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Comment by beat | Hacker News Reader

Solar, maybe, for now. But I can't imagine that there is a need for large amounts of exotic metals in a wind turbine, which is a simple generator. Exotic materials might give a percent or three more operational efficiency, but they're not actually necessary.

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As far as I know neodymium is currently used for magnets in a lot of wind turbines and electric motors among other things. It's not rare but the vast majority of it comes from China right now. I can't speak to how much efficiency it adds.

Actually, that makes a lot of sense. Neodymium magnets are much lighter and more compact for the same strength. (I know this from being a guitar player - exact composition of magnets in guitar pickups and speakers is a subject of substantial controversy, both technical and magical.)

But it also seems to me this might be a cost issue... it's possible that neodymium magnets are used because they're cheaper in context than ceramic, alnico, or other materials. That could change if neodymium prices increase substantially due to scarcity.

I wouldn't worry much about China refusing to export things for money.

Wind turbines are currently over 100 meters high and installed into places that see lot of wind. It's a rule of thumb that you should keep the natural frequency of any large steel building above 20 hz. Swiching to heavier magnets will increase the mass of the generator which is mounted on top. That in turn will make the whole thing more wobbly (ie lower the frequency). To combat this you need thicker frame. Which in turn will cost more and weight more.

It's completely possible that current windmill designs are only possible with neodymium magnets. We would need to ask turbine designer.

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