As a clean and renewable energy source, wind power is gradually becoming a significant force in the global energy transition. A wind turbine is a device that converts wind energy into mechanical power, which drives the rotor to rotate and ultimately generates electrical power.

When you mention "wind turbine," do you immediately picture the "classic three-blade white windmill"? Besides this iconic design, real wind turbines come in various intriguing forms.

Why three blades?

Windmills, as the precursors of wind turbines, played a significant role in drainage in the Netherlands, becoming famous worldwide. The image of the four-bladed Dutch windmill is deeply ingrained in people's minds. Multi-bladed windmills for water pumping were also popular in the American West. Multiple blades can generate greater power for the entire wind wheel, providing more ample power.

So why did wind turbines become three-bladed instead of four or more?

The number of blades doesn't directly affect energy utilization efficiency.

On the contrary, too many blades can disrupt airflow, reducing the utilization efficiency of wind energy. Wind energy utilization devices can capture and utilize a maximum of 59.3% of the kinetic energy in the wind. This means that even a wind turbine with only one blade can generate the same amount of electricity.

However, single-blade wind turbines have not become mainstream. A single blade would cause an extreme imbalance in the wind wheel, posing a severe threat to the safety of the entire wind turbine assembly. Imagine a bunch of clothes tangled together during spin-drying... The entire washing machine would vibrate violently, possibly even breaking down.

Symmetrical two-bladed designs can improve this imbalance, but they are still unstable. Applying two-bladed wind turbines remained limited before more ideal load control technologies emerged.

Three-bladed wind turbines solve the balance problem with their optimal layout. However, "weight" has become one of the "pain points." A wind turbine blade weighs up to 20 tons, and a wind wheel with three blades exceeds 60 tons, making it a hefty heavyweight. If there are any issues with the ground foundation, the entire assembly could topple over.

Some manufacturers "break down" wind turbines into multiple small blades, transforming them into multi-headed, multi-armed configurations. In 2016, the wind energy leader Vestas installed a wind turbine with four wind wheels at the Technical University of Denmark.

After operating silently for two years, the assembly was completely dismantled. Due to the model's rarity, related data remains exceptionally valuable, and the two institutions have never publicly disclosed any data to date.

No blades, no problem

Scientists are not content with mediocre blade designs and have proposed "bladeless" solutions. The legendary electrical genius Nikola Tesla once applied for a patent for a bladeless turbine, but it never materialized due to a lack of suitable manufacturing materials.

Based on this concept, people developed bladeless wind turbines with a snail-shell-like appearance. Wind drives the internal disc to rotate, powering the generator to produce electricity. However, these "Piggy Peppa"-like wind turbines- require strict precision when manufacturing each component. Additionally, the wind must align with the inlet, limiting their development.

People developed bladeless wind turbines with an "inverted horn" shape to harness winds from all directions. Installed and used in Hengshui City, these wind turbines can capture wind energy from all directions and fully utilize gentle breezes as airflow enters the interior and travels through gradually narrowing ducts, its speed increases, ultimately driving the generator at the narrowest section to produce electricity.

In addition to "tricking" the wind into their interiors for electricity generation, some companies have gone a step further, reverting to the simplest pillar-like structure and introducing bladeless vortex generators (Vortex Bladeless).

These generators utilize the "Kármán vortex street" phenomenon: as air flows past, it creates vortices, inducing the pillar to oscillate. Simply put, the pillar sways, and electricity is generated. However, the efficiency of this model is extremely limited, and prolonged vibration exacerbates material wear. As of now, it lacks commercial viability.