How do wind turbines work?

Wind turbines are one of the cheapest forms of making energy available to us, and they generate clean renewable energy, all from the power of the wind. Here’s everything you need to know about how wind turbines work.

What are wind turbines?

A wind turbine, or windmill, is used to turn the wind’s kinetic energy into renewable electricity. Around 40% of all wind energy in Europe blows over the UK, so we’re an ideal place to create green energy from the wind.

You can find out more about wind energy here.

How do they work?

The blades of a wind turbine are built to be as aerodynamic as possible – so they can make the most of the energy from the wind, and turn it into rotational energy (this is what makes the blades spin!).

There are lots of different types of wind turbines, but most modern turbines have three blades which rotate clockwise. The blades are connected to a generator, which converts the rotational energy into green electricity.

Wind turbines can run at fixed or variable speeds:

  • Fixed speed machines run at one speed of rotation, whatever the wind power. They use a gearbox to generate electricity at the correct frequency for the grid.
  • Variable speed machines speed up and down with the wind. The correct grid frequency is generated by electronics.

Once the electricity is generated and converted to the correct frequency, it’s sent to the local grid via underground cables. That electricity then finds its way into homes around the country.

How are wind turbines controlled?

Wind turbines are controlled by computers, which monitor the direction and speed of the wind, using instruments mounted to the top of the turbine.

The ‘hub’ of the windmill (the part the three blades are attached to) is turned, so the blades are always facing into the wind. And the blades themselves are pitched (twisted) to either catch the wind, or to shed it as needed.

Advantages of wind turbines

There are lots of advantages to making green energy from the wind:

  • It can help fight climate change by generating green energy with no carbon footprint
  • It’s safer than burning fossil fuels, both environmentally and for human health
  • It’s completely sustainable, as the source of energy will always replenish

You can find out more about the advantages of wind energy here.

Are there any disadvantages?

Even green energy generation can come with drawbacks – but the disadvantages of wind turbines are minimal in comparison to the positive impact they have on the environment.

Noise

The blades on a wind turbine make a whooshing noise as they cut through the air, but only 3% of wind farms have reported noise problems. While wind turbines have been problematic due to noise in the past, most modern windmills make very little noise and are unlikely to cause disruption.

Wind turbines are usually placed a minimum distance of 300 meters away from residential homes, with sound levels reaching just 43 decibels. That’s about the same noise level as a fridge.

Are wind turbines a threat to wildlife?

Lots of studies have been carried out to assess the impact of wind turbines on wildlife and, while they’re not completely risk free, the danger to wildlife from wind energy generation is very small:

  • Birds. Due to pre-construction surveys and assessments needed for the construction of new wind farms, the potential impact on birds is exceedingly low compared to other threats to birds. At Ecotricity, we work closely with the RSPB to ensure our windmills work in harmony with the local bird population.
  • Bats. Ecotricity played a leading role in a major research project on bats and wind turbines. The study found that bat casualties at wind turbines are rare but that they occur on warm evenings in late summer, when wind speeds are low. We switch off our wind turbines in these conditions, to minimise risk even further.
  • Butterflies. While there’s no evidence that wind turbines pose any threat to butterflies, we don’t consider building windmills close to sites with high flying species, like the Purple Emperor.

Where can wind turbines be built?

There are a mix of offshore and onshore wind parks around the UK, but the government isn’t supporting wind energy production. Current government policy makes it very hard to get planning permission for onshore wind parks in England, so it might be a while before any more are built.

There’s a long list of rules which affect where wind turbines can be built, which includes:

  • How they would impact the local environment
  • The visual impact of the turbines
  • Noise levels
  • The minimum distance from residential properties (600 – 800 meters for large turbines)
  • The minimum distance from roads, power lines and gas pipelines

You can find out more information on the Local Government Association website.

Domestic wind turbines and home generation

If you’ve got the space and the budget, you could install a domestic wind turbine at home. They cost anything from £3,000 to £30,000, depending on size, but once they’re installed, they can generate 100% green energy for more than 20 years.

You can then use the electricity you generate to power your home, and you can also get paid for exporting it back to the grid.

Reasons to switch

Bill Clinton

"The earth is warming at an alarming rate, we are running out of fossil fuels, and it is long past time for us to take action to correct these problems."

Bill Clinton