I am on flux and it's really good. On sunny days I'm making about £7 - £9 while using nothing from the grid. Being saved as credit for when solar isn't making as much in winter. So really I'm not making money I'm building up credit for winter months. Makes the pay back for my panels a lot faster.
Thank you Tim. I have registered my interest for the Flux and waiting for the tariff to go live. At the moment we are on Go (with 7.5p import and 4.1p export) that expires on 1st April. On 27/2 when the new price cap for April-July will be announced, probably we ‘ll see new rates for many tariffs. From March till October we produce more pv electricity than the total consumption and most of it is exported, as we are not at home during the day. For our circumstances Flux is great for the summer and in October switch back to Go, if still available.
Thanks Tim for the breaking news, this is super interesting to add to the Octopus range of tariffs. I think the snag/catch for me and anyone who’s had panels since the FiT system is the loss of 50% deemed export payments. As we have an EV and heat pump, and a small battery, a heck of a lot less than 50% of our generation is actually going to the grid! Looking forward to seeing how you manage to get this into the spreadsheet!
OK. I use Octopus and export metered, not deemed 50%. Octo will do this; all you need is ask their FiT team. I export about 70% and get 15p per kWh; the export deemed 50% only pays @ c. 5p per kWh. So, export £ up by c. x4 and almost same ££ as generation income. Nice!
It’s good that Octopus are looking at different customers set up and I missed out switching to Go before they changed the rules to say you had to have an EV. But I am on their Economy 7 type tariff and my nighttime rate between 12.30am and 7.30am is cheaper than their 3 hour window and although my battery would charge to 100% in that time, I also put other appliances like dishwasher and washing machine on overnight during the winter months - typically Dec - Feb. And discharging your battery to then import at a higher price seems madness. So I’m not really seeing any benefit to this tariff.
This is very much a Summer tariff, I suspect. Not really beneficial in Winter I doubt. Hopefully I'll be able to calculate that properly in due course but that's my hunch.
@@TimAndKatsGreenWalk Go is no doubt better in winter if you have an EV. This tariff is essentially what I have been doing on Agile this winter. I charge the battery and run the Dishwasher/Washing machine during the 2-5 slot when prices have been between 10-25p a unit. Then I run the house off the battery and whatever solar generation we get. Most days that has been enough to through the day. Tumble dryer has been the main problem and I have been setting an alarm and getting up at 3am to put that on.
Yes, exactly, that's my hunch too. It all depends if it's worth the hassle of switching every six months or not! Did you decide what batteries you were going to get in the end?
@@TimAndKatsGreenWalk Still exploring. If we want to be able to run the heat pump or oven during a power cut, it will determine the size of inverter we need, and therefore battery type.
The benefits between switching twice a year will likely end up being eaten up by the cheap rate increasing every time you renew, we'll head into winter and renew at 15p+ overnight instead of holding onto what we had
The panels provide free energy during the day and charge the battery for evening/night use. If you discharge your battery in the evening it means that you'll have to pay for energy use in the evening at the higher rate. There are times when Agile goes well below that rate in the early morning. For instance there's three hours this evening when the price hovers around 11-14 p.When it's windy this is usually in single figures and often negative (They pay you to charge battery/heat water tank etc.). It's cloudy tomorrow so I'll charge the battery for use tomorrow. If it was going to be sunny I wouldn't bother. I think that the new tariff will take away flexibility and the whole idea of charging only to discharge to the grid later is a bit of a faff which may even cost you money. I'm sticking with Agile. Thanks for taking the time to make your videos though, I appreciate them.
You're not obliged to charge overnight and sell at the peak, but it gives you that option on a sunny day. Agile suits some folks while others will appreciate the more stable nature of the Flux prices, as opposed to the quite variable prices of Agile. It's always good to have the option to choose what's right for you.
That is just what I need when my current Agile tariff ends in May. Thank you for sharing this. No idea where you found out about it as I had not seen anything.
Tempting. But in winter, our Tesla Powerwall 2 is often out of charge by that time of the evening because we are heavy electricity users. In summer, the solar exporting would be great though. I wonder how the system instructs the Powerwall to export at that time? Some Octopus tariffs demand an excessive 20% reserve for power outages, we normally set 16% as our minimum.
Thanks Tim - another great video! It's hard to keep up with Octopus these days, eh? Every few days they're announcing something new! I'm hearing that if you have an EV (like you do), then Flux might not be as good as say Go (even on the latest Go tariff) but maybe your spreadsheet can confirm (looking froward to that btw). So, not long until your installation now. Hope it all goes well. Mine was to be February 20th, but there was a slight issue with getting the number of panels I want onto my roof (there are 6 pesky velux windows in the way!) but I've agreed with the installer 17x415W (and a spare, which I still think they might be able to fit onto the roof as well - we'll see on the day). New installation date March 20th 🙂
Our install is now booked for 9th March! Can't wait. I very much suspect you're right that Go will still be best for us, certainly during winter. I'm going to have to think of a better way to calculate the cost and benefit of Flux though as my daily spreadsheet won't cut it, I don't think. I'll need some half hourly data to do it properly. It's at this stage I'd usually turn to code rather than a spreadsheet but I'll see what I can do!
For the EV it’s really the low price, not the extra hour, which makes the big difference. Though I do appreciate being able to charge empty to full in only two nights (can be useful occasionally). The low rate just isn’t low enough - Id happily have this rate as a “secondary” low (cf+ cozy) with a real peak rate… but that 7.5p, or 12p is hard to pass up.
@@TimAndKatsGreenWalk Just over 3 weeks away - fab! Mine just a couple of weeks behind that then... Regarding spreadsheets, feel free to steal ideas from the one I did recently (in my "Maximise the payback..." video) - I'll likely be modifying that soon so it can be used to compare tariffs (like Flux and Go). Well, I say that - but trying to find the time is hard - I've got loads of video topics in the pipeline. I'm also working with a friend on a coded version, but he's just as busy as I am!🤣Btw, did you see my message reply to you about the show (other thread)?
@@GaryDoesSolar thanks Gary, I'll take a look and see if there's anything I can steal! That's weird, I don't see any reply from you after my question in that thread. I wonder what happened to it? I'm glad to hear you've got plenty more videos in the works, I look forward to seeing what they're about!
@@TimAndKatsGreenWalk Hi Tim, I've no idea what's happened to my messages - I think any messages with email addresses in them are automatically deleted. So, any chance you could send me your email via the email address is any of my video descriptions please? Ta 😃
I think at the time of this video the Flux tariff was announced only but it's now open and you can apply to transfer over. I've done this already as it looks to be a clear winner for me financially. I have a 8.97KW system taking import from Octopus on Economy 7 and export at 15p with Outgoing Octopus. I charge the 5KW battery overnight and basically try to stay off the day rate. On a reasonable day I export enough to break even but on a clear day I'm comfortably in profit with Octopus. I've tried to model this Flux tariff against the data I collect and it looks like my cost of import goes up by about 20p per day. So with the export rate going up from 15p to 25p I only need to average 2 units per day to make up for the more expensive import. Since the middle of December I've averaged over 6, however since the start of March it's 11.5 and in April it's nearly 19. So this is a no-brainer for us and across summer could be worth £2-3 per day.
Tesla Powerwall 2 does have options for peak, mid and low prices so I believe would do it's best to fill up at low, but unsure how it would export at the correct times? Also in winter ASHP and home use would likely empty the battery before the peak rate and you would be cooking on peak rate electric (if you have electric oven!). Also very expensive if you are likely to add an electric vehicle into the mix! For those with solar and a large battery but no ev or ASHP this could be a great idea.
Interesting but that very short window of cheap night rate incoming from the grid limits how much you can store in the winter months when solar production is non existent. My solar install (electrics portion) has been delayed by yet another week so like you I will be looking into what Octopus tariff best suits me. Currently I'm on the std Octopus tariff which has a 15p cheap night rate for 4 hours. Your spread sheet should make interesting reading & thanks for the update.
