Energy

Offshore wind farm

The most recent wind farms are usually placed offshore, on the sea, far from the coasts, where it is possible to exploit the strong winds not delayed by obstacles. This happens on the sea surface, but also on the great lakes. Unluckily, the realisation and maintenance costs of these offshore wind farms are more elevated than the onshore ones, because of the transportation costs, the great building problems, the difficulty to anchor their towers on the bottom and, in the end, the corrosive action of the sea water on their structures. For instance, it would be possible to work on a maximum depth of 200 meters, but usually no more than 20 m or not beyond than 20 km from the coast, to allow low costs. Anyway, these marine plants have great productivity advantages. On the sea surface, as matter of fact, winds blow without any obstacle, with a higher speed and with less changeableness. The offshore placement of great wind farms also solve the acoustic and aesthetical problems, the tower being placed beyond the line of the horizon, at least 3 km from the coast. This would solve the danger for the most part of bats and birds, migratory and birds of prey, too. Some researchers affirm that the creation of undersea platforms and pylon and cable systems could realize, after some time, restocking and biodiversity areas on the sea bottom, like it currently happens with the anchorages of the offshore rigs.
Therefore, the offshore plants represent, according to the most part of the specialists of this sector, the true future of the aeolian energy, for what concerns both the environmental problem and the production potential. In 2007, the offshore plants produced about the 3,5% of the European aeolian energy, owned for the most part from Denmark and United Kingdom, followed by Holland and Sweden; in 2008 the largest aeolian offshore production happened in the UK, followed by Denmark. At present, the largest offshore wind farm is placed off the Lincolnshire coasts (Great Britain), with an installation power of 194 MW. Nowadays, we may see great projects for the offshore aeolian: the United Kingdom planned to enlighten every house of the country with the wind farm offshore energy within 2020, while Canada is planning to build an offshore wind farm on the Great Lakes. One of the world's largest offshore wind farm, called London Array, will be built on the estuary of the Thames, with an installed power of 630 MW (then, 1 GW). This plant will give energy to 750.000 houses, about ¼ of the London houses, with 341 turbines placed 12 nautical miles from the coast. Even this European offshore wind farm will be interconnected, also connected with all the onshore farms.