How a wind turbine makes electricity
A wind turbine converts the kinetic energy of moving air into rotation, then into electricity. It cannot capture all of the wind’s energy: some air must keep flowing past the rotor.
In 60 seconds: how it works
A wind turbine turns the push of moving air into electricity. The wind spins the blades, the blades turn a generator, and electronics and a transformer match the power to the grid.
- Wind pushes on the blades, which are shaped like aeroplane wings, so they lift sideways and spin the rotor.
- The slowly turning rotor drives a shaft. In most turbines a gearbox speeds the rotation up.
- The generator turns the spinning shaft into electricity.
- Power electronics convert that electricity to the exact frequency and voltage the grid needs.
- A transformer raises the voltage so the power can travel through cables to the grid.
Want the engineering detail? Explore the 3D model, then read the engineering notes and the types and variations.
By Power Stations Worldwide · Related reading updated · Preparation and review scope. Educational illustrations; no independent engineering peer review is claimed.
Explore the equipment in 3D
Rotate equipment, follow energy flows and inspect each component. Read the steps below at any time.
Choose a step to read the process. Activate the 3D model or start a guided tour to use the animation controls.
Geared horizontal-axis turbine with a permanent-magnet synchronous generator and fully rated back-to-back converters. The nacelle, gearbox, generator and converter cabinets are educational cutaways. The simplified 12:1 ratio, dimensions and efficiencies are illustrative; direct-drive and doubly fed machines are different architectures. Motion is slowed for inspection. Coloured overlays reveal flow through enclosed equipment; gold pulses show net electrical energy transfer, not individual electrons.
How it works
- Moving air
- Blade lift and rotor torque
- Generator rotation
- Electrical conversion
- Transformer and grid
Wind turbines take energy from moving air. Airfoil-shaped blades develop lift, creating torque around the rotor shaft. The main bearing supports the rotor loads; a drivetrain carries the turning force to a generator. In the illustrated turbine, gearing increases rotational speed before the generator. Other machines connect the rotor directly to a generator designed for slower rotation. Neither arrangement creates extra energy: mechanical and electrical losses reduce the power available for export.
The turbine is an actively controlled machine. Yaw turns a horizontal-axis nacelle towards the wind, while blade pitch changes the aerodynamic loading. The generator and power electronics regulate electrical output, and a transformer connects the turbine to the collection network. Output varies with the available wind and operating limits. The moving blades therefore should not be read as a promise of constant generation. A wind farm combines many turbines with cables, controls and a shared grid connection.
From wind capture to grid-compatible AC
The model shows one coherent geared turbine, not every wind-turbine architecture. Use a stage button or click equipment in the activated 3D view to inspect the same stage. Selecting a stage changes only the explanation and camera.
Selected stage: Whole-system overview
Simple explanation
Lift on the twisted blades creates shaft torque. Pitch bearings turn each blade to regulate capture. Bearings and the bedplate support the loads through the yaw bearing, tower and foundation; shafts, gears and the coupling carry torque to the generator. These are different paths. [W1]
A permanent-magnet synchronous generator (PMSG) produces AC as its magnets rotate past stationary stator windings. A fully rated converter carries all generator power: generator-side voltage-source converter (VSC) → capacitor-equipped DC link → grid-side VSC. Pulse-width modulation (PWM) controls switching. The generator frequency can vary while the selected grid stays at 50 Hz. [W2]
The AC filter precedes switchgear, the tower-base transformer and the collector network. Friction and conversion losses become heat; lubrication and cooling remain necessary. The capacitor is a short-term electrical buffer, not an energy source or a wind-farm battery. No separate DC/DC stage is required by this chosen architecture. [W1] [W2]
Engineering details
Equations, controller assumptions and gear speeds
Uniform steady inflow supplies P_air = ½ρAv³; rotor capture is P_aero = CₚP_air; tip-speed ratio is λ = ωR/v for v > 0. Here ρ is air density (kg/m³), A = πR² is swept area (m²), v is wind speed (m/s), R is tip radius (m), ω is rotor angular speed (rad/s), and Cₚ and λ are dimensionless. [W2]
Our original teaching curve is Cₚ(λ, β) = 0.46 max(0, x(2 − x)) cos³β, with x = λ/7 and β the collective pitch angle in radians. This constructed curve is not from the books or a manufacturer. Below rating, ω = 7v/R; above rating, ω is capped and inverse pitch reduces shaft input to its limit. Parked states use zero speed, zero capture and 90° feather pitch. This does not model aerodynamic forces, inertia, startup, braking or controller stability.