Import: Seems like basic Agile can frequently be cheaper than Flux though there will be times (let's say "December") when the new tariff will be a much better deal. Export: Flux day rate is pretty good, and peak nice, often significantly better than Agile export. All in all this seems like a tariff for exporters, and those with a large solar array and battery will benefit most. Mid-sized and small systems will continue to make the best return from not buying from the grid and self-use where possible, or sticking with Go.
Yes, indeed, I think for most folks this will only make sense in the Summer. Hopefully I'll be able to get this added to my spreadsheet to answer that question for sure though.
I'm about six weeks in to my solar & battery chapter (6.48kWh & 20kWh) and have opted for Agile Import and Outgoing Fixed (15p per kWh). My reasoning is that I don't want to use up the import/export cycles that would shorten the battery life. I use the excess solar to charge the car up before I allow it to go to the grid. Come winter I'll be looking to charge the car in the cheap slot and the batteries too as and when required. Thanks for the video, always interesting to hear an analysis.
Great video, cheers Tim. Looks like quite an interesting tariff. I guess they can offer such rates at peak time as most people will be consuming energy (therefore importing from the grid or discharging batteries for their own use) between 4 and 7pm and there probably won't be a massive export going on with dinner times / kids etc not being too flexible outide those hours. EV chargers would be paying 20.4p during the off peak window too, which is a considerable hike from 12p , or whatever Go is at the mo. My inner cynic is whispering in my ear that Octopus probably aren't in the business of doing anyone any favours....but still it does look interesting!!! ......i must ruminate a while! lol. Cheers for the heads up, keep up the great vids too!
Yeah, I reckon Go for Winter time and Flux for Summer might be the best combination. I need to expand my spreadsheet to include Flux and then I'll be able to calculate it properly.
@@TimAndKatsGreenWalk That's a pretty good idea. I hope they'll continue to allow peeps to change tariff as and when we like. Considering the pressure on the grid that EV take up is no doubt having, and will continue to have as the take up grows, it should stand up that in order to balance the grid at peak times supply companies should be paying top dollar for micro producers to export as it can't be cheap / ecological to have to fire up the turbines at the coal power stations everytime folks have a cup of tea in the evening! lol I think the main problem with Octopus at the mo is that there is no viable competition so they can write their own tickets. Hope that changes soon.
When your Flux Export tariff was finally approved, how long did it take and did they backdate the payment to your application date ? I have seen conflicting comments on that, so would be interested to hear your experience.
It took about two weeks after sending the necessary documentation for the export tariff to kick in. There was no back-dating though as the export MPAN number and meter readings didn't start until it was all set up, so they wouldn't have been able to calculate it anyway. If we'd already had an export MPAN then it would have all happened a lot quicker, I think, but this was our first export tariff so it took a little while to set that up first.
I've been on Flux since 1th April and it's been amazing. I top my battery up during the cheap period and then I'm on battery or solar for the rest of the day. I have an EV which I've had to top up during the day a couple of times due to unexpected long journeys. However so far this month (to 25th May) I've exported 363kWh and only imported 237kWh. I reckon I put 90kWh of that imported electricity into the car - not something I would usually do but it was necessary this time For the summer months I'll keep it on Flux and then I might change to a different tariff when the sun isn't so obliging. I have a 5.6kW inverter, 5.8kW of solar panels and an 11.6kWh battery. The car is an MG4 Trophy with a 64kWh battery pack. I charge it through my Zappi 3ph charger - this normally harvests the solar, rather than using the imported or battery power
With this tariff, it seems to me that it would make sense to fill up to 100% at 2am-5am when it is cheap, regardless of how much sun there is going to be, because at any point during the day, selling excess back to the grid would make you more money than it cost to buy it. But also, it would make sense to sell as much as possible between 4pm and 7pm, down to 0%, because any electricity you are forced to buy back between 7pm and 2am will cost less than you would have sold it for. So is that what the Powerwall actually does? If not, why not?
Not just the Powerwall. Many batteries allow you to fully charge at one time and fully discharge at another. There may be reasons you don't want to do that though, as doing so can degrade your battery lifetime slightly. You'd have to decide if doing that works out better for you in the long run or not.
@@TimAndKatsGreenWalk From what I've read of the Powerwall, you input the prices of import and export at different times and it makes decisions about what it's going to do, i.e if it's going to import from the grid or sell to the grid, with little transparency as to the reasoning behind it. I'm just wondering if the Powerwall actually does what I've described, for optimal profit, when programming in the Flux prices, or if it does something else. I'm getting a Powerwall in a couple of months, so just interested.
Not all batteries are willing to export to the grid, (Tesla Powerwall being a prime example, it can export but won't) worth bearing in mind in the calculations
@@TimAndKatsGreenWalk Indeed -- and there probably isn't a 'best' solution across the entire year and all patterns of use. Just degrees of better and worse. The good news is that companies like Octopus (others please take note) are coming up with comparatively equitable and very innovative solutions to give consumers a better chance of matching tariffs to their situations. Lets hope this continues and evolves.
@@spubbler Absolutely. I'm planning a huge upgrade to my tariff comparison spreadsheet that will be a bit more flexible, I hope, but it's gonna take a lot of work and I need to find the time to fit it in around all the videos I'm aiming to get done too. I honestly don't know when I'll get to it but hopefully in time for the summer when this tariff looks to be the most beneficial.
The “gotchas” are not with Octopus but potentially with your DNO. My PV generation was limited to 3.7 kW because I am what is called “end of line”. Whether this is still the case I do not know. Therefore the best thing to do before getting a whopping PV array, a humungous battery and giant inverter is make sure you can connect it all to the grid by having a chat with your DNO. Other things to consider with PV’s and batteries are as follows: Shade (neighbours houses, trees, stack pipes, TV aerials, your own building) - if this might be a problem consider installing optimisers, micro inverters or having an inverter that will take multiple feeds. Now for the charger. What rate can you charge your batteries? I have a 10 kWh battery but the maximum charge it will take is 1,800 W. This needs to be considered because if your panels are banging out say 7 kW, 5.3 kW needs to be dumped somewhere. If your DNO has a limit on your generation then this has to be taken into account especially if you have full batteries and a powerful inverter on your battery. This idea does make sense but you have to have both eyes open, find a good installer and speak with your DNO before committing.
All sensible points. I cover many of these in some of my other videos, as does Gary Does Solar (an excellent channel). This video is more about the existence of the Flux tariff rather than a thorough exploration of all the implications.
Really interesting option. Like you we are about to go solar + batteries (everything is installed, I just need my installer to connect the panels to the inverter...) and I'm also about to get an EV. So what will be better, Go, Flux or Agile? On Flux the cheaper rate is only 3 hours and is a higher price than Go, so that's less good for charging my EV and batteries, but the day rate is also cheaper than Go - 34p Flux vs 41.6p Go. That might be significant for us as my wife often needs to charge her PHEV during the day and it is easier to avoid a short peak period than have to wait until midnight... Decisions, decisions
Indeed, it's not a straightforward calculation. My spreadsheet for comparing tariffs is already creaking at the seams and I don't think it's up to the job to handle Flux too, so I'm going to have to think about how to do that one in a better way. Urgh, and I was just about to record an update for that spreadsheet today too.
I have (small) solar, biggish batteries and on Go with an EV. 97% of my use is off-peak. So “high” peak rate is not an issue. As long as you have enough battery to last your day…no problem
I'll wait until we've had our battery and solar panels installed (also in a few weeks) and see how much we generate. I suspect we will still be better off with Go for charging our EV.
@@chriss4949 Flux is only good for the exact opposite of what you got, i.e. big solar, small or no battery, low EV usage or no EV. Otherwise financially it's a lot worse than Go. See my post elsewhere in this thread with some basic calcs.
when i looked at it it gives less ability to charge at 3 hours (cosy is 6 hours in total) which is better for the winter dates. I feel the period of export is the time that you want the most power from your solar and battery due to the peak demand (evening meals etc) so in summer it would be good but flip flopping the tariffs all the time sounds like a pain and potentially not worth it. I think the main thing you want to be doing with any solar production is prioritising your own consumption to the max and not paying anything and maybe getting enough export revenue back to pay off the standard charge. The SEG export is 15kWh through out the whole day the flux is only high for a short period. It would be interesting to see what you come up with on your modeling but I think its best to be on Cosy with the SEG for export in my humble opinion. Thanks for the posting the Video Tim always appreciated
Yeah, I suspect you're right. My hunch is that for us Go will be better in the winter and maybe Flux in the Summer. As you say, switching is a pain but it'll be interesting to see how much better it'd be in the Summer and if that would offset the hassle of switching.
