Installing solar panels on your home or business is common in many European countries. But they really come into their own during energy crises.
“If you’ve got a solar roof on your home and you’ve got a battery then, depending on how much energy you can generate, you are substantially insulated from importing electricity,” explains Matthew Clayton, CEO of UK-based Thrive Renewables.
Dynamic tariffs are becoming more common in Europe. This is where the price of electricity varies throughout the day and night, with costs going up during peak periods, like dinner time, when households are using more.
This means that if you store up solar power during daylight hours, when the sun is at its strongest, then you can use that energy, rather than drawing it from the electricity grid, during the most expensive periods. “Your relationship with the grid is totally changed,” says Clayton.
If you're framing it as "...worth spending..." then you can do the sums, if you like.
e.g. if you have a 1 in 1000 event that is 24h without electricity (once every 2 or 3 years?) You'd normally spend 30 a day on electricity, plus a cost for the convenience of not having it happen, lifetime of what 10-20 years, so multiply that up.
And if you can quantify the other benefits (using the variable daily rates, etc) then you get a better estimate.
So your thought is valid (in a quantitative / utilitarian kinda way), but not new. It looks to me like we are at or approaching the point where for people who put high value on convenience, it is worth it. For those who don't, it isn't.