If you’ve every wondered what happens to the energy when a solar panel is unplugged, you’re not the only one.
If you think about it, when a 20% effecient solar panel (about average for the latest models) is generating electricity, about 20% of the energy from the all that sunlight leaves the panel and goes into the grid or your home. The rest of the energy is either absorbed or reflected. Since solar panels are dark, they don’t reflect much light so most of that 80% is absorbed and is turned into heat (which means all the atoms in the panel jiggle around more – that’s all it means).
So if you unplug the panel, the 20% of the energy that was going to the grid now has no place to go. And, since the panel doesn’t get lighter, it must just get hotter. That’s exactly what happens.
In fact, most large solar farms use drones with thermal infrared cameras to find disconnected or malfunctioning panels. Really! Pretty cool, eh?