David and Kate, a young professional couple, installed a 1.52 kW solar power system on the roof of their small modern house in the new suburb of Douglas in March 2011, as described here. Having recently summarised the performance of my own solar power system over its first year, I asked David how their experiences compared. This is what he said:
We’ve had the solar installed for 532 days so far, and generated 3440 kWh in total, so an average of about 6.47 kWh per day. It’s not quite a fair average since we started counting from a March install [i.e. it includes two winters but only one wet season], but it still gives an idea of the output.
From memory, I believe we’ve sold about 2200 kWh in total, which would make it about 1240 kWh used off the panels in the house, giving us a net benefit of about $1240 for that time – around $2.33 per day.
Those calculations say the panels will have paid for themselves in two more years time – even earlier if (when) the power price goes up again.
David also celebrated the fact that the power supply company has been paying him, instead of vice versa, because the value of his excess power has been greater than the cost of the power he has used from the grid. What next?
Next step is investigating solar hot water to reduce the reliance on gas…
As for the more distant future, he is not impressed with the slashing (and possible abolition) of the feed-in tariff:
It’s pretty disappointing to not even get 1-to-1 for power sold to the grid – and maybe soon to get nothing at all. So if we were to get solar at a new house, I think we’d just pay the extra and get a battery storage system.
That’s quite a big step to take, and one that probably deserves a post to itself, but the fact that he would even consider it says a fair bit about how positive his solar experience has been.