Comment by ajsnigrutin

In many countries, energy production was (and still is) owned by the countries and power prices are regulated. In cases of total system failures (eg. look at ukraine), power usage is restricted by shutting down different parts of the country at different times, so your area has power from 4pm to 6pm, other area has it from 6pm to 8pm, etc, industry gets partially shut down, partially works at night if it's needed. Everybody gets to cook and wash in their timeslots, and the rest of the time, they're equally without power.

In case of some failure of the system you're proposing, the prices would skyrocket, the poor would not get power at all, and the rich would have power all the time but for a very high price. Economically speaking, that's great for investors in batteries and supporting systems, socially speaking, it's a horible world to live in. And the system is very unstable already, in portugal it already failed horribly not long ago.