How does a wind turbine work?

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Wind power is one of the most efficient forms of renewable energy. It can generate electricity to run homes and offices.

There are many advantages of wind energy. Not only does it have a smaller carbon footprint than fossil fuels, it also produces fewer pollutants. Plus wind is an infinite resource so it's constantly replenished.

But how does wind energy work? Just as solar power requires solar panels, wind power requires a  wind turbine. Keep reading to discover how wind turbines are used to generate renewable electricity.

How does a wind turbine work?

A wind turbine uses large blades to convert kinetic energy — which is energy from movement — into electricity. There are two types of wind turbines: horizontal-axis turbines are more common and typically have three blades that face into the wind, and vertical-axis turbines, which can operate no matter which direction the wind is blowing.

Wind turbines can operate alone but they typically run in a group called a wind farm. There are two types of wind farms: onshore and offshore. As the names suggest, onshore wind farms are situated on land, whereas offshore wind farms are located in large bodies of water, usually in the sea.

Here's how a wind turbine works:

  1. The wind blows against the blades of a wind turbine, making the blades turn.
  2. The rotor starts to spin, causing the shaft to turn.
  3. The shaft connects to the gearbox and increases the rotations from 30 to 60 per minute to 1,000 to 1,800 turns per minute.
  4. When the rotation speed is high enough, the generator uses magnetic fields to convert the rotational energy into electrical energy.
  5. The electrical output from the generator is sent to a substation, where transformers convert high voltages of energy into lower voltages that are safer for transmission.
  6. Transmission lines (also called power lines) carry the energy to homes and businesses.

How much electricity can wind turbines generate?

The amount of electricity wind turbines produce depends on their design, location, and generator power. For example, larger blades and taller towers may capture more wind, while larger generators can help convert greater amounts of rotational energy. Offshore wind turbines also tend to generate more power because they have access to stronger, steadier winds on the open water.

Most wind turbines have an ideal wind speed they operate at, usually between 48 and 88 kilometres per hour. When confronted with wind speeds higher than 88 kilometres per hour, generators typically shut down automatically to protect the turbine from mechanical damage. On the other hand, if the wind speed is minimal, the turbine may not rotate fast enough to generate substantial power.

How efficient is wind power?

Every wind turbine has a capacity rating, which indicates how much energy it could produce if it ran perfectly 100% of the time. The average capacity rating for an onshore wind turbine is 2.5 megawatts (or the equivalent of 2,500 kilowatts); an offshore turbine, however, might produce over 3 megawatts1.

Keep in mind, though: wind turbines can't operate at full capacity 100% of the time. Like any other machine, they have to undergo routine maintenance checks. Plus, the changing wind conditions affect how much energy a turbine is capable of generating on any given day. Because of these factors, it's common for most wind turbines to operate between 25% to 50% capacity.

But if you know how efficient a wind turbine is, you can predict its estimated electrical output each year2. For example, a wind turbine with a capacity rating of 2.5 megawatts and a capacity factor of 30%, would generate 6,570,000 kilowatt hours of electricity per year – enough to power roughly 2,260 homes3. That's just one wind turbine, though. An entire wind farm will generate considerably more power.

Wind power is the future

Like any source of renewable energy, wind power is dependent on nature, which means it's not always consistent. However, it's an incredibly efficient and affordable form of power, one that's becoming increasingly more popular throughout the UK.

And at E.ON we’re providing 3.4 million customers’ homes with 100% renewable electricity from sources including wind, biomass and solar4.

1. EWEA: Wind energy's frequently asked questions (FAQ)

2. Expected kilowatt hours per year = (365 days a year) times (24 hours a day) times (maximum capacity) times (capacity factor).

3. Based on national average consumption of 2,900 kWh for unrestricted electricity.

4. Electricity backed by 100% renewable sources. E.ON's renewable generation assets, agreements with UK wind generators and the purchase of renewable electricity certificates. The electricity supplied to your home comes from the National Grid and DNOs.