Offshore Wind Energy and Noise Monitoring

An important implementation issue for wind farms is the risk of bird collision. A lot of the existing knowledge on birds and wind energy is based on studies at onshore sites. With respect to wind energy implementation especially offshore, more information about the environmental impact is needed. Several countries carrying out environmental base line studies focuses on offshore wind farm sites. Monitoring wildlife is very labour intensive. That's why ECN develops a computer based efficient environmental monitoring tool. The aim is to demonstrate the proper operation of the bird collision registration system that has been developed by ECN. The system must be relatively inexpensive, robust and applicable for offshore conditions. The system identifies bird impacts by noise measurements and a camera identifies the specific species. The system can also distinguish between turbine specific sounds and a collision of a bird against tower, nacelle and rotor. The ECN bird collision registration system is proven to be a very promising way to detect and record bird collisions against wind turbines. The first experimental results are good. This way of detecting the collisions of birds can be very useful for the future implementation of offshore wind farms. 1 – Dutch offshore wind energy plans and the environment In the Netherlands the Dutch government has set a very ambitious target for offshore wind energy of 6000 megawatt in 2020. Environmental impact of wind energy plays an important role in the public acceptance that also influences the decision-making processes. Since the introduction of wind energy, there is a concern that turbines would cause harm to birds. A lot of studies about nuisance to birds from wind turbines onshore are executed in the last decade. Still many questions are left related to the development of wind energy offshore. In most countries, wildlife protection organisations and environmental groups follow the development of offshore wind energy. In order to get more information about birds at sea, new tools and methods are needed to increase knowledge in this field. The lack of appropriate tools and information evoked a lot of negative publicity on wind energy and reduced the opportunities to realise projects. An inventory on bird’s detection systems and methods shows a lack of appropriate methodologies to study bird victims caused by wind turbines [1]. That's one of the reasons why ECN started the development of an automatic bird collision detecting system called WT-Bird [3].