you are right, Waste heat would be a problem because the only way you can dissipate it is by radiation. but that would become a problem much much farther out. I

you are right, Waste heat would be a problem because the only way you can dissipate it is by radiation. but that would become a problem much much farther out. I mean we are talking 100+ billions people. Also, if you have plentiful energy you can build way cheaper orbital launch tech. translation you are not bound to earths gravity well anymore. So its not too far fetched to imagine living in space habitats (forget mars that just good for gravity). those will be much better at dissipating waste heat (volume/surface area thing). Like I said its a whole another ballgame.