I work for Big Oil. I am an exploration geologist. I find oil and gas for a living:)
Yet my home is basically off the grid, net year on average. I don't generate enough over the summer (Houston is very hot, A/C is expensive in terms of wattage), but mostly make up during the winter, as winter here is sunny, unlike UK.
My problem is I don't have enough south facing area on my roof. You can see above, I have only 8 panels facing south, they are more efficient. The west facing panels don't generate enough.