I am trying to work out my ROI on my DIY solar and the returns graph just doesn’t seem to add up, I think I am just misunderstanding how it is calculating the ROI.
I have 4 x 260w (1kw) of panels and a few batteries I use to shift my power usage for my agile power tariff but I am using 15.5p in pvoutput as an average p/kwh, I would of said very roughly this would save me around £120 > £160 per year.
Solar was installed end of July last year and I have made some improvements since it went in, bigger batteries and I charge overnight now as well.
So in the nearly 9 months installed I have generated 531kwh x 15.5p has me at £82.31 and the amount generated has improved with the batteries and charging etc so I might get to the £120 ish per year, maybe more.
Total system cost was roughly £500 so I would of thought £500 / £120 would have me around 4 and a bit years ROI, not counting for derate, inflation and deprecation but the returns graph looks like this with my ROI Jun 2035.