Yes power usage is constantly predicted by utilities. Production must match consumption exactly at every moment. This means weather forecasting is an essential part of managing a power grid, and doubly so with intermittent renewables.
I think the local overloading has something to do with transformers not being able to handle the massive local overproduction. It's not just power not being consumed, it's power being injected into the grid.
I was thinking of other countries where the billing system has only variable fees. Which used to work when you didn't have many people who are dependent on the grid but have a (almost) net zero power bill.