We’d like to remind Forumites to please avoid political debate on the Forum.
This is to keep it a safe and useful space for MoneySaving discussions. Threads that are – or become – political in nature may be removed in line with the Forum’s rules. Thank you for your understanding.
The MSE Forum Team would like to wish you all a Merry Christmas. However, we know this time of year can be difficult for some. If you're struggling during the festive period, here's a list of organisations that might be able to help
📨 Have you signed up to the Forum's new Email Digest yet? Get a selection of trending threads sent straight to your inbox daily, weekly or monthly!
Has MSE helped you to save or reclaim money this year? Share your 2025 MoneySaving success stories!
New Octopus tariff for solar and battery users - Octopus Flux
Comments
-
My solar installation switched on over 7 years ago and I have been trying to financially justify a battery ever since. I just can't. Over the Easter holidays I became aware of Flux and having received an email from my FiT company stating that as I am on a Smart meter my 50% deemed export is being migrated to metered, I did the sums and decided to apply for Flux. Having done the sums to confirm moving to Flux was fiscally prudent, I did the sums again to see if the new tariff made a Powerwall fiscally viable. For me it did not. The way I see it is this. I have a split array, 4 kWs due East and 3.12 kWs due West. I currently import around 3.4 Mwhrs and have around 4.5 Mwhrs available for export. My spare 4.5 Mwhrs will net me around £1k1, an extra £900 over deemed export. I will pay extra for gas as I have a solar divert which I'll switch off as it's better for me to export the electric and use more gas. That will cost around £100 making Flux worth around £800pa. So what would a £12k 13.5 kWhrs Powerwall bring to the party? Well it could timeshift 13 kWhrs from Flux rate to peak export rate at £2.05 a day or £750 a year, taking ~ 16 years to RoI. In a best case (though not reality based) scenario the battery could also eliminate 3.4 Mwhrs of import at say an average of 33.5p by sacrificing export at 22.5p, a gain of £374 pa bringing the RoI of a Powerwall down to around 10 year, the warranty period. In other words, a battery is still too expensive for me as putting £10k into my Sipp and watching it increase to £12500 and then immediately taking £3125 tax free (of which £2500 the government just gave me) is more appealing. Flux, for me, grabs most of the low hanging fruit by itself.Meatballs said:Has anyone rerun the numbers of solar Vs battery and solar with flux?
It would appear the payback period for solar is greatly reduced, but including a battery isn't as beneficial as it once was? Ditto for adding a battery to an existing install.3 -
@pensionpawn Newsflash, other batteries are available
Someone I know has just installed a 5.2kWh battery (8yr UK warranty), cost £1350, Solis 3kW inverter, cost £649, add in a little bit extra for cables etc and he has paid just over £2k, he has another two batteries on order.Edit. I don't think you've factored in using cheap rate electric through the winter, this will decrease the costs further, or the smug feeling you get seeing how small your electric bill is
Also don't know why people are so concerned with ROI in the warranty period, they don't suddenly stop working.3 -
This content has been removed.
-
Thought you needed a battery to be on Flux though?pensionpawn said:
My solar installation switched on over 7 years ago and I have been trying to financially justify a battery ever since. I just can't. Over the Easter holidays I became aware of Flux and having received an email from my FiT company stating that as I am on a Smart meter my 50% deemed export is being migrated to metered, I did the sums and decided to apply for Flux. Having done the sums to confirm moving to Flux was fiscally prudent, I did the sums again to see if the new tariff made a Powerwall fiscally viable. For me it did not. The way I see it is this. I have a split array, 4 kWs due East and 3.12 kWs due West. I currently import around 3.4 Mwhrs and have around 4.5 Mwhrs available for export. My spare 4.5 Mwhrs will net me around £1k1, an extra £900 over deemed export. I will pay extra for gas as I have a solar divert which I'll switch off as it's better for me to export the electric and use more gas. That will cost around £100 making Flux worth around £800pa. So what would a £12k 13.5 kWhrs Powerwall bring to the party? Well it could timeshift 13 kWhrs from Flux rate to peak export rate at £2.05 a day or £750 a year, taking ~ 16 years to RoI. In a best case (though not reality based) scenario the battery could also eliminate 3.4 Mwhrs of import at say an average of 33.5p by sacrificing export at 22.5p, a gain of £374 pa bringing the RoI of a Powerwall down to around 10 year, the warranty period. In other words, a battery is still too expensive for me as putting £10k into my Sipp and watching it increase to £12500 and then immediately taking £3125 tax free (of which £2500 the government just gave me) is more appealing. Flux, for me, grabs most of the low hanging fruit by itself.Meatballs said:Has anyone rerun the numbers of solar Vs battery and solar with flux?
