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Comment by throwaway2037 | Hacker News Reader

throwaway2037

    > The cost of building that steel structure that will hold up against maximum in 100 year wind forces isn't cheap.

I'm surprised by this comment. (Is this area known for strong winds?) If your comment is true, wouldn't all warehouses using the same type of standard "bents" also be very expensive? I doubt it.

    > Large PV panels make very good sails.

A quick Google search tells me:[1] "Most modern solar panels can withstand winds of up to 140 miles per hour." For all of the things I have read about large commercial solar panel installations, never once did I read anything about the risk of wind tearing off PV panels. If this were really a serious threat, wouldn't we see regularly local news stories about large PV panels "flying" away in big wind storms? And, yet, I never saw one.

[1] https://www.makemyhousegreen.com/green-guides/can-solar-pane...

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> I'm surprised by this comment. (Is this area known for strong winds?)

Areas of the central valley are legendary for strong winds. A large stretch of the aqueduct (200km?) runs along the valley's West edge. So does the interstate highway I5.

The I5 has frequent high wind advisories. In the area around Pacheco Pass there are frequently gusting cross winds between 55 and 70km per hour. I use the I5 as my reference here, because I have spent many hours of my life driving it in these conditions.

> If your comment is true, wouldn't all warehouses using the same type of standard "bents" also be very expensive?

What makes you think building a warehouse in earthquake country is cheap?

> For all of the things I have read about large commercial solar panel installations, never once did I read anything about the risk of wind tearing off PV panels. If this were really a serious threat, wouldn't we see regularly local news stories about large PV panels "flying" away in big wind storms? And, yet, I never saw one.

The statement about solar panels making very good sails obviously true. Everything thin and flat makes a good sail.

PV panels don't go flying away because people spend a lot of money attaching them to the ground. They're expensive systems, and any installer that didn't make sure they were bolted down effectively, would be sued out of business after the first windstorm.

You can meet code requirements on rocky ground with relatively small concrete block anchoring systems. The cost of the blocks plus the metal pipe structure for a ground mount system is typically 10% or so of the total system install.

If you're on excavatable ground, the cost goes up a little (paradoxically, way more concrete is required to meet code).

There are also companies do this sort of thing with earth anchors/helical ground screws, which are VERY fast to install, but tend to cost more than the concrete. Nice that they can be (re)moved, though.

    > The I5 has frequent high wind advisories. In the area around Pacheco Pass there are frequently gusting cross winds between 55 and 70km per hour. I use the I5 as my reference here, because I have spent many hours of my life driving it in these conditions.

This is a classic bullshit HN reply. Literally, Brandolli law rules here!

My original post said that most panels with installation are good up to 140 mph (or 225 kmph). Your example is less than half my examplle.

    > The statement about solar panels making very good sails obviously true.

Ok, please provide five+ example from local news that shows poorly tied solar panels flying away in a wind storm. The "obvious" thruth: You cannot.

> Ok, please provide five+ example from local news that shows poorly tied solar panels flying away in a wind storm. The "obvious" thruth: You cannot.

Everything flat and thin catches the wind. That's physics.

The reason solar panels don't go blowing around is that we spend money and engineering effort to prevent this from happening. You know what else generally doesn't go blowing around? Sails from boats. Same reason: Because they're well attached to a strong structure.

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