Introduction

Denmark is in a leading position in the area of offshore wind energy. Two demonstration projects at Horns Rev and Nysted build in 2002 and 2003 are to date the largest offshore wind turbine projects in the world. During six years the environmental impact of the wind farms was studied.
The results of this monitoring programme were presented in 2 days. The Danish are generous by making all results public available on http://www.hornsrev.dk and on a new website: www.ens.dk (look for the UK flags for English language reports). This unique knowledge is now available for everyone.
The effect of the construction and exploitation of the two wind farms, Horns Rev (160 MW) and Nysted (165.6 MW) on the marine environment was studied. The base line survey was performed in 1999-2001, followed by measurements during the engineering en constructions works (2001-2003). The program was concluded with follow-up measurements and monitoring during several years running (2002-2006). The environmental monitoring program covered the impact of offshore wind farms on public perception, seabed fauna and flora and the new fauna and flora on piles and scouring protection, fish, marine mammals and birds.

The general outcome
Results show that people adapt their view, foundations and corrosion protection on sandy beds create new artificial habitats for animal and plant life. It also showed that vulnerable marine mammals such as porpoises are affected during the construction stage (ramming) and do not necessarily fully return to the area. The results also left questions with respect to the impact of electrical cables with respect to fish migration. Effects on bird populations are negligible and the collision risk with turbines is low.
The public attitudes to offshore wind farms were also a part of the environmental monitoring programme. The sociological survey exists of in-depth interviews with local residents in the vicinity of both wind farms. These surveys were combined with surveys among a national reference group
In general the results of the environmental monitoring programme show that offshore wind farms cause no significant damage to the marine environment. As authorities and developers respect the vulnerable marine environment, offshore wind energy can contribute to a great extend to the use of sustainable energy.

Summary table from the website:

http://www.ens.dk/sw42149.asp

Main results of the environmental monitoring programme of the Horns Rev and Nysted offshore wind farms.

Detailed outcome and potential consequences for offshore wind energy (In yellow attention points or subjects for further discussion.)