On IOF tariff since July, my GE battery has daily charged fully from the grid and never from excess to home use solar. Octopus has recommended "checking the setting on the battery to ensure it is configured to charge from solar when available". Any ideas how to do this or what the problem is.
Thanks Annie B
That sounds quite normal behaviour on IOF.
Think of IOF as treating the grid as being a giant limitless and lossless battery. All solar generation is usually exported as you will get paid the same rate for that export as for import. There is no benefit to charge your battery from solar and discharge it to the home later on as you will incur about 15% conversion losses from the battery round trip.
Instead export to the grid with just the inverter losses (no battery losses), and then import later on when you need the energy, again no losses.
IOF generally works best when you have plenty to export, its not really the best tariff to be on in the winter as the import/export rate is comparatively high. You might find ordinary Flux is better for you.
But your battery is “doing the right thing” under IOF and the advice Octopus gave is incorrect, they don’t know how their tariff works!
The above is correct
I ran IOF from May until October, when my average weekly generation was over 1.5 times my use, made a load of credit, enough to pay for a few months on COSY only buying low rate units.
The grid is your giant lossless battery, and you hand your battery over as a small part of grid balancing, mostly 1600-1900
I am on IOF and it's ok, but my timed charge and export keeps being changed so I'm having to change it back every day. Any ideas why. Not getting any replies from GivEnergy.
DavidE45 I am on IOF and it's ok, but my timed charge and export keeps being changed so I'm having to change it back every day. Any ideas why. Not getting any replies from GivEnergy.
If you are on IOF, you have no business changing timed charge and export. You have given control of your battery to Octopus to use as they see fit.
If you want to use the battery yourself, you're on the wrong tariff.
DavidE45 Octopus controls your battery and so it charges and discharges the battery when it needs to. If you try to change things then quite quickly Octopus changes it back. When on IOF you just need to forget about what is happening and remember you are using the grid as a giant lossless battery. If you want to control things normal flux might be an alternative for you.....
geoffreycoan
Your comment re conversion loss is interesting as presumably that negates any gain from off peak top up solar import to battery exporting during peak.
Does not explain tho why IOF says it imports available solar to top up battery but in fact only imports from the grid. Is this the normal pattern?
Bowdler1 I had a quick look on the IOF website and the FAQ’s https://octopus.energy/intelligent-flux-faqs/, I found it says “Overnight & day time charging. Your battery will charge up using the greenest and cheapest energy - some of this will come from your solar and some from the grid. We will also export any excess solar if it's sunny. Your matched import and export unit rates mean your bill will be unaffected by whether your battery is charged from solar or whether you solar supports the grid and the battery charges overnight instead.”
So its vague as to precisely what happens, only says that some of the battery charging will be solar and some grid, and that it will do what’s greenest and cheapest.
Basically its up to Octopus as to how they treat your battery and solar, that’s the thing with IOF, you hand control over to them and since the import and export rates are the same, as I said before, due to battery charging losses you are better off exporting than topping up the battery.
IOF will charge your battery at some point, usually overnight, when rates are lowest and the grid is greenest, but whether that is done at 3am, 7am or 3pm it makes no difference to you, you’ll still pay the same import rate, and then when its discharged and exported in the peak you’ll get get the higher peak export rate - so your profit will be the difference between the two rates minus conversion losses.
If you look at Tim & Kat’s Green Walk channel on youtube, Tim did an analysis of the different tariffs and came up with some rules of thumb as to which was most profitable and when. For IOF if I remember right it was that your generation is at least 1.4 times your daily consumption. So particularly in summer when you are generating loads, IOF pays more than Flux and other tariffs. In winter less benefit and other tariffs will probably pay more/cost less.
The key point to answer r/e your question though is that its up to Octopus as to what they do with your battery, you’ve handed control in IOF. And what they do one day may be different to the next. If its a sunny day and there’s relatively little grid demand they may charge your battery rather than export it, but what Octopus actually plan, its up to them
geoffreycoan
Thanks for your comprehensive reply. Tim and Kat's Green Walk is always informative, I also follow Gary Does Solar.
As you say, Octopus do control the battery with IOF but they should still follow their own description of what the tariff provides. As they confirm that "if there's any excess energy, it should then charge your battery" then that is what should happen.
Coincidentally and for the first time, this morning it did just that! Out of a clear blue sky, my battery imported the excess solar.. I hope this is the result of my interactions with the Octopus Energy team but I'm not holding my breath.
Am I right that the advantage of importing solar to battery off peak and exporting during peak will be the difference between the two rates per kWh (ie 7.26p at the moment)? Minus the conversion loss.
The way I worked it out was 1.2kWh in and 1kWh out. For a rough and ready 20% round trip efficiency loss.
So 23p * 1.2 = 27.6p
30p * 1 = 30p
2.4p for each kWh exported that was from grid charging.
I think that makes sense.
And if it is charged only from solar, you obviously get the full 30p (or whatever the rate is) for each kWh exported during peak.
Or somewhere in between if it's a mix of grid and solar charging.
Bowdler1 Coincidentally and for the first time, this morning it did just that! Out of a clear blue sky, my battery imported the excess solar.. I hope this is the result of my interactions with the Octopus Energy team but I'm not holding my breath.
The problem is that the exact logic of what happens on IOF is somewhere in the bowels of a program in Octopus land. I suspect the helpdesk staff are never going to get close to understanding what it does day to day other than broad-brush statements! The wholesale market rates (as I see on Agile) have been quite flat recently so this probably means reduced activity on IOF. Today blue skies for you (not for me, a miserable 2.7kWh generated) means different behaviour.
Am I right that the advantage of importing solar to battery off peak and exporting during peak will be the difference between the two rates per kWh (ie 7.26p at the moment)? Minus the conversion loss.
Yes. IOF for my region has a slightly higher spread - 23.02 / 30.69p - but yes, your profit is on using the battery is the rate difference minus conversion losses at say 15-20ish %.
TX200 The way I worked it out was 1.2kWh in and 1kWh out. For a rough and ready 20% round trip efficiency loss.
So 23p * 1.2 = 27.6p
30p * 1 = 30p
2.4p for each kWh exported that was from grid charging.
Yep, more like 3p in my region. The ‘rate arbitrage’ on IOF is not a lot really when other tariffs such as Cosy, Flux and Go/IOG you can make 5-10p difference. Where it makes a difference as Tim says in his video is when you’re generating lots and exporting it directly. 23p day-time export is much better than anything else around and 30p peak even better.
I was looking at Flux rates on another thread, 13.64p day-time export is poor, the peak export rate of 27.44p is better but for most people there’ll be limited opportunity for peak rate export and it would be better to preserve the battery through to the next day as the overnight Flux import is 15.6p.
Another way of thinking about IOF is that the day import rate is not that different from the SVR rate so as long as your battery will see you through the evening peak and you don’t import at peak rates, all solar generation is a positive upside.
I,m on my second attempt to connect properly to IF. Once again the Octopus team have problems. I think I'm connected now but they say they can't control the battery themselves as they should be able to - and were supposed to be talking me through disconnecting and reinstalling it this morning but didn't phone when they said they would. At least this time GE seems to be doing as you describe. But I guess they aren't in charge of the tariff. I have had a separate conversation here about this but just saw yours and am reassured that I am not alone in feeling that the understanding of the advisors is limited if things aren't right. At least they aren't shoving it all back on me by giving me a series of links that don't work this time! One person has taken responsibility which is an improvement, too.