0% VAT on Battery Retrofit installs from 2/2024

EricMears

Grandad2b said:

Well, this is timely I'd just been thinking that with conversion losses etc the best case is a saving of around 10p per unit at current prices [I am simply considering a battery as a means to time-shift my PV generation]. Is that going to be worthwhile without a TOU tariff and exporting the excess?
Over the last year my highest daily usage is <11kWh, daily average >6kWh.
Assuming I'm able to empty it overnight (unlikely given my daily average use) a 5kWh battery might at best gain me 90p/day during the generating season; but the reality is that the average from May to July would have been about 48p/day. Try as I might I can't see how to justify a battery on that basis

Don't forget that you can also use the batteries in winter to charge them at offpeak rates and not need to buy anything at peak rates,

Heedtheadvice

I have beennin a similar position to you @grandad2b.

Over the years I have optimised pv use and, as is typical, still exported a significant quantity so there  was potential to time shift.

My import was slightly higher than yours at 2600kWh.

Installing approx 7kW batteries has enabled from May through September to for a practical calculation purposes nearly zeroed export and zeroed import over that period. Import has come down to about 1600kW per annum (assuming consumption is as last year) so saved approx 1000 x 0.30 = £300.

Of course there are losses but also some savings in the shoulder months too which could well balance out.

Assuming no power import cost change and no inflation  that will be about 13 years to break even.

So maybe financially debatable but other benefits of battery backup, ease of utilising self generation without a lot of clock/sun watching and the eco power benefit. With luck battery life could well be over the break even time - difficult to forecast!

It also help with time shifting to charge up the hybrid car and that car also explain the high winter season import.

I am also happy I have gone downstairs route!

Spies

Don't forget to factor in how much you're being paid for each kwh of export if ROI is important. 

pensionpawn

My panels switched on almost 8 years ago and I've been trying to fiscally justify a case for adding a battery (Powerwall, due to island mode too..) ever since. With the exception of the short period of time during the meteoric rise in energy prices from late 2019 / early 2020, and before the price of batteries shot up due to increased demand, I have been unable to. I have split arrays 4kWs due east and 3.12 kWs due west producing ~ 6.32 Mwhrs pa with around 4.5 Mwhrs spare for solar divert / export. Since moving to Octopus Flux in May, for no capital outlay, I have been paid ~£620 for 2924 kWhrs of export against a cost of £683 for 2 Mwhrs for import. After FiT, gas and standing charges I'm still £100's in credit and fingers crossed will be cost neutral after 12 months, or just slightly negative. For me this makes the case for a battery ever harder to justify based on my current natural annual import of ~3.4 Mwhrs of which less than 21% (so far, however this will rise before next May) is at peak rate. I'm not going to make a decision until I've been on Flux for a year and have a better understanding of my evolving energy profile, whilst continuing to keep an eye on the developments in VTH EV tech. For me, the prospect of a mobile 60 - 80 kWhrs battery that can power the house (and hopefully also support island mode) as well as minimising my (already minimal as we're almost fully retired) commute costs, is more appealing. I also don't like the idea of justifying a battery based mainly on time shifting because if the tariff that makes your business case work is withdrawn, and your're probably hoping that this tariff is around for a good many years, the ROI for the battery's sky rockets, most possibly to longer than its warranty. Horses for courses....