On the other hand, since Tesla is also selling a battery specifically for grid backup I would assume that they've done some market research into it and this value might be higher than one would think.
Historically in Germany (and most of western and northern Europe AFAIK) a blackout is something that happens every ten years and lasts for two hours. It's rare and inconsequential enough that no-one bothers hedging against them.
Wind and solar are increasing the probability of large blackouts, but the proper solution to that is building more nuclear power, eventually transitioning to fusion.
Can we stop betting on pipe dreams? Fusion isn't proven, and while I'll advocate for continuing research into it, solar, wind, and geothermal is here today.
We should be advocating for the installation of solar on every roof, on every brownfield that can't be used for housing or agriculture, wind where ever possible, and geothermal where it makes sense.
It is silly that we continue this nonsense that nuclear (fission today and fusion tomorrow) are our saviors. We have proven, as a species, incapable of properly managing the small risks that nuclear presents.
It takes 10-20 years and over $1 billion US to bring a new nuclear plant online, and this does not take into account the government limiting their liability in the event of an accident. Wind turbine parks and solar fields can be developed in under a year, with fewer (if any!) cost overruns.
Fusion is the ultimate energy generation technology. It will be real soon enough.
Your comment reminded me of Interstellar :-)
Nuclear reactors can be build in a safe way, it's the storage of spend fuel that makes them uneconomical because of the high cost to do it properly.