Switched telephone networks run on lead-acid batteries, they will last for a few days without power.
Hospitals, airports and tower blocks have back up generators, although in the case of hosiptals, people on respirators can sometimes die as the generator takes a while to build up voltage.
vk6flab@lemmy.radio 1 day ago
I’m not familiar with how many telephones in Spain are landlines, but looking at Australia, where I am, the majority of connections don’t have an SLA battery, made even more power dependent because we have been rolling out fibre optic cable everywhere and the copper wire in the ground has been disconnected, preventing telephone exchanges from powering much of anything anymore.
The idea that generators will keep the essentials running is incomplete if not outright incorrect. Most of these systems have never been actually tested with an actual outage, look at Heathrow airport for a recent example.
At best a generator will run for up to 12 hours, and only if you have multiple generators and the fuel to run them will you have much in the way of energy security.
Of course if you’re already running on a generator then the picture is different, but even then, in the case of a country wide power outage, getting fuel for longer periods of time is going to be a challenge.