I’ve done some very high level calculations basing against the current flexible intelligent Octopus tariff with a 6.7kwh South array, battery and EV doing around 7.5k miles a year (at home around half the week) and based on solar generation and usage over the last year (prior to getting a A2A heat pump installed). I think savings would be around £30-£90 pm May-Sep for me so it would be worth switching at that time of year. It would be marginal Apr/Oct and more expensive in the winter. The A2A system would reduce those savings, guessing around half the savings. Next task is to see if I there’s a way to force a PW to discharge at a certain time!
That sounds like it backs up my intuition about this being a tariff with the most potential benefit in the Summer, and probably not good for the Winter. Thanks for sharing!
Only an opinion, but with an EV and Batteries and A2A, you will be using most of your solar production in any case, so your hunch that Go will suit you better is probably right. 👍
You seem to imply that the homeowner can decide when to export, ie, export in the peak period because it pays more than it charges for the cheap overnight rate? I thought it would only export if the battery is full and you are still generating. Not as much generation between 4 and 7 and only if full and not using it yourself.
It's a good concept but as someone with both an EV & solar/battery storage, Go (even at the revised rates) seems like a better deal. Interesting that the peak export rate is almost identical to the price capped rate on Agile - I think it needs to be higher to offset the loss of cheap overnight charging on Go for EV owners.
Yeah, it's gonna be interesting to see how this performs in the Summer as that might be beneficial compared to Go. Go is almost certainly better for the Winter though. Hopefully I'll be able to make a decent stab at calculating it properly in due course.
I'm on flux. The only downside is during the cold winter my 20KWh batteries can't charge fully between 2am and 5am due to the cold - currently struggling to make 61%. Since my solars will never be generating enough power to export in winter, I was thinking of switching temporarily to good old faithful Economy 7 as it has 7hrs of cheaper electricity instead of fluxes' 3...
@@rbee3936 last year we applied to Go before we had an EV and they let us switch regardless. They don't always check, so you might find it would work if you applied. Although at the moment the off-peak is 9p, you only get 7.5p with Intelligent Go, which definitely does require a compatible EV or charger to work.
Smart Meter not so smart when it comes to Octopus Flux:( We have switched to Flux and used 12.71kw between the hours of 2:00 am til 5:00 on the lower rate of around £0.19p SM states £4.63 so we phoned Octopus to be told they cannot tell us if this is what we have been charged for the 12.71kw....We could wait a month to find out if the SM is giving accurate price readings or change back? We will be exporting our battery back later today to start the whole process again and I don't know if I should stop the process...Any help would be appreciated:)
If you have the Octopus app on your phone you might be able to see your tariff there. Otherwise this is an Octopus issue, not really something I can help with.
No problem. I went with the GivEnergy Gen 2 5kW hybrid inverter with a 9.5 + 5.2 kWh battery combo. Loads of videos to come on the install plus how it works in practice in due course!
This Flux is a double edged sword. I have 3.92kW rated panels fitted in 2011 with the gold FiT so no SEG. I have 15kW battery storage. I have a SMETS1 dumb smart meter fitted in 2014. If I go for Flux I get low tariff for 3 hours to charge battery but high tariff later on😢 What to do? Any suggestions....
There is a "Got you" - the price will change based upon wholesale pricing! "Yes, it is a flexible tariff. This means the unit rate and standing charges can rise and fall with wholesale energy prices."
Interesting. Without re-jigging my spreadsheet and just going from experience so far with a battery, solar and a heat pump - certainly in December/January on Octopus Go with with four hours of cheap charging my battery has been prone to run out late afternoon to late evening depending on how much sun there's been so I don't think there would be much opportunity for export. I imagine it could be good in the summer though but I've not been there with the whole system running yet. I calculate I should be off grid between mid April to mid October and there have even been a couple of days this month when the battery got to 100%, the hot water up to max with the car full and I've started to export. I think that's going to be the problem in summer unless I'm using electricity to cool or driving a lot. Swapping between tariffs for winter and summer might not be practical so then it's a swings and roundabouts calculation. I can see a lot of spreadsheet editing coming on 🙄
I have 6.1 and get over 5 on sunniest days. That’s when pulling load and max exporting. Flux is useless for me though until Octopus fixes my BG Landis Gyr smart meter. DCC adopted but no reading received by them. 😡
I opted to have my batteries & inveterter fitted in the house to aid overnight charging time in the winter when I will need it most. This has caused an issue with noise, requiring a cupboard to be built around them (we needed a new cupboard for the consumer unit and meter anyway) so there are trade offs whatever you choose...
The peak rate is of no value in winter, (although if I read it right the day export rate of 23p seems good summer and winter), but it might be very good for your West facing panels in summer, kind of depends on how (and when) you cook your evening meal... Overall this is better than my bog-standard Economy 7 tariff with another provider though.
Hi Tim, How are you getting on with your spreadsheet comparison? So far my A2W heat pump plus solar and battery seems to be on track to my calculations but I've only had PV and battery since late October. My spreadsheet uses averages so is different than yours but it seems to be about right. I'm expecting from it at least a 50% saving over the year compared to gas and electric on Flexible Octopus and higher if I can use the summer surplus. With the new Octopus Flux Tariff that pays for export but with only three hours more expensive off peak but lower daytime and a lucrative evening peak export it's complicated to compare but initially it's looking like a 60% saving (still need to debug the spreadsheet - what a nightmare!). One thing that I've realised whilst doing it - if you have an Eddie it might be worth disconnecting or using this differently. If you heat up your DHW cylinder with solar it will stop the heat pump heating the hot water that day/night. So the saving you make isn't offset against daytime peak but offset against off-peak tariff with a COP of 3 to 4 as opposed to 1 with an immersion heater (if you heat up at night). That makes the saving something like 12 to 16 times less compared to a daytime grid electricity expectation - and if you instead get paid 2/3 the day rate to export on Flux it's around an order of magnitude more cost effective to export rather than directly heat your DHW with a resistive heating element. On Octopus Go it still makes sense to use it as you don't get paid to export of course. What would be better is to trigger your heat pump (that you are thinking of getting) to boost to a higher temperature DHW when there's a PV surplus. 300L with a 10°C rise would be 3.5kWh. It would come out of your already full battery and you'd need to stop boosting if the sun went in. Even that though only makes it COP times more efficient and then you are down to the tariff differences comparing night off-peak 20.4p/kWh import to 23p/kWh day export or the later peak 36.5p/kWh export if you can cope with draining the battery later. Anyway, it's still better to export surplus with Flux it seems than heat DHW which is a surprise.
Yeah, it's very complicated when you have to deal with changing solar and battery levels over the day and deciding whether to export or not. I'm going to have to build an hourly model to deal with that properly and I've got as far as obtaining 13 years of historical hourly weather data. But I've not yet built the calculation model around that yet. It's going to need hourly heat pump demand profiles for different loads, plus a model to convert the solar energy index to PV power output for different times of the year, plus typical hourly demand profiles for different tariffs, etc. etc. What I'm trying to say is, I've not started any of that yet as I've had too many other things to do! I'll get to it eventually but it might be a while and even then I won't have enough solar data to build a proper model for some months yet. Really I'd need a whole year of data to do that so it'll have to be an approximation at first and then get refined over time. My hunch is that Flux will be best for the Summer but Go in the Winter. Time will tell if my hunch is right.
@@johnh9449 I've been thinking about this and you're right. As long as the export day rate is higher than the import night rate that'll be the case. Heat pump hot water cylinders can sometimes be run from excess solar using an eddi too incidentally (I believe the aroSTOR has that functionality).
Great video Tim, has me now looking at the Solar I was about to get ordered, I had planned on 10.4kW of panels and a 17.6 kW battery with an Eddi unit. Now I am wondering if its worth reducing the system a little so I can go with the Flux tariff.
