The receiver on the right side image looks all shiny hence my assumption. I think laser light can be kept to a narrow beam. Still some sensitive ground equipment might not like an off-course microwave beam which makes the satellite a good target for the bad guys.

Darwinian -

As I recall, at least in the concept proposed by Peter Glaser, the microwave receiving array on earth would cover quite a large area, probably almost as large as the space-based collectors themselves. So, it appears to me that the spreading of the micro-wave beam has already been taken into account (though I am hardly qualified to prove this).

The proponents also argued that the microwave beam would be so dilute and have such a low energy flux that it would not endanger human or animal life that found itself within the beam. This could be true or just wishful thinking.

The beam issue you raised is probably the least of the many conceptual flaws inherent in this whole concept.

As I commented elsewhere, this whole thing has the distinct aroma of pork.

I a not scared by the technological complexity but by the lack of long term planning and investments as in this generation living on the hard work done by previous generations while not providing for the comming generations.

While the scifi nerd in me says "Yesss!" the rest of me says "Raise the funds, launch a prototype and prove that it works."

My sentiments exactly--almost.

This should be one of our sources of energy, but it should not necessarily be either the principal one or the most urgent.

Why not GEOTHERMAL? Free, always available, proven to work (see major cities in the Philippines, for example)--and also no CO2.