Since early march I have exported 1000kWh more than I have used and with Octopus Flux am making >£100 a month in may, june, July …. compared with paying £120 a month. Our leccy usage is/was similar to yours, but imminent heat pump will change that!
I'd be willing to bet that May and June were the bulk of that, but it's not normally that dry and sunny. Compare those months to this month. We've exported only 175 this month compared to almost 400 on each of the previous two months.
Its tricky for me to work out pure solar export as we have 12.8kWh of batteries that we charge and discharge on Flux every day. But so far in july 615kWh solar yeild. My Octopus app tells me that I have imported 369kWh and exported 644kWh.
July has been a bit manky compared with May and June. And our system was only commissioned in March and went onto Flux end of April so only decent data I have is for the late spring, summer which is obviously peak!
Total solar yeild from beginning of March is 3400kWh which I think is slightly better than I expected (estimated annual yield was 5200kWh on their calcs). As my system is AC coupled I assume a loss of c10% of generation vs usable energy (battery losses and AC/DC conversion. But the c1000kWh net generation is taken from my Octopus app so is real and billed as such, and yeah it is pretty much just may-july for export and march-july for import, so if Flux has been active in March and April my export would have been higher.
oops, i think i meant flux, not agile?
regards the types of inverters? school me? the more efficient inverter if you plan/calculate to export a decent amount?
Hmm, I'm the guy that was thinking of flooding is roof with solar panels incl batteries. Ended up being ~£20k and out of my league.
I've kind of got in my head now that it's better to throw the money at batteries on the grounds the payback on that is ~20p/Kw (cost avoidance difference between ~30p/Kw peak rate v ~10p Kw off peak, where the payback on the solar is only 10p/Kw (the cost of the off peak charge that i'd otherwise need to buy).
What am I missing please?
Using your figures, if you get a 10kwh (useable capacity) battery, your maximum earnings will be £2 a day. £730 a year.
The battery will cost you something like £7-8k
If you are buying just a battery, I think you pay VAT, so add that on (no vat if you do it with solar). Plus you need an inverter still. more £. plus installation.
Payback would be well over ten years and by that time, you'd be starting to see decrease in capacity, which will extend the payback time.
This doesn't allow for changes in import/export prices. Could go either way really.
Don't really understand your payback for solar calculation. If you plan to export your whole battery capacity, you need to import whatever you use - currently 30p/unit or so. Any solar generation is covering that, plus you can export excess at between 15 and 30 p depending on the time of day.
The battery idea is just wrong. You’d be installing it only to try and make it pay for itself, it wouldn’t help your energy bill at all. It’s basically an interest free loan for a depreciating asset. 10kW battery, inverter and installation will be £7-£8k inc vat.
Panels and a small (5kW) battery is the way to go. £10k max and you’d be able to reduce your peak consumption, export £700 a year, provide another £700 with of power, and import in the winter to reduce your price. Say £1500/y so payback in 6.5y at current rates on Octopus Flux
Maths turns out be dead easy on Octopus Flux when you have solar and a battery and the right mindset. Your panels will make whatever income they make, and every unit of electricity you use yourself costs you 20p. Simple as.
That might be 20p of lost export during the middle of the day, or 20p that you buy overnight. But the figure is 20p. You can sell everything that you generate during peak hours, and you only buy from the grid in the night when it is cheap.
Might not remain true in winter if your batteries dont cover a full 24 hours of usage. And it gets more complicated if you discharge your batteries to the grid (can anyone do that? Powerwall doesn't)
Mine (LG batteries via a Solis Inverter) can force discharge either dynamically (via a raspberryPi connected to the inverter) or by schedule directly programmed into the inverter.
I don’t bother. It’s a few £ at most (and less than you think once losses are taken into account) and it places extra wear on the batteries by charging and discharging at maximum rates for long periods.
The battery purchase can make financial sense if, and only if, the difference in price between when you would normally buy and when the battery allows you to buy, less the round trip efficiency of the battery system, gives you enough savings on lessor of the kilowatt-hours you use or the kilowatt-hours battery capacity (after efficiency) you have to pay for the battery.
