The generation of electricity using offshore parks of windmills is a new activity that requires a great deal of space. In early 2007 the first wind farm was completed off the coast at Egmond aan Zee. It consists of 36 windmills. The present cabinet has made wind energy a top priority and it plays a major role in helping the cabinet to achieve its challenging climate and sustainable energy objectives.
Pile-driving activities to anchor the offshore windmills can have negative effects on the orientation ability of marine mammals. Sound carries a great distance in water. It disturbs those marine mammals that use echo location to find their way and those that use sound to communicate with their fellows over great distances. During the pile-driving for the first offshore wind farm in the Dutch North Sea off the coast at Egmond aan Zee, IMARES carried out research into the possible effects on marine mammals.
The pile-driving activities could be carried out only in good weather and when the waves were no higher than 1 m. In view of this, the pile driving started in mid April. This is the time of year that harbour porpoise numbers at the site drop to their low summer level. In addition, the energy involved in the pile driving was increased gradually and before work commenced a ‘pinger’ was placed in the water to give harbour porpoises the opportunity to swim away before the pile driving was carried out at full force. There is no indication that as a consequence of pile driving more harbour porpoises are beached or die than would otherwise be the case. Offshore windmills have vanes ranging from 65 to 100 m in length. Birds can fly into the vanes. They do not survive such a collision.