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Comment by tsherr | Hacker News Reader

Isn't it a bad idea to build these in a corrosive environment like the ocean? Is there a reason, other than NIMBY to put them in the ocean?

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As other posters have mentioned, offshore is significantly more economical for a number of reasons (stronger, more consistent wind; large tracts of available area for large-scale farms; the capability to build turbines much taller where they can access stronger winds) - so instead I'll mention another problem facing offshore turbines other than corrosion: the air.

It turns out that offshore, the air contains a lot of minerals and water droplets that make it much more abrasive than the air over land. This is a particular problem for turbine blades, as their leading edge is moving through the air at a significant speed: enough to gradually ablate away the leading edge material! Consequently, offshore turbine blades need to be replaced more often than onshore turbine blades. This is one of the reasons that larger turbines are more economical: fewer larger turbines mean fewer, larger blades that need to be periodically replaced.

It's possible to build bigger turbines at sea, which are more efficient. The limitation on land is transporting the blades which often requires roads to be modified.

And wind is steadier out a sea plus there is a Nimby aspect in the UK.

It’s not so much “not in my back yard” as there is no back yard big enough. The article says the new digger bank wind farm will be as big as Yorkshire, which is really very big (in UK terms)

I've read that the wind is more consistent in the ocean.

Not just more consistent, but also usually stronger. Currently, for example, wind speeds over the North Sea and the Baltic are stronger than over the adjacent land, and the change at the coastline is quite striking (I'm assuming that the model behind this map is reasonably accurate in that regard.)

https://www.windy.com/53.744/-0.339?53.372,-0.339,8

As I understand it this technology has developed because the government (David Cameron) essentially banned onshore wind by removing the subsidies for it.

They changed the rules back again last year though [1].

[1] https://www.theguardian.com/business/2020/mar/02/uk-governme...

Some oil and gas related gear stays subsea for 20 years before it's pulled up, so presumably similar alloys/paints/techniques are being used.

Source: I've worked, within IT, in the oil and gas sector for many years.

Especially in a geographically pretty small country like the UK, NIMBY (or indeed anyone else's back yard) may be a perfectly valid argument. These things are big and somewhat noisy.

You also can’t live or work anywhere that would be hit by the strobing shadow cast by the blades.

Somebody posted a link to the YouTube video that showed a Dutch turbine exploding. In the description it said pieces went 500 meters. So there probably needs to be a physical safety zone of 1km or more, not that turbines seem to explode very often.

Also noise has been mentioned by some people as a consideration. https://www.ramblingsdc.net/wtnoise.html has an interesting page on it (and a 2012 vibe).

Corrosion on the submerged parts is quite simple to mitigate with sacrificial as also used on ships. The hard part is the splash zone which is only intermittently submerged.

There's a huge amount of experience in this area from oil and gas infrastructure; there've been large-scale offshore rigs in the North Sea since the 60s.

More consistent wind due to a lack of elevated land to slow it down via friction.

Perhaps somewhere during the planning, design, development and testing phases they considered this issue and mitigated it?

you'd think but...

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