I'd possibly only drop the eddi and maybe get an immersion timer instead for £20 to heat your hot water during cheap rate periods. Then any excess would get exported instead at the decent export rates during the day. Keep the size of the rest of the system as big as you can manage, as I doubt you'd regret it later if this sort of tariff goes away for whatever reason.
@Tim & Kat's Green Walk I got a Tesla immersion heater last year when it started to be cheaper heating the water at night with that than buying more oil. It's nice knowing what the temperature is to. I need to work out what tariff I can have when I get the solar installed and leave the standard octopus one we are on now
@Kayoed Owner I had it confirmed by Octopus to, they stated they could not impose a limit that and was between me and the DNO. I have also managed to modify a spreadsheet to compare flux and go tariffs. This has all my 2022 hourly usage data in it. I found that with my current usage, Flux is better, but once I start to add in charging an EV at night, then Go becomes better. Over about 20kW of EV charge a day.
Hi Tim! We are now on Flux (I think) do you know what settings to use on the Eddie for it to boost in the cheap period but not take any surplus in the day? Like you said, a very expensive smart switch although we may go back to another Go like tariff in the winter. Thanks
I think you can fiddle with the export settings under the advanced menu. Set the export threshold really high and that should stop it boosting using excess solar. Or perhaps there's another setting I've not found yet. The manual might tell you more.
Yup, I've had a look through the manual again and I can't find any other setting. The one you're after is on page 15 (Supply Grid - Exp Threshold), assuming your manual is the same as mine.
@@TimAndKatsGreenWalk Thanks Tim, I've set the exp threshold to 3500. I had actually put the added complexity for us to the back of my mind...our dno export limit is 3.68kw, we have the ac coupled 3kw inverter with 9.5kwh battery and solar will peak around 7.5kw for an hour a day (i think). It will take a little more consideration but I'm still hoping flux works for us in the summer atleast
Yup, that's the killer. I think in Winter this tariff won't be useful, but in Summer when you can charge the batteries during the day too it might be a lot more viable.
Agreed it would be better for the summer, given all Octopus tariffs are now variable switching multiple times a year wouldn’t be an issue as you’ll just go from one variable rate to another. But 3 hours isn’t enough especially with an EV as well thats not at home all day to charge. I cant make use of the peak export rate either as I’ve got a Powerwall and you cant force it to discharge to grid.
I am not really interested in exporting during the peak period. I don’t think it is worth the extra cycling on the battery. I would however use the cheep rate to charge the battery sufficiently to avoid importing during the peak period. Particularly important during winter when we get little or no solar.
Great video Tim thanks. I think it could work for me, last summer I was exporting over 400 kwh per month so rough estimate that would be a return of £120. Charging my EV I would need 200 kwh so charging at night would cost around £40 (800 miles) . So free power for the house and £80 profit. Can anyone point out what I may be overlooking? Also I don't think it would work out during the winter months.
So you can make 16p/kWh every day by charging during the cheap period at night and exporting in the afternoon. That's £58 per year. Taking Pylontech as an example, batteries are about £500 per kWh, so the ROI is about 12 years. That's not bad, but it's not a licence to print money either, especially as there's no guarantee that they won't change the rules. It would be pretty good in the summer, if you have spare power, but in the winter you'll be buying power and better off with Go or Cosy. I guess that if it were easy to make money from a big battery, the energy companies themselves would be installing more grid scale storage.
£58 per year if you export one kWh per day. In summer you might be exporting many kWh, so could be a lot higher, potentially. But yeah, it all depends on whether you can actually achieve that. Still, an interesting option to explore.
@@TimAndKatsGreenWalk Sorry, that should have been £58 for every kWh of battery that you buy and use. I was trying to take the battery size out of the equation.
@@robinbennett5994 ah yes, I see what you mean now. In the Summer you have solar that could be exported too, so could make it more beneficial than just using batteries.
You need an huge battery and large amount of solar generation to make this work. No point in discharging 4-7pm then having not enough SOC to get to 2am again.
@@TimAndKatsGreenWalk thanks Tim. I looked at the FAQs a week ago and it said the solar has to be MCS. didn't say about the battery. Perhaps it's changed I'll check.
@@TimAndKatsGreenWalk Yes the FAQs say "A copy of the MCS document for your solar system" so if you have an MCS solar system and 'A.N.Other' home battery I've been trying to find out what the requirements are for the home battery. I've asked Octopus but so far no reply. As you can gather I don't have an MCS installed home battery.
@@Willy_Eckerslyke ah, I see. Do you have a MCS solar system though, or just the battery on it's own? I think just a solar certificate would be sufficient.
It's still an absolute piss take. People seem to be forgetting that we were paying around 12p / kWh for years before they decided to triple the charges last year. It's a complete scam!
Yes the bumper profits announced from energy suppliers show that they've been cashing in at the expense of some of the poorest in society. Meanwhile the government gets us further into debt with handouts to partially mitigate the crazy prices.
@@TimAndKatsGreenWalk Me, you, Kat and the rest of the supporters on this channel know that you will love messing about with the Spreadsheet to work out if its worth it or not :)
I am on flux and it's really good. On sunny days I'm making about £7 - £9 while using nothing from the grid. Being saved as credit for when solar isn't making as much in winter. So really I'm not making money I'm building up credit for winter months. Makes the pay back for my panels a lot faster.
Yup, similar here. It's a good tariff.
Thank you Tim. I have registered my interest for the Flux and waiting for the tariff to go live. At the moment we are on Go (with 7.5p import and 4.1p export) that expires on 1st April. On 27/2 when the new price cap for April-July will be announced, probably we ‘ll see new rates for many tariffs. From March till October we produce more pv electricity than the total consumption and most of it is exported, as we are not at home during the day. For our circumstances Flux is great for the summer and in October switch back to Go, if still available.
That sounds like an excellent plan. Glad I could help bring it to your attention
Thanks Tim for the breaking news, this is super interesting to add to the Octopus range of tariffs. I think the snag/catch for me and anyone who’s had panels since the FiT system is the loss of 50% deemed export payments. As we have an EV and heat pump, and a small battery, a heck of a lot less than 50% of our generation is actually going to the grid!
Looking forward to seeing how you manage to get this into the spreadsheet!
Yeah, it's gonna be a challenge!
OK. I use Octopus and export metered, not deemed 50%. Octo will do this; all you need is ask their FiT team. I export about 70% and get 15p per kWh; the export deemed 50% only pays @ c. 5p per kWh. So, export £ up by c. x4 and almost same ££ as generation income. Nice!
It’s good that Octopus are looking at different customers set up and I missed out switching to Go before they changed the rules to say you had to have an EV. But I am on their Economy 7 type tariff and my nighttime rate between 12.30am and 7.30am is cheaper than their 3 hour window and although my battery would charge to 100% in that time, I also put other appliances like dishwasher and washing machine on overnight during the winter months - typically Dec - Feb. And discharging your battery to then import at a higher price seems madness. So I’m not really seeing any benefit to this tariff.
This is very much a Summer tariff, I suspect. Not really beneficial in Winter I doubt. Hopefully I'll be able to calculate that properly in due course but that's my hunch.
@@TimAndKatsGreenWalk Go is no doubt better in winter if you have an EV. This tariff is essentially what I have been doing on Agile this winter. I charge the battery and run the Dishwasher/Washing machine during the 2-5 slot when prices have been between 10-25p a unit. Then I run the house off the battery and whatever solar generation we get. Most days that has been enough to through the day. Tumble dryer has been the main problem and I have been setting an alarm and getting up at 3am to put that on.
@@TimAndKatsGreenWalk How frequently are you allowed to switch?
@@alastaircooper8075 good question. I believe you can switch as often as you like, but I've not looked into it to confirm yet.
@@alastaircooper8075 Every 30 days for smart tariffs I believe.
Could be interesting to use this tariff during the summer, and flip to Go or whatever has the minimum night time import cost during the winter.
Yes, exactly, that's my hunch too. It all depends if it's worth the hassle of switching every six months or not! Did you decide what batteries you were going to get in the end?
