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.