Viking Supporters Co-operative
Viking Chat => Off Topic => Topic started by: Superspy on January 20, 2023, 05:24:03 pm
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Following me derailing the heat pumps thread (https://www.drfc-vsc.co.uk/index.php?topic=282673.msg1209889#msg1209889 (https://www.drfc-vsc.co.uk/index.php?topic=282673.msg1209889#msg1209889)) I wanted to start this one to just answer any real-life-usage type questions about Solar as I've had my system in for a few months now, and thought it was quite tricky when I was looking around to find real experiences that weren't driven at sales etc.
When I've had it for a year I intend to come back and report on the generation of the system over the year and compare how it stacks up with the original quote and assumptions.
To start things off:
That's really useful SS.
Question from me if you don't mind. What's the peak wattage output that you get from your battery? Checking my Loop app data, we rarely use above 3kW (usually when the oven and several hob rings are on). I'm wondering if a battery would be able to service that requirement without drawing from the grid (assuming it was sufficiently charged up of course).
Also, when charging your battery from E7, can you program that? I'm thinking that I';d want to fully charge it every night in winter, but probably not in high summer, when the solar panels would do the job.
The timing of the question about peak output is really interesting because of something that happened this week.
Bear in mind not all batteries and inverter systems are made equal, so you have to check the performance capabilities of the specific hardware you would be looking to buy, but for my stuff (up until yesterday) the peak output was 3kWh, and the peak charging rate was about 2 to 2.2kWh. The batteries are marketed with these figures in mind - although they usually are limited by current.
The interesting part is that the engineers who fitted my system came out yesterday to reconfigure a few "dip switches" as part of a firmware update that had been deployed and now my batteries are able to charge and discharge at 4kWh. That was a pleasant surprise. The cynic in me says they just didn't configure it properly in the first place - but actually everything I can find online in the marketing says the old figures were correct. I'll be monitoring for a couple of days to make sure those numbers remain.
With regards to E7 - again I can only speak to my specific hardware - the inverter can indeed be programmed for the charging. Mine is currently configured as follows:
Charge level: 95%
Charge time: 12:31am - 7:30 am
I have a 9.6kW battery, so in practice what happens is
- at 12:31 am the battery starts to charge at full power (4kWh as of last night)
- Once it has finished charging the battery, because I've told it to charge until 7:30, this effectively acts as a "hold this charge" command...so all power required by the house comes from the grid
- at 7:30, the battery takes over the house load and the grid is no longer required
This can be seen in this image of last nights charge. The reason it took less than 2 hours to charge is because the battery still had some juice in it from yesterday.
(https://iili.io/HcMdxQs.png)
The inverter I have has 3 charging time periods, so if I wanted to boost the battery again later in the day I could - but the only reason to do this is if you can then export it at a high rate to make money. I've done this a couple of times but not very often. In summer I'll just knock the charge off completely as it definitely won't be needed.
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That's really, really useful background stuff SS. Many thanks.
Can I just ask - do you have the Greenlinx batteries?
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You're very welcome.
I do indeed, 3 of the 3.2kW ones.
Having a battery of that size, for my usage, has meant that switching to E7 has knocked about 30 quid a month off my winter bills. The only behavioural change we've done to achieve that, other than charging the battery over night, is putting our dishwasher on a timer to also run during that cheaper period overnight.
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Do you mind if I ask how much each battery unit costs? I've had a quote for a solar PV system with 2x3.2kWh batteries. I was thinking of going for 3, but they didn't itemise the individual components of the quote, so I've no idea how much the batteries are.
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I have just got some solar panels (16) and a battery (5.12) for £10,700
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I've said for years that every new house with a suitable aspect should have Solar Panels fitted as standard.
This would reduce the price through economies of scale, and the price of awful new shoebox houses seems to be heading upwards of £250k, it wouldn't add much to the price percentage wise.
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Agreed Mug. It's a no brainer. A sensible Govt would massively subsidise this to make sure it actually did happen. Then pay for it by increasing taxes to reflect the benefit that people got from this subsidised free power.
Instead, this lot cut subsidies to green power 10 years ago.
Then, when the shit hit the fan, they had to pay subsidies straight into the pockets of BP and Norwegian gas producers.
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Do you mind if I ask how much each battery unit costs? I've had a quote for a solar PV system with 2x3.2kWh batteries. I was thinking of going for 3, but they didn't itemise the individual components of the quote, so I've no idea how much the batteries are.
Ask anything you like mate.
When I had them fitted I think they were either 1k or 1.1k per battery, and because they were fitted with the system they were VAT free... I'm not 100% sure but I think the company I used have since upped them to 1250, still vat free with no additional fitting costs if included with a system... but obviously retrofitting makes them much more expensive due to vat and fitting.
If you're a moderate to high user I would definitely get 3 at the point of the panels going in. I certainly don't regret it and could probably have justified 4 for the winter E7 benefits, but less needed in summer due to the longer days.
My system, with 19 panels, was about 13k, for what it's worth.
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Who did you get them fitted by?
I had a quote of £10,700 for 10x400W panels and 2x3.2kWh batteries, plus inverter. Sounds like your quote was a good bit less than mine.
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Ask Renewables in Barnsley. Really happy with them throughout the process.
Similar to you...no itemised quote, but I'm pretty sure mine is 19 x 385 panels, across 2 strings (east and west), 3 x 3.2 batteries, and a Lux Power 5kW inverter.
Just bear in mind this was about 6 months ago, before some of the pricing went up.
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They did a quote for my mum in November which was the same batteries and inverter but 17 x 375 panels for 12k.
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Who did you get them fitted by?
I had a quote of £10,700 for 10x400W panels and 2x3.2kWh batteries, plus inverter. Sounds like your quote was a good bit less than mine.
Theres a guy I use for all my electrical work that does solar, he’s a real good lad, and takes pride in his work, R S Electricals and Security, he’s on Facebook, but don’t let that put you off getting a quote. He did my 4 camera CCTV for £650 when others were quoting double that
This is what he was quoting last summer:
4kW Solar PV system + 6.5kW Battery Storage
Supplied and installed
10 x 400w Black Mono Suntech
1 x 3.6kw Growatt Hybrid inverter
1 x 6.5kaw Growatt Battery storage
1 x WiFi Data Logger + Smart phone app
Roof mounting Rail + Clamps
2 X DC Isolators + Cable
2 X AC Isolators + Cable
1 X Generation meter
1 x CT clamp
1 x Battery Lead
Installed to one roof
Roofer + Electrician
G98 forms + RECC + MCS
Fully installed £9850.00
4kW Solar PV system + 6.5kW battery storage
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Interesting read this.
I've had solar panels for best part of ten years now, even though I could only get 2.6kw worth on my roofspace they've paid for themselves now. Been thinking of a battery/batteries for a while now, do they work in a power outage still? I read somewhere that not all of them have the smart technology to do so, to do with backfeeding into the grid & potentially electrocuting engineers working on it.
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That's what I was told when I had mine fitted Spud - H&S risk of backfeeding into the grid when they think the power is down. Apparently there was a legal case somewhere (Germany rings a bell) where an engineer did actually die as a result. Either way the point is your system is down during a power outage. Disappointing, but it is what it is. They are able to fit a socket to the battery/inverter (not sure which) to use as a backup with an extension cord I believe, but I didn't ask any further about this with my system as it's not of huge use to me.
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I've got a 4kw system that pays approx. £600 per year.
