rarely fly on exactly the same paths, so experts include a ‘buffer zone’ of 200–500 m to record all flight activity through and in the immediate vicinity of the site.

“You then record all the birds that travel through your site, the height at which they are flying, the direction in which they are flying and their behaviour; for example, hunting, in the case of birds of prey,” says Gash. “In the breeding season, you also use the vantage points to identify which birds are breeding on the site. The whole purpose of these studies is to ascertain the nature and the fullest extent of the avian use of the site. Where necessary, we undertake migration surveys in which we perform vantage-point surveys on the route for a whole season.”

Tracking birds using computer modelling

The survey results are marked out on maps using special notation that identifies each bird and describes its behavioural patterns. A collision risk assessment is conducted if a significant bird population is found in the area.

This involves putting the collected data into a complex computer model, along with the turbine specifications and bird statistics such as wingspan, body size, flight speed and avoidance rate. Ornithologists can then create an individual assessment for each bird species.

Specialists like Gash use such study and assessment data to determine applicable mitigation measures. One of the most common solutions is to identify which route the birds regularly take when they enter a site and then to simply build the turbines away from it. This creates a safe travel corridor without turbine impediment.

“Building turbines in the wrong location – for example, on a migratory route – can have a catastrophic impact on local bird populations,” warns Gash.

Unfortunately, the consideration given to birds differs widely from country to country, even within the EU. It is the developer's responsibility to conduct an environmental study, but regional governments and planning authorities need to take a share of the responsibility as well. “You have to be aware that there are wind farms in the world where there is a high and ongoing mortality rate among birds,” says BWEA's Pickering. “Developments that are always quoted are those in the Altamont pass in California, USA, and a couple in Spain.”

Building reliable wind farms

As well as environmental concerns, taking birds into consideration makes good business sense. Scotland, with its commendable ornithological credentials, is far ahead of the UK in terms of online wind power. Most environmental studies for UK wind farm developments now follow guidelines based on those set by Scottish National Heritage.

By contrast, Bulgaria had a poor record for building bird-disrupting structures before it joined the EU in January 2007. According to Gash, the country is now a showcase for how dramatic improvements can be made as long as best practice is embraced.

In the past year, RSK Group has undertaken several environmental impact assessments for European Bank for Reconstruction and Development (EBRD)-funded wind energy developments in Bulgaria, many of which have involved extensive ornithological assessments.

One such project is the Saint Nikola wind farm – near the city of Kavarna in Northwest Bulgaria – which is on a major migration route for storks, pelicans and birds of prey flying from Northern Europe to sub-Saharan Africa. The project was started in 2002 by a Bulgarian company which initially planned to build 60 turbines about three to five kilometres from the coast. Four years later, US renewable company AES Corporation took over the project with an aim to secure funding from either the International Finance Corporation (IFC) or the EBRD.

“We knew we needed Western expertise for our environmental work,” says John Bottomley, Managing Director of AES' European wind project development. “Consequently, we brought in a Swiss ornithologist who confirmed that there was value in bird monitoring.

“Once we had attracted both the IFC and the EBRD to the project they asked us to perform a gap analysis. This is where RSK Group came in to work its magic.”

A collision risk assessment was undertaken, based on data collected from the Bulgarian Society for the Protection of Birds and data from AES's partner company. From this, RSK Group was able to confirm that the development would have minimal impact on local birds.

It also agreed with the previous environmental expert's conclusion that building on the steppe (flatland) would be unethical and that it would pose a greater threat to the birds as the area is closer to the coast. The AES team decided it would monitor the birds' migratory routes every season and a system has now been set up to shut down relevant parts of the wind farm if large groups of birds approach.

Gash also spent time with AES' on-site ornithologist to identify suitable positions for a mobile radar unit, which will be moved according to the season to help observers spot incoming bird populations. “AES has really grabbed the bull by the horns with this one,” he says. “Using our advice, the company has put together one of the best mitigation packages I have ever seen.”

In all, 52 turbines have been built by the company. AES is currently testing the substation and power was expected to start feeding into the grid by the end of last year.

“Because of all the stakeholders involved, we have made commitments to this project that have made me proud of AES,” says Bottomley. “I would go as far as to say that this is a world-standard project. It is in an area where there is a perceived risk and we have completed sufficient studies and have put in place enough mitigation to enable us to coexist peacefully with the birds.”

As European countries continue to grapple with the challenges of boosting renewable energy generation through wind energy, the role of the ornithologist is set to become increasingly influential. Bottomley even travelled to Brussels to tell the EU Commission about the company's avian project.

“I went armed with all the analyses, studies and best-practice approaches that RSK Group's ornithologists had helped us to develop,” he says. “It really opened their eyes and showed them that not all developers should be tarred with the same brush. Perhaps it showed them that they need to start differentiating between us a bit.”

Share this article

More services


This article is featured in:
Energy infrastructure  •  Wind power



Kari Williamson, Assistant Editor said

09 July 2010
Thanks for bringing our attention to that tautology - we have now amended.


tmckayuk said

09 July 2010
AES relocaating a mobile RADAR...joke

Note: The majority of comments posted are created by members of the public. The views expressed are theirs and unless specifically stated are not those Elsevier Ltd. We are not responsible for any content posted by members of the public or content of any third party sites that are accessible through this site. Any links to third party websites from this website do not amount to any endorsement of that site by the Elsevier Ltd and any use of that site by you is at your own risk. For further information, please refer to our Terms & Conditions.