Noise Pollution from Wind Turbines Infographic

Source: Twin Cities Star Tribune

16 thoughts on “Noise Pollution from Wind Turbines Infographic

    • that’s what I liked about it, and where do the windies have people stand to say “listen how quiet they are”. At the last Essex meeting the CAW guys as usual trot out ” well I’ve stood under them and I didn’t hear anything”

  1. From TVO, Pro engineers Ontario, they would know all this stuff right….but they did say who ever is paying……….have they not got a mandate or it’s who is paying…tad of a conflict in their mandate overall……

    • As I recall the question was who do the pro engineers work for? The answer was pro engineers work in many industries including renewables? They work wherever the cheques don’t bounce?

  2. What they leave out is probably the most inmportant part of the noise equation.

    They leave out the interaction of the turbines. They leave out the beat notes of multiple turbines that cause the noise to ebb and flow in the most irritating manner.

    Oh wait — a prominent politically active musician says they only swish — my apologies.

  3. What happened to the wasted energy?

    How much kinetic energy is in the wind?
    I shorted the explanation so it is easier to read. 2 behind a number means squared, 3 means cubed.

    Kinetic Energy = 0.5 x Mass x Velocity2
    Mass/sec (kg/s) = Velocity (m/s) x Area (m2) x Density(kg/m3)
    Power = 0.5 x Swept Area x Air Density x Velocity3

    A 2.1Mw turbine has a rotor blade diameter of 93 metres and so the rotors sweep an area of PI x (diameter/2)2 = 6790 m2

    Wind speed 14m/s (maximun output for a wind turbine) about 30mph

    Wind Power = 0.5 x 6790 x 1.23 x (14 x 14 x 14)
    Wind Power = 11,500,000 watts = 11.5Mw

    So we have 11.5Mw of energy available in the wind and yet the turbine is only able to harness 2.1Mw of that energy. What happened to the wasted energy? There is no such thing as wasted energy. All ‘wasted energy’ always has to do something, heat, noise, vibration.

    • Wind is a very poor source of energy anyway. Maybe someday the eco-nuts will be able to learn this basic fact.

    • The 11.5 MW is the kinetic energy in the wind due to its mass and velocity. The theoretical maximum energy that can be converted by a wind turbine is 59.7%….this is referred to as the Betz Limitation and you can find out how that value is derived here… http://www.wind-power-program.com/betz.htm. However, the Betz limitation as indicated is a theoretical value that can’t actually be achieved. A typical performance coefficient (Cp) for a horizontal axis IWT is more likely to be in the 35% to 45% efficiency range. There are two more efficiency values to be concerned about. One is the gearbox (Nb) which is usually in the 95% range and the second is the generator efficiency (Ng) which is dependent on a variety of factors which could put it in the 50 to 80% range. There may be other losses as well on the electrical side after the generator but I don’t think that those are included in the way that an IWT is typically rated. With regards to the gearbox, the 5% inefficiency is lost mostly as heat. With regards to the generator, the 30 to 50% inefficiency is also lost as heat along with some minor losses as well such as windage. There will also be other equipment in the IWT that takes power at various points in time (usually referred to as parasitic losses)…. lights, fans, cooling equipment, switchgear, heat tracing to keep the ice off the blades, immersion heaters to keep the oil in the gearbox warm enough (winter time) etc. These losses are more pronounced for winter operation and if there is no wind for a period of time, one can see that this is a real problem because now energy from the grid has to go to the IWT to keep it ready to go into action (plus deal with things like lighting).

      If you want to figure out the overall generator output (and assuming for simplicity that the parasitic losses are minor), just multiple the efficiency values of the individual components since they all act in series. An overall efficiency that addresses the combining of all the components is typically in the 20% range (as you will see in your example of only getting 2.1 MW out of the generator when the wind has 11.5 MW of kinetic energy).

      Generator output in MW = Wind kinetic energy x Cp x Nb x Ng

      If the generator output is 2.1 MW for this example where the kinetic energy was 11.5 MW, you will see that the above suggested efficiency values works out about right i.e. 2.1 is fairly close to 11.5 x 0.4 x 0.95 x 0.5.

      An even bigger issue of course is that the rated power is only achieved when the IWT is operating at the maximum wind speed (higher wind speed means that it has to be shut down. Since power varies as the cube of wind, less than rated wind means that power output drops fast i.e. at one half of its maximum rated speed, power output is ½ X ½ x ½ or 1/8. It may be even less than this depending on the efficiency of the generator at this speed range.

  4. Thanks Marty and David,
    I did not know that
    That sure shines even more light on this BS……….

    • A demonstration that hicks from the stix know how to do math calculations as well as how to read and write.

      • Yup, and fyi
        I understand a lot of testing of the IWT’s (engine/generator) is done at Ricardo’s in West Sussex UK

    • Betz’ Law is from 1920, yes 100 years ago all of this was known.

      Marty has done an excellent job of demonstrating why any future technological improvements will be very small and insignificant. The technology has nearly reached the limits of the laws of physics.

      If just 0.1% of the wasted energy is converted to audible noise that is the same as 10,000 watt speaker on top of a 300 foot pole.

  5. Dollar for dollar……….
    Instead of taking responsibility – Mr. McGuiinty chooses to ignore the facts.

    McGuinty’s motto: I ‘m a risk taker

    Therefore, the only conclusion can be:
    Human Well Being must be sacrificed – to save the planet.

    Pounding his chest:
    “We need those jobs, we need clean electricity and we need to assume our responsibility in the face of climate change,” McGuinty said.
    http://www.thestar.com/news/ontario/article/585591–mcguinty-vows-to-stop-wind-farm-nimbys

    McGuinty Liberals live in the ‘dark ages’ – refuse to get off the couch!

    ……and the ‘drumbeat’ carries on……..

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