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That's what I was told when I had mine fitted Spud - H&S risk of backfeeding into the grid when they think the power is down. Apparently there was a legal case somewhere (Germany rings a bell) where an engineer did actually die as a result. Either way the point is your system is down during a power outage. Disappointing, but it is what it is. They are able to fit a socket to the battery/inverter (not sure which) to use as a backup with an extension cord I believe, but I didn't ask any further about this with my system as it's not of huge use to me.
I'm sure i read the Tesla power wall has the smart technology.
Can't remember too many power cuts, but who knows where we're heading on that score.
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I've got a 4kw system that pays approx. £600 per year.
Yeah, I get around £400 from my 2.6kw system, plus what I save when they're generating.
No idea what rates are being offered nowadays, mine is 19p generation & 5p export.
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That's what I was told when I had mine fitted Spud - H&S risk of backfeeding into the grid when they think the power is down. Apparently there was a legal case somewhere (Germany rings a bell) where an engineer did actually die as a result. Either way the point is your system is down during a power outage. Disappointing, but it is what it is. They are able to fit a socket to the battery/inverter (not sure which) to use as a backup with an extension cord I believe, but I didn't ask any further about this with my system as it's not of huge use to me.
I'm sure i read the Tesla power wall has the smart technology.
Can't remember too many power cuts, but who knows where we're heading on that score.
Yeah, it may well have, I'm not sure, but then isn't the power wall something like 10k on it's own? Out of reach for a lot of people. As you say though - not many power cuts round here, that's why I didn't really look into that side of things any further, for me it was all about reducing bills over the long term.
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I've got a 4kw system that pays approx. £600 per year.
Yeah, I get around £400 from my 2.6kw system, plus what I save when they're generating.
No idea what rates are being offered nowadays, mine is 19p generation & 5p export.
These days you don't get anything for the generation directly - that was part of the Feed In Tariff stuff several years ago. Now it's all export.
Export rates vary from as low as 3 or 4p up to 15p with Octopus or 24p (I think) on the Tesla power plan - but you need Tesla hardware for that.
Personally I'm on the "agile" export tariff with Octopus where the export rate changes every half an hour. I've seen it as high as £1.80 a unit when there has been high demand on the grid, but most of the time it is much lower than that. Today for example the price is between 12p and 33p.
Overall, on my 7.3kWh split system, when you factor in the 3 ways of earning with it (export, reduced bills and Economy 7 charging) I've saved about 300 quid between mid September to the end of December - so just over 3 months. However, I wasn't on an export tariff until some time in November so the savings would have been higher than that, as I was exporting more in September/October.
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Thought I'd add a bit of info regarding the savings I'm making and where the numbers come from now that we've rolled into another month.
The image below shows where I've saved as a result of generated power I've used, power I've been paid to export, and the differential between a standard unit rate and what I've saved by charging the battery over night on the cheaper Economy 7 rate and then using that power through the day.
(https://i.postimg.cc/3JCCmWcr/solar-Generation-To-Feb23.png)
It's not a perfect formula as there are some nuances, but generally the calculations are:
- Generation: (generated units - units exported) * standard price per unit ignoring E7 savings (roughly 33p). September was low because I only got the panels fitted mid-month
- The export saving is simply the amount Octopus have paid me during that month, rather than using a formula, as it will all balance out over time anyway. December is high because there was a bit of energy trading going on where I was force-discharging the battery because they were paying up to £1.80 per unit for it (that was a fun couple of days). September and October show 0 because I wasn't on an export tariff at that time.
- TE7: (total units used * standard unit cost) - ((day units used * day unit cost) + (night units used * night units cost)). Or in other words, the difference between what I would have paid for all my grid usage on a standard rate, versus what I actually paid for the same usage split between the Economy 7 rates (as per my meter readings at the start of each month).
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Thanks SS. Really useful stuff again.
Your electricity generation in winter is more than I've been quoted: It's very interesting to see real figures rather than a generic model.
It's all tipping me further towards going for solar this spring.
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Yeah - the biggest problem I had beforehand was finding real-world examples of actual systems rather than just stuff based on predictions and calculators.
For what it's worth, these are my total actual generation figures (in kWh) - so independent of unit prices and before exported units are taken off:
September (2nd half): 189
Oct: 299
Nov: 100
Dec: 69
Jan: 127
As mentioned before, that's on a 7.3 KW system, split between east and west facing, with some some shading on the west. I've nothing to confirm this but I read that the difference in energy that hits a south facing roof versus a 90 degree offset (east or west) is about 15%.
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SS, does force discharging of the battery have the same effect on it as accumulative charging, ie, in wear and tear on the battery over time, im asking because of the way the buy back scheme works with suppliers like Octopus Energy i would imagine this would be something you would do on a regular basis as and when the buy back price is elevated.
I just wondered if this would have a detrimental effect on your equipment or would the additional monies earned add to an overall gain over the lifetime of your generating and storage kit?
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I would assume the wear and tear is the same - in the sense that the battery doesn't care whether it's discharging because the house is demanding power, or because I'm telling the system to discharge to take advantage of higher export rates. I'm not a battery-tech expert, but I'd expect it's all just about the battery having a serviceable life in terms of number of charge/discharge cycles.
With that in mind it makes sense to make those cycles as financially beneficial as possible, so yes, unless somebody tells me otherwise, when the price is energy is high I'll discharge back to the grid and take the money for it.
Octopus release the following day's pricing at about 4 in the afternoon, so I tend to check it after that time to see if it's worth doing anything the day after. There's no point forcing it to discharge if the rates are below about 50p though, as 40p is the day rate so I'd pay that to import it back, and you get some losses over the system. In summer I may change approach as they'll generate so much energy I'll be exporting at some point during the day anyway, so it might be worth me tweaking it to make sure I'm discharging at the best time of day based on the pricing.
Tomorrow the highest rates are about 24p so I don't bother. And during the morning and early afternoon they're around 14p...which is less than I pay to charge the battery during the night, so I'll try to avoid exporting during those times if I can help it and make use of the power instead. Of course this only translates into a cost saving if you're actually using power you would normally use (just at a different time) - if you're using it for the sake of it then you aren't really benefiting.
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Update after the first 10 days of my new panel and battery system.
It's still not even the equinox yet, but I've had 2.5kW peak power out of a 4kWh system.
The panels have been covered in snow for three days when they gave only minimal power. And the sun's only been out briefly over the last couple of weeks. But I've had 40kWh of solar production. That's about £13's worth at current rates.
And for the other usage, the batteries and the Octopus Agile tariff are brilliant. I reckon I've paid about 24p per unit on average, and saved about £6 on what I'd have spent on that electricity at a standard tariff.
So, £19 saving in the first ten days. In this weather. At this time of year. When I'm still getting used to running the system.
Very pleased with that.
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A new report looks at the combined savings from installing solar alongside a heat pump;
https://www.pv-tech.org/solar-pv-and-heat-pumps-can-cut-european-household-energy-bills-by-84/
This summary does not look at UK data, but Germany is included so that is the best for us to compare.
Significant findings, if this replicates across the sector.
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03:30-07:30 this coming night, the Octopus Agile rate averages 15p/kWh. So a 10kWh battery can be charged to full for £1.50 rather than £3.30.
Small gains each day but I guess that's the idea. And at that rate, direct heating with electricity is getting close to being down to gas prices. Using electricity at that cost to power a heat pump would be way cheaper than using gas for heating.
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It'll be interesting to find out what sort of savings you start making when you start to plan your energy using activities around the peaks and troughs, could be some big gains to be made there.
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It'll be interesting to find out what sort of savings you start making when you start to plan your energy using activities around the peaks and troughs, could be some big gains to be made there.
