The Tahkoluoto Offshore Wind Farm expansion project comprises 40 turbines of over 15 megawatts. The area is located off the coast of Pori, 4–22 kilometres from the shore. The offshore wind turbines will be erected at a depth of 15–45 metres. The construction of the expansion project is expected to take place in 2027–2029.
At the beginning of 2025, Tahkoluoto Offshore, the Port of Pori and the City of Pori signed a letter of intent on cooperation. The letter of intent defines in more detail the use of Pori Offshore Wind Hub as the primary logistics and pre-installation centre for the Tahkoluoto Offshore Wind Farm expansion project.
The areas of Pori Offshore Wind Hub will be developed to make their infrastructure meet the needs of the expansion project. The letter of intent provides a clear two-year window for implementing the necessary investments in the port area.
Pori as the primary operator
“For us, Pori Offshore Wind Hub is the primary operator that we wish to utilise in the expansion project. Proximity is a source of competitive advantage, but, naturally, in a project of this scale, we are also building a nationwide cooperation network,” says Manu Grönlund, Project Director, offshore wind projects at Arenso Oy.
In autumn 2024, Suomen Hyötytuuli prepared for the large offshore wind power investment in Tahkoluoto by carrying out a full demerger. In the demerger, the wind farms of the former Suomen Hyötytuuli Oy were transferred to the ownership of the new Suomen Hyötytuuli Oy, and the newly established entity Tahkoluoto Offshore Oy focused on the implementation of the Tahkoluoto expansion project. Another new company, Arenso Oy, provides its services for the development, implementation and life-cycle management of the wind power projects of Suomen Hyötytuuli Oy and Tahkoluoto Offshore Oy.
The owners of Suomen Hyötytuuli, which are eight regional energy companies, will continue as the owners of all three new companies.
“The demerger is part of preparing for the implementation of this large project, which is valued at over EUR 2 billion.”
Tahkoluoto is already home to the world’s first offshore wind farm that operates in frozen sea conditions. The wind farm is operated by Suomen Hyötytuuli.
“The first turbine has been in operation for 15 years now, and the subsequent 10 turbines have been in operation since 2017. We have not had any significant unexpected problems with the turbines. The overall availability rate of the wind farm as a whole is 98%. This would not be possible without proactive maintenance.”
Proximity saves money
According to Grönlund, the highly reliable wind farm is an excellent reference that has attracted attention around the world. In the spring, Arenso signed an agreement with the Estonian company Utilitas Wind on the basic design of the Saare-Liivi offshore wind farm, which will comprise 80 turbines.
“The existing Tahkoluoto Offshore Wind Farm is unique in many ways. It is exceptional to have a commercial port located so close to a wind farm. The installation work can practically be done on-site. Not having to bring components and installation vessels from 100–200 kilometres away reduces risks. Proximity saves money.”
The advantage of proximity takes on a concrete form, particularly when it comes to the use of installation vessels.
“Their daily cost is so high that the use of the vessels must be very efficient.”
Having the foundations manufactured close by is also a source of advantage.
Pori Offshore Wind Hub ensures smooth logistics
According to Grönlund, key partners play a critical role in the construction and operation of wind farms. The logistics, warehousing and processing of components delivered from various parts of the world must be highly optimised, as the effects of any delays are multiplied.
Reserving installation vessels and making efficient use of their window of operation is a particularly important aspect of the project.
“The expansion of Tahkoluoto will be a world-class project. The construction will require the largest vessels, and reserving their time slots in advance is of critical importance,” Grönlund points out.
In practice, the vessels are reserved as soon as the investment decision is made and the wind turbine supplier is selected. It could be up to three years before the vessels are actually needed.
A strong spirit of collaboration in the Pori region
“The investment decision on an expansion project is made when the project is profitable for the owners. That is why it would be important for the real estate tax rate for offshore wind power to be lowered to the same level as onshore wind power, for example,” Grönlund says, describing the factors that influence the investment decision.
Grönlund characterises the Pori region as having a strong spirit of collaboration. Quality standards and the level of ambition are high, as they should be in a world-class project.
“We are very pleased that the City of Pori is closely involved in the development of Pori Offshore Wind Hub, which is essential for the expansion. Everything affects everything else. For example, the turbine supplier must be confident that the facilities are in order. We communicate the needs of the equipment suppliers to the city so that all of the parties involved can prepare for the right level of requirements. There is a strong spirit of collaboration — everyone knows that the challenges cannot be solved alone.”