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.
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."