I think there's more to be squeezed out DD, but we've already started to get the main benefits of the battery by charging it at the times when tariffs are low and using it to power the house when tariffs are high. You can easily shave £1/day, day in, day out off your electric costs by just doing that.
With tonight's really low tariffs, that'll go up to £1.70-1.80, saving just by charging the battery up overnight.
As you say, you could get more out of the deal by setting the washer, dishwasher or even oven to come on overnight. I reckon you could probably work it to be able to save £1.25-£1.30 every day and upwards of £2 when the tariffs were very low. And that's before you factor in the free stuff from the panels and the export to grid payments.
It's not exactly life changing amounts but it's not bad as a constant saving.
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It'll be interesting to find out what sort of savings you start making when you start to plan your energy using activities around the peaks and troughs, could be some big gains to be made there.
I think there's more to be squeezed out DD, but we've already started to get the main benefits of the battery by charging it at the times when tariffs are low and using it to power the house when tariffs are high. You can easily shave £1/day, day in, day out off your electric costs by just doing that.
With tonight's really low tariffs, that'll go up to £1.70-1.80, saving just by charging the battery up overnight.
As you say, you could get more out of the deal by setting the washer, dishwasher or even oven to come on overnight. I reckon you could probably work it to be able to save £1.25-£1.30 every day and upwards of £2 when the tariffs were very low. And that's before you factor in the free stuff from the panels and the export to grid payments.
It's not exactly life changing amounts but it's not bad as a constant saving.
Yes, on those figures you could end up saving up to£100 a month for the winter autumn part of the year, when you compound that over the year on year costs that's some decent saving to be had, if the price cap goes up again next winter then the savings will make a big difference.
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3:30 am tonight, the Octopus Agile tariff is 1p per kWh!
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Awesome.
Everything you've described is exactly how I've been operating with mine, only I opted not to go for the Agile tariff and just went Economy 7 instead - 18p/KWh every night between 12:30 and 7:30. At the time when I signed up the peaks of the agile tariff just weren't worth the risk, and the lows (on average) weren't really beating the E7 rate - clearly things have come back down!
You'll likely find that in a month or so none of it will matter as the huge majority of your usage will come straight from the panels - you'll be generating so much between 5am and 9pm your battery will still have juice in it the following morning when the sun comes up.
As you've said, the daily gains might be relatively small but if you're willing to put the effort in it could mean the difference of a year or more on the payback timescale. Not to be sniffed at.
I've just checked my numbers and between generation, export and E7 I'm now up to over £500 in savings since mid-September, and that's without me being on an export tariff until November, so I missed out on a significant chunk of export payments there. Overall I'm really pleased at saving 500+ over winter!
It'll be really interesting to see how things goes in summer for me in terms of savings, as obviously using the energy is more financially beneficial than exporting it, and I'm a little different to most in that my circumstances mean I use more leccy in summer than I do in winter, so I'm expecting the overall savings to be massive.
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The amount of electricity we've used today would normally cost us just under £5. Today I reckon it's cost us 23p.
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Fun game isn't it?
We've generated 9.5kwh today, even with the weather being crap. Still got 70% in the battery so will be charging very little tonight... tomorrow could be a zero cost day...as was last Wednesday.
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I've just bit the bullet and signed up for Octopus Flux in place of my E7 import / Outgoing Agile combo. The more I thought about it the more it made sense to have a shorter cheap charging window over night but be in a position where the export price is always higher than the cheaper import. It means, rather than having to wor k out how much I should charge the battery at night I can just fill it, and anything I generate the day after goes back to the grid for a higher export cost (albeit not much, but that's not the point).
In another few weeks when overnight charging becomes completely irrelevant, the flat daily export rate of 22p is significantly higher than the average agile export rate for most of the day.
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15.5 kWh produced by our system today and it's not even the equinox and it's been cloudy all afternoon.
I'm fascinated to see what it will produce on a clear June day.
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5am tomorrow morning, the Octopus Agile electricity price is -0.3p per kWh.
They are paying me to take electricity off them.
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22.9 kWh produced by my solar today.
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21,17,20 for me over the last 3 days. Haven't bothered charging the battery much over night this week so starting to see the saving figures flip from an E7 based bill reduction towards an Export payment.
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15, 17, 15kWh for us. We are less than perfect position with a tall and wide chimney stack on the house next door that throws shadow over our roof from about noon. It'll be better later in the year as the sun gets higher.
Very happy with that output from a 4kW system though, given that it's been broken sunshine with a lot of cloud. I'm expecting to get into the high 20s in June.
We haven't got the DNO authorisation for feed in payments yet, but to my way of thinking, filling up the battery to full at last night's rates is a no brainer once you do get feed in.
I filled up our 9.6kWh battery last night for less than 4p. Then the 12kWh our panels have produced so far today could all be sent to the grid at 15p/unit on Octopus Outgoing. That'd be basically free electricity all day and the thick end of 2 quid back.
Like I say, it's not going to buy you a Caribbean island, but marginal gains like these will add up significantly over months and years.
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the other solar panels .......
''Concentrated solar power is an old technology making a comeback. Here's how it works''
https://www.abc.net.au/news/science/2023-04-06/concentrated-solar-power-technology-comeback-electricity-mirrors/102184372
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So today is going to be my first day totally off the grid (1). 20kWh produced, even with a fir bit of cloud around noon.
I'm chuffed to bits with this system. It's madness that we don't have them on every house in the country.
(1) There's the odd bit of energy dribbles in from the grid when demand in the house suddenly surges (eg toaster going on) because it takes the inverter a few seconds to respond and feed the demand from the panels or the battery storage. But over the whole day it's added up to less than 0.1kWh.
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Yup, you'll see a lot of that now we come into Summer. October will be the first month with a lower generation than March was.
First 7 days of April look like this for me:
Import from grid: 27.79 kWh - approx £6.40
Export: 75.16 kWh - approx £16.53
I've dropped my direct debit with Octopus to a quid a month.
The reason my import is still relatively high is because the Flux tariff means you can charge the battery over night still and never be any worse off because the export rate during the day is equal to the import rate over night. If I didn't charge the battery instead I'd export less, but the delta (about £10 last week) would be the same.
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Our figures for the first 7 days of April are
Import 37.2kWh. Estimated cost about £6.70 at estimated Octopus Agile average price of 18p/unit (almost all overnight charging)
Export to grid: 16.5kWh, but still not registered for feed in tariff.
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Octopus Agile tariff overnight is as low as -5p per kWh.
There are 3 hours tonight where they will be paying me to charge up my batteries and run washing machine, dishwasher etc.
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Looking at he bigger picture, an interesting 15 minute talk on energy costs and futures;
https://youtu.be/EAU5D8hqIUI
The importance of who controls the transmission infrastructure is clear.
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Update from our system.
Just got the first monthly bill since installing the panels and battery. We've used pretty much exactly the same amount of electricity as the same period last year. We are heavy users as we have electric induction hob and oven, and several computers on for long periods of the day, as well as electric blankets to cut down gas central heating costs, so we've used about 400kWh in a month.
At standard rates, if we'd bought all that, it would have cost £140 including VAT. We've actually paid £31.5. It would have been £19 if our registration for feed-in payments had gone through.
The breakdown is interesting. Of the 400kWh used, only about half has come from the panels (they've produced nearly 280kWh, but a big chunk of that has come on a few very sunny days when they've produced a lot more than we could use or store in the batteries, so we lost that back to the grid.)
The other half has been bought in at low tariffs and stored in the batteries on days when there was little sun. The average tariff for that bought in electricity was 15p/kWh - less than half the standard tariff.
Story seems to be that if you can manage your usage times and more importantly, spend a little time every day planning when to programme the system to top up batteries from the grid, there are very big savings to be made. Even in a month like we've just had, with a lot of very cloudy days.