In the fixed-ring planetary stage, (1 + N_r/N_s)ω_c = ω_s + (N_r/N_s)ω_r. N denotes tooth count; subscripts s, r and c mean sun, ring and carrier. With N_s = 24, N_r = 72 and ω_r = 0, the sun turns at 4ω_c. Each 24-tooth planet turns at −3ω_c relative to its moving carrier, or −2ω_c absolutely. The 36:12 external pair then gives generator speed −12ω_c. Negative signs indicate relative rotation, not negative exported power. [W5]
Revolutions per minute (rpm) are n = 60ω/(2π). For the illustrative 16-pole PMSG, generator fundamental frequency f_gen = 8|n_gen|/60 (Hz), using eight magnetic pole pairs. [W6] The grid-side converter maintains the grid interface independently; switching ripple, waveform harmonics and reactive-power control are not computed.
Each stage uses P_out = ηP_in and P_loss = P_in − P_out, where η is its assumed efficiency. Rotor torque magnitude is T_rotor = P_aero/ω; generator input torque is gearbox output divided by |12ω|. These steady-state torque identities are evaluated only while rotating. Net export equals the final collection output minus modeled auxiliaries.
Illustrative assumptions and checked example
Not a real turbine specification: R = 68.4 m, ρ = 1.225 kg/m³, peak Cₚ = 0.46, optimum λ = 7, net rating = 5.000 MW; gearbox and generator efficiencies each 0.96; both converters each 0.98; transformer plus collector 0.99; producing auxiliaries 20 kW. The 12:1 overall ratio is simplified for teaching and is not a commercial gearbox rating.
At the reset example v = 8 m/s: 4.609 MW available wind → 2.120 MW rotor input → 1.838 MW net export. Losses/use total 0.282 MW. The checked balance is 2.120 = 1.838 + 0.282 MW (display values rounded). Physical rotor speed is 7.818 rpm, generator speed -93.818 rpm, λ = 7, pitch 0°, and generator fundamental 12.509 Hz.
The derived rated wind is 11.142 m/s, using P_shaft,rated = (P_grid,rated + P_aux)/∏η and v_rated = [P_shaft,rated/(½ρACₚ,max)]⅓. The region definitions follow the books, but our 3 m/s cut-in, 25 m/s cut-out and every numerical setting above are illustrative. No hysteresis or real-turbine standby import is included. [W1] [W2]
What the cutaway does not prove
The scale is approximately 10 m per scene unit. Components are enlarged for readability; station distances are compressed; open housings and simplified gear teeth are teaching views. The 8.6 m rotor overhang is deliberately exaggerated to keep the enlarged pitch bearings clear of the supporting bedplate. The rigid model checks geometric clearance, not blade bending, stress, fatigue, foundation safety, cooling capacity or standards compliance. Background turbines provide context; the calculations describe only the selected turbine.
- A gearbox increases speed and reduces torque; it does not multiply power.
- A transformer changes AC voltage; it cannot perform AC/DC conversion.
- Motion, camera selection and particle density are not electrical measurements. Gold pulses show energy direction, not electron speed.
- Rated output is a limit, not continuous generation. This is a bounded steady-state teaching model, not validated plant-operation simulation.
Main book references
- [W1] J. F. Manwell, J. G. McGowan and A. L. Rogers. Wind Energy Explained: Theory, Design and Application, 2nd ed., Wiley, 2009. ISBN 9780470015001; DOI 10.1002/9781119994367. Checked Chapter 1, §§1.1–1.1.2, printed pp. 2–7 in the lawful publisher excerpt.
- [W2] O. Anaya-Lara, N. Jenkins, J. Ekanayake, P. Cartwright and M. Hughes. Wind Energy Generation: Modelling and Control, 1st ed., Wiley, 2009. ISBN 9780470714331. Checked Chapter 1, pp. 4–5, equations (1.1)–(1.4), and §1.2.2.2, pp. 9–10 in the lawful publisher excerpt.
- [W3] R. W. Erickson and D. Maksimović. Fundamentals of Power Electronics, 3rd ed., Springer, 2020. DOI 10.1007/978-3-030-43881-4. Only the public introductory abstract was checked. Detailed PWM/inverter chapters remain unverified further reading; W2 supplies the accessible book basis for the selected topology.
- [W6] H. H. Woodson and J. R. Melcher. Electromechanical Dynamics, Part I, Wiley, 1968; lawful MIT OpenCourseWare reissue, 2009. Checked §4.1.8, equation (4.1.95), in the MIT-hosted chapter for the synchronous mechanical/electrical frequency relationship.
Supplementary technical sources
- [W4] US Department of Energy, How Do Wind Turbines Work?: supplementary equipment overview.
- [W5] MathWorks, Planetary Gear: ideal gear constraints and ratios: kinematic equations, not tooth-strength certification.