@@TimAndKatsGreenWalk Still exploring. If we want to be able to run the heat pump or oven during a power cut, it will determine the size of inverter we need, and therefore battery type.
@@AndrewSmithThomas yup, realistically your heating will be the first thing to sacrifice during a power-cut unless you have a monster battery!
@@TimAndKatsGreenWalk You need an EV for Go, which I lack. Unless something changes this looks like better summer time rates than Agile outgoing.
The benefits between switching twice a year will likely end up being eaten up by the cheap rate increasing every time you renew, we'll head into winter and renew at 15p+ overnight instead of holding onto what we had
The panels provide free energy during the day and charge the battery for evening/night use. If you discharge your battery in the evening it means that you'll have to pay for energy use in the evening at the higher rate. There are times when Agile goes well below that rate in the early morning. For instance there's three hours this evening when the price hovers around 11-14 p.When it's windy this is usually in single figures and often negative (They pay you to charge battery/heat water tank etc.). It's cloudy tomorrow so I'll charge the battery for use tomorrow. If it was going to be sunny I wouldn't bother. I think that the new tariff will take away flexibility and the whole idea of charging only to discharge to the grid later is a bit of a faff which may even cost you money. I'm sticking with Agile.
Thanks for taking the time to make your videos though, I appreciate them.
You're not obliged to charge overnight and sell at the peak, but it gives you that option on a sunny day. Agile suits some folks while others will appreciate the more stable nature of the Flux prices, as opposed to the quite variable prices of Agile. It's always good to have the option to choose what's right for you.
Ive just been able to switch, so far so good :)
That is just what I need when my current Agile tariff ends in May. Thank you for sharing this. No idea where you found out about it as I had not seen anything.
No problem. I spotted it on Twitter when Octopus put a tweet out earlier today. I got on it straight away!
@@TimAndKatsGreenWalk Thank you. I do not use Twitter.
@@lyracian I don't blame you, honestly.
Tempting. But in winter, our Tesla Powerwall 2 is often out of charge by that time of the evening because we are heavy electricity users. In summer, the solar exporting would be great though. I wonder how the system instructs the Powerwall to export at that time? Some Octopus tariffs demand an excessive 20% reserve for power outages, we normally set 16% as our minimum.
Yeah, this is a Summer tariff, for sure.
Thanks Tim - another great video! It's hard to keep up with Octopus these days, eh? Every few days they're announcing something new! I'm hearing that if you have an EV (like you do), then Flux might not be as good as say Go (even on the latest Go tariff) but maybe your spreadsheet can confirm (looking froward to that btw).
So, not long until your installation now. Hope it all goes well. Mine was to be February 20th, but there was a slight issue with getting the number of panels I want onto my roof (there are 6 pesky velux windows in the way!) but I've agreed with the installer 17x415W (and a spare, which I still think they might be able to fit onto the roof as well - we'll see on the day). New installation date March 20th 🙂
Our install is now booked for 9th March! Can't wait.
I very much suspect you're right that Go will still be best for us, certainly during winter. I'm going to have to think of a better way to calculate the cost and benefit of Flux though as my daily spreadsheet won't cut it, I don't think. I'll need some half hourly data to do it properly. It's at this stage I'd usually turn to code rather than a spreadsheet but I'll see what I can do!
For the EV it’s really the low price, not the extra hour, which makes the big difference. Though I do appreciate being able to charge empty to full in only two nights (can be useful occasionally).
The low rate just isn’t low enough - Id happily have this rate as a “secondary” low (cf+ cozy) with a real peak rate… but that 7.5p, or 12p is hard to pass up.
@@TimAndKatsGreenWalk Just over 3 weeks away - fab! Mine just a couple of weeks behind that then...
Regarding spreadsheets, feel free to steal ideas from the one I did recently (in my "Maximise the payback..." video) - I'll likely be modifying that soon so it can be used to compare tariffs (like Flux and Go). Well, I say that - but trying to find the time is hard - I've got loads of video topics in the pipeline. I'm also working with a friend on a coded version, but he's just as busy as I am!🤣Btw, did you see my message reply to you about the show (other thread)?
@@GaryDoesSolar thanks Gary, I'll take a look and see if there's anything I can steal!
That's weird, I don't see any reply from you after my question in that thread. I wonder what happened to it?
I'm glad to hear you've got plenty more videos in the works, I look forward to seeing what they're about!
@@TimAndKatsGreenWalk Hi Tim, I've no idea what's happened to my messages - I think any messages with email addresses in them are automatically deleted. So, any chance you could send me your email via the email address is any of my video descriptions please? Ta 😃
I think at the time of this video the Flux tariff was announced only but it's now open and you can apply to transfer over. I've done this already as it looks to be a clear winner for me financially. I have a 8.97KW system taking import from Octopus on Economy 7 and export at 15p with Outgoing Octopus. I charge the 5KW battery overnight and basically try to stay off the day rate. On a reasonable day I export enough to break even but on a clear day I'm comfortably in profit with Octopus.
I've tried to model this Flux tariff against the data I collect and it looks like my cost of import goes up by about 20p per day. So with the export rate going up from 15p to 25p I only need to average 2 units per day to make up for the more expensive import. Since the middle of December I've averaged over 6, however since the start of March it's 11.5 and in April it's nearly 19. So this is a no-brainer for us and across summer could be worth £2-3 per day.
Tesla Powerwall 2 does have options for peak, mid and low prices so I believe would do it's best to fill up at low, but unsure how it would export at the correct times? Also in winter ASHP and home use would likely empty the battery before the peak rate and you would be cooking on peak rate electric (if you have electric oven!).
Also very expensive if you are likely to add an electric vehicle into the mix!
For those with solar and a large battery but no ev or ASHP this could be a great idea.
This is a Summer tariff, really, it makes no sense for the Winter, as you say.
Interesting but that very short window of cheap night rate incoming from the grid limits how much you can store in the winter months when solar production is non existent.
My solar install (electrics portion) has been delayed by yet another week so like you I will be looking into what Octopus tariff best suits me. Currently I'm on the std Octopus tariff which has a 15p cheap night rate for 4 hours. Your spread sheet should make interesting reading & thanks for the update.
Yeah, I think this is very much a Summer tariff. It's gonna be interesting adding this to my spreadsheet.
Import: Seems like basic Agile can frequently be cheaper than Flux though there will be times (let's say "December") when the new tariff will be a much better deal.
Export: Flux day rate is pretty good, and peak nice, often significantly better than Agile export.
All in all this seems like a tariff for exporters, and those with a large solar array and battery will benefit most. Mid-sized and small systems will continue to make the best return from not buying from the grid and self-use where possible, or sticking with Go.
Yes, indeed, I think for most folks this will only make sense in the Summer. Hopefully I'll be able to get this added to my spreadsheet to answer that question for sure though.
@@TimAndKatsGreenWalk can you share your spreadsheet so i can input my numbers please ?
@@MrRussLock take a look in the description of the next video, you should find a link there.
I'm about six weeks in to my solar & battery chapter (6.48kWh & 20kWh) and have opted for Agile Import and Outgoing Fixed (15p per kWh).
My reasoning is that I don't want to use up the import/export cycles that would shorten the battery life. I use the excess solar to charge the car up before I allow it to go to the grid.
Come winter I'll be looking to charge the car in the cheap slot and the batteries too as and when required. Thanks for the video, always interesting to hear an analysis.
Great video, cheers Tim. Looks like quite an interesting tariff. I guess they can offer such rates at peak time as most people will be consuming energy (therefore importing from the grid or discharging batteries for their own use) between 4 and 7pm and there probably won't be a massive export going on with dinner times / kids etc not being too flexible outide those hours. EV chargers would be paying 20.4p during the off peak window too, which is a considerable hike from 12p , or whatever Go is at the mo. My inner cynic is whispering in my ear that Octopus probably aren't in the business of doing anyone any favours....but still it does look interesting!!! ......i must ruminate a while! lol. Cheers for the heads up, keep up the great vids too!
Yeah, I reckon Go for Winter time and Flux for Summer might be the best combination. I need to expand my spreadsheet to include Flux and then I'll be able to calculate it properly.