It beggars belief that we don't have a more pro-active Govt approach to incentivise people to make the up front investment. We could give Govt funded interest free loans to encourage people to install these systems. The payback for individuals and the country over 20 years would be enormous.
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Did I say it beggars belief?
Stupid me.
I forgot that the Tory party is full of this sort of shit for brains, masquerading as Very Serious People.
https://twitter.com/DavidDavisMP/status/1650460298350940160?s=20
Solar farms are a blot on the landscape. But not a word of criticism for oil refineries or massive fossil fuel power stations. d**khead.
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David Davis is part of a government which could add solar to all available roofspace on industrial units, and instruct new build housing to include solar provision.
The French are installing them over parking lots, providing cover and power to existing land uses.
Reservoirs could host floating solar, which has the advantage of reducing transpiration losses in high summer.
If they did these easy options, there would be a greatly increased generation capacity without other land use conflicts.
Solar on farmland can be combined with some crops and livestock.
It is called agrovoltaics, where the panels are raised on a frame above ground level. Some crops benefit from the partial shade given.
The post below Davis claim saying that fossil fuel back up is required is complete nonsense.....storage technologies are cheaper than retaining redundant fossil fuel as reserve.
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Albie, I have seen several field full of solar panels which has also had grazing sheep in them feeding off the grass.
As you say, the two can go together.
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Yes, it would be good if we had some politicians who have a science/tech background, or could do basic research before commenting.
Short video on Agrovoltaics here:
https://youtu.be/UeqGMPmYsdw
The World Economic Forum are also aware of the potential;
https://www.weforum.org/agenda/2022/07/agrivoltaic-farming-solar-energy/
We keep electing planks as decision makers, and that's a problem!
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I can’t see how that will end though.
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I'm hoping the solar farm in Marr goes ahead, but waiting to hear what happens when they put the planning permission in.
Anyway, update for me this month is as follows - approximate saving so far is £160, with a week of generation to go.
Octopus do their export payments and billing on the 24th, so basically between 24/3 and 24/4 I've been paid £64 in export, and saved about £16 based on being able to charge the batteries cheap. Generation between 1/4 and this morning is about £80. So it's looking like a £180 is saving this month when I run the final figures in a week.
As you say BST - few minutes of effort planning can make a big difference. It also helps that the Flux tarrif I'm on has paid me an average of about 24p a unit to export - means there's less pressure to save by using what is generated, albeit it's still not AS good, but a lot closer than previous export payment rates.
I'm about to start taking advantage of this even more though - just ordered myself an EV after test driving one on Sunday. I'm REALLY excited. Can't wait for it to arrive.
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Solar panel costs continue to fall;
https://www.solarpowerportal.co.uk/news/uk_consumer_solar_costs_dropped_by_13_in_six_months
With energy costs still too high for many, installing solar is a no brainer, IF you have the money for the purchase and a suitable roof.
A new Dutch panel gives a 50% reduction in weight, which is important for load bearing on certain types of roof;
https://solarge.com/en/producten/solarge-solo
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Just a reminder that anyone who isn't on Octopus Agile for their electricity is choosing to be shafted by the big energy companies.
Even if you haven't got batteries to take the very best advantage, it's still a no brainer. The standard electric tariff at the moment is about 31-33p per kWh.
Octopus Agile's average rate for May so far has been 19p. From 12:00-16:00 today it's between 0-4p.
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I'm sticking with the Flux tariff. Paying a bit extra for the energy i do import is significantly outweighed by the higher export rate with the amount I'm exporting.
I got paid 90 quid in exports this month. Utilisation will be higher now though (and therefore lower export payments) I've got my pool heat pump set up, and the EV should hopefully be here in a couple of weeks or so.
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SS. I'm sure that's the right tariff for you with the huge amount of feed-in energy you've been producing.
I'm saying that Agile is a no brainer for people without solar panels, even without battery storage.
Anyone using 10kWh/day who can switch half their usage out of peak times (put the dishwasher and washing machine on at 2pm or the middle of the night, cook tea a bit earlier or later) can easily save £4-500 a year over a standard tariff.
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Yup, you just have to be willing to manage it properly. :)
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Exactly.
For example, today if you were going to use a big oven for 2 hours at standard tariff, it would cost about £2 for the electric.
If you were on Agile and cooked at the time of the very highest tariff today (16:30-18:30) it would cost £1.75.
If you cooked at the time of the very lowest tariff (14:00-16:00) it would cost 50p.
Little bit of planning and flexibility and there's decent amounts of money to be saved. It's scandalous that the big energy companies are charging top whack 24/7. But they will while ever people accept it.
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Solar benefit split between usage, export payment and night-rate differential ended up being a touch over £250 for May.
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Solar benefit split between usage, export payment and night-rate differential ended up being a touch over £250 for May.
That's good going. Ours, being a smaller system, can't match that. But we have saved £136 in May and I'm dead chuffed with that. With the amount of electricity we've used, we'd have paid £125 at standard tariff. Instead, we have paid £15 (we've imported only 25% of what we've used and on average, because that's mostly been imported at night to top up the batteries, we've paid less than 50% of the standard tariff for that) and received £26 back for what we've exported to the grid. So instead of paying out £125, we've received net £11.
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Remind me - is yours roughly 5kw and south facing?
Would be interested in a straight comparison of generation. Ours was 844kWh for the month.
Everything I've seen online suggests, for my roof pitch, a reduction of about 15% as a result of it being east/west.
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Solar benefit split between usage, export payment and night-rate differential ended up being a touch over £250 for May.
That's good going. Ours, being a smaller system, can't match that. But we have saved £136 in May and I'm dead chuffed with that. With the amount of electricity we've used, we'd have paid £125 at standard tariff. Instead, we have paid £15 (we've imported only 25% of what we've used and on average, because that's mostly been imported at night to top up the batteries, we've paid less than 50% of the standard tariff for that) and received £26 back for what we've exported to the grid. So instead of paying out £125, we've received net £11.
it's not that long since we had these ambulance chasers. Yes it's a different world now
https://mis-sold-solarpanels.co.uk/?gclid=EAIaIQobChMIgoj11qSk_wIVEvDtCh0BdQ2_EAAYASAAEgIAafD_BwE
sadly we have to "get real here" that £10,000 invested at 4,5% yields say £450 per year that's £37.50 per month "rising steadily " as interest rates go up
I won't waste my time mentioning other depreciating variables .
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Yeah, I didn't go ahead with a quote for solar on my previous house quite a few years ago because the vibe I got was just "this isn't realistic" - his numbers didn't make sense at the time, and I would have had to finance it at a stupidly high rate, and I'm glad I didn't.
Feeling much more confident about this system though. Yes it was 13k, but my savings for the first 8.5 months are about 1k, and that covers a full winter, not a summer.
It helps that I have significantly high usage in the summer vs winter months to take advantage of the generation though.
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A few thoughts from me:
1) Putin's War has changed the financial case for domestic solar beyond recognition. When electricity was 10p/unit there was no way the financial case could add up. With electricity at 30p/unit, it's a no brainer. Personally, I think the days of 10p/unit are gone forever. Europe is never going back to living off Putin's cheap gas, so there will be far more demand for other power sources.
2) Including a decent sized battery in a solar power system also radically changes the financial case. There's a £3-5k increased initial investment, but it gives such flexibility on usage vs production times that it pays back very handsomely.
electric tariffs. Batteries allow you to buy at the cheapest times and sell at the most expensive. In simple terms, they give you power in the marketplace that you don't have without your own storage system.
