It was a love of music that made Jorn Goldenbeld a sound wizard within Team Solutions, where he is also team leader of wind wizards Romana Madić and Ryan Sondij and sign wizard Bojan Antonijević. Jorn, drummer, djembe player, pianist, guitarist, mouth harp player and saxophonist, prefers to play didgeridoo. "That one also has a typical sound. I find it extremely interesting to know and measure how people experience sound."

"Our team is expert in interpreting wind turbine data such as sound curves. That's the amount of sound a wind turbine produces at certain wind speeds. The harder it blows, the faster the rotor spins and the more sound you have," Jorn explains.

"Noise is very complex. Based on calculations, we know what a wind turbine produces on average over a year in terms of noise and whether that is acceptable. For low-frequency noise, we take the NSG curve as the noise threshold, which assumes what 90% of the population hears. People generally get used to high frequencies, but low frequencies cause the most irritation."

Tonality
With noise pollution, Jorn first enters into the conversation to see what the noise pollution is in. The tonality, low-frequency sound and amplitude modulation of the wind turbine may play a role, he explains. Briefly, tonality refers to the sound and amplitude modulation refers to the volume and rhythm of wind turbine noise. "Besides noise reduction measures at home, sometimes we can also do something in the turbine tuning. In addition, I think there is still much to be gained if wind turbine manufacturers pay attention to the noise spectrum. It would be nice if a wind turbine sounds like music to your ears."
 

Are you as much of a wind wizard as Jorn? Test it via the quiz below!

Question 1. Why is it so important to set up a site-specific measurement campaign at the site where you want to develop a wind farm? 

A.  Because you want to show the environment that you have started as soon as possible
B. Reality can never be fully replicated in a simulation model.
C. Data from nearby wind farms, for example, can be misleading
D. Because you want to know which paint to use for the wind turbine

Question 2. What percentage of the time are the wind conditions of a standard power curve met in practice?
99%
75%
50%
25%

Question 3. Suppose you have two wind turbines, how much less power does the rear wind turbine produce if the wind direction is exactly parallel to the setup direction at the time?
20%
40%
60%
80%

Did you get all the questions right? Congratulations, you are a true wind specialist! Didn't get so many questions right? Read the detailed answers below

 

 

 

Answers
Question 1: B & C
Question 2: D
Question 3: D

Explanation
Question 1. Why is it so important to set up a site-specific measurement campaign at the location where you want to develop a wind farm?
When we analyze the wind within the rotor surface, we not only look at speed and wind direction, but also turbulence, wind shear, angle of attack, air density. All these data determine the yield and lifetime of a wind turbine at a given location. The very best way to measure these conditions is to run a year-long site-specific measurement campaign. However, that is an expensive option, so initiators sometimes rely on pre-existing data. For example, SCADA data from operational wind farms or climatological data. However, these are a lot less accurate. A location-specific measurement campaign is therefore recommended! And let Green Trust be the expert in that....

Question 2: What percentage of the time are the wind conditions of a standard power curve met in practice?
A power curve? What is that? A power curve shows how much power the wind turbine produces depending on wind speed at shaft height. If you request a power curve from a manufacturer without specifying how you want to see it, you will get a standard power curve (also called the sales power curve). As you can imagine, it is advantageous for a wind turbine manufacturer if the sales power curve shows high values. After all, that means higher power production. But this salespower curve is often based on the ideal conditions for a wind turbine. These conditions are met only 25% of the time in a year. So it is more accurate to collect wind data yourself and send it to the wind turbine manufacturer. Then you get a site-specific power curve that can be used for calculation.

Question 3 When two wind turbines are placed in the same wind direction, how much less power does the rear wind turbine produce?
It is important to pay close attention to where wind turbines are placed in a wind farm because they affect each other. If the wind direction is exactly parallel to the erection direction at any given time, it causes the rear wind turbine to get much less wind through its rotor. This can be as much as 80%! We call this the "zogeffect.