by John Dray

The Vindeby wind farm in the Baltic Sea off the coast of Denmark

Wind power has been the second most successful source of renewable energy in the developed world (HEP being the most successful). However, in the past wind power has been limited to only a few sites for various factors providing little energy. Until now.   Denmark leads the way in the development of offshore wind farms. In 1997 alone the total wind-power capacity in Denmark was close to 1,000 MW, Wind power corresponded to more than 6% of total Danish electricity consumption. However, there are only two 'test' farms offshore but results from these wind farms is so positive that there is every indication that offshore wind farms will be the big area of focus in future. There are now plans for large-scale offshore wind farm development in Denmark.

The offshore wind industry is expected to play a considerable part in helping the UK to work towards the Government's target of 10% of electricity supplies from renewable sources.

Windfarms are being built at sea because of the strong winds and because suitable sites are difficult to find onshore due to the population density and visual scenic considerations.

The first offshore windfarms were small scale affairs built by the Danish at Vindeby in the Baltic Sea off the coast of Lolland and Tunø Knob in Kattegat between Jutland and Tunø, both erected in the early 1990s However, current offshore projects have much higher establishment costs than those onshore, first and foremost due to the costs of foundation construction.

The first large offshore wind farm in Europe will be Middelgrunden off the coast of Copenhagen where twenty, 2MW wind turbines will be erected. Future wind turbines for offshore sites will become even larger. Wind turbines of sizes up to 5 MW are under development.

Unfortunately, costs for servicing of offshore turbines may alone approach a factor 10 compared to that for onshore turbines. There are other problems. The possible impact on wildlife is one important matter. Large-scale offshore wind-farm development would require thorough studies of the possibility of significant impact on birds.

But the future for offshore wind farms is good. Not only is there a need for more renewable energy sources power from large farms will be similar in price to those from coal and other power stations (coal $0.04 kwh, wind $ 0.05 kwh). Wind power seems to be the only existing source from which large amounts of renewable energy can be produced. It will not, however, ever play more than a supporting role in energy generation because of its utter unreliability.