Solar PV installation – second review
In August 2011 I had a 3.9kW solar PV installation popped on the house roof. I was fortunate enough to get that in before the government reduced the Feed in Tariff (FiT) payout from its initial £0.43 per kW hour generated. That said, PV installation costs soon dropped along with the FiT, so by today’s standards I did pay over the odds for the installation.
I now have both a full year’s worth of data, from August 24th 2011 to August 23rd 2012, and a full calendar year of data for 2012.
Full year data
In the first 365 days of service my PV array generated 3,690kWh of electricity. That’s a significant contribution! Financially, with inflation and export top-up, it amounted to just shy of a £1,700 payout, or more than an eighth of the installation fee. I’m pretty pleased with that – I’ll have paid this off before I turn 40!
The graph below shows house consumption in blue bars, and generated power as the green line.
The trends are pretty much as I’d expect. We consume a lot more power in the winter. I think December is higher than January and February mainly because I was around the house more, and doing quite a bit of work in the garage which required heating. The major step down in the spring and up in the autumn mark the points at which the storage heaters are switched off and on. We naturally generate a lot more power in the summer.
I’m sad to note that we don’t produce as much power as we consume even in the summer months. I’m certain this is because our hot water is stored in an immersion heater which is charged at night. This year I will investigate solar thermal water heating, although with such a massive PV array already in place, locating it may be quite a challenge!