neighbourhood-planning-wind-guidance

The numbers game ... 

Below is the illustration used on page 17 of CSE’s guidance note How to identify suitable areas for 

onshore wind development in your neighbourhood plan. It illustrates the point that while smaller wind 

turbines obviously have less visual impact, taller ones with longer blades can supply power to many more 

homes. So how did we get the numbers? 

The first thing to be aware of is that for each given ‘size’ (e.g. kW rating) of wind turbine in our illustration 

we’ve taken a ‘typical’ figure from within a range of possible blade lengths, heights and power outputs. So 

while our 10kW turbine has a blade length of 4.5 meters and is 15 meters tall, other 10 kW turbines may 

have shorter or longer blades or be taller or shorter in height. And likewise, depending on the turbine’s 

height and the wind speeds it is subjected to, it may produce more or less power in the course of a year. 

And we’ve deliberately erred on the conservative side. Most 100 kW turbines with a height of 30 meters and 

a swept area diameter of 22 meters will likely produce more than the 209,000 kWh that we have given the 

second smallest turbine in the graphic below. 

Figure 3: Comparing the annual output of different sizes of wind turbine. The figures are based on typical outputs 

and wind speeds and are on the conservative side. The height is measured at the hub, and is within the typical range 

for turbines of this rating. Each yellow square (n) represents one house. 

Rating: 10kW 

Rating: 100kW 

Rating: 1MW 

Rating: 2.5MW 

Diameter of 

swept area 9m 

Diameter of 

swept area 22m 

Diameter of 

swept area 52m 

Diameter of swept area: 

100m 

Height: 15m 

Height: 30m 

Height: 60m 

Height: 80m 

Annual output: 

22,800 kWh 


209,000 kWh 


2,190,000 kWh 


5,457,000 kWh 

Homes: 5 

Homes: 55 

Homes: 550 

Homes: 1,350 

nnnnn 

nnnnnnnnnn 

nnnnnnnnnn 

nnnnnnnnnn 

nnnnnnnnnn 

nnnnnnnnnn 

nnnnn 

nnnnnnnnnnnnnn 








































nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn 









































nnnnnnnnnnnnnnnnnnnnnnnn 

The hub of 

the London 

Eye is about 

65 meters 

above the 

ground

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