So if you can buy at 10p instead of 30p (20p saving, 90% round trip efficiency, so roughly 18p saving) and you have a 13kWh Powerwall (assume £9k purchase - mine was £8.8k) and use 10kWh per day, the battery will save you £1.80 a day or £657 per annum.
On a cash cash basis that’s a 14 year plus payback period. All costs are pre VAT so that ought to net off assuming they’re all 5% rated.
But you could have stuck that £9k in savings / stock market / etc (or avoided borrowing £9k) and over 14 years it ought to be significantly more than £9k you need to make to break even (even after inflation). Google DCF or NPV for more info on that.
So on those prices and usages I wouldn’t do it. But prices and costs change. As do interest and inflation rates.
There’s also the fact that the battery powers the inverter, so on a daily basis you can lose 1-2kWh just running the system. Mine is 130-180W/h dependent on temperature.
When ran via solar, you just accept it, but if you’re grid charging, you’re losing 10-20% of your profitability.
Also, and I don’t know what this is like for other battery manufacturers, but my batteries stop discharging at max rate at 20%. At this value, the discharge rate is just above the system required power level. So on my 19kWh usable battery, 3kWh is largely inaccessible. At 10%, the batteries automatically force charge from the grid.
any idea where i can find a detailed solar calculator? i had one a few months back ( i think it was installable), had a quote and they have calculated based off at home all day, funny rates etc and id like to clean it up
I agree Daffy - there’s standing losses as you point out as well as round trip losses. Good point.
Fair point on usable capacity and force charging too.
The discharging rate shouldn’t matter too much given most of the time your house is doing 200W or so. Except when it isn’t of course.
Thanks so much everyone, I really appreciate the time taken.
I apologise, I'd failed to re-mention something important: I already have a fairly inefficient 3.6Kw solar array (~2000Kw/year) already which is on a FIT agreement so I won’t have the opportunity to either expand it or export from any new array.
So what I'm hearing is I need to forget about:
- a year round approach of importing offpeak
- my 15-20Kw daily use.
Instead I should focus on:
- moving to a variable rate tariff
- shifting usage as much as possible to offpeak
- summer: avoiding peak rate by capturing my net solar generation (i.e. gross generation less what I use) by getting a ~5Kw battery on the existing array.
- winter: importing offpeak for onpeak use
I guess what I'm saying is I'm right 🙂 [to abandon the idea of a 2nd array and to focus on batteries] but with a different reason/scale.
I think I’m saying do the sums carefully. And be aware that tariffs, interest rates and costs will change so the calculations will change over time.
Beyond that, what works for someone may or may not work for others.
Just a quick PSA: I know most posters on this thread use Octopus Flux but for those who don't, British Gas (yeah, go on, judge me...) sent me an email last night explaining that they were changing their SEG tariff for their customers (so you need to be a British Gas customer using their SEG scheme) to Export and Earn plus at 15p per kWh exported with immediate effect.
This appears to now match the basic OVO customer and Octopus fixed schemes.
Some quick calculations last night with my 3.6kWh solar install plus 3kWh battery and this looks like it should just about cover the both the standing charge and the costs of importing power from the grid for the coming year. I don't get hung up on the "payback period/return on investment" thing but the increased savings now being made have reduced this significantly.
My advice to anyone thinking of fitting solar panels is this: if you can afford to, and if you have the space, then even for a modest system with a few kWh of storage its a complete no brainer, just do it.
The bg tarrif has some belting hoops to jump through.
A bank certificate to prove you have an account for example.
Just logged into the solaredge app to find they have added full charge and discharge control of the battery 👍.
quotes out to 4 different companies
2 came back with issues, and when followed up on the issues asking for clarification, no reply
Ive started the ball rolling on a 3.44kw system, due to limited space and some stupid boiler flue (8x230w panels)
and a 10.4kw Givenergy battery with 3.6 inverter, for just under 11k
the Givenergy was the deal breaker as i just found out that was the first system with detailed API control which can work with Octopus Intelligent Flux, as a good chunk of my saving will be from battery management, this seems like the right way for me
july 2023 was grim
billing landed over the weekend.
imported 161 units (night charging )
Exported 300 units
total bill after standing charges - 10 quid in my favour.
changing sun and cut to tariff made a big difference for us compared with June.
