April 21, 20233 yr 1 hour ago, Dave Jones said: do read this correctly, you are paid 34.9p kw/h if you export during peak rate ? Why not arbitrage it with a battery, charge at cheap export at peak ? greenenergy uk off peak is 9.52p kw/h which is what i ise to charge up the powerwall if it needs it. Yes, but you have to be on Flux import too, so the cheapest you can buy it in is 19.67p. You can still profit of course, just a smaller gain.
April 21, 20233 yr 2 hours ago, Dave Jones said: Why not arbitrage it with a battery, charge at cheap export at peak ? That's exactly what I do, I charge the batteries every day on the off peak, then export down to 60% during the peak period, any excess once the batteries are charged is exported.
April 24, 20233 yr Quote from an FB group - Octopus say "nobody can swap to flux right now and they don't have an ETA for when that plan might be available again" That pretty much kills some of the economics for my planned PV system 😞 Just did a bit more checking - apparantly if you're on an existing Octopus tariff you can still switch to Flux. You can't switch direct if you're not already with Octopus Edited April 24, 20233 yr by Rob99
April 24, 20233 yr I don't want to be a smarta55 - but 20 year economic calcs probably don't want to rely on today's grid conditions or supplier pricing schemes ...
April 24, 20233 yr 25 minutes ago, Alan Ambrose said: 20 year economic calcs Don't think I mentioned anything like that...
May 16, 20233 yr Author Decided to swap to flux especially with another 9.7kw of storage on the way . Once winter begins can swap to go again perhaps ( though will be a higher rate than I pay now ) . 35p kw export is too good to miss . Also with ( once installed ) 30kw of storage I should be able to weather the odd cloudy day in summer
May 19, 20233 yr Author Enjoying flux 35p ( ish ) for 52kwh = £ 18.20 When you factor in the ‘earnings ‘ , the fact it’s powering your house , charging an EV ( only 4000 miles per yr ) . ROI ( as some of you are obsessed with that ) gets considerably better .
May 19, 20233 yr Author Today though due to wank pot algorithm it’s not doing what I want . Really would like a “ (expletive deleted) off just do it button “ . For 1 hour I exported just excess solar ; why ? ; who knows ! Anyway ! Changed it now my flux ‘peak’ export starts from 15h not 16h ; also I bang the SolarEdge battery into export mode from 16h until 19h . Want to max out my export at peak rate !
June 20, 20233 yr Flux seasonal offset couldn't be working better here, I've just hit £0 net bills since joining in mid March - gas and electric including standing orders. I'm now building up a reserve to offset September usage. Average import price 21.73p Average export price 25.16p 8% of the PV/A2A ASHP investment repaid in those three months of Flux
June 20, 20233 yr Author 1 hour ago, S2D2 said: Flux seasonal offset couldn't be working better here, I've just hit £0 net bills since joining in mid March - gas and electric including standing orders. I'm now building up a reserve to offset September usage. Average import price 21.73p Average export price 25.16p 8% of the PV/A2A ASHP investment repaid in those three months of Flux Flux is pretty much a game changer . My import since joining is 0 ( though the algorithm goes to the grid if it deems fiscally better ) . Daily export is around £7 . Obviously once we approach winter the rates will undoubtedly change ; but ; it could still be potentially making money !
June 20, 20233 yr 10 minutes ago, pocster said: Flux is pretty much a game changer . My import since joining is 0 ( though the algorithm goes to the grid if it deems fiscally better ) . Daily export is around £7 . Obviously once we approach winter the rates will undoubtedly change ; but ; it could still be potentially making money ! What you going to do when they pull this tariff from the market?
June 20, 20233 yr Author 13 minutes ago, SteamyTea said: What you going to do when they pull this tariff from the market? Erm , change to another tariff .
June 20, 20233 yr Just now, pocster said: Erm , change to another tariff . Won't be as good, b cause it is not a game changer. 7 quid is about 35 kWh on the original FiT. How many do you think you are exporting?
June 20, 20233 yr Author Just now, SteamyTea said: Won't be as good, b cause it is not a game changer. 7 quid is about 35 kWh on the original FiT. How many do you think you are exporting? So ? it’s a game changer for me from 4p a kwH . Equally I don’t care as my original plan was storage for self consumption. Generating 1k a year though reduces roi which everyone obsessed about . What are you going to do when boe rate gets to 9% ?
June 20, 20233 yr Author 7 minutes ago, SteamyTea said: Won't be as good, b cause it is not a game changer. 7 quid is about 35 kWh on the original FiT. How many do you think you are exporting? That’s an interesting post . You know the future tariffs octopus plan . Can you post a link to this please ??
June 20, 20233 yr Flux seems almost too good to be true to me, and I'm trying to get on it. I just hope that "forced discharge" in my inverter setting means what I think it does! (ie that the battery is used even if there is solar, so any generation gets exported during the peak times).
