6 ms·

123 meter blades, that’s insane. This means the tip of the blade travels 772 meters in a single rotation. The speed of sound is 340 meters per second, meaning i

123 meter blades, that’s insane. This means the tip of the blade travels 772 meters in a single rotation. The speed of sound is 340 meters per second, meaning if it travels more than 0.44 rotations in a second, the tips of the blades are breaking the sound barrier.

rcme 3y ago
That is crazy, but, on the other hand, seeing this rotate faster than once every two seconds would be insanely fast.
- civilitty 3y ago
  We just need to hook it up to a flux capacitor and the next typhoon will give us time travel.
  - dylan604 3y ago
    I did the math, but we didn't hit 1.21 jigawatts
    - djbusby 3y ago
      Back in the day, it was still spelled Giga but pronounced Jiga. I heard from some old-heads at power company.
      - rainbowzootsuit 3y ago
        Jigga What, Jigga Who Hard Watt Life
        esafak 3y ago
        Gettin' jiggy wit it
- gnatman 3y ago
  Here's turbine in Denmark that lost its brakes and disintegrated in 2008. The description says the tower was 60m tall. https://www.youtube.com/watch?v=7nSB1SdVHqQ https://www.youtube.com/watch?v=7nSB1SdVHqQ
  - themitigating 3y ago
    You'd think there would be a backup brake kit on these
    - SoftTalker 3y ago
      I thought they would feather the turbine blades so that they didn't generate rotation. Maybe that failed as well?
      - jacquesm 3y ago
        There is so much power in the wind. If you are a little late with feathering you might end up having too much momentum to be able to use a friction brake without burning it up. So a long period of steady wind followed immediately by an increase to the point where you can no longer stop the machine is quite risky: all that stands between you and certain destruction is either a lucky lull in the wind or your continued ability to feather it and that can get surprisingly hard when you are dealing with high winds. To the point that if you go 'coarse' at high RPM you end up pulling over the tower due to the extremely long arm for that force to take effect. Never ever underestimate what the wind can do. Wind turbines will always have some latent risk (as do most other activities and constructs). For every design there is a pathological set of circumstances that should never happen. But once in a long while it does. What should surprise you is that so few of these accidents happen that they are news.
      - thebruce87m 3y ago
        On the smaller turbines I worked on, the speed of rotation was controlled by feathering the blades as you’d expect. Braking was also achieved the same way, with the friction brake acting as a “handbrake” once the blades were slow enough. One thing that some people don’t consider is that the direction the turbine faces is also controllable and therefore used for braking. A lot of people think the turbine is blown by the wind to face the correct direction, but there is a separate wind direction sensor and a motor to turn the turbine. The friction brake could be applied at speed, but that was for emergencies.
ragebol 3y ago
If they do break the sound barrier, that's also when the efficiency drops iirc. So I guess they'll switch it to a heavier load or RPM, or apply the brakes? Not sure how that works for a wind turbine
- pengaru 3y ago
  I presume the pitch is adjustable, so unless the mechanism fails you can just relax the pitch like pointing a sailboat directly into the wind to depower the sails.
  - bluGill 3y ago
    The mechanism is designed (or at least should be designed) so that if anything breaks the blades rotate to the no power position. There is a lot of engineering and redundancy that i'm only partially aware of.
    - pengaru 3y ago
      I guess the real question is how bad can conditions get before the "no power position" is still too much force for the structure to withstand. You can't escape the fact that the blades are a ton of surface area on a long lever... and if the winds are both forceful and directionally chaotic, there isn't really a "no power position" to be found. Going back to the sailboat metaphor, it's the conditions where you douse the sails entirely. At most flying a little storm jib. Pointing upwind is just to enable doing so.
      - bluGill 3y ago
        The tower catches more wind than the blades and will fail first. And the tower is built dor the force of strong winds with the blades resiting the wind. Though they are built in rural areas and at sea so even in the worst case disaster (manufacturing flaw, not wind) nobody is hurt.
  - nuccy 3y ago
    Even if pitch is adjustable the problem is very non-trivial given the size of the blades and different wind speeds and directions on different elevations. Putting the blades in no-power position along the main wind direction, but having small sidewind 200m above the surface would rotate it.
Qem 3y ago
Birds won't be happy, unfortunately. Yet, better than wrecking Earth's cycles by pumping to much garbage in the atmosphere like we do today.
- steelbrain 3y ago
  Not trying to pick a fight but just posting because I hear this often from my friends, re birds being happy. The choice, if between coal-fired plants and windmills should be pretty obvious to birds. Sure we may not see them getting splashed to bits with coal-fired plants but they are silently getting ill/dying over time.
  - mirko22 3y ago