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To add to that, those thinking that they will next get an EV.
How much are you spending on fuel at present, and how much of that can be displaced by charging up from your own solar?
The answer will be different for everyone, but don't forget to include that in your calculation.
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Albie.
I'm not at all convinced that EV really changes the financial argument. For the following reasons:
1) Most domestic solar systems simply don't produce enough energy. It's been sunny most of today. We are close to the solstice. I've got a standard 4kWp solar system and it'll produce about 22kWh today. Of that, I'll need 11-12 for my own domestic use. So there's about 10kWh left. A Nissan Leaf as a random example does about 35 miles on 10kWh. So even in close to ideal conditions, I'd only just be able to get a typical daily car mileage from my system (based on a typical average of 10,000miles/year).
2) And that's assuming my car was plugged into my solar system while the sun was shining, and I didn't have it at work. If the car wasn't at home, the only way I could charge it from my own solar generation would be to store the solar production in a 10kWh battery - but I already rely on my battery to power the house after the sun has gone, so I'd have to buy a new one on top and that would cost me an extra £3-5k investment.
Where EV does make sense is if you can use an ultra-low import tariff overnight, like Octopus Intelligent, where you can get electricity at 7.5p/kWh for 6 hours a night. If you also have a decent size battery, you can charge that up overnight at the same rate and run the house off that during the day. That's a stone cold no-brainer for anyone with an EV. Unfortunately, I can't get that as I don't have off street parking and therefore can't get the EV charge point that is a pre-requisite for that rate.
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All depends on individual circumstances, not withstanding your point that my system is larger than average.
For someone like me, with a larger than average system and working from home, the EV will definitely be charged from the surplus solar.
Part of the problem is that taking it as a simple calculation of daily generation minus daily home requirement = surplus doesn't really work in practice because of the limited window in which the power is generated. If I don't use it in the middle of the day then it's exported and isn't available for me at night, so charging an EV at lunch time doesn't take away from power the house would use later, it kust takes away from the amount I'd export.
I reckon when my EV arrives I'll be dropping my 1400 per year fuel cost down by about 80 a month at least. However, it isn't really saving me anything in the grand scheme as the new car is more expensive than my current one.
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SS.
Seems to me you are far better off just using/exporting your solar generated electricity, then charging the EV at low tariff times at night?
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Just done some fag packet calcs based on those Nissan Leaf numbers.
The reported figures for the Leaf are that it does about 3.6 miles/kWh. If you charge up at 7.5p/kWh, that means you'd get 48 miles per pound.
At current petrol prices, you'd need an IC car that did 300 mpg to match that.
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SS.
Seems to me you are far better off just using/exporting your solar generated electricity, then charging the EV at low tariff times at night?
Ah, but the missing piece of the puzzle there is that I currently get 22p per kWh as an export rate but only because I'm on the Flux tarriff - which is dual income/outgoing tarriff. My night rate is about 19p to import.
So, if I was to move onto Intelligent Octopus to get the 7.5p night rate, I'd have to sacrifice the export rate down to 15p. So I'd be gaining 11.5p per unit for each unit imported over night, but losing 7p for each unit exported at all times. The amount I'm likely to be charging the car is very small compared to the amount I'll be exporting in summer (estimate 50kWh charging for May vs 350kWh export). In winter I'll be switching onto a more cheap-import focussed tariff. While the market is as it is I'm expecting to be swapping tarriffs every 6 months - export based with daytime charging in summer, import based with night time charging in winter.
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Solar car park canopies on the way:
https://www.bbc.com/news/business-65626371
Many opportunities to include solar on existing infrastructure, as well as buildings.
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BST,
You have bit of a tendency to extrapolate from your own situation, but that is not representative of all users.
You are not taking into account those who have solar, but do not have battery storage.
This might for some be because of the additional cost, and I think that they are the majority of solar owners in the UK today.
In this situation, storing electricity at lower night time rates is not an option.
If you have an EV, and bi-directional charging, the EV becomes the storage medium by default. It is called vehicle to grid (V2G).
You can then choose to use that energy for either transport or domestic consumption.
The point being that you have the flexibility to decide how best to use the resource. Behaviour then changes to match the incentives.
Given that most cars are parked for 90% of the time, that waiting time is a charging opportunity looking for an opening.
Again, the optimum solution will differ person to person...there is no right answer!
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Solar car park canopies on the way:
https://www.bbc.com/news/business-65626371
Many opportunities to include solar on existing infrastructure, as well as buildings.
Stuff like this seems like a no-brainer.
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Solar panels - an eco-disaster waiting to happen? https://www.bbc.co.uk/news/science-environment-65602519
Trust the Beeb to temper your fun.
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The idea that a recycling industry will not emerge is just bonkers.
Once the volume of end of life panels becomes a significant number, then recycling the aluminium and other elements will be a valuable activity.
The panels should last 20 years plus, so the replacement date is not imminent yet for most installations.
All recycling operations need an input quantity to give a baseline to the business.
Article in the Times on the uptick in solar installs:
https://www.thetimes.co.uk/article/d7e405e6-fc70-11ed-aa31-73394e195d29?shareToken=9f47caea3f077a793c475a722752538e
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BST,
You have bit of a tendency to extrapolate from your own situation, but that is not representative of all users.
You are not taking into account those who have solar, but do not have battery storage.
This might for some be because of the additional cost, and I think that they are the majority of solar owners in the UK today.
In this situation, storing electricity at lower night time rates is not an option.
If you have an EV, and bi-directional charging, the EV becomes the storage medium by default. It is called vehicle to grid (V2G).
You can then choose to use that energy for either transport or domestic consumption.
The point being that you have the flexibility to decide how best to use the resource. Behaviour then changes to match the incentives.
Given that most cars are parked for 90% of the time, that waiting time is a charging opportunity looking for an opening.
Again, the optimum solution will differ person to person...there is no right answer!
Albie.
I'm not extrapolating from my own situation at all. I'm looking at typical averages.
The average domestic solar installation is 4kWp. The average domestic electricity usage is around 10kWh/day. The average mileage is about 10,000 per year.
Do the maths. You said "How much are you spending on fuel at present, and how much of that can be displaced by charging up from your own solar?". I'm saying "Not very much if you think.of that as additional to your domestic requirements" (SS is a bit of an outlier that this doesn't apply to and of course there will be some like that - big system: work from home - but I'm looking at the average.)
I do get the idea that the car can be the storage and yes that does increase flexibility and may obviate the need for domestic batteries if you don't need all the car range every day.
My basic point though is that (for most people) to make the economics work for EV, the cheap overnight tariff is doing far more of the heavy lifting than the solar production. Which I think you agree with.
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BST,
You reckon " I'm saying "Not very much if you think of that as additional to your domestic requirements"...my point is that is the wrong comparison to make.
It is possible that the benefit from using solar energy to fuel a vehicle gives a greater benefit than only using it AFTER domestic needs are met. This will depend upon the future electricity tariffs, and displaced petrol/diesel prices.
This is particularly relevant when solar owners do not have battery storage.
These consumers can only use daytime gain by using the grid as a reserve, with a different rate applied to solar input and later evening usage.
The question is how to use the energy gain to best effect, by displacing the highest cost usage.
Looking forward across the expected lifetime of the panels, it is impossible to call this on the basis of current averages...this tells you very little useful information.
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So what do we think the current saving per year is Vs cost to install? I still struggle with the payback period if I'm honest.
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So what do we think the current saving per year is Vs cost to install? I still struggle with the payback period if I'm honest.
Depends on how the price of grid electricity goes of course.
