I have a new hobby – my solar electricity system I installed on my roof last week. I have wanted solar for years however I never pursued it because I was under the impression that it only made economic sense if the panels were on a north facing roof. Recently I heard that west facing roof can be good because it gets the afternoon sun at the same time as the peak electricity prices are in play – in summer at least. So I investigated and my provider told me that I should be able to get about 70% of the efficiency of a north facing roof from my south west facing roof (5.9 year payback). That was good enough for me and I decided to do it. Here are the details for the benefit of others considering the same.
- 18 x 330 watts LG Neon 2 Mono-crystalline Silicon PV Modules
- 18 x SolarEdgeDC Optimisers
- 6kW SolarEdgeSolar Photovoltaic Inverter with back-up
Here is my roof showing the south west panels. The location is Gladesville NSW 2111.
Here is my production on the first full day of monitoring.
It is hard to be precise here, but this is what I have to go on. On this day (19th Sept 2017) I produced 26.05 kWh from 5.94 kW of panels. I then compared this to another north facing solar system I had access to data for on the same day (see below).
My panels produced almost 86% of the total production per kW of panels as the reference system. There are a couple of caveats.
- I have a whirlybird on my roof that is currently partially shading 2 of my panels. When that is moved it should be better.
- The comparison site is in Adelaide (different weather, latitude etc).
- The comparison site has older panels which are likely not as efficient as mine
So my assessment is that it is reasonable to expect that I am getting around 70% efficiency with my panels. I will see if I can get some better comparison data for a future update and review, and I will also post back in the future how the production goes in summer.