    So are people, yet we are afraid of nuclear power…
    - kdmccormick 3y ago
      Bird death from turbines small-scale and highly predictable. Deaths from nuclear can range from zero to regional catastrophe and it's basically impossible to predict when it'll happen and how bad it'll be. I'm not anti-nuclear, but the risk profile is SO different from wind.
      - fasterik 3y ago
        The worst case is worse, but nuclear disasters are so rare and reactors produce so much power that nuclear is safer than wind in terms of deaths per TWh. https://ourworldindata.org/safest-sources-of-energy https://ourworldindata.org/safest-sources-of-energy
        Gwypaas 3y ago
        Let's stop subsidizing their accident insurance then. https://en.wikipedia.org/wiki/Price%E2%80%93Anderson_Nuclear_Industries_Indemnity_Act https://en.wikipedia.org/wiki/Price%E2%80%93Anderson_Nuclear...
bobthepanda 3y ago
Do you transport something like this in pieces, or as a single blade?
- mschuster91 3y ago
  A German company says they can transport blades of up to 100m length as a single piece [1]. For longer things I'd guess there is no option other than to manufacture them on site or near-site, as the Danes are doing for offshore projects [2]. [1] https://www.doll.eu/de/produkte/schwertransport/nachlaeufer-kombination/windfluegeltransport.html https://www.doll.eu/de/produkte/schwertransport/nachlaeufer-... [2] https://www.wiwo.de/technologie/wirtschaft-von-oben/wirtschaft-von-oben-165-daenemark-ein-paar-kilometer-hinter-der-deutschen-grenze-entstehen-die-groessten-windkraftfabriken-der-welt/28453364.html https://www.wiwo.de/technologie/wirtschaft-von-oben/wirtscha...
  - tjoff 3y ago
    That is on land, there is a reason a lot of wind production is close to a harbor. So near-site in practice means, near-harbor. Possibly you can have an agile vessel doing the last stretch so that you can change that to ~near-sea.
    - jayGlow 3y ago
      the US Midwest has a ton of wind power, if you drive through there you have a decent chance of seeing a truck carrying a blade. pretty interesting stuff. obviously those are a lot smaller than this windmill though.
      - fbdab103 3y ago
        If you drive through Iowa, it seems like you will see nothing but windmills. Just an enormous amount of installed capacity.
        SoftTalker 3y ago
walnutclosefarm 3y ago
The GE Haliade X, smaller but not by a lot, maxes out at 7 rotations per minute, giving a rotor tip velocity in the vicinity of 80m/s. Generally noise considerations mean you don't aim for a tip velocity faster than that, although for a turbine that is only installed in offshore or other uninhabited locations, you might design for a higher tip velocity. Despite some advantages to higher velocity, though, considerations related to erosion caused by high speed impact of dust, water drops and ice particles become an issue long before you'd get to supersonic speeds.
- antisthenes 3y ago
  > The GE Haliade X, smaller but not by a lot, maxes out at 7 rotations per second I think you meant per minute. Per second would mean that the rotor tips are travelling faster than SR-71.
  - mcronce 3y ago
    Although I'm glad it's not reality, the imagery of a massive wind turbine whizzing around at 420 RPM is pretty amusing
    - tengwar2 3y ago
      > Regular turbine spotters judged that the best sound balance was usually to be heard from within large concrete bunkers some thirty-seven miles away from the wind farm, whilst the engineers themselves operated their turbines by remote control from within a heavily insulated spaceship which stayed in orbit around the planet - or more frequently around a completely different planet.
      - jacquesm 3y ago
        Hehe, just to let you know your effort wasn't in vain, I got that.
  - walnutclosefarm 3y ago
    Yes. Thanks.
mytailorisrich 3y ago
This made me think that people in the West imagine East Asia like Japan or Hongkong, ie. everything is packed and very small. But China in general really is like the US (and indeed the country is of similar size): everything tends to be big. Certainly, coming from Europe, everything is huge in China.
askvictor 3y ago
Given that the wind is pushing it, wouldn't the blade tip's speed somehow be naturally limited by the wind speed?
- jakewins 3y ago
  At least in sailing, you can go a lot faster than the wind; I assume the same is true for these blades.
  - adgjlsfhk1 3y ago
    it would be except that the goal of a wind turbine is to generate power rather than go fast
    - wffurr 3y ago
      How do you go fast except by generating power? Force times distance over time, that’s how sailboats move too.
      - doctor_eval 3y ago
        It's not the blades that have to go fast, but the generator.
      - raverbashing 3y ago
        More specifically, power is Torque x Omega (rotational speed) for a rotational system So yes, faster means more power. Torque is limited by the generator and how much power is "being pulled" from it. (which is a bad description but there you go)
  - flangola7 3y ago
    How can you travel faster than the wind that is pushing you?
    - LorenzoGood 3y ago
kitd 3y ago
I don't know about this one, but a single rotation of the turbines recently installed in the North Sea can generate enough electricity to power an average family home for a day.
- appplication 3y ago
  Wow that is a really interesting and coherent way to conceptualize how much power it makes, and how quickly.

