---
title: "Wind availability factor and turbine components"
subject: "Energy Environment and Society"
chapter: 3
key: "semester_7/energy_environment_and_society:wind-availability-components"
source: https://www.bctengineer.com/q/semester_7/energy_environment_and_society/wind-availability-components
site: BCT Engineering
---

# Wind availability factor and turbine components

Energy Environment and Society · Chapter 3: Renewable Energy Sources

- Asked in: 2070 Asar, 1+3 marks
- Video: [How does a Wind Turbine Generate Electricity (PLUS HOW MUCH)](https://www.youtube.com/watch?v=9D1bXGUuqlc) — ENERGY WARDEN
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/energy_environment_and_society/wind-availability-components
- Whole chapter: https://www.bctengineer.com/md/semester_7/energy_environment_and_society/chapter-3

## Question

What is the major factor determining the availability of wind power? What are the major components of wind turbine?

## Short answer

Wind speed is the major factor because power varies as the cube of wind speed (P = ½ρAv³). Main components are rotor blades, hub, nacelle containing gearbox and generator, yaw drive, brake, tower, controller, anemometer/wind vane, and transformer.

## Answer

#### Major factor determining availability of wind power
**Wind speed** is the major factor, because wind power is proportional to the cube of wind speed (P = ½ ρ A v³). A small increase in speed gives a large increase in power. Other factors are air density, swept area, height and the terrain.

#### Major components of a wind turbine
1. **Rotor blades:** capture wind energy; made of fibreglass or carbon fibre (usually 2 or 3 blades).
2. **Hub:** connects blades to the main shaft; may include a pitch mechanism.
3. **Nacelle:** housing on top of the tower that contains the gearbox, generator and controller.
4. **Low-speed shaft, gearbox and high-speed shaft:** gearbox raises 15–30 rpm up to 1000–1800 rpm for the generator.
5. **Generator:** converts mechanical energy into electricity (induction, synchronous or permanent magnet).
6. **Controller, anemometer and wind vane:** measure wind speed and direction and start or stop the turbine.
7. **Yaw drive:** turns the nacelle to face the wind.
8. **Brake:** stops the rotor for maintenance and in strong wind.
9. **Tower and foundation:** support the rotor at height (60–120 m for large turbines).
10. **Transformer and power cables.**

```text
     \ | /   rotor + hub
  [ gearbox | generator ]  nacelle
        ||
        ||  tower
      -----
```

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Why is wind speed the major factor in wind power availability?
   A. Power is proportional to the cube of wind speed
   B. Power is proportional to speed
   C. Power depends only on blade count
   D. Speed sets the air density
   Answer: A. P ∝ v³, so a small increase in speed gives a large increase in power. (Key point: Major factor)

2. What does the nacelle contain?
   A. The gearbox, generator and controller
   B. The tower foundation
   C. The transformer substation only
   D. The rotor blades only
   Answer: A. The nacelle is the housing atop the tower containing gearbox, generator and controller. (Key point: Nacelle)

3. What is the gearbox for?
   A. Reducing generator speed
   B. Raising rotor speed of 15-30 rpm to 1000-1800 rpm for the generator
   C. Turning the nacelle
   D. Braking the rotor
   Answer: B. Rotors turn slowly but generators need high speed, so the gearbox steps it up. (Key point: Gearbox role)

## Related in Energy Environment and Society

- [Wind sources, turbines, parks, power control](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Awind-sources-turbines-parks-control) — Energy Environment and Society, chapter 3
- [Hydropower site power and turbine](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Ahydro-site-power-numerical) — Energy Environment and Society, chapter 3

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