At the moment, with current tariffs and some pretty active use of when to charge and discharge batteries, I reckon I've got about a 9-10 year payback period.
My advice to anyone thinking about this is to get the very largest set of panels possible. With hindsight, I wish I'd realised this when I had the panels fitted. With a bit more thinking about the layout, I could have got 13 rather than 10 panels on my roof. I was quoted £200 Inc VAT for each additional 400W panel at installation. From the figures I've got so far, I reckon each panel will produce at least 300Wh per year. At 15p feed in tariff, that's less than 5 years payback period for the additional panels. If you use that extra to offset importing from the grid, the payback period is only just over 2 years.
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So what do we think the current saving per year is Vs cost to install? I still struggle with the payback period if I'm honest.
I think I mentioned this in earlier posts, but the most important things to take into account when looking at payback periods in terms of the quotes solar companies provide are the assumptions they make for the variables.
My experience is as follows (in terms of the original quote):
- Assumed energy price inflation = 8%. This last 18 months has completely smashed that, but the decade previous averaged 5% a year, so this felt a bit disingenous and sales-pitchy to me. 5 minutes with a compound interest calculator will show that 5% vs 8% year on year is a HUGE difference, so this is a set of figures where you have to be careful of
- Assumed utilisation = 70%. Piece of cake to smash this in winter (I was getting 95%+ most of the time), but in the brighter months this is really hard to achieve with a bigger system. For May I only untilised about 59.5%. The reason this has such an impact is because the difference between the import and export prices is so big, even with the 15p export you can now get.
- Assumed export rate = 5p ish. Tied to the above point, post FIT (feed in tariff) but Pre Octopus doing Octopus things, export rates were trash. You could be in situation where you were paying 20p+ to import but only getting 5p back for export, so utilisation was a HUGE factor, because each unit you used knock 4 times as much off your bill vs selling it back to the grid. Now that export prices are a bit more favourable, utilisation isn't AS important, but it's still the biggest determining factor for how much money you'll save/make in one year.
That example BST gave is great because it's a nice and easy one that highlights just how much of a difference the current export rates make in terms of the "worst case scenario" of exporting everything extra panels generate and using none of it. Last year the best you could get on an export was half of that 15p...so worst case you were looking at the panels taking 10 years to pay back instead of 5. Massive difference in terms of long-term benefits of the system.
I've saved about £1k over the first 8 months or so of using mine, but most of that time has been over a winter, and I didn't get on an export tariff until November (when generation falls off a cliff). My overall savings for May were approx £250, and June, July and August should be the same or better, with September being roughly equivalent to March. If this happens, I expect my 1 year saving from the system to be approx £2k. That's a payback of 6-7 years even if energy prices stagnate.
Realistically, I think panels are a no-brainer (and the payback time is realistic) if you're at home all day, because that gives you the flexibility to maximise your utilisation. If you're not at home all day, I'm not sure what that picture would look like, but I would say batteries are a must. Ironically, they don't have as much impact as a result of the increased export prices - but if you're out all day then the bulk of your daily usage is going to be in the evening, so you need the storage solution to get your utilisation figure up.
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And to add - batteries are still hugely beneficial in the winter because of the cheap-rate night tariffs we've been talking about, where you all-but-ignore your solar generation and just max-charge the battery every night and use it through the day.
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BST,
You reckon " I'm saying "Not very much if you think of that as additional to your domestic requirements"...my point is that is the wrong comparison to make.
It is possible that the benefit from using solar energy to fuel a vehicle gives a greater benefit than only using it AFTER domestic needs are met. This will depend upon the future electricity tariffs, and displaced petrol/diesel prices.
This is particularly relevant when solar owners do not have battery storage.
These consumers can only use daytime gain by using the grid as a reserve, with a different rate applied to solar input and later evening usage.
The question is how to use the energy gain to best effect, by displacing the highest cost usage.
Looking forward across the expected lifetime of the panels, it is impossible to call this on the basis of current averages...this tells you very little useful information.
Albie.
I'm not sure what your point is on the averages.
The average figures I gave are broadly right as of today. You have to start from somewhere if you're going to make a sensible assessment. It seems to me to be unlikely that those averages will change dramatically in the foreseeable future (except for one issue - see below).
I'm not sure I get your comment about using the solar gain to offset your most expensive alternative. If you have an EV, both your domestic electic appliances and your car require electricity. If you're buying that electricity in, it doesn't matter whether you are buying it to roast a joint or to use in driving.
The point still stands that the majority of cases are going to require at least as much cheap electricity from the grid as the amount they can generate by domestic solar. That doesn't in any way belittle the benefit of domestic solar - it just sets it in a fair context. It's not likely to cover all, or even most of future electric needs.
And when you include heat pump central heating, the importance of cheap tariff imported electricity becomes even more dominant.
I agree that there's a big learning curve for all of us as we learn to adapt on how and when and where to store electricity, when to import it, when to use it and when to export it. It's a totally new world to get used to.
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And to add - batteries are still hugely beneficial in the winter because of the cheap-rate night tariffs we've been talking about, where you all-but-ignore your solar generation and just max-charge the battery every night and use it through the day.
Bang on regarding the winter, but on the Octopus Agile tariff there's even a bonus in brighter months.
For the past several weeks, the import tariff overnight has been around 10-15p per unit tops, often much less. But the export tariff on Octopus Outgoing is 15p per unit 24/7.
So, you can charge up the batteries overnight at, say 10p per unit. Then during the day, run the house off solar during the day and battery once the sun has dipped, and export any excess solar to the grid for more than it cost per unit to charge the battery.
I honestly don't see how Octopus can make that business model work long term. Be interesting to see.
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Billy,
"It seems to me to be unlikely that those averages will change dramatically in the foreseeable future."
With regard to averages, high electricity prices are likely, particularly if the UK chooses to bankroll very expensive nuclear, paid for up front by a consumer levy.
This is the position of both Tory/Lab parties at present, and is ignorant nonsense from both.
Current average prices will very likely reduce in the price of installed solar, and the capacity/cost of batteries (both EV and standalone).
Both of these are falling down a technology experience curve, year on year. The average costs in these sectors are reducing, as a capital outlay and as distance travelled per unit of charge.
So the economics of self generation improves going forwards, in relation to buying from the private sector providers.
"I'm not sure I get your comment about using the solar gain to offset your most expensive alternative. If you have an EV, both your domestic electic appliances and your car require electricity. If you're buying that electricity in, it doesn't matter whether you are buying it to roast a joint or to use in driving."
It does matter what you are using it for, because that will determine the time constraint on the electricity used.
You might not want to cook a roast at 3am, but if you do not have battery storage then you cannot use the cheaper tariff.
The point here is those currently driving an ICE vehicle choosing an EV when it comes to replacement. I think this will be normal later this decade.
The price of petrol v the cost of electricity is another unknown, but climate policy suggests the leccy must become the cheaper.
At that point, the available solar resource can be allocated to the most pressing need. That may be in the home, or it may be for transport.
The private sector providers will only offer decent rates where it suits their business interests, failing regulation by government.
By all means use the cheapest method of meeting energy requirements, and time shifting demand is key to that.
An EV is just a bigger battery, which also works as a car!
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Albie.
I never mentioned electricity prices, or relied on them in my reasoning. Did you read my first post in this exchange?
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The only thing you have to be careful of in the import cheap - export expensive game is accounting for round trip losses through the system. I believe this is why, on the flux tariff for example, there is an offset of a couple of pence between the night import and day export rate (19.4 vs 21.3) - the idea is you can't game the system, but if you choose to fill your battery overnight you won't be worse off either. It takes the management pressure off without screwing the customer.
