Wind turbines are now a relatively common sight across Europe, with
countries such as Denmark, the Netherlands, Germany, UK, Spain and latterly
France, all investing in wind farms. Offshore wind development, although far
less advanced, is the greatest prize in this field. However, relative costs of
offshore compared to onshore are higher.
This project is aimed to demonstrate the economic as well as technical
viability of offshore wind energy. The former was achieved through the
innovative use of a floating jack-up barge which reduced the time and costs of
installation. The latter was achieved mainly through the incorporation of new
electronic control systems which improved the compatibility with the grid
network, and reduced the need for expensive grid strengthening measures.
Five turbines were installed, about 4 km off the coast of Gotland. Each
turbine is rated at 500 kW. The average annual output is some 8 GWh/y, from
mean wind speeds of 8 m/s. Rock-socketed steel mono-pile foundations, to
water depths of 5 to 6.5 m were used to secure the turbines. Total construction
time was only 35 days. Monitoring of impacts on local flora and fauna, such as
the seal population, is also being carried out.