> The ability to reuse more and more will improve over time so yes it's perfectly feasible.
Well, if that "counts", then solar power will become totally free and have a net positive environmental impact, we'll just plant some nanobots that grow and repair solar panels inside a marked area, and can be scooped up should we need them elsewhere, hence "100% free once we perfected them". They'll smell like vanilla, and change color according to the moods of people using the energy.
Latter on we make nanobots and send them to the sun to hang out there for a few thousand years and grow a scaffolding from, uhh, space dust or something, and then we shoot nanobots at it that grow solar panels on it, and we have our Dyson sphere. Add some nanostuff that creates material from energy and flings that at Earth, then convert material back to energy.
This didn't even take me 5 minutes, so I really don't get what the problem is :P