Power Production

Q: How much energy will a VAWT - Vind Turbin C.O. wind turbine produce?

A: At VAWT - Vind Turbin C.O. we believe that the most important figure to talk about when discussing wind turbine power generation is what the wind turbine and generator will generate over a given period of time. kWh Over a one year period or more.

It is one thing to have a generator that produces 2kW at a wind speed of 15 m/s wind speed, however if the turbine does not generate power until 4.8 m/s wind speed, only reaches optimum generation at 15 m/s wind speed and then has to stop generation at 25 m/s wind speed, then for a large proportion of the time it will do nothing or very little.

The example below is from a real world, working installation in Finland. All figures used are real world figures and not wind tunnel tests or theoretical models. Wind in the real world is an ever changing and turbulent force that does not obey the rules.

Customer.        Mylly Shopping Centre.
Location.          Raisio in Finland.
System.           Two VAWT - Vind Turbin C.O. WS-12 Vertical Axis Wind Turbines.
Swept Area.     24 m²
Conditions.       Average annual wind speed in the area is below 5 m/s.

Between 3rd March 2005 and 14th Feb. 2006 this system generated 16552 kWh

This equates to 17360 kWh/year.

Expressed as kWh/m²/year = 723 kWh/m²/year

During this period the worst month of production if extended to one year gave a figure of 220 kWh/m²/year.

Estimated production of a propeller of similar swept area in similar conditions are between 100 kWh/m²/year and 300 kWh/m²/year.

These are real world results, and not theoretical or wind tunnel predictions.

Annual wind speed is made up from windy days and calm days.

The power available from the wind increases exponentially with wind speed the result of this can be seen from the examples below.

Example 1.

A turbine runs for one year.
Half the time the wind is 10 m/s.
Half the time there is no wind at all.
Therefore the average wind speed is 5m/s
Power generated is 1752 kWh

Example 2.

The same turbine runs for one year.
The wind blows at 5 m/s all year.
Therefore the average wind speed is also 5m/s
Power generated is 613 kWh    

Note, both examples have the same average wind speed but example 1 produces 2.85 times as much power as example 2.

This demonstrates that it is impossible to put a finite figure on what a wind turbine and generator will generate as the wind is ever changing, however if turbines are monitored over a long enough period of time in real world conditions where these conditions are known then an honest figure can be arrived at.

Q: How much will VAWT - Vind Turbin C.O. WS-0,30 produce energy

A: The amount of energy a WS-0,30 will deliver in a year is dependent on the wind speed, its electrical set up (star or delta) and its voltage (12 or 24V).
 
The most common use for the system is 12V Star connected charging a 12V battery bank. This could mean energy production from anywhere between 70 kWh/year at an average of 5 m/s to 290 kWh/year at an average of 10 m/s. It is impossible to be precise on these figures as it all depends on how the average wind speed is made up.