On Jun/11/2020 at 18:09, JF Mezei wrote :
On 2020-06-11 13:37, David Spain wrote:

Actually, have read articles that suggest rocket propulsion for this
purpose.


The space elevators I have seen used mag lev engine to cause it to rise
along the spine. (for instance, when Neelix and Tuvok use on in S03E19
of Star Trek Voyager :-)

Hydro Québec has a 450kv DC power line from James Bay to Boston which is
nearly 1500kim long. (it is +450kv and -=450km so really 900kV line). It
is nearly uninterrupted eccept for one station near St-Lawrence river
(Nicollet) where they draw some power from it to feed the QUébec grid,
with the rest going to USA.

That 1500 km line is *very* heavy. You want to use the best strength to
weight ratio, you don't want to add the constraint that the material is
also a good electrical conductor.


Alain Fournier