Offshore wind power

Forerunner in offshore wind power

Working in icy conditions and taking into account the effects of frozen sea when planning, constructing and maintaining wind turbines, is in the core of our expertise. Especially in our offshore projects on the coast of Pori and Raahe, the effects of ice can be dramatic because there is no archipelago breaking the masses of ice in front of the WTGs. Ulkonahkiainen is located in the northernmost part of the Gulf of Bothnia where the ice conditions are even more demanding than at the coast of Pori because of longer winters and pack ice.

When planning an offshore wind farm, the effects of the snow and ice load on the structures must be taken into consideration, and the structure must planned accordingly. Our construction schedules take into account the fact that the time-period for full-blown construction work lasts only from spring till autumn when the sea is open. Therefore, it takes two to three open water seasons to build an offshore wind farm. Taking care of maintenance in icy conditions requires careful planning as well. Suitable equipment is required for getting to the WTGs for maintenance when the sea is frozen.

Suomen Hyötytuuli's own foundation concept

In Tahkoluoto, the bedrock is close to the sea floor, which makes it impossible to use the monopile foundation generally used in offshore WTGs. Suomen Hyötytuuli uses a new kind of earth-banked foundation for offshore wind turbine generators which makes use of the mass of the WTG and the foundation. This so called gravity-based foundation makes it possible to build offshore wind turbines on load-bearing sea floor. Additionally, the structure is designed in a way that reduces the pressure and vibration caused by masses of ice: the conical shape steers the ice so that it does not hit the foundation directly.

Ongoing technological progress

Offshore wind power technology is developing at a rapid pace, thanks to great demand and investments. It has been estimated that in the next few years the production power of WTGs will rise up to 11–20 MW and that they will get as tall as 310 metres. The working life of WTGs is growing from the current approximately twenty years to over 35 years.

The infrastructure at the ports

Offshore wind power projects are demanding for port areas. In the winter there is a need for service vessels capable of breaking ice, and the port basin has to be kept clear of ice so that vessels are able to make maintenance visits. In addition, the port has to have enough areas for pre-assemblage and storage during both construction and production. Therefore, offshore wind power projects help develop infrastructure in these ports.