How Does a Wind Turbine Work? From Blade to Grid

A wind turbine works by converting the kinetic energy of moving air into electricity. The wind pushes three aerodynamic blades, the blades spin a rotor, the rotor drives a generator, and power electronics shape that output so it can be fed into the grid. Everything else (the gearbox, the yaw drive, the pitch system and the control software) exists to do that one job safely and for as many hours a year as possible.

This is the foundation article for our wind-energy series. You can also watch an airborne alternative in the Solutions library: EnerKite reaches stronger, steadier wind with a flying kite instead of a fixed tower.

What are the main parts of a wind turbine?

A modern horizontal-axis turbine has five component groups:

• Rotor and blades. Three fibreglass or carbon blades, 50 to 90 metres long on utility machines, bolted to a central hub. Their aerofoil shape generates lift, not drag, which is why they can spin faster than the wind itself.
• Nacelle. The housing on top of the tower that holds the drivetrain, generator and controls.
• Drivetrain. On geared turbines a gearbox steps the slow rotor speed (around 10 to 20 rpm) up to the roughly 1,000 to 1,800 rpm a conventional generator needs. Direct-drive turbines skip the gearbox and use a large low-speed generator instead.
• Generator and power electronics. The generator makes variable-frequency AC, and a converter plus transformer turn it into grid-synchronised power.
• Tower and foundation. A steel or concrete tower, typically 80 to 120 metres, on a reinforced foundation that carries the whole load into the ground.

How does a turbine turn wind into electricity?

Wind flowing over the curved blades creates aerodynamic lift, which rotates the hub. The hub turns the main shaft, the drivetrain delivers that rotation to the generator, and the generator converts mechanical energy into electrical energy. A converter conditions the current, a transformer in or near the tower steps the voltage up, and the power travels through the wind farm's collector network to a substation and the grid.

How much electricity does one wind turbine produce?

A modern onshore turbine is rated at 3 to 6 megawatts. Because the wind does not always blow at full strength, what matters is the capacity factor: the share of its theoretical maximum a turbine actually delivers over a year. Good onshore sites run at 35 to 45 percent, so a single 4 MW machine can generate roughly 12 to 16 gigawatt-hours a year, enough to power several thousand homes.

What are cut-in, rated and cut-out wind speeds?

A turbine starts generating at the cut-in speed, around 3 to 4 metres per second. It reaches full rated output at roughly 12 to 15 metres per second. Above the cut-out speed, about 25 metres per second, it pitches its blades and shuts down to protect itself in a storm.

How is a wind turbine kept running safely?

Two control systems do most of the work. The yaw drive rotates the nacelle to face the wind, and the pitch system twists each blade to manage power and loads. A supervisory control and data acquisition (SCADA) system watches temperatures, vibration and output in real time, and mechanical and aerodynamic brakes can stop the rotor. Keeping all of this healthy over a 20 to 30 year life is the job of wind turbine maintenance, which we cover next, along with how onshore and offshore wind compare.

For more real-world energy solutions, from printed solar film to ocean power, explore the full Solutions collection or read about the web series.