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Energy prices - gone nuts.

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There's even a campaign for it. Will certainly be 'interesting' if it takes hold. Would probably send even more energy companies under : https://dontpay.uk/
Well our leaders f‘d up by not building nuclear power stations years ago and now we are paying the price.
Bad situation for a lot of people, bad enough now but what’s coming is seriously bad.
Power to the people!!!!!!!!
 
There's even a campaign for it. Will certainly be 'interesting' if it takes hold. Would probably send even more energy companies under : https://dontpay.uk/

This just seems badly thought out to me, if people just cancel their direct debits they are still going to get charged to their account for their uages and then when they get sent a bill (Without the discount most companies give or used to give for paying by direct debit) if they dont pay they will just keep sending further bills until it ends up being sent to debt collectors.

I also dont really see much of a way that the government can reduce peoples bills above what they are doing already, anything the government would do would come from tax payers money so we would just end up paying for it one way or another anyway.
 
If there is mass disobedience they can't sent debt collectors to everyone. And if the monies are being withheld not deliberately refusing to pay its a different kettle of fish.
 
So, decided to have a go at trying to work out as accurately as I can, the payback time on a solar system.

First I looked at current usage so I plugged my current usage into a spreadsheet

it’s not a good read.

i’m on a fixed tariff that ends 7th oct, so going to get a double hike when the price cap rises in Oct again.

Based on current predictions my bill is going to rise from £410 a month to £1,263 a month. Absolute Madness. I was moaning when it went from £250 to £410 last October.

Heavy gas user as the house c/h, hot water and pin room ufh all gas and it’s a big house.

Split is £8,500 gas and £6,700 electric. Electric usage is 13,000 kwh per year.

So next onto cost up a system and then work out saving.

System cost I guess at £15-20k. let’s say £20k to get as much roof coverage and battery capacity as possible.?

I’m in all day most days. 6 fridges and freezers on all time. hot tub in summer months. quite a few computers on all time, lights on a lot in the kitchen as it’s a dark room and spend a lot of time in there, washing machine seems to be on all the time. tumble dryer in winter but washing line in summer.

if i’m using 13,000 kwh a year then that’s like 35.62 a day or 1.5 an hour on average. so i guess peak will be 2-3X that = 4.5kw

What i can’t really figure is how much i’ll generate and use?

I know that if system costs £20,000 and i was generating everything i need and not using any from the grid, the breakeven would be about 5.5 years on current price cap and 3.5 years on the predicted oct price cap, but of course it won’t work like that. i’ve figured it won’t even cover 50%, but if it was 50% then b/e is 11 / 7 years, but if it only saved 25% it would be 22 /14 years.

So i need to really home in on how much you can actually save?
1k a month on energy is crazy money! Certainly need a biggest system to cover 35kw a day usage. Our background load is like 200w with big spikes for washer/dryer/dish washer/hob/oven etc..
 
This just seems badly thought out to me, if people just cancel their direct debits they are still going to get charged to their account for their uages and then when they get sent a bill (Without the discount most companies give or used to give for paying by direct debit) if they dont pay they will just keep sending further bills until it ends up being sent to debt collectors.

I also dont really see much of a way that the government can reduce peoples bills above what they are doing already, anything the government would do would come from tax payers money so we would just end up paying for it one way or another anyway.

Not quite sure what this campaign will even do, the company who gives you your power just buy it from another company, if you don't pay your energy supplier (who have already paid the big boy supplier in advance for it) they just go broke not the big boy supplier. We already lost a **** ton of them who was keeping prices low due to competition. Do we want to lose more? Think we need to look at the root cause of the problem not just cripple the energy company resellers.
 
1k a month on energy is crazy money! Certainly need a biggest system to cover 35kw a day usage. Our background load is like 200w with big spikes for washer/dryer/dish washer/hob/oven etc..
just got a few quotes from suppliers. they’ve all factored in a big price rise in october already. best quote i got was £1644 a month. 😂😂😂😂😂

so i’m gonna hook the mrs and the kids and the cats up to bikes with alternators charging up a rack of batteries.
 
