The Lestijärvi wind farm will be equipped with 69 units of Siemens Gamesa’s SG 6.6-170 onshore wind turbines. Credit: Siemens Gamesa.
The Lestijärvi facility will be the biggest wind farm in Finland, upon completion. Credit: YIT Corporation.
The project area is located on the south and southwest sides of Lake Lestijärvi. Credit: Tetopa/Wikipedia.

The Lestijärvi wind farm is an onshore wind farm under construction in Finland by OX2, a Swedish renewable energy developer.

The 455MW wind energy project will produce more than 1.3TWh of green power a year, enough to meet the needs of approximately 280,000 homes and equivalent to 2% of Finland’s total energy production upon completion.

The wind farm is expected to be the biggest in Finland, once it becomes operational in early 2025.

Project acquisition and proposed sale

The project rights for the Lestijärvi wind farm were acquired by OX2 from Finnish construction company YIT in February 2021.

OX2 reached an agreement to build the wind project and then sell it to a Finnish consortium for €650m ($737.31m), in November 2021.

Electricity generation company Kymppivoima will hold 65% stake in the project, while the remaining partners in the consortium, Oulun Energia and Kuopion Energia, will own 25% and 10% respectively, according to the agreement. OX2 will also provide technical and commercial management services for the project for 15 years, upon commissioning.

Lestijarvi wind farm location

The Lestijärvi wind farm is located in the municipality of Lestijärvi in Central Ostrobothnia, on the south and southwest sides of Lake Lestijärvi. It is being developed in an area spanning approximately 11,000ha and mainly comprising a drained, forested marshland.

Lestijarvi wind farm make-up

The Finnish wind farm will be installed with 69 units of Siemens Gamesa SG 6.6-170 onshore wind turbines from Siemens 5.X onshore platform series. The wind turbines will feature rotors with a diameter of 170m and a swept area of 22,697m2.

The turbines are equipped with a 6.6MW generator, which provides one of the lowest levelised cost of energy (LCoE) across the industry. Out of the 69 turbine units, 64 will be mounted on 155m-high towers, while the remaining five will be mounted on 145m-high towers.

The 5.X onshore platform series incorporates a doubly-fed generator and partial converter combination, and a compact drive train design with a three-stage gearbox layout.

Power transmission

The electricity generated by the Lestijärvi wind farm will be transferred to a new 110/20kV substation that will be constructed within the project area. A 110kV overhead transmission line will transfer the power from the substation to the north-west of the site where a new 400/110kV substation will be constructed.

A 400kV overhead line from the 400/110kV substation will then redirect the power to the Alajärvi substation in Ostrobothnia, which will further transmit the power to the national electricity grid.

The new 400kV transmission line will be installed along national electricity transmission grid operator Fingrid’s existing 2x400kV Pikkarala-Alajärvi transmission line route. The 110kV section of the line will have a length of approximately 8km, while the 400kV section will be 58km long.

Contractors involved in Finland’s largest wind project

The turbine supply contract for the project was awarded to renewable energy technology company Siemens Gamesa. It also includes the provision of full-scope services for the turbines for 35 years.

Finnish law firm Borenius provided advisory services to OX2 for the divestment of the Lestijärvi wind farm to the Finnish energy consortium.

Roschier, a Nordic law firm, represented the Finnish energy consortium in the transaction.

Hannes Snellman was appointed as the counsel for OX2 in the negotiations for the construction contracts for the full grid and balance of plant package, which includes balance of plant works, transmission lines, substations, and transformers.

OX2 executed two contracts with Eltel Finland, a field service provider for communication and power networks, to build the 110kV and 400kV transmission lines.

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