A modern wind turbine can generate hundreds of thousands to tens of millions of kilowatt-hours (kWh) of electricity per year, depending on its size, wind conditions, location and capacity factor.
A large 5-megawatt (MW) wind turbine, for example, could theoretically produce 43.8 million kWh per year if it operated at full power continuously. In reality, wind turbines do not run at maximum output all the time. At a 35% capacity factor, the same turbine would generate about 15.3 million kWh per year, or an average of roughly 42,000 kWh per day.
The important point is that a turbine's advertised capacity is not the same as the amount of electricity it actually produces.
So how much electricity does a wind turbine really generate? Let's work through the numbers.
The amount of electricity a wind turbine produces depends mainly on:
- the turbine's rated capacity
- wind speed and consistency
- rotor size
- turbine height
- location
- capacity factor
- maintenance and downtime
- restrictions imposed by the electricity grid
Wind turbines vary enormously in size. The U.S. Energy Information Administration (EIA) notes that small turbines can have capacities around 10 kW, while the largest operating turbines are around 15 MW. (U.S. Energy Information Administration)
That means there isn't one answer to the question.
A useful way to think about it is:
Bigger turbine + stronger, more consistent wind = more electricity generated.
But even a very large turbine won't produce its maximum rated output every hour of the year.
Before looking at the calculations, it helps to understand two terms that are often confused: power and energy.
Power is the rate at which electricity can be produced.
It is measured in:
- watts (W)
- kilowatts (kW)
- megawatts (MW)
A wind turbine rated at 5 MW can produce up to 5 MW of electrical power under the conditions for which its rated output applies.
Electricity generation is the amount of electricity produced over a period of time.
It is commonly measured in:
- kilowatt-hours (kWh)
- megawatt-hours (MWh)
- gigawatt-hours (GWh)
For example, a 1 MW generator operating continuously for one hour produces 1 MWh of electricity. (U.S. Energy Information Administration)
This distinction is crucial when answering how much electricity a wind turbine produces.
A 5 MW turbine doesn't necessarily produce 5 MWh every hour.
It might produce 5 MW for part of an hour, 3 MW at another time, 1 MW later, and nothing when the wind is below its operating range.
Let's use a 5 MW turbine as an example.
There are:
8,760 hours in a year
If the turbine somehow operated continuously at its full 5 MW capacity:
5 MW × 8,760 hours = 43,800 MWh
That's:
43.8 million kWh per year
But this is a theoretical maximum.
Wind turbines don't operate at full output continuously, so we need to account for their capacity factor.
Capacity factor measures how much electricity a generator actually produces compared with what it could have produced if it operated continuously at full power during the same period.
In simple terms, it tells us how much of a turbine's theoretical maximum output is actually being generated over time. The EIA defines it as the ratio of actual electrical energy produced to the energy that could have been produced at continuous full power.
But turbines don't operate at full power continuously.The wind itself is constantly changing. Wind conditions vary enormously across Europe — and even at the same location, they change from hour to hour. This variation is one reason a turbine's rated capacity doesn't translate directly into its annual electricity production.
Suppose our 5 MW turbine has a 35% capacity factor.
First, calculate its theoretical maximum annual generation:
5 MW × 8,760 hours = 43,800 MWh
That's 43.8 GWh if the turbine operated at full power for every hour of the year.
Now apply the 35% capacity factor:
43,800 MWh × 0.35 = 15,330 MWh
So the turbine would generate approximately 15.3 GWh per year, or 15.3 million kWh.
Using our 5 MW example and a 35% capacity factor:
15.33 million kWh ÷ 365 = approximately 42,000 kWh per day
So, on average, our hypothetical turbine would generate about:
But there's an important qualification.
That does not mean the turbine generates exactly 42,000 kWh every day.
Wind is variable.
One day might be exceptionally windy and produce considerably more electricity. Another could be relatively calm and produce much less.
The 42,000 kWh figure is simply the annual average divided by 365.
Wind generation also varies seasonally. For example, EIA analysis of U.S. wind plants has found substantial seasonal differences in capacity factors. (U.S. Energy Information Administration)
So, how much electricity can a wind turbine actually produce? The answer comes down to three numbers: its capacity, the hours in a year, and its capacity factor.