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Albie.
I never mentioned electricity prices, or relied on them in my reasoning. Did you read my first post in this exchange?
Don't be silly, electricity prices are central to the whole debate.
Without an estimation of future grid supply costs, no assessment can be made for payback time or how to best use the leccy produced by your solar.
Interesting article on agrivoltaics on Reuters;
https://www.reuters.com/business/sustainable-business/with-agrivoltaics-we-dont-have-choose-between-solar-power-producing-food-2023-03-20/
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Albie.
I never mentioned electricity prices, or relied on them in my reasoning. Did you read my first post in this exchange?
Don't be silly, electricity prices are central to the whole debate.
Without an estimation of future grid supply costs, no assessment can be made for payback time or how to best use the leccy produced by your solar.
Interesting article on agrivoltaics on Reuters;
https://www.reuters.com/business/sustainable-business/with-agrivoltaics-we-dont-have-choose-between-solar-power-producing-food-2023-03-20/
So you didn't read my post. Thanks for clearing that up.
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The batteries made a huge difference to the Energise Barnsley project I did. We fitted OAP bungalows with solar pv, and despite the tenants mainly being in all day, utilisation was only around 45% of generation, and that was with an education piece on how to get the most out of the free power. Adding just a 3kW battery took utilisation to over 75%, plus set up as a virtual power plant gave DSR and arbitrage opportunities.
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BST,
Of course I read your post.
You argued the point I am making in reply 79, then reverse your position to say that electricity prices do not effect the outcome!
So what do we think the current saving per year is Vs cost to install? I still struggle with the payback period if I'm honest.
Depends on how the price of grid electricity goes of course.
At the moment, with current tariffs and some pretty active use of when to charge and discharge batteries, I reckon I've got about a 9-10 year payback period.
My advice to anyone thinking about this is to get the very largest set of panels possible. With hindsight, I wish I'd realised this when I had the panels fitted. With a bit more thinking about the layout, I could have got 13 rather than 10 panels on my roof. I was quoted £200 Inc VAT for each additional 400W panel at installation. From the figures I've got so far, I reckon each panel will produce at least 300Wh per year. At 15p feed in tariff, that's less than 5 years payback period for the additional panels. If you use that extra to offset importing from the grid, the payback period is only just over 2 years.
The argument you later make about averages is beside the point, because the situation is evolving very quickly.
We can hold different opinions without difficulty in my book.
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The batteries made a huge difference to the Energise Barnsley project I did. We fitted OAP bungalows with solar pv, and despite the tenants mainly being in all day, utilisation was only around 45% of generation, and that was with an education piece on how to get the most out of the free power. Adding just a 3kW battery took utilisation to over 75%, plus set up as a virtual power plant gave DSR and arbitrage opportunities.
That's an awesome real world example. :)
For my part, my EV has now arrived on Tuesday (yay!) so my utilisation has gone through the roof. For this week I'm at 88.5% - 135.5 generated, 15.6 exported.
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The batteries made a huge difference to the Energise Barnsley project I did. We fitted OAP bungalows with solar pv, and despite the tenants mainly being in all day, utilisation was only around 45% of generation, and that was with an education piece on how to get the most out of the free power. Adding just a 3kW battery took utilisation to over 75%, plus set up as a virtual power plant gave DSR and arbitrage opportunities.
That's an awesome real world example. :)
For my part, my EV has now arrived on Tuesday (yay!) so my utilisation has gone through the roof. For this week I'm at 88.5% - 135.5 generated, 15.6 exported.
In a couple of weeks I'll be integrating an EV charger with the Solar to automate some of the manual monitoring I'm having to do at the minute to get the best out of it all.
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BST,
Of course I read your post.
You argued the point I am making in reply 79, then reverse your position to say that electricity prices do not effect the outcome!
So what do we think the current saving per year is Vs cost to install? I still struggle with the payback period if I'm honest.
Depends on how the price of grid electricity goes of course.
At the moment, with current tariffs and some pretty active use of when to charge and discharge batteries, I reckon I've got about a 9-10 year payback period.
My advice to anyone thinking about this is to get the very largest set of panels possible. With hindsight, I wish I'd realised this when I had the panels fitted. With a bit more thinking about the layout, I could have got 13 rather than 10 panels on my roof. I was quoted £200 Inc VAT for each additional 400W panel at installation. From the figures I've got so far, I reckon each panel will produce at least 300Wh per year. At 15p feed in tariff, that's less than 5 years payback period for the additional panels. If you use that extra to offset importing from the grid, the payback period is only just over 2 years.
The argument you later make about averages is beside the point, because the situation is evolving very quickly.
We can hold different opinions without difficulty in my book.
Albie
Look at my post 76. The "averages" I was talking about are domestic PV production and domestic and EV usages.
That's the post that you haven't taken on board.
The simple fact is that, on average, domestic PV can only produce enough power to service both average domestic consumption and average EV need on the very best days of the year.
I'll repeat. For most people, on average, getting imported electric from the grid is vital if you want to have an EV. There's no getting round that by talking about electricity prices or times of production or times of usage. It's just a basic fact.
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Just finished my first full month of getting feed in tariff.
With the amount of electricity we've used, the usual bill if everything was coming from the grid at standard rates would have been £132, including the standing charge. Actual bill has been minus £5.70.
OK, so June is probably the best month of the year for solar, but I'm well pleased with that.
And tomorrow afternoon, the Octopus Agile rate is as low as minus 18p/kWh. So instead of you paying 30p/kWh, they are paying you 18p to take the electricity off them.
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Not trying the “oneupmanship” line but my electric bill including standing charges for the last month was £12.38 and I exported £72.56 back to the grid.
My account is with Octopus.
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I don't tend to look at my actual bill at the minute as I know I'm exporting more than I'm using, so I'm just making a direct debit of £1 a month into my Octopus account to keep the dd going. I just tend to look at my generation and utilisation numbers to get an overall monthly benefit amount.
So for me June looks like this:
Generated and used: 710.6 kWh = £229.95
Export: £52.33
Cheap-rate charging offset: £11.42
For a total benefit in June of £293.70
That means I'm at approx £1150 saving since November, so I'm on for a year 1 saving of approx £1800. If that lands I'll definitely be happy but should likely also beat it next year by being on an EV specific tarriff over the winter months.
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I don't tend to look at my actual bill at the minute as I know I'm exporting more than I'm using, so I'm just making a direct debit of £1 a month into my Octopus account to keep the dd going. I just tend to look at my generation and utilisation numbers to get an overall monthly benefit amount.
So for me June looks like this:
Generated and used: 710.6 kWh = £229.95
Export: £52.33
Cheap-rate charging offset: £11.42
For a total benefit in June of £293.70
That means I'm at approx £1150 saving since November, so I'm on for a year 1 saving of approx £1800. If that lands I'll definitely be happy but should likely also beat it next year by being on an EV specific tarriff over the winter months.
I only had my solar and ASHP fitted last November so haven’t yet had a full year to do a meaningful comparison to previous years.
Also, my two year fixed deal ends this month so that will make it further difficult.
However, the new Octopus tariff isn’t as high as I thought it was going to be so I am confident that the solar over twelve months will still be advantageous to me.
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Yeah mine was fitted in September but I wasn't on an export tarrif until November so I missed out on about 6 weeks...so I'm taking November to November as the first year. It feels more accurate that way. Another reason I don't focus on the bills is because comparing with previous years doesn't mean anything in my circumstance because my usage has changed hugely for a variety of reasons.
In terms of payback period you're better off if energy is more expensive - if by some miracle energy prices dropped to pre-Covid levels it would take a lot longer for your system to pay itself off.
