I have a modest set of solar panels on an entirely ordinary house in suburban London. On average they generate about 3,800kWh per year. We also use about 3,800kWh of electricity each year. Obviously, we can't use all the power produced over summer and we need to buy power in winter. So here's my question: How big a battery would we need in order to be completely self-sufficient? Background …
To be fully self sufficient you have to meet your energy consumption during the most cloudy days in winter.
2 days storage gives you a 5% chance of a blackout at some point during the year.
4 days storage gives you a 1% chance of a blackout at some point during the year.
You will not get to 0%.
I see we are including the nuclear winter scenarios!
Actually, I was thinking volcanos. They can reduce sunlight over a large area for prolonged periods.