Average daily export prices in june were 24-27p, now they are down to 19-23.
production: 1.04MWh
consumption: 496
export 760
import 216
net payment from octopus £76 compared to about £200 for June.
the Givenergy was the deal breaker as i just found out that was the first system with detailed API control which can work with Octopus Intelligent Flux
If Octopus ever actually make Intelligent Flux anything more than a waiting list...
The GivEnergy app, website and API are great; oodles of data and lots of control to run the system pretty much however you want to either manually or automatically.
It's a good job screens don't suffer from burn-in any more or the main screen of the app would be permanently visible on my phone.
July for me on Octopus tracker
electric
Exported 474 kwh
imported 33 kwh
Gas
65 kwh
total bill after standing charges £71 credit to account
Happy enough with that
Not as good as June but not terrible:
Exported: 646 kWh
Imported: 181 kWh (exclusively for the car)
Import will be less for August 'cos I've found an ultra-rapid charger near home with a broken card reader that lets me charge for free.
Thanks everyone (re: adding more solar/a battery to my existing array). I couldn't even make the smallest battery work payback wise so have gone for a small investment of a solar diverter. I think it suits our situation (limited excess, FIT so no further exporting, plug and forget) nicely and I've gone for a more expensive one (Eddi) almost purely to be able to report on whether I reach payback in a reasonable period.
Please can I pick your brains as a long time lurker, short time Solar stresser. Ive just had installed a 7kw system and car charger (as in the scaffolding is still up). The installer I’ve used mentions SEG payments on their website and the contract I signed states that they are a member of the mcs and the recc. I can’t have done my research very well as they are a member of the recc but not the mcs. After speaking to the installer they at first said he didn’t realise I wanted to export! Then that he had his sign off next month and wanted to bring them to our house to complete the sign off. My questions are can we delay commissioning the system until next month when he is signed off or is that done automatically at some point? (It’s already producing power). Does anyone have a system without mcs sign off and does that cause issues with support/ home insurance etc? Is it possible to get a mcs from someone who isn’t your installer? Finally, please if you are going to get a system installed please don’t get giddy like I did and not do your research.
thank you.
Apparently mcs sign off is no longer necessary for export so you may be OK. Only what I've been reading on Facebook Solar groups mind so check it out yourself.
FlaperonFull Member
Not as good as June but not terrible:Exported: 646 kWh
Imported: 181 kWh (exclusively for the car)Import will be less for August ‘cos I’ve found an ultra-rapid charger near home with a broken card reader that lets me charge for free.
Really? That’s a lot. How much did you generate if you’re exporting 646kWh?
From our S facing 5.5kWp array, we only generated 636kWh in July in the SW. We exported ~210 and imported 18.
He’s got east west iirc
in summer this will yield more over a day.
welshfarmerFull Member
Apparently mcs sign off is no longer necessary for export so you may be OK. Only what I’ve been reading on Facebook Solar groups mind so check it out yourself.
I didn’t even think to check facebook groups, loads of info, thank you. As it stands British Gas, octopus etc only accept mcs accredited installs but several are looking at ways to get around this. It is a more common issue than I thought. Looks like there is a process for an mcs installer to sign a non mcs system off as well all though it may be costly. Hopefully my installer will come good.
First day of charging the car from the sun and seeing the power come through is great though. Even if too much is going to the grid for nothing!
Yay, after 6-7 weeks of being down we've finally started producing again. Been a slog involving a cherry picker and scaffolding to find a wire fault.
Now just need to fix the car charger which has started to refuse to charge the car.
3.9kw + 10.4kwh commissioned yesterday. Givenergy batteries and inverter.
I understand is going to take several weeks to potential months to get the DNO in place which will take me into autumn winter with limited export. In the mean time, i'm on an octopus fixed tariff at about 31p a unit, i'm wondering if i should jump onto another tarriff for cheap imports when the winter comes in, on the premise that when i can start getting paid exports, to change again. i know some tarriffs have early cancel fees. with that in mind is it worth me just jumping on agile and deal with the export part later?