rcme 3y ago

That is crazy, but, on the other hand, seeing this rotate faster than once every two seconds would be insanely fast.

civilitty 3y ago
We just need to hook it up to a flux capacitor and the next typhoon will give us time travel.
- dylan604 3y ago
  I did the math, but we didn't hit 1.21 jigawatts
  - djbusby 3y ago
    Back in the day, it was still spelled Giga but pronounced Jiga. I heard from some old-heads at power company.
    - rainbowzootsuit 3y ago
      Jigga What, Jigga Who Hard Watt Life
      - esafak 3y ago
        Gettin' jiggy wit it
gnatman 3y ago
Here's turbine in Denmark that lost its brakes and disintegrated in 2008. The description says the tower was 60m tall. https://www.youtube.com/watch?v=7nSB1SdVHqQ https://www.youtube.com/watch?v=7nSB1SdVHqQ
- themitigating 3y ago
  You'd think there would be a backup brake kit on these
  - SoftTalker 3y ago
    I thought they would feather the turbine blades so that they didn't generate rotation. Maybe that failed as well?
    - jacquesm 3y ago
      There is so much power in the wind. If you are a little late with feathering you might end up having too much momentum to be able to use a friction brake without burning it up. So a long period of steady wind followed immediately by an increase to the point where you can no longer stop the machine is quite risky: all that stands between you and certain destruction is either a lucky lull in the wind or your continued ability to feather it and that can get surprisingly hard when you are dealing with high winds. To the point that if you go 'coarse' at high RPM you end up pulling over the tower due to the extremely long arm for that force to take effect. Never ever underestimate what the wind can do. Wind turbines will always have some latent risk (as do most other activities and constructs). For every design there is a pathological set of circumstances that should never happen. But once in a long while it does. What should surprise you is that so few of these accidents happen that they are news.
    - thebruce87m 3y ago
      On the smaller turbines I worked on, the speed of rotation was controlled by feathering the blades as you’d expect. Braking was also achieved the same way, with the friction brake acting as a “handbrake” once the blades were slow enough. One thing that some people don’t consider is that the direction the turbine faces is also controllable and therefore used for braking. A lot of people think the turbine is blown by the wind to face the correct direction, but there is a separate wind direction sensor and a motor to turn the turbine. The friction brake could be applied at speed, but that was for emergencies.

ragebol 3y ago

If they do break the sound barrier, that's also when the efficiency drops iirc. So I guess they'll switch it to a heavier load or RPM, or apply the brakes? Not sure how that works for a wind turbine

pengaru 3y ago
I presume the pitch is adjustable, so unless the mechanism fails you can just relax the pitch like pointing a sailboat directly into the wind to depower the sails.
- bluGill 3y ago
  The mechanism is designed (or at least should be designed) so that if anything breaks the blades rotate to the no power position. There is a lot of engineering and redundancy that i'm only partially aware of.
  - pengaru 3y ago
    I guess the real question is how bad can conditions get before the "no power position" is still too much force for the structure to withstand. You can't escape the fact that the blades are a ton of surface area on a long lever... and if the winds are both forceful and directionally chaotic, there isn't really a "no power position" to be found. Going back to the sailboat metaphor, it's the conditions where you douse the sails entirely. At most flying a little storm jib. Pointing upwind is just to enable doing so.
    - bluGill 3y ago
      The tower catches more wind than the blades and will fail first. And the tower is built dor the force of strong winds with the blades resiting the wind. Though they are built in rural areas and at sea so even in the worst case disaster (manufacturing flaw, not wind) nobody is hurt.
- nuccy 3y ago
  Even if pitch is adjustable the problem is very non-trivial given the size of the blades and different wind speeds and directions on different elevations. Putting the blades in no-power position along the main wind direction, but having small sidewind 200m above the surface would rotate it.

Qem 3y ago

Birds won't be happy, unfortunately. Yet, better than wrecking Earth's cycles by pumping to much garbage in the atmosphere like we do today.

steelbrain 3y ago
Not trying to pick a fight but just posting because I hear this often from my friends, re birds being happy. The choice, if between coal-fired plants and windmills should be pretty obvious to birds. Sure we may not see them getting splashed to bits with coal-fired plants but they are silently getting ill/dying over time.
- mirko22 3y ago
  So are people, yet we are afraid of nuclear power…
  - kdmccormick 3y ago
    Bird death from turbines small-scale and highly predictable. Deaths from nuclear can range from zero to regional catastrophe and it's basically impossible to predict when it'll happen and how bad it'll be. I'm not anti-nuclear, but the risk profile is SO different from wind.
    - fasterik 3y ago
      The worst case is worse, but nuclear disasters are so rare and reactors produce so much power that nuclear is safer than wind in terms of deaths per TWh. https://ourworldindata.org/safest-sources-of-energy https://ourworldindata.org/safest-sources-of-energy
      - Gwypaas 3y ago
        Let's stop subsidizing their accident insurance then. https://en.wikipedia.org/wiki/Price%E2%80%93Anderson_Nuclear_Industries_Indemnity_Act https://en.wikipedia.org/wiki/Price%E2%80%93Anderson_Nuclear...

