"Offshore developments are unlikely to be as lucrative as good onshore projects and we must tap all possibilities for improving their economics," says Frank Richert of GEO. Grid connection for DanTysk will be expensive. To reach an interconnection point of sufficient capacity for 1500 MW of wind generation, a cable must be brought onshore at the Schleswig-Holstein coast and then extended over land for 200 kilometres to reach a transformer station at Brunsbüttel Wilster. There, it would feed into the 380 kV network of E.On Netz. Total cost: about DEM 1 billion (EUR 511.3 million).
A possible alternative is to use most of the DanTysk electricity to run an electrolysis plant at sea for the production of hydrogen from water. "By the time the wind station is running in about 2005, companies like Shell and BMW will be well advanced with their plans for hydrogen cars and may be interested in buying the hydrogen," says Richert. "The surplus electricity, from about 250 MW of wind generation, can be taken ashore and fed into the grid near Lübeck, a shorter route," he adds.
The offshore electrolysis unit would be about the same size as the wind plant's transformer station at sea: about 50 metres square, 30 metres high, and weighing about 1000 tonnes, Richert says. It is not yet clear whether the hydrogen would be compressed or liquefied for transport. GEO expects to have a detailed breakdown of the costs of its offshore developments once the so-called application conference -- at which all authorities and other interested parties discuss the options for each project -- is complete.
The Sky 2000 project, also known as Schleswig-Holsteinischen Offshore-Windpark Verwaltung (1.SHOW), is planned for 55 turbines located 19 kilometres from the east Holstein coast. It is 30% owned by GEO and 70% by other individuals. A contract has been signed with Vestas for supply of 17, 2 MW V80 offshore machines, but other suppliers have yet to be decided. Slots are set aside for five prototypes of up to 5 MW in size from different manufacturers, which will be tested for their suitability for the North Sea wind farm. GEO anticipates that construction of Sky 2000 will begin in 2003, with commissioning in 2004. The electricity will be brought onshore to a transformer station near Rostock to be fed into the network of utility E.dis Energie Nord.
The DanTysk project, owned exclusively by GEO, covers an area of 600 square kilometres straddling the latitude marking the German/Danish border beyond the 12 sea mile limit. The first 200 MW phase of construction is planned for 2005, says Richert.