Already emailed octopus to see the best way of working through it regardless
Oh, is there anything clever to be gained from using Solcast + Givenergy API ? i have seen a guide about using Home Assistant which combines the two and intelligently charges the batteries. But i don't want to set up a home server to do this
You're export is going to be declining anyway as we enter September, so I wouldn't base any decision on export rates. I'd be looking at what the best tariff is for the low yield months of October to February, something with cheap import in a fixed window to force charge the battery. The cheapest will be Octopus Go - whether you have an EV is somewhat irrelevant even though it will be a question from them to you and is a stipulation...How would they know?
When I switched to Octopus go there was no check made. More recently I switched to Octopus intelligent and they insisted on verifying a charge to the car before completing the switch.
I was on eco 7 over last winter and I'm on tracker for both electric and gas just now with 15p export rate . I might just wait and stay on tracker
SV price is red line
whether you have an EV is somewhat irrelevant even though it will be a question from them to you and is a stipulation…How would they know?
Been folk moaning about being asked to send proof because so many people were signing up without one.
yer let's say i do it legitimately, I'm pretty sure I cant get on flux without export being in place
But i don't want to jump on something and get penalised by early ending charges when i need a good export rate when its all set up
so Agile was looking logical? even if it means using agile export rates from spring until now next year? in case of any early cancelation fees?
And the best way of managing this without being on top of it every day? :S
Oh, is there anything clever to be gained from using Solcast + Givenergy API ?
I haven't done anything fancy with it but I have recently set up the solcast bit of the givenergy dashboard; normally it's pretty accurate so it might be a good guide to how much to charge the battery overnight in spring and autumn if you want to fiddle with it. It's definitely worth setting this bit up so you can see whether it's worth doing anything more complicated with it.
Can anyone comment on their experiences of withdrawing credit from their Octopus account please. It took 2 phonecalls to get it set up and I thought I was setting it up so that i could do it all online thereafter.
The first time I withdrew credit it took 23 days. I phoned them and explained I thought I'd set it up so I could withdraw credit online, the fellow I spoke to told me I'd have to phone each time I wanted to withdraw.
I phoned to withdraw credit again on the 7th and this was showing on my account as pending, but has now disappeared, everything is hassle with them so far.
I've only withdrawn once but I'm positive I just did it online.
Flux export was really fast for us - 14 days after signup and it was all done.
In general, Octopus have been pretty great. Everything has been done exactly when they said it would and did what it was supposed to.
I only joined in June and am already sat on £200 worth of credit for a single £30 direct debit. If we can get to October with £300 in credit, that should see most of our winter usage paid for and maybe a little paid toward the standing charge. We won’t be totally cost neutral, but using off peak to force charge the batteries, we may be able to come close, so circa £2000 saved this year, maybe a little more, but that would require the British summer to arrive some time.
We tripped over onto the grid (0.15kWh for 2 hours) for the first time this morning since early March. A combination of heavy oven use on Thursday evening with utter abysmal generation through the day (4.3kWh) meant we were a little short before sunrise.
A question on inverter and battery efficiency.
On the current flux tariff, import cost between 02:00 and 05:00 is marginally cheaper than the export rate (aside from 16:00 to 19:00)
given it’s cheaper to import than export why not charge the battery fully between 02:00 and 05:00 and do any high draw activities form the grid. Then during the day you will export a greater amount
muddyjames: thats exactly what I do. Though I suspect that with losses the gap between 0200-0500 buying and daytime selling is close to zero. What it does mean however is full battery every day irrespective of the weather. I also force discharge at 3kW between 4pm and 7pm. So about 9kWh discharge, leaving 3kWh approx to run the house between 7pm and the next 2am slot. Tweaked settings to maximise sale but also ensure enough remaining in batteries at 1901 to last a typical remainder of evening.
Those settings I suspect I will keep all year as the only variable really is solar yield and surplus of that goes straight to flux export.