bobthepanda 3y ago

Do you transport something like this in pieces, or as a single blade?

mschuster91 3y ago
A German company says they can transport blades of up to 100m length as a single piece [1]. For longer things I'd guess there is no option other than to manufacture them on site or near-site, as the Danes are doing for offshore projects [2]. [1] https://www.doll.eu/de/produkte/schwertransport/nachlaeufer-kombination/windfluegeltransport.html https://www.doll.eu/de/produkte/schwertransport/nachlaeufer-... [2] https://www.wiwo.de/technologie/wirtschaft-von-oben/wirtschaft-von-oben-165-daenemark-ein-paar-kilometer-hinter-der-deutschen-grenze-entstehen-die-groessten-windkraftfabriken-der-welt/28453364.html https://www.wiwo.de/technologie/wirtschaft-von-oben/wirtscha...
- tjoff 3y ago
  That is on land, there is a reason a lot of wind production is close to a harbor. So near-site in practice means, near-harbor. Possibly you can have an agile vessel doing the last stretch so that you can change that to ~near-sea.
  - jayGlow 3y ago
    the US Midwest has a ton of wind power, if you drive through there you have a decent chance of seeing a truck carrying a blade. pretty interesting stuff. obviously those are a lot smaller than this windmill though.
    - fbdab103 3y ago
      If you drive through Iowa, it seems like you will see nothing but windmills. Just an enormous amount of installed capacity.
      - SoftTalker 3y ago

walnutclosefarm 3y ago

The GE Haliade X, smaller but not by a lot, maxes out at 7 rotations per minute, giving a rotor tip velocity in the vicinity of 80m/s. Generally noise considerations mean you don't aim for a tip velocity faster than that, although for a turbine that is only installed in offshore or other uninhabited locations, you might design for a higher tip velocity. Despite some advantages to higher velocity, though, considerations related to erosion caused by high speed impact of dust, water drops and ice particles become an issue long before you'd get to supersonic speeds.

antisthenes 3y ago
> The GE Haliade X, smaller but not by a lot, maxes out at 7 rotations per second I think you meant per minute. Per second would mean that the rotor tips are travelling faster than SR-71.
- mcronce 3y ago
  Although I'm glad it's not reality, the imagery of a massive wind turbine whizzing around at 420 RPM is pretty amusing
  - tengwar2 3y ago
    > Regular turbine spotters judged that the best sound balance was usually to be heard from within large concrete bunkers some thirty-seven miles away from the wind farm, whilst the engineers themselves operated their turbines by remote control from within a heavily insulated spaceship which stayed in orbit around the planet - or more frequently around a completely different planet.
    - jacquesm 3y ago
      Hehe, just to let you know your effort wasn't in vain, I got that.
- walnutclosefarm 3y ago
  Yes. Thanks.

mytailorisrich 3y ago

This made me think that people in the West imagine East Asia like Japan or Hongkong, ie. everything is packed and very small. But China in general really is like the US (and indeed the country is of similar size): everything tends to be big. Certainly, coming from Europe, everything is huge in China.

askvictor 3y ago

Given that the wind is pushing it, wouldn't the blade tip's speed somehow be naturally limited by the wind speed?

jakewins 3y ago
At least in sailing, you can go a lot faster than the wind; I assume the same is true for these blades.
- adgjlsfhk1 3y ago
  it would be except that the goal of a wind turbine is to generate power rather than go fast
  - wffurr 3y ago
    How do you go fast except by generating power? Force times distance over time, that’s how sailboats move too.
    - doctor_eval 3y ago
      It's not the blades that have to go fast, but the generator.
    - raverbashing 3y ago
      More specifically, power is Torque x Omega (rotational speed) for a rotational system So yes, faster means more power. Torque is limited by the generator and how much power is "being pulled" from it. (which is a bad description but there you go)
- flangola7 3y ago
  How can you travel faster than the wind that is pushing you?
  - LorenzoGood 3y ago

kitd 3y ago

I don't know about this one, but a single rotation of the turbines recently installed in the North Sea can generate enough electricity to power an average family home for a day.

appplication 3y ago
Wow that is a really interesting and coherent way to conceptualize how much power it makes, and how quickly.