@@TimAndKatsGreenWalk That's a pretty good idea. I hope they'll continue to allow peeps to change tariff as and when we like. Considering the pressure on the grid that EV take up is no doubt having, and will continue to have as the take up grows, it should stand up that in order to balance the grid at peak times supply companies should be paying top dollar for micro producers to export as it can't be cheap / ecological to have to fire up the turbines at the coal power stations everytime folks have a cup of tea in the evening! lol I think the main problem with Octopus at the mo is that there is no viable competition so they can write their own tickets. Hope that changes soon.
@@GGR_Matt indeed, a bit of competition wouldn't hurt.
When your Flux Export tariff was finally approved, how long did it take and did they backdate the payment to your application date ? I have seen conflicting comments on that, so would be interested to hear your experience.
It took about two weeks after sending the necessary documentation for the export tariff to kick in. There was no back-dating though as the export MPAN number and meter readings didn't start until it was all set up, so they wouldn't have been able to calculate it anyway. If we'd already had an export MPAN then it would have all happened a lot quicker, I think, but this was our first export tariff so it took a little while to set that up first.
I've been on Flux since 1th April and it's been amazing.
I top my battery up during the cheap period and then I'm on battery or solar for the rest of the day. I have an EV which I've had to top up during the day a couple of times due to unexpected long journeys. However so far this month (to 25th May) I've exported 363kWh and only imported 237kWh. I reckon I put 90kWh of that imported electricity into the car - not something I would usually do but it was necessary this time
For the summer months I'll keep it on Flux and then I might change to a different tariff when the sun isn't so obliging.
I have a 5.6kW inverter, 5.8kW of solar panels and an 11.6kWh battery. The car is an MG4 Trophy with a 64kWh battery pack. I charge it through my Zappi 3ph charger - this normally harvests the solar, rather than using the imported or battery power
Very nice. Yeah, we're planning on switching to Go for the winter, probably, as I think Flux is only better for us during the summer.
With this tariff, it seems to me that it would make sense to fill up to 100% at 2am-5am when it is cheap, regardless of how much sun there is going to be, because at any point during the day, selling excess back to the grid would make you more money than it cost to buy it. But also, it would make sense to sell as much as possible between 4pm and 7pm, down to 0%, because any electricity you are forced to buy back between 7pm and 2am will cost less than you would have sold it for. So is that what the Powerwall actually does? If not, why not?
Not just the Powerwall. Many batteries allow you to fully charge at one time and fully discharge at another. There may be reasons you don't want to do that though, as doing so can degrade your battery lifetime slightly. You'd have to decide if doing that works out better for you in the long run or not.
@@TimAndKatsGreenWalk From what I've read of the Powerwall, you input the prices of import and export at different times and it makes decisions about what it's going to do, i.e if it's going to import from the grid or sell to the grid, with little transparency as to the reasoning behind it. I'm just wondering if the Powerwall actually does what I've described, for optimal profit, when programming in the Flux prices, or if it does something else. I'm getting a Powerwall in a couple of months, so just interested.
@@user-cy3kj4dp8e I'm afraid I have no experience of the Powerwall so couldn't say.
Not all batteries are willing to export to the grid, (Tesla Powerwall being a prime example, it can export but won't) worth bearing in mind in the calculations
Yup, there's a lot to factor in.
@@TimAndKatsGreenWalk Indeed -- and there probably isn't a 'best' solution across the entire year and all patterns of use. Just degrees of better and worse. The good news is that companies like Octopus (others please take note) are coming up with comparatively equitable and very innovative solutions to give consumers a better chance of matching tariffs to their situations. Lets hope this continues and evolves.
@@spubbler Absolutely. I'm planning a huge upgrade to my tariff comparison spreadsheet that will be a bit more flexible, I hope, but it's gonna take a lot of work and I need to find the time to fit it in around all the videos I'm aiming to get done too. I honestly don't know when I'll get to it but hopefully in time for the summer when this tariff looks to be the most beneficial.
The “gotchas” are not with Octopus but potentially with your DNO. My PV generation was limited to 3.7 kW because I am what is called “end of line”. Whether this is still the case I do not know. Therefore the best thing to do before getting a whopping PV array, a humungous battery and giant inverter is make sure you can connect it all to the grid by having a chat with your DNO. Other things to consider with PV’s and batteries are as follows: Shade (neighbours houses, trees, stack pipes, TV aerials, your own building) - if this might be a problem consider installing optimisers, micro inverters or having an inverter that will take multiple feeds. Now for the charger. What rate can you charge your batteries? I have a 10 kWh battery but the maximum charge it will take is 1,800 W. This needs to be considered because if your panels are banging out say 7 kW, 5.3 kW needs to be dumped somewhere. If your DNO has a limit on your generation then this has to be taken into account especially if you have full batteries and a powerful inverter on your battery. This idea does make sense but you have to have both eyes open, find a good installer and speak with your DNO before committing.
All sensible points. I cover many of these in some of my other videos, as does Gary Does Solar (an excellent channel). This video is more about the existence of the Flux tariff rather than a thorough exploration of all the implications.
Really interesting option. Like you we are about to go solar + batteries (everything is installed, I just need my installer to connect the panels to the inverter...) and I'm also about to get an EV. So what will be better, Go, Flux or Agile?
On Flux the cheaper rate is only 3 hours and is a higher price than Go, so that's less good for charging my EV and batteries, but the day rate is also cheaper than Go - 34p Flux vs 41.6p Go. That might be significant for us as my wife often needs to charge her PHEV during the day and it is easier to avoid a short peak period than have to wait until midnight...
Decisions, decisions
Indeed, it's not a straightforward calculation. My spreadsheet for comparing tariffs is already creaking at the seams and I don't think it's up to the job to handle Flux too, so I'm going to have to think about how to do that one in a better way. Urgh, and I was just about to record an update for that spreadsheet today too.
I have (small) solar, biggish batteries and on Go with an EV. 97% of my use is off-peak. So “high” peak rate is not an issue. As long as you have enough battery to last your day…no problem
I'll wait until we've had our battery and solar panels installed (also in a few weeks) and see how much we generate. I suspect we will still be better off with Go for charging our EV.
@@chriss4949 Flux is only good for the exact opposite of what you got, i.e. big solar, small or no battery, low EV usage or no EV. Otherwise financially it's a lot worse than Go. See my post elsewhere in this thread with some basic calcs.
when i looked at it it gives less ability to charge at 3 hours (cosy is 6 hours in total) which is better for the winter dates. I feel the period of export is the time that you want the most power from your solar and battery due to the peak demand (evening meals etc) so in summer it would be good but flip flopping the tariffs all the time sounds like a pain and potentially not worth it. I think the main thing you want to be doing with any solar production is prioritising your own consumption to the max and not paying anything and maybe getting enough export revenue back to pay off the standard charge. The SEG export is 15kWh through out the whole day the flux is only high for a short period. It would be interesting to see what you come up with on your modeling but I think its best to be on Cosy with the SEG for export in my humble opinion. Thanks for the posting the Video Tim always appreciated
Yeah, I suspect you're right. My hunch is that for us Go will be better in the winter and maybe Flux in the Summer. As you say, switching is a pain but it'll be interesting to see how much better it'd be in the Summer and if that would offset the hassle of switching.
I’ve done some very high level calculations basing against the current flexible intelligent Octopus tariff with a 6.7kwh South array, battery and EV doing around 7.5k miles a year (at home around half the week) and based on solar generation and usage over the last year (prior to getting a A2A heat pump installed). I think savings would be around £30-£90 pm May-Sep for me so it would be worth switching at that time of year. It would be marginal Apr/Oct and more expensive in the winter. The A2A system would reduce those savings, guessing around half the savings. Next task is to see if I there’s a way to force a PW to discharge at a certain time!
That sounds like it backs up my intuition about this being a tariff with the most potential benefit in the Summer, and probably not good for the Winter. Thanks for sharing!
Only an opinion, but with an EV and Batteries and A2A, you will be using most of your solar production in any case, so your hunch that Go will suit you better is probably right. 👍
Yup, in the Winter absolutely Go will be better. The Summer might be a different situation though. I need a bigger spreadsheet!