Solar newb here - we were fortunate enough to get a fixed tarrif just before energy prices went mad, but now that's coming to an end and that's probably the final shove we needed to do something about solar plus battery etc.
So, first question - is there an unbiased idiots guide anywhere that will let me work out how many panels to put where (tiny bit of roof faces S, most is more or less E or W), what size battery makes sense etc.
Second question - how to find an installer and what questions to ask them (Swinley area if anyone has a recommendation)
And finally for now - MrsP is a structural engineer who wants lots of stuff about roof loading, fixing systems, maintenance etc - any helpful resources there?
Number of panels is dictated by the size of the roof, the size (both capacity and size - the former drives the latter), the inverter and in some cases the mounting system. Also what the customer wants,
Most panels are affixed using brackets to the roof joists modifying the tiles and sealing again often using leadwork. The panels aren’t usually a huge weight compared to the tiles. A typical 1.8*1.2m panel will be around 18kg, so 20kg per panel with the brackets.
If installed on-roof as above, you may want some protection (mesh netting) around the edges of the panels to stop birds nesting underneath them.
Mine are slightly different as mine are in-roof. Essentially, the tiles are replaced by overlapping plastic mounting trays and the panels are attached to these with a border of tiles and galvanised steel. The roof weight is now lower with the panels than it was before as almost 100 concrete tiles are removed. There’s also no need for bird protection and, IMO, it looks better, but they will be slightly less efficient on VERY hot days, maybe 5% as they have less convection cooling. In roof is around £2k more expensive.
Batteries and sizing are tricky. Cost effectively, smaller batteries and a good tariff and management will work great, but if you want true self sufficiency, bigger batteries will do this, but the economic argument loses weight.
In a gas heating cooking household, 5kWh is probably around the right value. In an electric cooking household, maybe 10kWh.
Hope this helps.
Thanks Daffy - some great info. Our current energy supplier says we're using about 3300kwh per year but I'd want to leave headroom for when we finally get an EV.
In roof is around £2k more expensive.
Is this just for fitting to an existing roof? We're building a new extension and I've currently specced in roof as I figured it would be cheaper (due to fewer tiles) than on roof
Your best bet is to get a couple of quotes rolling, they can make a pretty good estimate from google maps
i used a company called dual fuel solutions and i have no complaints, and the pricing was competive, and they were flexible with my quotes until we got where we needed to be, installation from first quote to sign off was 12 days... insanity, if you speak to them please mention me as a referral (PM'd)
Battery sizing, i figured bigger was better, as its easier to keep a little in reserve, for a bad day, or a missed low cost charge etc
On a new roof it should be slightly more expensive, but not by much. The tiles will be about the same as the trays, so cost neutral. But the steel sheeting, sealing, extra wood work and bolts will all add up. Labour will almost certainly be higher too, especially if tiles and ridges need to be trimmed or shaped.
To keep ours near perfectly centred in the roof, every border needed all the tiles trimmed after careful measuring.
Hi All, apologies if this is covered elsewhere, but what are the best online resources for interfacing third party apps, raspberry pis, controllers etc to one's inverter ?
Ta.
Usually people use Home Assistant through a Pi to perform the interface. Some inverters and Batteries can be directly connected.
Most panels are affixed using brackets to the roof joists modifying the tiles and sealing again often using leadwork.
They cut a slot in the slate tile for the bracket which goes under the slates against the joist. A plastic sheet sits over that and then they replace the slate tiles. Takes a while as each bracket requires two slates to be notched by hand using an angle grinder.
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[url= https://live.staticflickr.com/65535/52544034681_778b64fc1c_w.jp g" target="_blank">https://live.staticflickr.com/65535/52544034681_778b64fc1c_w.jp g"/> [/img][/url][url= https://flic.kr/p/2o48UUr ]Solar install[/url] by [url= https://www.flickr.com/photos/brf/ ]Ben Freeman[/url], on Flickr
[url= https://live.staticflickr.com/65535/52544030721_291078510a_w.jp g" target="_blank">https://live.staticflickr.com/65535/52544030721_291078510a_w.jp g"/> [/img][/url][url= https://flic.kr/p/2o48TJa ]Solar panels on South facing part of the roof[/url] by [url= https://www.flickr.com/photos/brf/ ]Ben Freeman[/url], on Flickr
Looking out of my office window it does not look like our tiles were modified. The mounting system has stainless bracket that slip under the tiles.
