system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Where does excess electricity go on a grid, is it just grounded?
gpt
Because of how generators work, there just isn't excess electricity. Generated electricity is pretty much instantly consumed somewhere.

Now if for some reason power consumption drops suddenly, like say a major power line gets cut, the generators that make electricity start spinning faster because they don't have anywhere to dump power. There's a lot of mass in big generators so it still takes some time, but going too fast is still a problem. 

For something like a steam turbine, if the power plant can't reduce steam input fast enough (it's hard to turn off a coal fire after all) they vent excess steam into the air.