Offshore wind turbines in an energy policy perspective


The Danish Government’s energy action plan "Energi 21" targets a reduction in CO2 emissions by 50% by 2030 (as compared to 1988). Wind power is the most economical means of reducing the emission of CO2 as far as the production of electricity is concerned. As the erection of additional land-based wind farms would create unacceptable concentrations of wind turbines, the target is to establish 4000 MW at sea by 2030, as they will be less of a nuisance there.         

 

Siting and visualisation
Since 1983, several studies concerning the siting of wind turbines at sea have been completed. And in 1994, the builders began gathering insight on the various interests of officials and others, interests which would have to be taken into consideration in the establishment of an actual offshore wind farm. The next step was to identify appropriate locations for carrying out the demonstration project. This phase culminated in two central analyses: a landscape project designed to shed light on the impact an offshore wind power installation would have on the nearby coastal landscape, and a survey project designed to register all known interested parties. Based on the findings of these projects, the builders arrived at four main areas for siting offshore wind farms. These included an area near Horns Rev and a larger area south of the island of Læsø in Skagerrak.

 

 

Plan of action
I 1997, a plan of action dubbed the "Action Plan for Offshore Windfarms in Danish Waters" was conceived. This report concluded that large-scale offshore wind farms are interesting, technically and economically as well as environmentally. The recommendation? Prepare for the construction of "stage-one demonstration projects!"

Demonstration installation
In 1998, Danish power suppliers were challenged to erect five offshore wind farms which could produce a total of approx. 150 MW. Two of those are located west of the Great Belt – one at Horns Rev and the other south of Læsø.

Preliminary permission
In mid-1999, the power suppliers received the preliminary go-ahead to begin the construction of four offshore wind farms: Horns Rev, Læsø, Omø Stålgrunde, and Rødsand. The approvals were a sign that the power suppliers could expect a definitive green light for the projects unless the EIA (Environmental Impact Assessment) process turned up unfavourable results. So the preliminary technical and environmental studies could begin.

Adjustment in 2002
The Danish government cancelled the order given earlier to the utilities for three Danish offshore wind farms, the construction of which has not yet started. The cancellation involves the Læsø, Omø Stålgrunde and Gedser Rev wind farms.

Builders
As regards the projects at Horns Rev, Elsam is responsible for the actual wind farm – installing and maintaining the turbines, the turbine foundations, the internal cabling, the accompanying remote control unit, and auxiliary installations. Eltra is the builder in charge of the installations designed to convey the power ashore, that is, the offshore transformer substation, the sub-marine cable leading to land and the onshore cable leading to the general transmission grid.

Project Committee
Elsam established a Project Committee based on resources from Elsam and Elsam Engineering. This committee gathered expertise in all aspects of the field of wind power, from planning, engineering and  environment to the financial and operational aspects. Elsam Engineering A/S is a subsidiary of Elsam.