It would appear the payback period for solar is greatly reduced, but including a battery isn't as beneficial as it once was? Ditto for adding a battery to an existing install.PV total 19.8 kW system:
23 x 420W East/West split over two flat roof areas at 10 degrees inclination.
13 x 390W South spit over two flat roof areas at 5 to 20 degrees inclination.
6 x 390W south wall mounted at 90 degrees inclination.
7 x 390W West wall mounted at 90 degrees inclination.
2 x 5 kW hybrid inverters
4 x 9.5 kWh batteries (38 kWh total)0 -

I was going by this, has it changed then?
Or is it similar to Go and managing to be accepted without an EV?PV total 19.8 kW system:
23 x 420W East/West split over two flat roof areas at 10 degrees inclination.
13 x 390W South spit over two flat roof areas at 5 to 20 degrees inclination.
6 x 390W south wall mounted at 90 degrees inclination.
7 x 390W West wall mounted at 90 degrees inclination.
2 x 5 kW hybrid inverters
4 x 9.5 kWh batteries (38 kWh total)0 -
I think its always said that, but they don't ask, I know off people who are on it without a battery, and someone posted on here that a battery is not a requirement as it is not mentioned in the T&C (they read them).
1 -
That does sound similar in some ways to people managing to be on Go - I'm still sitting on the fence with 19kWh batteries, still have Go until July at 7.5p/kWh.Ron-ski said:I think its always said that, but they don't ask, I know off people who are on it without a battery, and someone posted on here that a battery is not a requirement as it is not mentioned in the T&C (they read them).
With the recent announcement of price drops, I'm swaying towards Intelligent but also might run the numbers on this for the brighter months.PV total 19.8 kW system:
23 x 420W East/West split over two flat roof areas at 10 degrees inclination.
13 x 390W South spit over two flat roof areas at 5 to 20 degrees inclination.
6 x 390W south wall mounted at 90 degrees inclination.
7 x 390W West wall mounted at 90 degrees inclination.
2 x 5 kW hybrid inverters
4 x 9.5 kWh batteries (38 kWh total)0 -
My last weeks electric bill is -£20.81
0 -
That's the drive and the weather has been great, forecast for the next 7 days doesn't look to good though.Ron-ski said:My last weeks electric bill is -£20.81
PV total 19.8 kW system:
23 x 420W East/West split over two flat roof areas at 10 degrees inclination.
13 x 390W South spit over two flat roof areas at 5 to 20 degrees inclination.
6 x 390W south wall mounted at 90 degrees inclination.
7 x 390W West wall mounted at 90 degrees inclination.
2 x 5 kW hybrid inverters
4 x 9.5 kWh batteries (38 kWh total)0
Confirm your email address to Create Threads and Reply
Categories
- All Categories
- 352.9K Banking & Borrowing
- 253.9K Reduce Debt & Boost Income
- 454.7K Spending & Discounts
- 246K Work, Benefits & Business
- 602.1K Mortgages, Homes & Bills
- 177.8K Life & Family
- 259.9K Travel & Transport
- 1.5M Hobbies & Leisure
- 16K Discuss & Feedback
- 37.7K Read-Only Boards