I’ve been trying to get away from theoretical figures to see what impact PV on our roof could actually have.
I measured our electricity use for the last 24 hours. With seven of us here, the washing machine used a lot and a certain amount of heating as the day was colder, I expected the total to be on the high side. But I was surprised that it turned out to be 60 kWh.
Then I found a useful site with very detailed stats from a house in Gloucestershire. They’ve put in 11 panels with a total output of 1.8kW at a cost (in 2004) of £11,300. And it’s producing between 7 and 10 kWhs a day. They are facing SW rather than S.
So even if we could afford the cost and the roof space for a 3Kw array it would cover at best a quarter of our electricity use.