Group 5 Wind Power in the UK
by kaurimut on November 21, 2014 - 6:16pm
Early European offshore wind energy studies, carried out during the late 1970s and early 1980s, generally concentrated on assessments of three key interrelated issues:-
• wind speeds and wind characteristics,
• The magnitude of the energy resource,
• The feasibility and cost of building wind turbines offshore
Most of the studies looked at the feasibility of using machines with ratings in the range two to 5 MW, arranged in clusters of up to a hundred or more machines. Although there were no commercial machines of this type in operation, there were a number of land-based prototypes and experimental machines, and the expectation was that commercial designs would soon follow.
The power outputs from these conceptual wind farms were in a range from about 300 MW upwards and they were capable of producing electrical energy on a similar scale to a conventional power station. Most envisaged sites around 20 km or more offshore
Studies of this kind were carried out in Denmark, the Netherlands, Sweden and the United Kingdom. Elsewhere, the Westinghouse Corporation carried out an extremely detailed study for United States Department of Energy, which looked at both horizontal and vertical-axis designs.
These early studies were possibly ahead of their time. Offshore development, in practice, has proceeded in a more evolutionary manner, initially with relatively small machines sited close
6to the shore. Nevertheless, they identified many of the key issues involved in the exploitation of offshore wind energy. The increased wind speeds at offshore sites were, and are, a key issue and the importance of water depth and seabed conditions was also recognised. It was clear that adequate information about wave conditions was needed, partly ensure that there were no problems with machine dynamics and partly to ensure that the turbine blades were clear of the waves at all times. The cost of the grid connection to the shore showed up as a significant proportion of the total – typically around 25%.