An easy comparison based on last months figures is that £229.95 saving last month would be £207.94 for this month as a result of the unit price drop a couple of days ago.
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What happens when your panels get covered in bird shit, I’ve got Wood Pigeons all over and any panels i would have will be covered in shit in no time
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Hope the rain cleans it off for you :D
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Yeah mine was fitted in September but I wasn't on an export tarrif until November so I missed out on about 6 weeks...so I'm taking November to November as the first year. It feels more accurate that way. Another reason I don't focus on the bills is because comparing with previous years doesn't mean anything in my circumstance because my usage has changed hugely for a variety of reasons.
In terms of payback period you're better off if energy is more expensive - if by some miracle energy prices dropped to pre-Covid levels it would take a lot longer for your system to pay itself off.
An easy comparison based on last months figures is that £229.95 saving last month would be £207.94 for this month as a result of the unit price drop a couple of days ago.
It took me about three months to get my export sorted but the first monthly payment was only £1.35 so I’m guessing that the winter months won’t be very good in that respect.
The summer months though look like being quite lucrative.
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Absolutely, here are my export figures since November:
Nov: £2.46
Dec: £20.28
Jan: £2
Feb: £4.80
Mar: £11.21
Apr: £64.09
May: £88.48
Jun: £52.33
December was an anomaly because it was quite a bright month and I filled the battery overnight a lot so ended up exporting significantly more than I otherwise would have.
June generated more but was a drop off in export due to me massively increasing my utilisation. My utilisation in May was 58% (493 kWh out of 843 generated), Jun was 80% (710 kWh out of 887 generated). I'm hoping to get that up towards 90% for July.
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Those are some impressive numbers SS. They really demonstrate the benefit of going for a large system if you can.
The cost of an additional 400W panel in a system is about £200. I reckon each panel in my system will produce about 350kWh per year. At the 15p/kWh feed in rate I've got with Octopus, that means a payback period of about 4 years. Your 22p feed in tariff will cut that to less than 3 years. (Of course, those are the marginal figures for additional capacity, assuming the fixed costs are the same regardless of the system size.)
With our 10 panel system and relatively high usage, we got £35 feed in payment in June. That's much better than I expected. And taking advantage of low import costs to charge batteries meant that our payment for import was less than £20.
This weekend just gone was interesting. There was a huge plunge in import costs, down to as low as minus 18p/kWh. So we were able to get paid to charge up the batteries and consume, while also getting paid for discharging the batteries and exporting the solar production. I've not done the detailed numbers, but I reckon we will have been paid net about £8-10 just for Saturday and Sunday. As I say, it's not going to make anyone into a Great Gatsby, but it's a no brainer if you can do it. As well as doing a little bit to help the bigger climate challenge.
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Octopussy;
https://www.current-news.co.uk/octopus-smart-tariff-hits-record-price-plunge-as-electricity-prices-turn-negative/
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Something I thought may be interesting to those of you still following the thread.
I fitted an EV charger last week which has a solar integration where it can detect the surplus being generated by the panels and divert it to charge the car instead of exporting it back to the grid. Today has been the first day where it's been sunny enough to really put it to the test and the graph below shows the result. I thought it was pretty cool so wanted to share.
The 2 highlighted areas represent the EV charger automatically scaling the demand based on the surplus being generated - up before the midday peak and back down again at the other side.
Using a hybrid inverter (also a known as 'DC coupled' in terms of the battery) means that you can't directly distinguish between surplus coming from the panels vs the battery, so you have to set an export offset up...basically the EV charger targets exporting a small amount whilst the solar inverter/battery targets zero import/export, so when it detects that the export drops below the offset, the charger stops as it knows this is a result of solar generation drop off (all demand being supplied by the battery at that point. That's why the consumption line is always a little bit below the generation line.
(https://iili.io/Hsftj0N.png)
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New tariff from Octopus which might be suitable for some with solar and batteries;
https://www.solarpowerportal.co.uk/news/octopus_launches_new_solar_and_battery_optimisation_smart_tariff
Lots of innovation around tariffs going off!
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Just reviewed my system numbers now that I've had it for 7 months.
We are heavy users of electricity. The amount we have consumed in 7 months would have cost about £850, paying at standard tariff rates.
We've actually spent net £24.
It'll be interesting to see how this goes over the winter. Obviously there will be precious little solar production - my system is producing less than a quarter of our daily usage so far in October. But the increasing wind is leading to some very low Octopus Agile buy-in rates
For example, last night, between 3-5am, the buy in price was 0.0p per unit. At the moment it is 2.3p. That compares with standard tariffs of about 30p. So we can effectively charge up the battery system for free and live off that.
Be interesting to see what the pay back time will be based on the first full year of use. I'm expecting about 8-10 years.
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This is a useful website by the way. Real time data from National Grid on the amount of electricity being generated by coal, gas, wind, solar etc, plus the current market rate for electricity and the amount of CO2 generated per unit.
https://grid.iamkate.com/
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This is a useful website by the way. Real time data from National Grid on the amount of electricity being generated by coal, gas, wind, solar etc, plus the current market rate for electricity and the amount of CO2 generated per unit.
https://grid.iamkate.com/
Are you running an ev Billy? Be interested in your take on certain tarrifs I’m looking at
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Ldr.
No. I don't have off street parking so I can't get a charger that would make me eligible for the low overnight Octopus tariffs. I'd do it like a shot if I could. It's a no-brainer.
How much electricity do you typically use?
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I was going to wait a little while to give my next update on here but seeing as BST has revived it early I'll jump in.
Our system has been up for a little over a year now, although we didn't get onto the export tariff until early November last year, so bear that in mind.
The savings from our system since installing it in mid September 2022 are a little under £1900, made up of £1310 of utilised generation, 340 quid in exports, and 240 quid in savings by charging the battery at a cheaper rate and using the leccy through the day.
Now that I've got an EV I've moved off the Flux tariff I was on previously and moved onto Octopus Go, to take advantage of the cheaper rate over night as I'm exporting very little.
Accounting for the lack of export tariff for the first 6 weeks of the system being up I reckon that puts our annual savings at around 2k. 6-7 years payback should be do-able at those kind of numbers, which would be awesome. Of course it's harder to calculate accurately now because of the EV - using more leccy but spending nothing on petrol - I'm choosing to believe that I'd have gotten the EV anyway (even if I didn't have the solar) so that I don't have to account for that in the numbers.
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Ldr.
No. I don't have off street parking so I can't get a charger that would make me eligible for the low overnight Octopus tariffs. I'd do it like a shot if I could. It's a no-brainer.
How much electricity do you typically use?
Currently around 6700 kWh per year with a phev
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Ldr.
No. I don't have off street parking so I can't get a charger that would make me eligible for the low overnight Octopus tariffs. I'd do it like a shot if I could. It's a no-brainer.
How much electricity do you typically use?
Currently around 6700 kWh per year with a phev
I'm guessing most of your electric goes on the car? If it does, you'd be mad not to get the Intelligent Octopus tariff. 7.5p per unit overnight.
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Probably best to add this update here, as the thread contains more information.
New solar roadmap published today;
https://www.gov.uk/government/news/homeowners-could-save-hundreds-on-energy-bills-from-solar-drive
The big takeaway is that balcony solar panels are likely to be approved.
Very popular in Germany, you just hook them over the balcony, connect to the inverter, then plug in to the nearest socket.
Very easy DIY, and no scaffolding costs involved.
Guardian business coverage here;
https://www.theguardian.com/business/2025/jun/30/britons-could-soon-install-balcony-solar-panels-in-flats-and-rental-homes