Wind-upgrade passages and sources checked . No independent engineering peer review, commercial-equipment validation or design approval. Full aerodynamic chapters, switching-control chapters and manufacturer drawings were not reviewed.
Inside the engineering
Follow the machinery, the working fluids and the electrical connection.
Mechanical
Twisted aerofoil blades develop lift. The main bearing carries rotor loads, while the low-speed shaft, planetary gearing and high-speed shaft transmit torque to the generator. The tower carries these loads into its foundation.
Thermal & chemical
There is no combustion. Bearings and gears still require lubrication and cooling: friction and electrical losses become heat. Blade pitch controls captured power, including limiting loads in strong winds.
Electrical
The 16-pole generator feeds variable-frequency three-phase AC into a generator-side PWM voltage-source converter, paired DC rails and capacitor, then a grid-side PWM converter and AC filter. All generator power traverses this full converter, with no separate DC/DC stage. The selected grid interface is 50 Hz. Tower cables, switchgear, transformer and collection network carry the output onward.
Main types and variations
The model shows a geared horizontal-axis turbine. Drivetrain and location are separate choices: an onshore or offshore turbine can use either a geared or direct-drive generator. The foundation changes with the site.
Geared drivetrain
A gearbox accepts the rotor’s relatively slow rotation and high torque, then drives a faster generator shaft. Its ratio changes speed and torque in opposite directions. Bearings, gear teeth and lubrication carry loads and remove frictional heat; the gearbox does not multiply the available mechanical power.
What changes in practice
A faster generator can be more compact, but the gearbox adds components to inspect and maintain. Generator size and drivetrain maintenance must be considered together.
Direct-drive generator
The rotor drives a low-speed generator without a speed-increasing gearbox. The generator must produce electrical power while turning slowly, so its construction differs from a high-speed machine. Permanent-magnet and electrically excited designs exist; direct drive describes the mechanical connection, rather than specifying one magnet or winding technology.
What changes in practice
Removing the gearbox reduces one source of moving parts. It also changes generator mass, nacelle layout and material requirements, so it is an engineering trade-off rather than a universal improvement.
Onshore wind
A land-based turbine transfers rotor and tower loads into a foundation in the ground. Turbines may supply a nearby user or form a wind farm connected to the wider grid. The energy conversion remains aerodynamic lift, shaft rotation and generation, regardless of the size of the installation.
What changes in practice
Location and grid connection distinguish a local distributed project from a utility wind farm. Neither label tells you whether the machine has a gearbox.
Fixed-bottom offshore wind
A monopile, jacket or another fixed structure supports the turbine from the seabed. A monopile is a large tubular foundation; a jacket uses a braced framework. Foundation selection responds to seabed conditions and structural loading, while the turbine above still converts wind-driven rotation into electricity.
What changes in practice
The support structure is a major part of the offshore plant. Installation methods and seabed conditions can change the appropriate foundation even for otherwise similar turbines.
Floating offshore wind
A buoyant platform supports the turbine and mooring lines restrain it relative to anchors on the seabed. Spar, semi-submersible and tension-leg arrangements achieve stability differently. The platform can move, so designers consider the combined response of the wind turbine, floating structure and mooring system.
What changes in practice
Floating supports open access to deeper-water wind resources. Platform motion and station keeping become additional engineering questions beyond those of a turbine on a fixed foundation.
Worth knowing
- Rated capacity (MW) is an output limit, not continuous production. Pitch control limits power and loads; turbines may stop in extreme winds or be curtailed by their operator.
- The turbine manufacturer (for example Vestas, Siemens Gamesa or Enercon) supplies the equipment; the wind farm’s owner and operator are usually different companies.
- Offshore turbines use the same principle, with foundations fixed to the seabed or floating.
See real examples
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Show on the mapRelated answers
Textbook references
Suggested technical background for this topic. These books are further reading, not proof that every explanation was checked against every edition. See the full bibliography and review scope.
- Wind Energy Explained: Theory, Design and ApplicationBlade aerodynamics, the Betz limit, power curves and turbine design.
- Wind Energy HandbookLoads, control systems, wakes and offshore support structures.
Sources
- EIA: Electricity generation from wind ↗
- EIA: Types of wind turbines ↗
- US DOE: Wind turbine aerodynamics and drivetrains ↗
- Manwell et al.: Wind Energy Explained, 2nd ed., checked Chapter 1 excerpt ↗
- Anaya-Lara et al.: Wind Energy Generation, checked Chapter 1 equations and full-converter topology ↗
- MathWorks: ideal planetary-gear constraints ↗
Cutaways reveal enclosed equipment. Layouts, dimensions, materials and animation speeds are illustrative; this is an educational model, not a plant design or a thermodynamic simulation.