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Taller turbines used to help protect seabirds off Norfolk coast

During the design phase of its Norfolk projects, Swedish energy group Vattenfall sensitively sited individual turbines and made them taller, maximising the wind energy that could be generated off the Norfolk coast, whilst minimising the impact on biodiversity. 
By: Rebecca MacNaughton
VFALL Kitpic-c-Mark-Lewis-scaled
Up to 360 offshore turbines on the Norfolk Vanguard and Norfolk Boreas windfarms have been raised by the equivalent height of a two-storey house to accommodate safe flight paths for birds like the kittiwake after research revealed higher towers and rotors further from the sea surface would minimise collisions with turbine blades. decrease. Picture: Mark Lewis

So far, Vattenfall has engaged with more than 100 specialists on its Norfolk Vanguard and Norfolk Boreas wind farms, which will see up to 360 turbines providing clean energy to 3.9 million homes.

Protecting flight paths, breeding habitats, food chains and foraging areas of kittiwakes, gannets, black backed gulls and other seabirds, led the company to employ the expertise of top ornithologists during the five-year planning process for the wind farms.

VFALL Large-Screen-72-DPI-Vattenfall_Kentish_flats_10Each of the turbines have been sited strategically and sensitively to allow for safer bird flight. Picture: Vattenfall
Extensive data from seabird studies around the world, illustrating their behaviour and how they reacted when something different, like wind turbines, appeared in their environment, revealed that flight heights were key to deciding on effective mitigation measures.
 
Data revealed that most birds fly close to the sea surface. Higher up, the number of birds decreases. So, if developers put turbines on higher towers and moved rotors away from the sea surface, collisions would decrease. 

Much time, resources and focus were devoted to defining the safest turbine height for birds during the development of the Norfolk projects.

 

 

Vattenfall Turbine Raise Infographic v05
Data analysed by top ornithologists demonstrated that most birds fly close to the sea surface with a decreasing number higher up. Picture: TMS Media
Acting on this evidence, Vattenfall chose to increase the minimum blade tip clearance from 22m to 30m from sea level on each of the 360 turbines. The density of the turbines was reduced and the team had to investigate if turbine installation vessels existed large enough to install the taller turbines.

Kathy Wood, head of consenting at Vattenfall said: “Delivering fossil fuel-free energy must be done in a way that protects biodiversity and Vattenfall is continually working to minimise negative impacts.

“Consultation is a central part of the environmental impact assessment process, and on these projects we have deployed this to its fullest potential. This has prompted us to come up with many, and innovative adaptations to our initial plans, and we are really happy that this engagement from communities and experts has led to sensitive design.”

Mark Trinder, ornithologist at MacArthur Green said: "Responsible developers employ specialists like us to assess the impact of their developments by mapping seabird behaviour in their planned development area.

”Early on, site consultation and data gathering meant that the wind farm areas were chosen further offshore, as far away as possible from coastal bird breeding sites.

“All infrastructure projects have some form of impact, but Vattenfall has done everything possible to sensitively design the Norfolk projects.”