4 ms·

That's interesting. Hydro is crap at startup too (they need black start units, at least the big ones do) [What I wrote here about black start was pretty much wr

That's interesting. Hydro is crap at startup too (they need black start units, at least the big ones do) [What I wrote here about black start was pretty much wrong, not sure what I was thinking] so maybe that's not too big of a problem, but that sound thing seems bad, even if the units are out on the water. Those things are loud, I had no idea! "The noise emission from the wind turbine was measured, at wind speed 8 m/s, 10 m above ground, to 96.2 dBA" https://www.mdpi.com/1996-1073/9/1/19/htm https://www.mdpi.com/1996-1073/9/1/19/htm [Edited to add: What I wrote about hydro black start units was really wrong, I wasn't thinking when I wrote that, it needs far more detailed explanation like the comment below.]

probablypower 6y ago
> * Hydro is crap at startup too (they need black start units, at least the big ones do) * This is a misunderstanding. All generators require an excitation current to start up. Most generators get this excitation from the grid. For large, important generators they also have black start, so that they can provide excitation on-site. This means they don't need to bootstrap themselves from a grid. Hydro tends to have black start not because 'they need it' but because it is critically important from a grid security perspective. During a blackout, you want your high inertia, flexible machines online first - these are hydros for systems that have them. If you don't have blackstart on these machines, you need them on some other machine online first to energize the grid. You wouldn't put blackstart units on wind turbines, simply because they are worthless if there isn't already an energised grid to support into (they aren't grid forming). So you can always assume grid-based excitation current for wind generators. I think OP was talking about the cut-in speed (at what wind speed can the turbine start producing power). For HAWTs this is at wind speeds of around 5 m/s. For VAWTs, I don't know, but I assume it is a little higher based on the OP's comment, and that they may even need some mechanical assistance to get them spinning in the first place.
- blakesterz 6y ago
  Nuts, you're totally right. I really know better, not sure how I got that so wrong.
JohnJamesRambo 6y ago
Are you sure about that, because I was just reading the Black Start Wikipedia yesterday and it listed Hydro as one of the best at requiring little start up power. Hydro is often the Black Start source for other power plants.
- blakesterz 6y ago
  I am sure I was wrong :-)
antiterra 6y ago
The paper you linked suggests that horizontal turbines are even louder: “The noise emission at 6 m/s 10 m above ground was measured to 94.1 dBA, this while while operating at optimum tip speed. Available noise surveys performed on similar sized operating at optimum tip speed. Available noise surveys performed on similar sized HAWTs [27–30] HAWTs [27–30] has established noise emissions of 95.1–100.2 dBA and 97.3–102.4 dBA for 6 m/s and has established noise emissions of 95.1–100.2 dBA and 97.3–102.4 dBA for 6 m/s and 8 m/s respectively”

probablypower 6y ago

> * Hydro is crap at startup too (they need black start units, at least the big ones do) * This is a misunderstanding. All generators require an excitation current to start up. Most generators get this excitation from the grid. For large, important generators they also have black start, so that they can provide excitation on-site. This means they don't need to bootstrap themselves from a grid. Hydro tends to have black start not because 'they need it' but because it is critically important from a grid security perspective. During a blackout, you want your high inertia, flexible machines online first - these are hydros for systems that have them. If you don't have blackstart on these machines, you need them on some other machine online first to energize the grid. You wouldn't put blackstart units on wind turbines, simply because they are worthless if there isn't already an energised grid to support into (they aren't grid forming). So you can always assume grid-based excitation current for wind generators. I think OP was talking about the cut-in speed (at what wind speed can the turbine start producing power). For HAWTs this is at wind speeds of around 5 m/s. For VAWTs, I don't know, but I assume it is a little higher based on the OP's comment, and that they may even need some mechanical assistance to get them spinning in the first place.

blakesterz 6y ago
Nuts, you're totally right. I really know better, not sure how I got that so wrong.

JohnJamesRambo 6y ago

Are you sure about that, because I was just reading the Black Start Wikipedia yesterday and it listed Hydro as one of the best at requiring little start up power. Hydro is often the Black Start source for other power plants.

blakesterz 6y ago
I am sure I was wrong :-)

antiterra 6y ago

The paper you linked suggests that horizontal turbines are even louder: “The noise emission at 6 m/s 10 m above ground was measured to 94.1 dBA, this while while operating at optimum tip speed. Available noise surveys performed on similar sized operating at optimum tip speed. Available noise surveys performed on similar sized HAWTs [27–30] HAWTs [27–30] has established noise emissions of 95.1–100.2 dBA and 97.3–102.4 dBA for 6 m/s and has established noise emissions of 95.1–100.2 dBA and 97.3–102.4 dBA for 6 m/s and 8 m/s respectively”