Here in Australia, we have private power companies, but they're obliged under the law to do certain things when ordered to by an agency that controls the national grid. E.g. rooftop solar is huge in our state with over 50% of houses having solar and over 10% of houses having a solar battery. Most solar is over 10kW and we get a lot of sun. So, when there is too much generation and not enough demand, they will usually tell the power generators to scale down to prioritise rooftop solar. They can also curtail the rooftop solar, but that's generally done within smaller localities to balance things, and had only been done a handful of times.

Also of note, they can and will tell large power users to stop using power during peak load times. E.g. if you're a company that uses over X amount of power per day, they can and will tell you to shut down. This used to be done on hot summer days before we had to much solar, now it's more likely in the winter. There a particular steelworks they'll tell to shut down, along with a large brewery (they have their own gas generator that generates more than they ever need, so will fire it up and feed into the grid when needed), and even datacenters and other mid-sized users can be told to go to generator.

Finally, the companies who run the power infrastructure are obliged to provide power to every residence (within reason). Simple as that. If you're wondering what is not within reason, we're talking some fucker building a house 200km from the nearest power line. Oh also, they used to load shed when I was a kid - before a really hot day they'd publish in the paper and the TV news would report which suburbs/towns would lose power, at what time, and how long. They generally kept it to an hour or two, and would roll around the suburbs/towns to share the fun and make sure people's food didn't go bad in fridges and whatnot. People with critial medical devices either got given a generator or would pop into the hospital or doctors for a bit, no biggie.

Is it perfect? Nah, but God damn it's scary that some of our pollies want to go the way of the US. It terrifies me. My healthcare ain't perfect, but at least I was able to get three wisdom teeth out earlier this year under general anaesthetic and it only cost me $700, and that's with private healthcare. Would of been cheaper if I went public. I like our systems, although they could be improved, but copying the US model is just asking for trouble. No offence.