Looking out of my office window it does not look like our tiles were modified. The mounting system has stainless bracket that slip under the tiles.
Depends on the tile design. If you do that with slates you'll end up with flying tiles.
Odd question, I'm keen on Solar but concerned of hassle(cost) if we need to replace the roof in the next 10-20 years.
Has anyone fitted solar and then paid to have it removed and refitted for roofing work?
Was it expensive?
Current roof in good enough state to justify not replacing it as part of Solar install.
Cheers
@jacobff. I got a real finger in the air "£2k" to remove 16 panels so I guess you'd need to add a bit more to put them back up again. Hope that helps, that's a big ol' dent in the payback hey - I only know this as I was weighing up getting a 2nd array that we felt we may want to remove for the purposes of selling the property as it's a period cottage
I got my whole roof/gutters/soffits redone at the same time just to make sure this didn't have to happen.
Truthfully though, I'm not sure how much of a big job it would be - If the scaffold is going up anyway to fix the roof, the panels are held on my a few brackets and an electrical connector. They're not heavy and can be easily stacked. You'd likely need to get someone back to reinstall the brackets once the membrane and battons are replaced, but most of the hard/technical work would already be done. Panels are already up there, wiring is already in place.
Current roof in good enough state to justify not replacing it as part of Solar install.
But not in a good enough state for the lifetime of the panels? Pesky. I’d suggest sort out the roof now and then no problem in 20 years.
It was easy for us, the roof needed replacing before the panels went on.
Likewise, we did the roof first, then added panels.
Realised I didn't update this for August: 5.5kWp array, south facing, in the southwest with battery storage.
613kWh generated,
280kWh exported, (£66 paid to us by Octopus)
16kWh imported. (£21.62 paid by us to Octopus inc standing charge)
£44.50 profit.
Anyone able to comment on the effect of hot weather on the output of their system?
Mine is an old system, 11 years now so well past it's pay-back period, but still well within FIT payment timescale so not worth replacing yet. I had to replace the inverter back in the winter so this is the first year I've had real-time stats of what they're producing.
On these significantly warm days, I've noticed my max output is 1.6kW, from a system that is rated at 2.25kW - so down about 25%. Can anyone comment - are you guys seeing a similar reduction?
Edit - I should point out that on cold days with a sudden sunny spell I get up to 2.5kW out of the system, so I reckon it's heat not simply age/deterioration.....
Lots of variables at play I suspect. Although very hot and sunny at the mo the sky is certainly not as clear as it is on those crisp sunny winters days. That takes the edge of it a bit. Mine was showing a max of just over 4.5K today. It can often go above 5.5Kw (Theoretical max of 6KW). Also my roof angle is quite steep so gets better maximum output in winter when the sun is a bit lower than it does now in summer. And when were your panels last cleaned. Maybe some summer dust on them?
I'm in Spain currently so can't even use my output but my system 4.14 panels 3.6kw inverter with batteries
I've been producing 5.2+ this week and the garden weather station showed 32degrees. .
Panel output degrades with heat.
August (4.2kW array split east/west, 3.7kW inverter, battery storage and EV).
Generation: 429 kWh.
Inverter calculated export: 280 kWh.
Import: 171 kWh.
Overall for August: £55 profit. Not brilliant but weather was awful. Full year generation of 3,600 kWh, exactly as predicted by the installers.
4kw array heavily shaded 🙁 4.2kW of batteries.
Generation 405.8kW
Consumption 196.9kW
of which Battery charging 81.7kW
Energy from grid 30.1kW
Export to grid 210kW
I think thats ok but i dont really know?
Well, I'm a month in of having added my solar diverter and it really isn't going to be worth it. I kind of expected it, our array doesn't produce much and we use alot of what's generated.
