Octopus Flux

[Lincs Robert]

Any takers?

Here’s a good overview:



I’m especially keen on knowing whether I could sign upto it if I’m in receipt of a feed in tariff? I’m in receipt of the 2011 FIT and although I don’t get paid for any actual export - I do get paid a “deemed” export rate of half what’s generated.

Cheers - Rob

[nowty]

We had a thread started here about Flux,
https://camelot-forum.co.uk/phpBB3/view ... =14&t=1875

If you want to get paid for export, you need to sign away your rights to FIT deemed export.
You can still keep your generation FIT.

[Lincs Robert]

I’ve done the sums & this isn’t for me …… It might work for some though

[Swwils]

I'm moving into it since it drastically simplifies the code require to force export at the right times.

The logic is very easy essentially any import is cheaper than the export you can get for it.

The website sign-up form is broken though it hangs when you select any drop-down.

[Krill]

I’ve done the sums & this isn’t for me …… It might work for some though

It looks interesting for us newbies, and it somewhat undercuts the argument about battery only installations because the day export rate is higher than the cheap rate import rate including VAT. So those who still have gas heating probably use around 10-15 kWh per day, fill up the battery on the cheap slot, use solar during the day (fill up any remaining ingredients battery/hw storage) and export the excess, then force export the rest in the in the peak slot and try to turn a profit. Looking at the numbers I think one year of flux at these rates would buy maybe 45 cells from Colin due to the profit.

This tariff fills a hole for those of is that are trying to build larger generating and storage systems but don't have the high use (heating, hot water, BEV) yet but will do in the next five years).

There is a tax implication in this though which makes it more complicated than it needs to be.

[Lincs Robert]

I think the devil really is in the detail with this one. You say “fill up the battery at cheap rate”. Great in theory - but the cheap rate is only for 3 hours, which means that with a 3600w charger/inverter that you would only be able to harvest about 11kWh during the slot. Coupled with the fact that the cheap import rate is roughly 50% more expensive than the Go equivalent. I didn’t get as far as the spreadsheet analysis as the back of the envelope calculations showed me that there wasn’t enough in it for me. Another factor is that very accurate weather forecasts would be essential to make it work. Imagine that the forecast showed that tomorrow would be sunny and that you were expecting a decent amount of sunshine & it didn’t materialise. I’m seeing that at the moment to some extent, but am somewhat protected as I’ve got a fairly decent amount of battery storage, 40kWh ish, so have a fair margin of error on my side.

I think this is one of those things in life where there is no right answer.

[nowty]

There is a tax implication in this though which makes it more complicated than it needs to be.

The export is effectively SEG, so should be tax free like FIT.

[Krill]

I think the devil really is in the detail with this one. You say “fill up the battery at cheap rate”. Great in theory - but the cheap rate is only for 3 hours, which means that with a 3600w charger/inverter that you would only be able to harvest about 11kWh during the slot. Coupled with the fact that the cheap import rate is roughly 50% more expensive than the Go equivalent. I didn’t get as far as the spreadsheet analysis as the back of the envelope calculations showed me that there wasn’t enough in it for me. Another factor is that very accurate weather forecasts would be essential to make it work. Imagine that the forecast showed that tomorrow would be sunny and that you were expecting a decent amount of sunshine & it didn’t materialise. I’m seeing that at the moment to some extent, but am somewhat protected as I’ve got a fairly decent amount of battery storage, 40kWh ish, so have a fair margin of error on my side.

I think this is one of those things in life where there is no right answer.

I agree, there is not much flexibility in a lot of cases becasuse of limitations from the inverter.

To be candid, I ran the calculations based on a 6kW Solis inverter connected to 6.4kWp south facing panels and a dual squirrel pod AC coupled battery inverter (so a 7kw charger), which does make things a bit easier to justify. I do not know the round trip efficiency for the cheap slot charge and peak slot discharge which will affect profitability (and did not consider equipment devaluation) which obviously has an effect. The other side of the equation is the upfront cost of battery storage: 20kwh of battery storage is not cheap even if it is a self build battery, and I agree with your suspicions that this strategy would really want a 40kwh battery such as you and other posters here have been putting together recently.

All that to say that if the system is not battery storage limited (and limited by the inverter), I found that I should make ~£3.30 profit from a three hour cheap slot charge and 3 hour peak discharge per day, but would need 20kwh storage just for the arbitrage and another 10kwh storage for general use minimum. Using PVGIS data for my location I then worked out about £550/year for the months where solar PV generates more than used (assuming day rate only, not peak), which assumes perfect use. So best case, maybe £1750/year revenue? And then best case, if that is offset against other costs, personally I would find that covers the standing charge for both electricity and gas and then the gas bill for the year. With a 3600w charger I don't see how it would be worth using?

FWIW, I still need to compare this to agile but as I'm not due to get everything fitted for another 2 weeks and still need Octopus to get around to fitting a SMETS2 meter I will be unlikely to pick a tariff before May and doubt the swap would be completed before early June so all my figures are nothing more than back of hte envelope either.

There is a tax implication in this though which makes it more complicated than it needs to be.

The export is effectively SEG, so should be tax free like FIT.

Sorry, I may have misunderstood, I thought that once the earnings go over £1,000 HMRC wanted their cut? It's relevant because anyone who pushes the arbitrage on Flux will approach that figure regardless of any other export?

[Lincs Robert]

That’s another good point. At the moment my “deemed” export is tax free income as part of the FiT I’m on, so I’d be silly to swap tax free income for taxable income.

I’m also a dual Lux user, so 2 x LXP3600 units. I really don’t get the “Squirrel Pod” handle though. I found it very frustrating that my installer was untrained on the upgrade path from a single to dual units & it took a lot of angst to get it operational. The physical installation was a doddle, not the case with the config. It’s all in and working well now though. I tried a forced discharge earlier - seemed simple enough, so it’s a facility that I could use if needs be in the future.

[nowty]

Reasonable amounts of domestic leccy export payments are tax free for FIT or SEG.

See here,
https://camelot-forum.co.uk/phpBB3/view ... 520#p21099

There was also an update to the FIT legislation which says something along the lines of, wherever it says FIT, it also includes SEG.

And SEG can include some "Brown" leccy imported from the grid and re-exported.
https://www.legislation.gov.uk/uksi/201 ... 005_en.pdf