The potential of offshore windpower is enormous

It could meet Europe’s electricity demand seven times over, and the United States’ electricity demand four times over. Over the last five years, offshore wind power has developed from a somewhat expensive, but promising segment in the green transition, to a full-blown contender to be the dominant source of electricity in Northern Europe, the Eastern Seaboard of the United States, Japan, Taiwan and elsewhere.

Due to the good wind resource and favourable shallow water conditions of the North Sea, this is by far the best developed offshore wind area, accounting for almost 70% of the world’s cumulative installed offshore capacity. Until now the majority of installations have been sited at locations less than 40 km from shore and at water depths rarely exceeding 30 m, since distances to shore and water depth are both significant cost drivers.

While the offshore wind industry is thriving in Northern Europe, many countries are prevented from utilizing otherwise favourable offshore wind resources due to scarcity of suitable shallow water, suitable legislation, and infrastructure in the form of fabrication yards and installation vessels. Stiesdal Offshore Technologies A/S has set out to change this.

Stiesdal Offshore Technologies A/S develops industrialized, low-cost floating and bottom-fixed wind turbine foundations

The solution to the challenge of genuine deep-water offshore wind power is floating offshore wind turbines. As the designation implies, a floating wind turbine is not permanently fixed to the seabed but floats, but kept in position by a mooring system. While floating foundations will take up a significant part of the future market, there will be also a rapidly growing need for cost-effective foundations for the large, 10+ MW turbines of the future, particularly at interim water depths, in the range of 30-60 m.

At the present time, floating offshore wind power is significantly more expensive than bottom-fixed offshore wind power due to non-industrialized manufacturing of the floating platforms. This also applies to bottom-fixed foundations for large wind turbines at large water depths. Furthermore, there is currently no economically viable solution for installation of the 10+ MW turbines of the future; the vessels required for this are scarce and the rates are very high.

Industrialized offshore foundations for any water depth

Stiesdal Offshore Technologies A/S has developed new concepts for both floating and bottom-fixed foundations, both suited for manufacturing in genuinely industrialized processes.

The TetraSpar floating offshore concept provides a low-cost floating offshore wind turbine platform suitable for installation under any conditions, leading to a cost of electricity similar to that of bottom-fixed offshore wind power.

The TetraBase bottom-fixed foundation concept provides a low-cost offshore wind turbine foundation that can be installed without the use of any installation vessel.

Both concepts are assembled from factory-made components, manufactured with semi-automated processes, leading to unprecedented low cost levels.