Musk explicitly mentions, "If you put solar panels on it, you generate more power than you would consume in the system. There's a way to store the power so it would run 24/7 without using batteries." [1]
I think that might be true of launch loops? The cable has incredible kinetic energy, but it is magnetically suspended in a vacuum tube, so its power loss could be low.
[1] http://www.theverge.com/2013/5/29/4378468/elon-musk-teases-j...