Offshore repowering in Bockstigen, Gotland
What is it?
What did we do?
Repowered five 20 year old turbines with 5 refurbished Vestas V47 (wings and nacelles)
What was the outcome?
The wind park is situated in Bockstigen in Gotland, Sweden and was the world’s third offshore wind park, erected in 1998.
The project consists of 5 pcs., 20-year-old, 550 kW Wind World turbines and the turbines have produced since then.
By the time of decision, 4 out of 5 turbines was still running but very near the end of their technical lifetime.
Low electricity prices and no subsidies had created an insecure future for the project and decisions needed to be made.
From plan to execution
Momentum made a plan for replacing existing turbines with refurbished or new turbines. It was decided to replace nacelles, wings and controllers from the old turbines with refurbished Vestas V47 nacelles and new DEIF controlling and monitoring system.
A sustainable approach to repowering
Technical lifetime extension of wind park by at least 15 years. Used existing tower, grid and foundations, saving the owners a fortune.
The use of refurbished main components such as gearboxes, wings, generators etc., was the first example of its kind in the area, giving new possibilities in similar projects.
From end of lifetime to an expected long-term double digit IRR on gross investment at market conditions (no subsidies).
Kim Madsen from Momentum says:
Next project is on the way
The Project shows that in many cases it is a better, and perhaps even the only, solution, to recycle and renovate old wind turbines and replace the existing and technically worn-out wind turbines with these.
Momentum Gruppen A/S therefore expects the wind turbine owners to increasingly look for similar solutions in the future, where the economy or local limitation or hinder the erection of new, large and modern wind turbines.
Momentum Gruppen A/S is already in the process of the next project in Sweden, where altitude restrictions in the area make the use of refurbished and technologically updated wind turbines the only economically viable option for the erection of wind turbines in the area.