Making structures "partially out of energy"

[Superfluous_Parentheses]

@YamatoTwinkie

A solid piece of steel is already held together by electromagnetic intermolecular forces. I may be wrong, but I don’t think there’s a commercial electromagnet out there that can even rival the forces generated by those.

Indeed, though it also shows the reverse - we know you can hold a building together using pretty much nothing but electromagnetism

I suppose it would be technically possible, but unrealistically costly in terms of energy to use electromagnets, and I would be amazed if it could hold a structure together and still be lighter than steel. My WAG is that you can build a steel structure a lot higher than one using electromagnets. And it would be a couple of orders of magnitude cheaper.

[Superfluous_Parentheses]

Oh and since idea seems to be to use repelling magnets, I would add that those don’t necessarily make the structure lighter in any conceivable way. You’re still adding all the mass together to calculate the force applied to the base.

[Chronos]

For supports, the problem is that supporting something with a repulsive force is a big pain – you can’t just stick one magnet on top of the other, because the top one would soon just slide off to one side and fall down. So you need lots of magnets, carefully arranged.

Careful arrangement of the magnets won’t help: There is no static arrangement of magnets that is stable. If you want stability, then you need to either put in some sort of dynamic feedback mechanism, or you need to add stabilizing forces from cables or the like (which, if you look at them at the atomic level, are in fact dynamic feedback mechanisms).