June 20, 20233 yr 28 minutes ago, MrTWales said: Flux seems almost too good to be true to me, and I'm trying to get on it. I just hope that "forced discharge" in my inverter setting means what I think it does! (ie that the battery is used even if there is solar, so any generation gets exported during the peak times). It probably does but I wouldn't get too carried away with the apparent benefit. On Flux, every solar kWh you use to charge your battery before 16:00 costs you 24p, plus say 10% charging loss = 26p. If you then export it at the 16:00-19:00 peak rate 36p/kWh you only make 10p/kWh.
June 20, 20233 yr 26 minutes ago, PhilT said: It probably does but I wouldn't get too carried away with the apparent benefit. On Flux, every solar kWh you use to charge your battery before 16:00 costs you 24p, plus say 10% charging loss = 26p. If you then export it at the 16:00-19:00 peak rate 36p/kWh you only make 10p/kWh. Yes but this seems damn good to someone who is exporting loads each day right now for nothing! Plus, my battery is 9.6kWh so I can set it to charge in the cheap period.
June 21, 20233 yr 8 hours ago, MrTWales said: Yes but this seems damn good to someone who is exporting loads each day right now for nothing! Plus, my battery is 9.6kWh so I can set it to charge in the cheap period. Does that just mean your system is oversized for your usage.
June 21, 20233 yr 9 hours ago, PhilT said: It probably does but I wouldn't get too carried away with the apparent benefit. On Flux, every solar kWh you use to charge your battery before 16:00 costs you 24p, plus say 10% charging loss = 26p. If you then export it at the 16:00-19:00 peak rate 36p/kWh you only make 10p/kWh. Is nobody assuming discharge losses? If you have a hybrid then this is far improved, but if you have an “AC coupled” battery then you go, DC from panels converts to AC in the Inverter Then that AC goes into a breaker in the CU The battery is connected by its breaker in the CU Then AC goes into the battery BMS That converts to DC to charge the battery Then the DC in the battery returns back to AC in the BMS for consumption or export For a summer pattern that’s 3x conversions, and a long round trip and defo more than 10% lost there Delete conversion 1 and jump to 3 if this is your winter pattern / maths. But still more than 10% Are members here quoting this from stated figures or from the actual sum of the round trip from actual, real life (live) data? Genuine question btw as I’m about to change my planned system (and install more) and hoped my maths here wasn’t wonky.
June 21, 20233 yr 16 minutes ago, Nickfromwales said: real life (live) data it is, in reality, the only method. Many battery systems have a thermocouple/temperature sensor on then. Monitoring that, along with the MJ delivered (either charging or discharging) may show a good correlation if efficiency. I am always surprised how warm my phone gets when it has been on the fast charger compared to the slow one I usually use. Edited June 21, 20233 yr by SteamyTea
June 21, 20233 yr 18 minutes ago, Nickfromwales said: Is nobody assuming discharge losses? If you have a hybrid then this is far improved, but if you have an “AC coupled” battery then you go, DC from panels converts to AC in the Inverter Then that AC goes into a breaker in the CU The battery is connected by its breaker in the CU Then AC goes into the battery BMS That converts to DC to charge the battery Then the DC in the battery returns back to AC in the BMS for consumption or export For a summer pattern that’s 3x conversions, and a long round trip and defo more than 10% lost there Delete conversion 1 and jump to 3 if this is your winter pattern / maths. But still more than 10% Are members here quoting this from stated figures or from the actual sum of the round trip from actual, real life (live) data? Genuine question btw as I’m about to change my planned system (and install more) and hoped my maths here wasn’t wonky. The figures I quoted here: 15 hours ago, S2D2 said: Average import price 21.73p Average export price 25.16p 8% of the PV/A2A ASHP investment repaid in those three months of Flux Are from billed data from Octopus, i.e. it is the real life performance of the system. That allows you up to 16% losses whilst still being a "symmetrical" tariff - the seasonal shifting I referred to before. I had some comments about use case/costings here, I think I have a different view to many on what the battery should be doing on this tariff: Agree that AC batteries have even higher losses, so the maths would change for those.
June 21, 20233 yr 1 hour ago, SteamyTea said: Does that just mean your system is oversized for your usage. No it doesn't, in the same way that my TV isn't too big.
June 21, 20233 yr 47 minutes ago, S2D2 said: The figures I quoted here: Are from billed data from Octopus, i.e. it is the real life performance of the system. That allows you up to 16% losses whilst still being a "symmetrical" tariff - the seasonal shifting I referred to before. I had some comments about use case/costings here, I think I have a different view to many on what the battery should be doing on this tariff: Agree that AC batteries have even higher losses, so the maths would change for those. Thanks. I usually quote 13-15% losses so about where you summarised it. That's the reason I'm such a fan of hybrids tbh. I doubt I will ever specify another true AC coupled inverter as it just doesn't seem to make any sense whatsoever (to me, anyways!).
June 21, 20233 yr Just to be clear, when you are with Octopus you can change tarrif without penalty? That's what they told me anyway. I have no idea what works best for winter, but Flux is way better than what I'm on now and I feel like I can manage things fairly well. It's also way better than what I'm on now for winter but it sounds like there may be better options, though of course all tarrifs can be changed or removed.
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