1. Wind speed
Wind speed is one of the most important factors.
A turbine needs sufficient wind to operate, and its electrical output changes as wind speed changes.
This means that two identical turbines can produce very different amounts of electricity if they are installed in different locations.
A turbine in an exceptionally windy location may generate considerably more electricity over a year than the same model in a less suitable location.
2. Turbine size
Larger turbines generally have the potential to produce more electricity.
Modern wind turbines can be enormous compared with the small turbines used for individual properties.
The EIA notes that turbine size varies widely, with small turbines capable of around 10 kW and the largest operating turbines reaching roughly 15 MW. (U.S. Energy Information Administration)
But generator capacity isn't the only factor.
3. Rotor diameter
The blades capture energy from the moving air.
A larger rotor sweeps through a larger area and can capture more energy from the wind.
This is one reason modern turbines have become increasingly large: increasing rotor size allows turbines to capture more energy, including in locations where wind speeds aren't exceptionally high.
4. Turbine height
Wind speeds generally increase with height above the ground.
That makes taller towers attractive for many wind projects.
The precise benefit depends on the characteristics of the site, including terrain and surface roughness.
5. Location
The same turbine model can have very different annual electricity production depending on where it is installed.
Developers therefore spend considerable effort assessing the wind resource before building a wind farm.
The EIA notes that wind generation depends strongly on the availability of wind resources, which vary by region and season. (U.S. Energy Information Administration)
6. Capacity factor
Capacity factor brings all of these variables together.
A high capacity factor means a turbine is producing relatively close to its maximum possible output over the course of the year.
A lower capacity factor means its actual annual generation is further below its theoretical maximum.
Importantly, capacity factor isn't the same thing as efficiency.
A 35% capacity factor does not mean the turbine is "65% inefficient."
It means the turbine's average electricity generation over the period was equivalent to operating at 35% of its maximum rated capacity continuously.
Offshore wind turbines can be substantially larger than many onshore turbines. They can also benefit from stronger and more consistent wind resources in suitable locations.
To see how this translates into electricity generation, consider a hypothetical 15 MW offshore turbine operating at a 45% capacity factor.
Under these assumptions, the turbine would generate approximately 59.1 GWh of electricity per year.
That figure is an estimate, not a fixed output. Actual generation depends on the turbine's design, wind conditions, availability and the characteristics of its offshore location.
A wind turbine's annual electricity generation can also be expressed in terms of household electricity consumption.
Take our hypothetical 5 MW turbine, which generates approximately 15.33 million kWh per year.
If a household uses 3,500 kWh of electricity per year, we can compare the two.
Under these assumptions, the turbine's annual generation is equivalent to the annual electricity consumption of approximately 4,400 homes.
This is an annual electricity equivalent, not a measure of how many homes the turbine supplies at any given moment. Wind generation varies over time, as does household electricity demand, and the electricity is delivered through the wider grid.
A wind farm is simply a collection of wind turbines operating together.
Suppose a hypothetical wind farm contains:
50 turbines
and each turbine produces:
15.33 million kWh per year
The total annual generation would be:
50 × 15.33 million = 766.5 million kWh
That's approximately:
766 GWh per year
or:
0.77 TWh per year
This illustrates why large wind farms can make a substantial contribution to electricity supply.
The actual production of a wind farm depends on the turbines, their spacing, wind conditions, availability, transmission constraints and other factors.
A common misconception is that a turbine is either producing its full rated capacity or producing nothing.
In reality, output can vary continuously.
A turbine may:
- produce relatively little electricity in weak winds
- increase its output as wind speed rises
- reach its rated output at sufficiently high wind speeds
- maintain rated output over a range of wind speeds
- shut down when winds become extremely strong
- stop temporarily for maintenance or technical reasons
The result is a fluctuating electricity output over the course of hours, days and seasons.
This is why annual electricity production is much more useful than simply looking at the turbine's nameplate capacity.
When wind speeds are too low for a turbine to operate, it produces little or no electricity.
