(Author here) My roof is full on both sides. There simply isn't any more room.
I do say:
> As solar panels increase in efficiency, it might be more sensible to replace the panels on my roof, or add some onto a shed.
Even in the darkest days of winter, they still generate something (unless they're physically covered in snow) - but they'd need to be 20x as efficient to power my typical winter usage.
Solar panels are already at least 20% efficient (most are better than that). I don't think they'll improve much beyond 30% within the next 20 years. Your 20x aspiration is of course technically impossible.
It's really interesting that you still get a smooth production graph with east/west, I wasn't sure what that would look like.
We have east and south and our peak production is when the sun is at the south-east, in the middle of the two faces. The east face production drops off from there on out until it's a fraction of what the south face is generating.
I do say:
> As solar panels increase in efficiency, it might be more sensible to replace the panels on my roof, or add some onto a shed.
Even in the darkest days of winter, they still generate something (unless they're physically covered in snow) - but they'd need to be 20x as efficient to power my typical winter usage.