With regard to solar panels:

You are limited by the amount of sunlight you are starting with.

So at the top of Earth's atmosphere solar constant is about 1300 watts per square metre.

At ground level you are down to less than half of this. Best insolation is at the equator and gets worse with increasing latitude.

Theoretical maximum efficiency for solar cells is about 60% with current designs and materials.

You could potentially concentrate incoming sunlight with mirrors and lenses but you're ultimately limited by the incoming light (inverse square law with distance, directly proportional to stellar luminosity,  peak wavelengths a function of stellar surface temperature).

Rob O'Connor
Sent from my android device.