Could We Really Have Space-Based Solar Power?

Image: Rhett Allain. Solar Panels in SPACE

I saw this IFLscience article about a Chinese plan to create a space-based solar power system. Of course, I have to add some comments and estimations about how this would work (but the Wikipedia page is pretty good too).

OK, let’s get to some questions (with answers).

Why would you put solar power in space?

I mean, first, space is just cool. Who doesn’t want to go work in space on some solar panels? Sign me up.

But other than that, let’s think about how a solar panel works. Basically, it’s a solid state device (no moving parts) that creates an electric current when light hits it. Normally, you would use light from the Sun (because if you use a light bulb it doesn’t work too well — obviously). We can calculate the power output (P) for a solar panel if we know the efficiency (e), the area (A) the angle between the light and a normal the the panel (θ) and the intensity of light (S).

For the angle (θ), the best case scenario is when the angle is zero. This happens when the solar light hits the panel at a perpendicular angle. At a 90 degree angle, all of the sunlight essentially misses the solar panel and you get zero power. The area (A) could be pretty much anything — but the panel mentioned in the proposal says “1 kilometer wide” — maybe it’s…