Are you assuming you'll use every single generated unit? This is where you'll realise that in summer months (June to August) you'll be exporting anything up to 50% depending on your usage and obviously in winter you'll be consuming every last drop, but you've obviously factored in hte full price units for when your battery runs out, sensible flexing of your habits to the overnight time (dishwasher, eddi, tumbledryer, washing machine) will certainly help.
Yes I am as its a basic model.
I flexed my usage up in winter a little (its pretty flat I think)
So June and July are supposed to be basically flat months.
June : 3900 units annual suggests 526 per month, or 17.5 average, which happens to be my estimate for daily usage in summer!
If the split of the 3900 is vastly out (likely), or the usage is vastly out (unlikely) then it may vary, and of course the big one is say I have 2-3 high generation days, I would be full battery basically most of the time. If thats followed by some low days then do I need to charge some.
So yeah its very much theory and I will be able to start refining as time goes by.
My generation will hopefully be a bit higher, but who knows!
As said I also have the diverter, so in theory probably 6kw or so can go there before export happens. Really what I dont want to see is very very peaky days and very very low days as thats dramatically going to increase the export potential and hence charge potential.
The more interesting months are the spring / autumn ones. They will be most difficult to take the best action as I see more variability in generation likely then from eg the numbers Hippo posts.
Sept for example. 3900 annual shows a month of 351kwh generation and my demand 525. So 175 short. On average needing to draw 5.8 units into the batteries to balance the 175 usage over the month.
No tweaking of usage included yet (ie when) that will come later
I am also going to rerun based on Go faster as I can move to that, just want to see the impact, but that makes it even easier to load shift, and some would naturally happen, especially at weekends.
Thats the next test to run.
I am sure real world vs theoryworld will be less efficient, but current pricing impact of ROI on likeforlike was what I was after, and seeing that at 6.25 was pretty good.
Bar terrible real world generation or messing up when to charge etc, its likely I can take 2 X £2k chunks out of that cost with the expected price cap this and next winter.
In investment terms it always helps to have heavy return at the beginning when its likely more predictable than having to rely on say elec pricing in 5 years time, I mean who knows right...
I've been in 2 minds for a while but finally decided to bite the bullet, EST Scotland funding, payback should be roughly what I save so it's a no brainer I think... Only one installer kept replying to me after it went mad, a 4th can't even survey for another month.
This is a great thread!
