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Enercon inaugurated its third 4.5 MW prototype wind turbine at the Wybelsumer Polder wind station at a coastal site in East Frisia, Germany, in early June. The machine will produce sufficient energy to cover the needs of 126,000 households, says Enercon owner Aloys Wobben. The giant Enercon prototypes, all turning in Germany, are the largest wind turbines in operation anywhere. The first was installed at Wilhelmshaven in September 2002 and was followed by a second at Magdeburg, where Enercon has a production facility for turbines and blades. "There aren't many differences between the prototypes, just some small things," says Wobben.

The East Frisia machine has a hub height of 124 metres and rotor diameter of 114 metres. Each blade weighs 20 tonnes and the rotor turns at a majestically slow 8-13 times a minute The nacelle without blades weighs 440 tonnes. The cut in wind speed is a low 2.5 m/s. Installation currently requires use of two cranes. "We are working on a method involving only one crane but that needs some time," says Wobben.

repowering

Another six 4.5 MW turbines are planned for the East Frisia wind station, which is operated by regional utility EWE. The foundation for the first is already being poured. The others will replace older machines, including five 500 kW turbines and one 1.5 MW machine, all originally supplied by Tacke, a company now absorbed into GE Energy. The same wind station also consists of a number of turbines supplied by Enercon. Wobben says that of these, five Enercon 500 kW units could also be repowered.

Sites at the port of Emden are being developed for two further Enercon units by wind plant developer Ingenieurgesellschaft für Energieprojekte, a company based in Emden. One is for the local port authority, while Enercon will own the other for testing of a wind powered desalination plant.

The first erection of a 4.5 MW unit in seawater is planned for the end of the year. It will be sited close to land in the Jade estuary near the port of Wilhelmshaven for Winkra Energie, a subsidiary of Dutch utility Essent.

Wobben notes that 7500 Enercon 4.5 MW machines could meet 25% of German electricity demand. He adds that 184,000 high-voltage pylons of comparable size already exist that have "aroused little complaint about landscape desecration."