Why can wind turbines generate so much electricity when their rotation speed is so slow?

On the vast sea, rows of wind turbines stand, slowly turning, continuously converting offshore wind energy into clean electricity and sending it to thousands of households. So, can wind turbine blades that turn so slowly really generate electricity? Is the electricity generated enough? Let's explore the mystery of wind turbine power generation.

In fact, the power generation principle of wind turbines is not complicated. It mainly uses wind power to drive the rotation of wind turbine blades, converts wind energy into mechanical energy, and then converts mechanical energy into electrical energy through the rapid rotation of asynchronous motors.

Since the fan blades rotate slowly, and the wind force and direction may change at any time, the motor speed is unstable. Therefore, each fan has a gearbox that can increase the speed to the rated speed of the generator, plus a speed regulating mechanism to keep the speed stable, and then connected to the generator. With the gearbox, even if the fan blades rotate slowly, the motor speed can be guaranteed to be stable.

In order to maximize the effect of the wind turbine, there is a tail rudder behind the wind rotor that can sense the wind direction. It can transmit information to the control system and notify the fuselage to correct the direction so that the wind rotor is always facing the wind direction.

Of course, the fan has a rated speed. When the wind speed is too fast, the angle of the blades must be rotated to change the windward area and reduce the speed of the blades. When the wind speed exceeds the fan's limited speed, the fan must stop working immediately, otherwise it will cause the blades to break and the cabin to catch fire.

So, how much electricity can a wind turbine generate in one rotation?

Let's dig deeper. Take the 18MW wind turbine that was just successfully developed in early 2023 as an example. The impeller diameter of this wind turbine is 260 meters, and the impeller swept area is about 53,000 square meters. At full wind speed, a single unit can generate 44.8 degrees of electricity per rotation, and can output more than 74 million degrees of clean electricity per year, which can meet the annual living electricity needs of 40,000 households of three.

Therefore, although wind turbines rotate slowly, they generate a lot of electricity. Since wind resources are inexhaustible, wind turbines can continuously generate electricity, which is transmitted to the shore via submarine cables, providing a clean power source for all walks of life. This is the secret of wind turbine power generation.