According to the paper you cited, such setup in Germany would cause 100-500 hours of blackouts each year.

Pg&e has performed similarly over the past 10 years, averaged across California.

"continent wide grid" is a key requirement.

I would assume that many/most countries in climates where power interruptions quickly turn into deaths to avoid building in a dependence on an extra-territorial grid for base-level power supply.

It's already a problem in Eurasia with nation states using eg. natural gas delivery as a means to apply political pressure on other states, and this while it is still (relatively) easy to solve energy needs as carbohydrates can be easily transported.

If all border crossing energy/power delivery is through a physical network of cables, adapting if delivery is cutoff would be almost impossible unless all gas/coal/oil plants were kept at/near operating condition.

Hence, yes, the buildout must be some X times necessary power, as much as possible locally. A significant fraction of that generated power should be used to create a) industrial feedstock b) to generate liquids/gas that can be easily used and transported.

The latter in the case some nation is being pressured by energy blockades where the existing grid can not supply enough energy through transmission lines from other bordering states.

You probably want a 6x overbuild to account for round-trip losses in your storage system. Cost of storage falls very fast as your efficiency requirements are relaxed, which becomes attractive as raw generating cost plummets.

or...

we could use space rocks to heat water.

just saying.