13 September 2023
By Michelle Lewis
 

Single-blade wind turbine works at wind speeds of 157 mph
The design takes out expensive components of the three-blade turbine while also offering lower costs for installation and servicing.

Artist's illustration of the single blade turbine at work

Netherlands-based TouchWind BV isn't a regular player in the wind energy industry, looking to make larger wind turbines to harness more energy. Instead, the company is working to change what a wind turbine looks like, dumping the three blades in favor of a single large one.

For years, the wind energy industry has adopted the three-blade model for its turbines. As the world looks for cleaner sources of energy, the turbines are getting larger and are also going deeper into the seas, where winds blow stronger.

The turbine design requires adaptions in these environments, such as pitch control, to generate maximum power. These additions add to the cost of the turbine, but when wind speeds exceed design specifications, the turbine needs to be shut down to avoid damage. Touchwind's single-blade design solves both these issues in one stroke.

How does a single-blade turbine work?
The blade is attached to the mast at a slight upward angle. When the wind speed is low, the mast tilts over and falls into the water but is prevented from doing so by a dangling buoy.

As the wind speed increases, the spin motion of the single blade generates lift and pulls the mast upright. The buoy is lifted out of the water and now serves as a ballast weight to keep the blade from taking off. Since the blade is no longer at an angle to the wind, it prevents it from spinning faster. The whole assembly is floating on the water's surface and anchored to the sea floor.

TouchWind claims that its turbine can function at wind speeds of up to 70 meters per second (157 mph), with the rotor finding its own pitch. In comparison, a conventional three-blade turbine has to be stopped at wind speeds exceeding 25 meters per second (56 mph).

The cost reduction
Since the design does not need pitch control systems, which are expensive components, TouchWind claims that costs of manufacture can be reduced by as much as 30 percent. The lack of multiple components also makes it feasible to manufacture the turbine at the harbor, further reducing the costs of transport.

Fully assembled single blade turbine can be towed to site of installation - TouchWind

The assembled turbine can simply be towed from the harbor to the site of installation and become functional after being anchored to the sea floor. A 656-foot (200 m) blade is estimated to generate 12 MW of electricity, sufficient to power 15,000 households.

As turbines get larger and farther into the sea, maintaining them is becoming a herculean task. Weather conditions can get quite rough in the deep sea, and taller turbines need access via a crane or helicopter to complete routine maintenance.

In TouchWind's design, the maintenance crew only needs to grab the cable connecting the buoy and rotor. With the rotor not spinning, the assembly lies closer to the water surface and can be serviced using a boat.

The company is currently carrying out field tests of its small-scale designs in the Netherlands and even received investments from a Japanese shipping Mitsui OSK Lines. The shipping company also invested in another wind turbine company, SeaWind, last year.

Details of the commercial rollout of the technology are not available yet.