An international team of scientists under the ‘Shiver Project’ is working to find out how well 200-metre tall wind turbines react to and function in chillier waters.
Led by Finland’s Aalto University and featuring Netherlands’ Delft University of Technology (TU Delft), and Spain’s Siemens Gamesa Renewable Energy, the scientists believe the results of their study could finally bring off-shore wind farms to more frosty regions across the globe.
At present, off-shore wind farms are largely located in waters that don’t enter deep freezes and there’s a reason for that.
Ice-induced vibrations, the tiny or large shakes that occur when ice collides with infrastructure, are one of the major concerns for bringing the massive turbines into ice-infested areas.
“We don’t actually know what kinds of force and pressure ice creates on off-shore wind turbines,” notes Aalto assistant professor Arttu Polojärvi.
“This is the first time anyone has carried out fully controlled model-scale laboratory experiments to find out,” says Polojärvi, alluding the Aalto Ice Tank.
The Aalto Ice Tank is the world’s largest indoor ice basin measuring 40 by 40 metres.
It is one of the only places globally where researchers can customize huge slabs of ice and precisely test how they interact with these kinds of human-made structures.
‘What’s special about our experiments that we tested at -11°C to make sure the ice is strong and breaks realistically,’ explains TU Delft assistant professor Hayo Hendrikse.
According to Hendrikse, the physical testing was carried out with a 30:1-scale model pile, with the help of numerical modelling to simulate wind and other conditions a wind turbine would encounter at sea.
In real-life terms, the load exerted from the ice during the experiments would be around 8 meganewtons – that’s the combined thrust of 16 of the largest aircraft engines!
‘The preliminary results show something that we haven’t seen before in other structures, like lighthouses, channel markers, or oil and gas platforms,” notes Hendrikse.
“A wind turbine is very tall and slender and can move a lot; what we’ve seen in our experiments seems to be a totally new type of ice-induced vibration.”
Going forward, the scientists plan to create more robust numerical models in order to test various scenarios that a wind turbine might encounter in chilly conditions over half a century of service.
Image and content: Anna Berg/Aalto University