Nope…you need a bigger battery 😂😂
@@chriss4949 also true!
You seem to imply that the homeowner can decide when to export, ie, export in the peak period because it pays more than it charges for the cheap overnight rate?
I thought it would only export if the battery is full and you are still generating. Not as much generation between 4 and 7 and only if full and not using it yourself.
Some battery systems allow you to define a force export period.
It's a good concept but as someone with both an EV & solar/battery storage, Go (even at the revised rates) seems like a better deal. Interesting that the peak export rate is almost identical to the price capped rate on Agile - I think it needs to be higher to offset the loss of cheap overnight charging on Go for EV owners.
Yeah, it's gonna be interesting to see how this performs in the Summer as that might be beneficial compared to Go. Go is almost certainly better for the Winter though. Hopefully I'll be able to make a decent stab at calculating it properly in due course.
I'm on flux. The only downside is during the cold winter my 20KWh batteries can't charge fully between 2am and 5am due to the cold - currently struggling to make 61%. Since my solars will never be generating enough power to export in winter, I was thinking of switching temporarily to good old faithful Economy 7 as it has 7hrs of cheaper electricity instead of fluxes' 3...
I switched to Go for the Winter and that's working pretty well for us.
@@TimAndKatsGreenWalk Unfortunately for me, I don't have an electric car, which is a requirement for Go... 7.5p/KWh would be lovely
@@rbee3936 last year we applied to Go before we had an EV and they let us switch regardless. They don't always check, so you might find it would work if you applied. Although at the moment the off-peak is 9p, you only get 7.5p with Intelligent Go, which definitely does require a compatible EV or charger to work.
Smart Meter not so smart when it comes to Octopus Flux:(
We have switched to Flux and used 12.71kw between the hours of 2:00 am til 5:00 on the lower rate of around £0.19p SM states £4.63 so we phoned Octopus to be told they cannot tell us if this is what we have been charged for the 12.71kw....We could wait a month to find out if the SM is giving accurate price readings or change back? We will be exporting our battery back later today to start the whole process again and I don't know if I should stop the process...Any help would be appreciated:)
If you have the Octopus app on your phone you might be able to see your tariff there. Otherwise this is an Octopus issue, not really something I can help with.
@@TimAndKatsGreenWalk Cheers,Tim....Lots to look at on the App:)
Thanks, Tim. I wasn't aware of this. Which inverter/battery combination did you choose in the end?
No problem. I went with the GivEnergy Gen 2 5kW hybrid inverter with a 9.5 + 5.2 kWh battery combo. Loads of videos to come on the install plus how it works in practice in due course!
@@TimAndKatsGreenWalk I will look forward to that!
This Flux is a double edged sword. I have 3.92kW rated panels fitted in 2011 with the gold FiT so no SEG. I have 15kW battery storage. I have a SMETS1 dumb smart meter fitted in 2014. If I go for Flux I get low tariff for 3 hours to charge battery but high tariff later on😢 What to do? Any suggestions....
Sounds like Octopus Go would suit you better, if you have an EV. Or else economy 7 perhaps. Flux is great if you don't already have a FiT.
There is a "Got you" - the price will change based upon wholesale pricing! "Yes, it is a flexible tariff. This means the unit rate and standing charges can rise and fall with wholesale energy prices."
Yup, a fair point. I think most of the Octopus tariffs are moving in this direction now.
Interesting. Without re-jigging my spreadsheet and just going from experience so far with a battery, solar and a heat pump - certainly in December/January on Octopus Go with with four hours of cheap charging my battery has been prone to run out late afternoon to late evening depending on how much sun there's been so I don't think there would be much opportunity for export.
I imagine it could be good in the summer though but I've not been there with the whole system running yet. I calculate I should be off grid between mid April to mid October and there have even been a couple of days this month when the battery got to 100%, the hot water up to max with the car full and I've started to export. I think that's going to be the problem in summer unless I'm using electricity to cool or driving a lot.
Swapping between tariffs for winter and summer might not be practical so then it's a swings and roundabouts calculation. I can see a lot of spreadsheet editing coming on 🙄
Yup, I think I'm going to need a much more complicated spreadsheet to handle this one.
I have 6.1 and get over 5 on sunniest days. That’s when pulling load and max exporting. Flux is useless for me though until Octopus fixes my BG Landis Gyr smart meter. DCC adopted but no reading received by them. 😡
I hope they fix it soon
Three hours at twice the price of four… but lower peak usage…
If only the battery could charge inside three hours during the winter…
Yup, I reckon Go for Winter and maybe Flux for Summer. But I need to do a proper calculation to be sure.
@@TimAndKatsGreenWalk and know you can switch every six konths
@@JohnR31415 yeah, I think Octopus are pretty flexible with switching tariffs, at least that's what I've heard.
I opted to have my batteries & inveterter fitted in the house to aid overnight charging time in the winter when I will need it most. This has caused an issue with noise, requiring a cupboard to be built around them (we needed a new cupboard for the consumer unit and meter anyway) so there are trade offs whatever you choose...
The peak rate is of no value in winter, (although if I read it right the day export rate of 23p seems good summer and winter), but it might be very good for your West facing panels in summer, kind of depends on how (and when) you cook your evening meal... Overall this is better than my bog-standard Economy 7 tariff with another provider though.
Yeah, my feeling is this a Summer tariff, really. Winter would be better with Go, I think.
Hi Tim,
How are you getting on with your spreadsheet comparison?
So far my A2W heat pump plus solar and battery seems to be on track to my calculations but I've only had PV and battery since late October. My spreadsheet uses averages so is different than yours but it seems to be about right. I'm expecting from it at least a 50% saving over the year compared to gas and electric on Flexible Octopus and higher if I can use the summer surplus.
With the new Octopus Flux Tariff that pays for export but with only three hours more expensive off peak but lower daytime and a lucrative evening peak export it's complicated to compare but initially it's looking like a 60% saving (still need to debug the spreadsheet - what a nightmare!).
One thing that I've realised whilst doing it - if you have an Eddie it might be worth disconnecting or using this differently. If you heat up your DHW cylinder with solar it will stop the heat pump heating the hot water that day/night. So the saving you make isn't offset against daytime peak but offset against off-peak tariff with a COP of 3 to 4 as opposed to 1 with an immersion heater (if you heat up at night). That makes the saving something like 12 to 16 times less compared to a daytime grid electricity expectation - and if you instead get paid 2/3 the day rate to export on Flux it's around an order of magnitude more cost effective to export rather than directly heat your DHW with a resistive heating element. On Octopus Go it still makes sense to use it as you don't get paid to export of course.
What would be better is to trigger your heat pump (that you are thinking of getting) to boost to a higher temperature DHW when there's a PV surplus. 300L with a 10°C rise would be 3.5kWh. It would come out of your already full battery and you'd need to stop boosting if the sun went in. Even that though only makes it COP times more efficient and then you are down to the tariff differences comparing night off-peak 20.4p/kWh import to 23p/kWh day export or the later peak 36.5p/kWh export if you can cope with draining the battery later. Anyway, it's still better to export surplus with Flux it seems than heat DHW which is a surprise.
Yeah, it's very complicated when you have to deal with changing solar and battery levels over the day and deciding whether to export or not. I'm going to have to build an hourly model to deal with that properly and I've got as far as obtaining 13 years of historical hourly weather data. But I've not yet built the calculation model around that yet. It's going to need hourly heat pump demand profiles for different loads, plus a model to convert the solar energy index to PV power output for different times of the year, plus typical hourly demand profiles for different tariffs, etc. etc. What I'm trying to say is, I've not started any of that yet as I've had too many other things to do! I'll get to it eventually but it might be a while and even then I won't have enough solar data to build a proper model for some months yet. Really I'd need a whole year of data to do that so it'll have to be an approximation at first and then get refined over time. My hunch is that Flux will be best for the Summer but Go in the Winter. Time will tell if my hunch is right.
@@TimAndKatsGreenWalk Did you get the but about the Eddie becoming redundant?
