Swept area
The Rutland 913 has a blade diameter of 0.91 metres. This means it has a swept area, or capture area of 0.65 square metres. This is all important when comparing wind turbines, since it directly relates to the amount of passing wind energy
the turbine blades can intercept.
Rutland 913 power output curve
The graph below shows the power produced (in watts) for the Rutland 913 at different wind speeds, based on
data supplied by the manufacturer.
The green line shows the actual output that the wind turbine achieves at the given wind speed,
according to the manufacturers.The dashed line in the graph shows the theoretical maximum energy that this turbine could extract from the wind,
according to Betz's Law (59.3%). At a typical wind speed of
5 m/s, the Rutland 913 is extracting
17 Watts of power from the wind, which is an efficiency of
34%.
How efficient is the Rutland 913?
Wind turbines can only convert some of the energy in the wind into electricity. The graph here shows how efficient the
turbine is across the range of wind speeds you might get.
The orange line in the above graph shows the efficiency ranging from 0 to 1. The grey line is the previously mentioned maximum efficiency - The Betz Limit. If this limit is exceeded, the manufacturer's claims are not to be trusted!
While these graphs give an indication of the instantaneous power and efficiencies you might expect from the
Rutland 913 turbine, working out annual power production is more complex.
Read more about the
Power Predictor
This turbine produces roughly 24 Watts power at wind speeds of 5m/s and can produce up to 300 Watts of power at high wind speeds.
This wind turbine alone costs £430 including VAT at 15%. Suitable steel tube towers cost £20-£30, however a full mounting kit costs roughly £110.
Very quiet machine due to compact size.
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