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 …
That’s a completely unnecessary way to do things. The mistake you’re making is that this specific way must provide all power.
It doesn’t. You combine methods for a reason. The wind blows at times when the sun isn’t shining, and vice versa. We have weather data stretching back many decades to tell us how much a given region will give us of each. From there, you can calculate the maximum lull where neither is providing enough. Have enough storage to cover that lull, and double it as a safety factor.
Getting to 95% water/wind/solar with this method is relatively easy and would be an extraordinary change. Getting all the way to 100% is possible, just more difficult.
That’s a completely unnecessary way to do things. The mistake you’re making is that this specific way must provide all power.
It doesn’t. You combine methods for a reason. The wind blows at times when the sun isn’t shining, and vice versa. We have weather data stretching back many decades to tell us how much a given region will give us of each. From there, you can calculate the maximum lull where neither is providing enough. Have enough storage to cover that lull, and double it as a safety factor.
Getting to 95% water/wind/solar with this method is relatively easy and would be an extraordinary change. Getting all the way to 100% is possible, just more difficult.