Located on Lake Vänern in Sweden, InnoVent’s unique offshore wind farm consists of 8 wind turbines with a capacity of 3 MW each. InnoVent, a Northern French SME specialized in the development of wind and solar farms, is dedicated to minimizing its environmental impact. It has partnered with Liftra, a Danish company specializing in lifting and transport solutions for the wind industry, to perform maintenance on two wind turbines of its offshore Swedish wind farm using a self-hoisting crane, a world first.

The maintenance and upkeep of an offshore wind farm can quickly become expensive, time-consuming, and environmentally damaging.

In practice, a massive 700-ton crane, around fifteen trucks, and a large barge to stabilize the crane are required for wind turbine maintenance, such as gearbox replacements. Besides being costly, this operation emits CO2 due to the diesel consumption of the trucks, crane, and the barge-towing boat.

By substituting the 700-ton crane with the Liftra self-contained crane, around 200 liters of fuel per day are saved. InnoVent goes further by powering other construction equipment from the wind turbine (like the boat), saving an additional 100 liters per day.

Advantages of the self-hoisting crane

This system eliminates the need for the 700-ton crane, reduces the number of trucks from fifteen to two, and employs a significantly smaller barge. The Liftra crane is self-hoisting, utilizing the wind turbine itself as its support structure.

No extra crane is required to hoist the Liftra self-hoisting crane to the top of the wind turbine. It is raised using cables stretched between the nacelle and the ground (or the barge in this case). Besides being three times cheaper than a conventional crane, this system results in substantial fuel savings: a total of 13,000 liters, equivalent to 35 tons of CO2. It is fully electric and powered from the wind turbine’s grid, recharging its batteries during descent.

Furthermore, the process is completed in just three days, compared to the usual week. As the barge is significantly smaller, only a three-month wait is required, in contrast to the standard year for traditional barges. A tremendous time-saving advantage!

New projects

In 2023, three more wind turbines on Lake Vänern will be serviced using the self-contained crane. Beyond this, the system will be used for upcoming gearbox replacements for our WWD3 models.

In the future, InnoVent plans to adapt the self-contained crane for use on their Siemens 3.6 wind turbine, the tallest in Africa. This solution offers significant savings compared to a standard crane for lifting components at a height of 150 meters.