Wind turbines use moving air to make electricity.
The wind turns the blades. The turbine then uses this movement to drive a generator.
In simple terms:
Wind → Blades turn → Generator → Electricity
However, the amount of electricity produced can change greatly with wind speed and location.
How Does a Wind Turbine Work?
Wind pushes against the turbine blades and makes them turn.
The blades are connected to a central hub.
This turns machinery inside the turbine, which drives a generator.
The generator then makes electricity.
Large modern turbines also have controls that help them face the wind and operate safely.
Why Are Turbines So Tall?
Wind is often stronger and less disturbed higher above the ground.
Closer to the ground, buildings, trees and hills can interrupt the airflow.
This creates turbulence and can reduce the useful wind reaching a turbine.
So, height can make a big difference.
It also explains why a turbine in an open, exposed location may perform very differently from one surrounded by buildings and trees.
Does More Wind Mean More Electricity?
Generally, yes — but the relationship is not simple.
A small increase in wind speed can make a large difference to the energy available.
However, every turbine also has operating limits.
If the wind is too light, there may not be enough energy for useful generation.
As wind speed rises, output increases until the turbine reaches its rated power.
Then, in very strong winds, the turbine may need to reduce output or stop for safety.
So, a turbine does not produce its rated power all the time.
What Does Rated Power Mean?
A turbine might be described as having a capacity of:
5 kW
500 kW
or several:
MW
This is its maximum rated power under the required conditions.
It is not the amount of electricity the turbine produces every hour.
For example, a 5 kW turbine will not normally make 5 kWh of electricity every hour of every day.
Actual generation depends heavily on the wind.
kW and kWh
These two measurements are easy to confuse.
kW measures power.
It tells you how quickly electricity can be produced at a particular time.
kWh measures energy.
It tells you how much electricity has been produced over a period.
So, when comparing turbines, do not look only at the kW rating.
The expected yearly generation in kWh is much more useful.
Why Does Location Matter So Much?
A wind turbine needs good-quality wind.
An exposed rural site may have much better conditions than a sheltered urban garden.
Nearby obstacles can also cause problems.
These include:
- houses
- trees
- walls
- other buildings
- hills and uneven land
So, putting a small turbine on a property does not automatically mean it will produce useful amounts of electricity.
The site needs to be suitable.
What Is Turbulence?
Wind does not always move in a smooth flow.
When it passes around buildings, trees and other objects, it can become disturbed.
This is called turbulence.
Turbulent wind can reduce turbine performance and place changing loads on the equipment.
So, simply feeling that a location is windy does not mean it is a good turbine site.
Wind quality matters as well as wind speed.
How Is Wind Speed Checked?
Wind conditions can be estimated using wind maps and local information.
However, these do not tell you exactly what will happen at one particular turbine position.
For a serious installation, better site information may be needed.
The important figure is the wind where the turbine will actually operate — at the correct height and position.
So, be cautious about estimates based only on a postcode or general area.
What Is a Capacity Factor?
You may see the term capacity factor when reading about wind power.
It compares the electricity actually produced over a period with the amount that would have been produced if the turbine had operated at full power for the whole time.
For example, imagine a turbine could theoretically produce:
10,000 kWh
if it ran at full power throughout a period.
If it actually produced:
3,000 kWh
its capacity factor for that period would be:
30%
This does not mean the turbine was only 30% efficient.
It mainly reflects the fact that wind conditions change.
What Happens When the Wind Stops?
The turbine stops producing electricity.
Electricity must then come from somewhere else.
For a home connected to the grid, the grid normally supplies the difference.
For the wider electricity system, other generators, stored energy, imports and changes in demand can all play a part.
Learn more: Offshore Wind and the Electricity Grid →
Can You Have a Wind Turbine at Home?
Yes, small wind turbines can be used at some homes and businesses.
However, they are much more dependent on location than many people expect.
A turbine may be worth considering where there is:
- a good wind resource
- an exposed location
- enough space
- few nearby obstacles
- a suitable turbine position
A sheltered suburban garden is a very different site from an exposed rural property.
So, the first question should not be:
“How big a turbine should I buy?”
It should be:
“Is there enough useful wind here?”
Roof-Mounted or Pole-Mounted?
Small turbines can sometimes be mounted on buildings or on separate towers or poles.
However, buildings themselves can disturb the wind.
So, a roof-mounted turbine may experience turbulent airflow.
A separate mast can sometimes place the turbine higher and farther from obstacles.
However, this needs space and may bring other practical issues.
Therefore, the best arrangement depends on the site.
What About Noise?
Wind turbines produce some sound.
This can come from the blades moving through the air and from the machinery.
The amount varies with turbine design, size, wind conditions and distance.
So, noise should be considered when choosing both the turbine and its position.
Nearby homes also need to be taken into account.
Do You Need Planning Permission?
Planning rules depend on the turbine, property and where you live.
Some installations may fall within permitted development rules when all the conditions are met. Others need planning permission.
Rules also differ across the UK.
So, check the current requirements for your property before buying or installing a turbine.
What Happens to the Electricity?
Electricity from a small turbine can normally be used by the property while it is being generated.
If the system is connected to the grid, extra electricity may be exported.
Depending on the installation and arrangements in place, eligible exported electricity may also receive an export payment.
However, export tariffs and eligibility rules can change.
So, check the current terms rather than building a long-term calculation around one advertised rate.
Will a Wind Turbine Save Money?
It can, but only if the site produces enough useful electricity.
The financial result depends on:
- turbine cost
- installation cost
- wind conditions
- yearly electricity generation
- electricity used on site
- export payments
- maintenance
- equipment life
So, a turbine with a low purchase price is not necessarily good value.
A poor site can make even a good turbine perform badly.
Before You Buy
First, establish whether the site has enough useful wind.
Then, look at the proposed turbine position and height.
Next, ask for an estimate of yearly electricity generation.
Also check:
- what wind speed the estimate assumes
- where that wind figure came from
- turbine rated power
- expected yearly generation in kWh
- nearby obstacles
- planning requirements
- noise
- grid connection
- maintenance
- warranty
- full installation cost
Finally, compare the expected yearly benefit with the full cost of owning the system.
Do not buy a wind turbine based on its kW rating alone.
Key Points
Wind turbines turn energy in moving air into electricity.
Wind speed, height and location have a major effect on generation.
Rated power does not tell you how much electricity a turbine will make over a year.
Small turbines can work well at suitable sites. However, sheltered locations can perform poorly.
For wind power, the site is just as important as the turbine.
Important Information
Energility provides general information to help you understand energy, household and business costs, services and ways to save money. It is not financial, legal, tax, technical or professional advice.
Prices, tariffs, grants, government schemes, regulations and other information can change. Costs, savings and calculator results are estimates and your actual results may be different.
Before making an important financial decision, signing a contract or carrying out significant work, check the latest information and consider getting advice from a suitably qualified professional where needed.
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Next: Offshore Wind and the Electricity Grid →
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