I'm consoling myself that it's nice to get a view of what I'm exporting (already had a view of generation total from the FIT meter and live generation from the octopus Ihd)
Well August wasnt the best month, but not too shabby.
18 panels (10 facing east, slight 15° towards south) 8 facing west (slight towards north) 12.8kw battery set to discharge/recharge to about 25% each day before recharging.
In Leeds we got 677kWh solar, with domestic usage 377kWh.
Combination of surplus solar and Lux/Hanchu battery load shedding we exported 696kWh at an average of 23.81p and imported 477kWh at an average of 17.86p.
Total for the month, about £60 profit even after standing charges etc.
So far in past 7 days we are £18.5 up, mainly due to sun since the weekend.
I'm a little disappointed by our generation this week. It's been uniformly sunny, but we've struggled to exceed 4kw of generation at peak power. That's on a 5.5kWp array with no shading.
I'm going to try cleaning the panels on Friday - they've been up for a year and are at quite a shallow 30deg, so maybe it's just dirt...?
Octopus billing problem: has anyone one else experienced this.
We were swapped from Bulb to Octopus in April this year and all was well I thought. In June I noticed I wasn't getting billed for electricity used, gas and export were fine. The app showed they were getting all the data, but no bills. It took a number of unanswered emails and finally a phone call to sort this, and now my August bill, and Octopus aren't billing me again for electricity! Has this happened to anybody else?
it took about 3 months for me to get a bill properly.
Yeah this week has been epic for me. Perfect parabolas since Saturday.
28kwh/day
And as I've used zero I'm up about 19-20 quid
Octopus billing problem: has anyone one else experienced this.
Yes. I’m in my third year of Octopus supply and I still can’t work out what the hell is going on most of the time.
I do get a bill once in a while and I go through it and it checks out, also the app shows me stuff in terms of usage so I know they have the data, it’s just weird that they don’t seem to have it automated.
@daffy, I'm assuming your baseline is actual data from a year back? (rather than an unreasonable expectation of what you'd generate?)
At the other end of the scale: 12 old panels in a valley (so partially shaded) and East:West (so presumably not as good as 12 all south facing).
Yesterday: 8kw generated!
I think it's the heat holding them back rather than any kind of problem but what's people's view? - get someone out to service/assess they're all working fine? Get up there and clean them?
My challenge is I don't have much in the way of reporting from 12yrs back to say that the generation would have been any different back then
My array wasn’t activated until late November last year, but was installed in September, so no data to directly compare to. What I’m comparing to is generation in March and May.
in March we were getting sustained peaks of 5.3kW, in May, it was sustained at 5.2kW, the rare days in August when it was sunny for longer periods were 4.6kW, now we’re down to 4-4.2kW. It could be simply what happens in September with the sun at a less than optimal angle, it could be dirt, temperature or something else or even a combination, but I think cleaning has to be the first step.
Our generation of the last 4-5days has been around 30kWh a day.
Ah, got you. I'd be surprised 9 months later if you're experiencing degradation as a result of dirty panels but it's a nice easy action to take
It could be simply what happens in September with the sun at a less than optimal angle, it could be dirt, temperature or something else or even a combination, but I think cleaning has to be the first step.
Mine are the same. I doubt it’s dirt - we’re just a long way past the solar irradiance peak of mid June and you should expect similar generation capabilities to early April. Couple this with hot panels and the output looks about right.
FWIW I have a 12 panel east/west split and generated 14 kWh yesterday. That would have been 30 kWh in June. Not helped at this time of year by tall trees to the west of the house.
August figures for us:
Production - 957
Import - 275
Export - 705
Net profit from Octopus for period 20July to 20 August was £91
Octopus give the breakdown of which rates we export at on flux.
We sold: 545 kWh @ 19.3p and 155 @31.4p
Had a quick look at production peaks vs temperature. Comparing two very sunny days. 8th June, whole day average temperature was 14.9, peak output was 5.86kw. This Monday, average temp was 20.9 and peak was 5.01. Panels are 2 years old and never been cleaned (its on the list!)
