Most proposals I've seen involve using microwave transmission to a ground-based receiver dish.

They did a test with microwave to transmit energy from space to Earth. There is some serious drawback in doing it via microwave though, so I'm curious on how they'll transmit a huge amount of energy without heating up or causing residual damage to the environment.

I imagine it would be something like the wireless energy beaming tech in this TED talk: https://www.youtube.com/watch?v=RxrB7PDLJ18

Last year, at the International Space Development Conference, a NASA official said the agency had begun a short-term study evaluating the prospects of space-based solar power. This was the agency's first real look at the subject in about two decades. However, that study has not been released publicly, as there were apparently some policy concerns about the first draft. The revised study may finally be released in late June or July.