An Electromagnetic Power Hotspot is a location on a planet that’s a potentially good spot for constructing your base. You can often find multiple hotspots that are of different types (resources) to maximize your base’s potential.
You will need to use the survey analysis visor and enable the survey mode to find these hotspots. Get all of that at the anomaly vendors in space.
Depending on the strength of the hotspot (its class), you can generate more or less power for your base.
However, in practice even a weaker hotspot will be sufficient for powering your whole base because you can construct as many electromagnetic generators as you want. You’ll need to clear terrain often but you can construct additional structures to pile them up on top of each other.
The further away you construct these from the hotspot, the weaker the strength or the amount of electricity you’ll generate from each generator. This also weakens if you construct many of them.
Generally speaking, you can make dozens if you want and there will be no issues. Just connect them all to a battery farm and you’re good to go.
The amount of energy that you harvest, as I’ve said, will depend on the hotspot’s class. Here is a simple breakdown of how much each gives:
C 50% 150 kp, B 73.3% 220 kp, A 83.3% 250 kp, S 100% 300 kp. Use your survey device to see power levels as field strength.
At the top I’ve embedded a nice video for you to watch with regards to base electricity and some various tips & tricks you should know about.