One comment regarding those proposed orbiting solar energy collection power plants. And this is a little amusing.

The drawings included with that report are of giant mirrors in space that reflect sunlight back to Earth where some type of power plant would collect it.

I hope that the original authors of that research report weren’t thinking of anything along those lines!

According to my own calculations, when you reflect sunlight from anywhere in space back to the Earth with any type of mirror including parabolic ones, you wind up with a very large image of the sun displayed on the surface of the Earth. It could be something like 200 kilometers wide. That might be okay for providing dim sunlight for an entire city. But it would be largely useless for any realistic type of power plant.

Instead, the sunlight would need to be focused using some type of optical lens system or perhaps an energy converter that would change the sunlight into laser (visible light – an optical maser) or more general maser (radio frequency and microwave) waves.