It seems to me that this is a bit like the iPhone, before it existed. Almost all of the technology exists, but nobody has put it together in the right way yet. Is that true? I wish I knew.
Would need very large ground target to absorb and convert to electricity and hope someone or some tech error doesn't change the coordinates. The standard cosmic ray/solar flare bitflipping or supervillain hacker.
Lose energy 2 steps more than a cell on the ground
Sunlight -> Battery (solar cell)
Battery -> Transmitter (magnetron?)
Transmitter -> Receiver (through atmosphere)
Receiver -> battery/grid (Receiver a PV cell or funky molten salt/water steam turbine?)
Just get started on that Dyson sphere and cut out the middle man...
the Sun provides much more power than any satellite could. Solar panels + batteries seem dramatically more realistic to me