Friday, December 8, 2023

World’s first contra-rotating floating wind turbine to begin testing

Most wind turbines look like a propeller on a stick – which is fine. But this design makes less and less sense when taken out into the deep ocean, where most of the world’s best wind energy potential is located.

Conventional horizontal-axis wind turbines (HAWT) need to hold a lot of heavy components – such as the rotor, gearbox, and generator – right up the top of a tall tower. This makes it difficult and expensive to build and maintain a floating version that doesn’t want to tip over in the wind.

That’s why the Norwegian company World Wide Wind (WWW) has come up with an alternative design for offshore floating wind turbines that makes sense in this scenario. Their contra-rotating VAWT (vertical-axis wind turbine) has blades that reach upward, but all the heavy components are at the bottom, making it easier to maintain its upright position.

Additionally, the design can accept wind energy from any direction, eliminating the need for heavy gear that would be required to turn a turbine to face the wind.

Counter-rotating offshore, floating wind turbine design.
Counter-rotating offshore, floating wind turbine design. Credit: World Wide Wind (WWW)

The gigantic wind turbine developed by the company is claimed to have the ability to scale up to 400 meters in height, unlocking unparalleled power and density. At this point, a single tower could harvest an enormous 40 MW – nearly twice what the world’s largest wind turbines can do. This, in turn, is expected to significantly reduce the Levelized Cost of Energy (LCoE) for offshore wind power.

Additionally, the vertical axis turbines have less impact on wildlife as the rotating turbine is perceived as a natural obstacle. The low speed of the rotor blade’s wing tip prevents bird strikes. The design also allows for increased use of recyclable materials.

Now, the company has partnered with AF Gruppen, one of Norway’s largest industrial construction groups, to test the first WWW prototype at AF’s Environmental Base in Vats, on the southwest coast of Norway.

With a total length of 19 meters, the 30kW prototype turbine will demonstrate the main innovative elements of the WWW design, such as two counter-rotating blade sets on a vertical axis, a generator placed at the bottom of the structure, and a tilting mechanism that allows the turbine to adjust to the wind direction like a sailboat.

The company says its next prototype will be a much larger 1.5-MW pilot that is planned to be tested in early 2025. Also, WWW targets launching a commercial 24 MW turbine before 2030. The unique WWW design allows for the turbines to be scaled beyond 40MW.

“Offshore floating wind is about to become a significant contributor to the global renewable energy mix, but to truly unlock its potential, we need to develop sustainable and cost-efficient floating wind turbine solutions – not simply move land-based turbines offshore. Our turbines are especially designed for floating operations,” says Bjørn Simonsen, CEO of WWW, in an official statement.