Originally Posted by Bourke

It's not. Microwave is good for sending signal modulation (data) but pretty much useless for transmission of power. Then you have the non synchronous orbit issues...
There is so much unused space here that could be put to good use for solar farms which would require far, far less investment and risk as well as not include a insane distance to try and transmit power, not to mention a lack of a stable, viable way to transmit it. Drive around any industrial area and there are HUGE factories the size of several sporting fields. With rooftop space that is completely unused. Spaces high enough to be above treelines, in areas near where 90% of power consumption is needed, near the right kind of infrastructure to get the power where it needs to go, owned by companies who would be quite happy to see their unused space put to a use that earns them some extra money.