As basis for the project, an extensive environmental impact assessment (EIA) has been carried out which in detail accounts for the expected environmental impacts on the wind farm. The EIS states that the construction phase will include a high level of activity both in and around the construction site, and in general there will be many activities that could cause environmental impacts.
The foundations will be monopiles which are driven into the seabed. The pile driving process will begin slowly and then become more intense. Acoustic devices will be used to scare off fish and sea mammals from the area before the pile driving process is initiated.
The effect of noise and vibrations as a consequence of pile driving will be brief. The animals will be able to use the construction area in the periods between the pile driving processes which only take a few hours; therefore, the total impact as a consequence of disturbance in connection with pile driving is assessed to be moderate. The EIS assesses that pile driving will not have significant impact on the animals’ communication.
Impact on fish
This also applies to fish, where the main impact of the noise will be that the fish will leave the area when the construction activities and the noise are most intense. However, it is expected that fish, which possibly have left the construction area, will return quickly when the construction work is completed. Only a small impact on fish as a consequence of noise in the construction phase is expected. Therefore, the impact on commercial fishing due to the evasive behaviour of the fish is expected to be limited and brief.
Disturbance of the seabed
As the upper layer of the seabed consists mainly of sand with only a small content of fine particles, the material suspended during jetting of cables and pile driving will quickly settle on the seabed. Therefore, no significant impact on flora and fauna is expected; neither as a consequence of the suspension in the water phase nor as a consequence of sedimentation on the seabed.
During construction works, flora and fauna on the seabed are expected to be affected only locally at the wind turbine foundations and at the array cables between the wind turbines. Altogether, these areas make up a very small area of the total project site, and in the EIS, the immediate loss of habitats for flora and fauna is assessed to be limited and of little account.
The visual impact is a very important parameter in terms of the recreational value on the stretches of coast of Djursland and the island of Anholt respectively. The presence of the offshore wind farm is assessed to be of significant importance. However, experience from existing offshore wind farms has shown that the general attitude towards wind turbines is positive due to the environmental image of the wind turbines, even though they may have a visually disturbing effect on the scenery.
Surveys from other wind farms have shown that the risk of other migratory water birds colliding with the rotating wings of the wind turbines is generally very small. The EIS states that the risk of water birds colliding with the wind turbines in Anholt Offshore Wind Farm is limited. The birds are expected to fly around the offshore wind farm at a distance of 3-5km. This ability to adjust the course compared to the collision risk supports the assessment that the wind farm will have only limited or no impact on the affected population of water birds.
Construction activities are assessed to have only a small impact on resting birds in the area. It is particularly stressed that no direct loss of habitat is expected as the affected area is very small.