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 …
It’s interesting to see the data though.
And I remember hearing about one german company, that sells a system of normal batteries for short time storage and electrolysis/fuel cell for long time storage. In summer you generate the H2 and in winter you use it up when the journal batteries are empty.