Tahkoluoto Extension

Tahkoluoto Offshore Oy cancelled the two-turbine demonstration phase associated with the Tahkoluoto offshore wind farm Extension project and decided to proceed directly with developing the full 40-turbine extension. The demo project, which had secured a EUR 30 million investment grant from Finland’s Ministry of Economic Affairs and Employment and was intended to pilot large 15 MW turbines, deep-water foundation concepts and construction methods at 15–45 metres depth, was discontinued because delivery schedule changes would have invalidated the grant and because of high cost pressures and uncertainty over offshore wind property taxation in Finland; the decision was stated not to affect the scope or 2027–2029 construction timeframe of the main extension project, whose investment decision remains scheduled for end-2026.

In 2024, following a full demerger of Suomen Hyötytuuli Oy into three companies, the entire Tahkoluoto offshore wind farm Extension project was transferred to a new project company, Tahkoluoto Offshore Oy, which became responsible for developing the 40‑turbine extension, while a new Suomen Hyötytuuli Oy retained the operating wind farms and Arenso Oy took over personnel and lifecycle service roles.

In early May 2024, Suomen Hyötytuuli (on behalf of Tahkoluoto Offshore Oy) carried out test dredging of the seabed in the Tahkoluoto offshore wind farm Extension project area off Pori to trial suitable methods for constructing offshore wind power in the site’s conditions, continuing earlier test dredging activities.

On 8 March 2024, Suomen Hyötytuuli Oy initiated a full corporate demerger by filing a demerger plan with the Finnish Patent and Registration Office. Under the plan, the company’s existing operating wind farms will be transferred to a new firm retaining the Suomen Hyötytuuli name, while a separate entity, Tahkoluoto Offshore Oy, will take ownership of the new Tahkoluoto offshore wind farm extension project off Pori. This restructuring, scheduled to be completed by the end of summer 2024, establishes Tahkoluoto Offshore Oy as the dedicated owner and developer of the extension project and its associated infrastructure, including the future grid connection, separating these assets from the legacy Tahkoluoto offshore wind farm and its existing export link.

Tahkoluoto Offshore Oy reported that the demo phase of the Tahkoluoto offshore wind farm Extension project, involving two large offshore turbines in deeper waters, had been granted the necessary water and building permits, authorising construction of the demonstration facilities linked to the extension.

Suomen Hyötytuuli initiated Front End Engineering Design (FEED) work for the turbine foundations of the Tahkoluoto offshore wind farm Extension project, which will use turbines of at least 15 MW in deeper waters than before off Pori. The FEED phase marks a key late-development step, defining technical solutions for gravity-based foundations suited to 15–45 metre water depths ahead of procurement and investment decisions.

On 15 February 2023, Finland’s Ministry of Economic Affairs and Employment awarded a EUR 30 million grant, funded via the EU Recovery and Resilience Facility, to the Tahkoluoto offshore wind power demonstration project associated with the Tahkoluoto Extension, supporting construction of two 15 MW deep-water turbines and de-risking offshore wind development at the site.

State land and water manager Metsähallitus and Suomen Hyötytuuli signed a long-term access right contract under which Metsähallitus leases the public water area off Pori’s Tahkoluoto to the developer for the Tahkoluoto Extension offshore wind farm. The agreement, described as Finland’s first long-running access right contract for a public water area designated for wind power, enables construction of up to 40 modern turbines of over 15 MW and allows the project to proceed to permitting, technical design and investment preparation.

The land use plan (component master plan) for the Tahkoluoto offshore wind farm extension, allowing for 40 modern offshore wind turbines of over 15 MW, was approved by the Pori City Council in November 2022, providing municipal planning consent for developing the extension area northeast of Tahkoluoto.

In summer 2022, the Finnish Government granted Metsähallitus the right to lease state-owned water areas off Pori Tahkoluoto specifically for the Tahkoluoto Extension offshore wind farm, enabling the state land and water manager to act as lessor for the project area. This decision established the legal basis for Metsähallitus to conclude a long-running access right contract with the developer for wind power production at the extension site.

BalticWind, citing Finnish broadcaster Yle, reported that the Environmental Impact Assessment for the Tahkoluoto offshore wind farm extension had been carried out, with the Finnish Environment Agency concluding that a significant expansion could negatively affect the environment but recommending that the project proceed with limitations, including capping the extension at 40 turbines and applying protection measures for nearby Natura 2000 sites and sensitive bird areas.

An Environmental Impact Assessment for the Tahkoluoto offshore wind farm extension identified significant environmental and landscape constraints, concluding that expansion should be limited to 40 turbines and must pay particular attention to nearby Natura 2000 sites. The Finnish Environment Agency highlighted main impacts on the aquatic environment during construction, on bird migration and foraging areas such as Pihlavanlahti and Preiviikinlahti, and on the seascape, and noted that the subsea cable could not be routed through the Gummandoor Nature Reserve.

The City of Pori’s planning unit announced that the draft component master plan, plan report and appendices for the Tahkoluoto offshore wind farm expansion would be available on its website from 8 April to 14 May 2021, opening a municipal land use planning consultation for the extension area.

The environmental impact assessment report for the Tahkoluoto offshore wind farm expansion project was scheduled to be made available from 1 March to 30 April 2021 on the official EIA website, initiating a formal period for the public and stakeholders to review the documentation and submit comments.

Suomen Hyötytuuli announced that a public information meeting on the Tahkoluoto offshore wind farm extension project, covering its Environmental Impact Assessment (EIA) procedure and zoning process, would be held in Pori on 28 September 2020 to inform stakeholders and invite feedback on the planned expansion.

Finland’s renewable energy developer Suomen Hyötytuuli began preliminary studies for expanding the existing 44.3 MW Tahkoluoto offshore wind farm, describing the Tahkoluoto Extension project as being in a preliminary study phase with environmental impact assessment and zoning about to start. The proposed extension at this stage envisaged 300–500 MW of capacity, with up to 45 turbines of 11–16 MW each across a 128–135 km² area off Pori in the Gulf of Bothnia.

Suomen Hyötytuuli defined a specific offshore area for the Tahkoluoto Extension, proposing a wind farm of up to 45 turbines with 11–16 MW unit capacity located in waters 10–50 metres deep, around four kilometres from the existing Tahkoluoto wind farm and covering 128–135 km². This marked the selection of the development site for the planned 300–500 MW extension offshore Pori.