That doesn't mean the electricity system stops working.
The electricity grid has to continuously balance electricity supply and demand. Other generators, energy storage, interconnections and changes in electricity consumption can all play roles in maintaining that balance.
This is one reason why understanding generation over time, rather than simply installed capacity, is so important when discussing wind power.
If you want to estimate the annual electricity production of a wind turbine, you can use this formula:
For example:
5 MW × 8,760 × 0.35
= 15,330 MWh
= 15.33 GWh
= 15.33 million kWh
You can use the same formula for almost any turbine.
For example, a 10 MW turbine with a 40% capacity factor:
10 × 8,760 × 0.40 = 35,040 MWh
So its estimated annual generation would be:
35.04 GWh
The calculation is simple. Determining a realistic capacity factor is the harder part.
A wind turbine’s capacity tells you how much electricity it can produce at its maximum output. Generation tells you how much electricity it actually produces over a period of time.
The difference is important because a turbine does not operate at its maximum output all the time. Wind speeds change, so the amount of electricity produced depends on how often the turbine is generating and how much power it is producing when it does.
To see why this matters, compare two turbines.
Turbine A has a capacity of 5 MW and a capacity factor of 35%.
Turbine B has a capacity of 10 MW, making it twice as large, but its capacity factor is only 20%.
Now calculate how much electricity each produces in a year.
Turbine A
5 × 8,760 × 0.35 = 15.33 GWh/year
Turbine B
10 × 8,760 × 0.20 = 17.52 GWh/year
Despite having twice the installed capacity, Turbine B produces only around 14% more electricity.
This is why installed capacity on its own does not tell you how much electricity a wind project will generate. The chart below explains the three measures to look for: capacity, generation and capacity factor. It shows what each one means and how they relate to each other.
Not necessarily on a simple one-to-one basis.
A larger turbine generally has greater generating potential, but the electricity it actually produces depends on the wind resource and how well the turbine is matched to its location.
A turbine with a very large generator installed at a relatively low-wind site could have a lower capacity factor than a smaller turbine at an excellent wind site.
The goal isn't simply to build the turbine with the biggest possible nameplate capacity.
The goal is to maximise useful electricity generation over the turbine's operating life.
One of the major trends in wind energy has been increasing turbine size.
Larger rotors and taller towers allow turbines to capture more wind energy and can increase electricity production from a given site.
Offshore wind has particularly benefited from this trend because transporting and installing very large machines can be more practical at sea than on land.
The IEA continues to track substantial growth in global wind capacity and generation as turbine technology develops. (IEA)
But bigger turbines also create engineering and logistical challenges, including transportation, foundations, installation, maintenance and grid infrastructure.
Here's the simplest way to visualise the relationship.
Imagine a 5 MW turbine.
If it operated at full output for every hour of the year:
43.8 million kWh/year
If its average capacity factor were 25%:
10.95 million kWh/year
At 35%:
15.33 million kWh/year
At 45%:
19.71 million kWh/year
So the same 5 MW turbine could have substantially different annual electricity production depending on the conditions under which it operates.
That's why the question "How many megawatts is the turbine?" doesn't, by itself, tell you how much electricity it produces.
So, how much electricity does a wind turbine produce?
The answer depends on the turbine and where it operates.
A useful example is a 5 MW wind turbine:
- Maximum theoretical annual generation: 43.8 million kWh
- At a 25% capacity factor: 10.95 million kWh/year
- At a 35% capacity factor: 15.33 million kWh/year
- At a 45% capacity factor: 19.71 million kWh/year
At a 35% capacity factor, that works out to an annual average of roughly 42,000 kWh per day.
The most important lesson is that a turbine's capacity isn't the same as its electricity production. Wind speed, rotor size, turbine design, location and capacity factor all determine how much electricity actually reaches the grid.
And as wind turbines have become larger, their potential output has increased dramatically. The largest operating turbines are now around 15 MW, according to the EIA, while the wind industry continues to develop even larger machines. (U.S. Energy Information Administration)
That makes wind turbine capacity only the starting point. To understand how much electricity wind power can really provide, you need to look at annual generation and capacity factor together.
