Rotating power outages

OK - another question about power failures. It’s hot and humid enough up here that they have had to implement rotating brief blackouts to conserve power. First time I ever recall that happening in Alberta!

My question - I trust that the power companies have good reason for doing that; however what would happen if they just said “screw it” and didn’t bother doing anything? Brownouts? Likelihood of catastrophic failure?

If the voltage gets too low, you’ll get brownouts. If it gets way too low, most of the grid will start to initiate protective measures and trip offline, resulting in a cascading blackout.