@@johnh9449 I've been thinking about this and you're right. As long as the export day rate is higher than the import night rate that'll be the case. Heat pump hot water cylinders can sometimes be run from excess solar using an eddi too incidentally (I believe the aroSTOR has that functionality).
Great video Tim, has me now looking at the Solar I was about to get ordered, I had planned on 10.4kW of panels and a 17.6 kW battery with an Eddi unit. Now I am wondering if its worth reducing the system a little so I can go with the Flux tariff.
I'd possibly only drop the eddi and maybe get an immersion timer instead for £20 to heat your hot water during cheap rate periods. Then any excess would get exported instead at the decent export rates during the day. Keep the size of the rest of the system as big as you can manage, as I doubt you'd regret it later if this sort of tariff goes away for whatever reason.
@Tim & Kat's Green Walk I got a Tesla immersion heater last year when it started to be cheaper heating the water at night with that than buying more oil. It's nice knowing what the temperature is to. I need to work out what tariff I can have when I get the solar installed and leave the standard octopus one we are on now
@Kayoed Owner I had it confirmed by Octopus to, they stated they could not impose a limit that and was between me and the DNO. I have also managed to modify a spreadsheet to compare flux and go tariffs. This has all my 2022 hourly usage data in it. I found that with my current usage, Flux is better, but once I start to add in charging an EV at night, then Go becomes better. Over about 20kW of EV charge a day.
Hi Tim! We are now on Flux (I think) do you know what settings to use on the Eddie for it to boost in the cheap period but not take any surplus in the day? Like you said, a very expensive smart switch although we may go back to another Go like tariff in the winter. Thanks
I think you can fiddle with the export settings under the advanced menu. Set the export threshold really high and that should stop it boosting using excess solar. Or perhaps there's another setting I've not found yet. The manual might tell you more.
For the overnight boost just use the scheduler in the app.
Yup, I've had a look through the manual again and I can't find any other setting. The one you're after is on page 15 (Supply Grid - Exp Threshold), assuming your manual is the same as mine.
@@TimAndKatsGreenWalk Thanks Tim, I've set the exp threshold to 3500. I had actually put the added complexity for us to the back of my mind...our dno export limit is 3.68kw, we have the ac coupled 3kw inverter with 9.5kwh battery and solar will peak around 7.5kw for an hour a day (i think). It will take a little more consideration but I'm still hoping flux works for us in the summer atleast
I was hoping not to divert any to the Eddi in the day but as you can see we may have to so we avoid clipping
Charge window is issue for this tariff, I need 6 hours to charge to 100% so 3 hours is not even enough to get through a cycle on the washing machine!
Yup, that's the killer. I think in Winter this tariff won't be useful, but in Summer when you can charge the batteries during the day too it might be a lot more viable.
Agreed it would be better for the summer, given all Octopus tariffs are now variable switching multiple times a year wouldn’t be an issue as you’ll just go from one variable rate to another. But 3 hours isn’t enough especially with an EV as well thats not at home all day to charge. I cant make use of the peak export rate either as I’ve got a Powerwall and you cant force it to discharge to grid.
That is either a lot of storage or a slow charge rate? I can get 4 kW/h charge rate meaning 2.5 hours is enough for my battery.
@@lyracian max charge rate from my GivEnergy Gen 1 hybrid is 2.6kWh and I have 15kWh of batteries.
I am not really interested in exporting during the peak period. I don’t think it is worth the extra cycling on the battery. I would however use the cheep rate to charge the battery sufficiently to avoid importing during the peak period. Particularly important during winter when we get little or no solar.
The 9kWp limit applies to the inverter, not your panels.
Yes, good point
@@TimAndKatsGreenWalk Yes and as you have East West you'll not have them peaking together but have a wider flatter curve than south facing.
Great video Tim thanks. I think it could work for me, last summer I was exporting over 400 kwh per month so rough estimate that would be a return of £120. Charging my EV I would need 200 kwh so charging at night would cost around £40 (800 miles) . So free power for the house and £80 profit. Can anyone point out what I may be overlooking? Also I don't think it would work out during the winter months.
I agree, in Summer this makes most sense but Winter is unlikely to be worthwhile. I'll report back once I've got the full calculation.
It appears Octopus has removed the 9kW peak requirement. The bullet has been removed from the 'Am I eligible to join Octopus Flux' FAQ answer.
Ah, interesting.
So you can make 16p/kWh every day by charging during the cheap period at night and exporting in the afternoon. That's £58 per year. Taking Pylontech as an example, batteries are about £500 per kWh, so the ROI is about 12 years. That's not bad, but it's not a licence to print money either, especially as there's no guarantee that they won't change the rules.
It would be pretty good in the summer, if you have spare power, but in the winter you'll be buying power and better off with Go or Cosy.
I guess that if it were easy to make money from a big battery, the energy companies themselves would be installing more grid scale storage.
£58 per year if you export one kWh per day. In summer you might be exporting many kWh, so could be a lot higher, potentially. But yeah, it all depends on whether you can actually achieve that. Still, an interesting option to explore.
@@TimAndKatsGreenWalk Sorry, that should have been £58 for every kWh of battery that you buy and use. I was trying to take the battery size out of the equation.
@@robinbennett5994 ah yes, I see what you mean now. In the Summer you have solar that could be exported too, so could make it more beneficial than just using batteries.
@@TimAndKatsGreenWalk In summer your battery is likely to be filled from the sun so rather than 16.1p profit it could be 34.5p potentially.
You need an huge battery and large amount of solar generation to make this work. No point in discharging 4-7pm then having not enough SOC to get to 2am again.
Yeah, it might be a good tariff for the Summer, but probably not for the Winter.
Hi Tim. Just wondering when you went over to Flux, what proof of having a home battery you had to provide?
Last week. MCS certificate and letter from DNO. It's in the Flux FAQs
@@TimAndKatsGreenWalk thanks Tim. I looked at the FAQs a week ago and it said the solar has to be MCS. didn't say about the battery. Perhaps it's changed I'll check.
@@Willy_Eckerslyke it's one certificate for the whole system, I don't think you need a separate one for the batteries.
@@TimAndKatsGreenWalk Yes the FAQs say "A copy of the MCS document for your solar system" so if you have an MCS solar system and 'A.N.Other' home battery I've been trying to find out what the requirements are for the home battery. I've asked Octopus but so far no reply. As you can gather I don't have an MCS installed home battery.
@@Willy_Eckerslyke ah, I see. Do you have a MCS solar system though, or just the battery on it's own? I think just a solar certificate would be sufficient.
do octopus control the battery
No, you control the battery. Different battery systems have different user controls though so some may allow more flexibility than others.
Did you sign up for this ?
Yes I did and it's been great so far (see my recent May stats video).
It's still an absolute piss take. People seem to be forgetting that we were paying around 12p / kWh for years before they decided to triple the charges last year. It's a complete scam!
The rise of gas prices leads to a rise in electricity prices too, so look to the recent world events to find your answer as to why it's so high now.
@@TimAndKatsGreenWalk Centrica making 3x 2021 profits in 2022 won't help.
Yes the bumper profits announced from energy suppliers show that they've been cashing in at the expense of some of the poorest in society. Meanwhile the government gets us further into debt with handouts to partially mitigate the crazy prices.
the enormous profits do seem to of averted a fuel crisis this (and next winter) by causing a huge investment in LNG.
Saw this yesterday and thought maybe no !
It's an interesting one. The spreadsheet is already bursting at the seams, adding this will be a challenge!
@@TimAndKatsGreenWalk Me, you, Kat and the rest of the supporters on this channel know that you will love messing about with the Spreadsheet to work out if its worth it or not :)
@@bobbazley5376 😄
No good if you have a heat pump in winter
Indeed, I'm currently waiting for a response from Octopus to see if they'd let me switch between Flux and Go every six months or so.
Just need a hydro plant in your garden
Yup, that'd be fab.
Tax on profit will stop it
I very much doubt most people will be able to make money from this. At best it'll be a reduction in your energy bills.
@@TimAndKatsGreenWalk only because greedy rich UK Government are after more vote for the general election, once that is over look out
fill up your battery free from solar and export!!
Yup