1k a month on energy is crazy money! Certainly need a biggest system to cover 35kw a day usage. Our background load is like 200w with big spikes for washer/dryer/dish washer/hob/oven etc..
Our background load at night is 900w !!
 
No idea

Fridges, nas drives, ups, access points.....
 
I sorta wanna see that graph when you got the washing / dryer going and cooking roast dinner :D
 
How do I calc how much a system will generate for me in my UK location?

I found this
but it doesnt tell me how it's worked out it's calculations - I want to understand the formulae.
 
How do I calc how much a system will generate for me in my UK location?

I found this
but it doesnt tell me how it's worked out it's calculations - I want to understand the formulae.
I just gave this site a try and the results are way off what my system produces / pays out. Not sure it’s a good indication of how well your system could do.
 
Ive been wondering if these would be a good idea with the imminent rise in electricty cost. I seem to average around 700kwh a month. not sure what that means but I figured id be wanting to have a battery system to "cache" the electricty.
Alas we need new felt on our roof - the stuff under the lats and tiles so would need do that first which would effectively increase the cost of the install :(
No idea what size system is needed to generate enough to cover the usage though. All the info seems to be a bit vague/all over the place.
 
this seems a better site to help calculate
and it has a load of info in the help menus.
it’s saying i should generate 5.35Mwh per year from a 6kw system.

I spoke to a supplier who suggested take 80% of that figure as a more realistic value, so that suggests 4,280 kwh. So, at 28p (current price cap) = £1,198 saving per year.
 
Ok snapshot today at 15:52 it’s been mixed weather sometimes cloudy sometimes sunny but nowt special.
Since battery’s have been fitted 2 days ago I’ve been totally off grid and throwing a ton of harvested power straight into the grid which is painful to watch.
Although only half of my batteries are fitted due to cockup so I’m running on 5.6k battery it’s still around 35-40% full at midnight (bedtime)
Once they fit the remaining battery’s I will be definitely covered and when winter hours kick in I’ll be force charging them at octopus 7.5p a KWh
Im loving them and have no negatives apart from fitting cost and the one thing I was worried about was how the house looks but it actually looks cool due to the pure black panels the company uses.
Early days but well happy and now all I need to do is stop looking at all the graphs the mesmerising 😂
Almost generated 17KWh today with best 24kw when it was crazy hot last week. B067EA5B-6E13-4EBF-A045-759D4A9A2E7E.jpegF7FDE3E2-D911-4927-835E-689910BEC9AE.jpeg
 
@AlanJ , I would have thought a 6kW array, facing pure south, should do 5000kWh to 5200kWh in a year based on experience. This depends on a fair few thing but if south facing and no shade, that should be achievable.

Price cap unit price is currently 0.29, so £1450 for 5000 if you can use it all. A battery will maximises your use but add to the spend. £14,500 saving over 10 years.

Based on estimates, I believe they are predicting 0.50 from October. So £2500 for 5000.
£25,000 if those prices stay for 10 years. Maybe the average will be less. The system will likely still be making money after it has paid itself off. We can look to the folks who have 10 year old systems still making money, there is a lot of them.

Seeing all the graphs changes behaviours. Reduces your excess use where you are motivated to chase the zombie energy use now you can see it on a graph. So you win by using less too.
 
Ok snapshot today at 15:52 it’s been mixed weather sometimes cloudy sometimes sunny but nowt special.
Since battery’s have been fitted 2 days ago I’ve been totally off grid and throwing a ton of harvested power straight into the grid which is painful to watch.
Although only half of my batteries are fitted due to cockup so I’m running on 5.6k battery it’s still around 35-40% full at midnight (bedtime)
Once they fit the remaining battery’s I will be definitely covered and when winter hours kick in I’ll be force charging them at octopus 7.5p a KWh
Im loving them and have no negatives apart from fitting cost and the one thing I was worried about was how the house looks but it actually looks cool due to the pure black panels the company uses.
Early days but well happy and now all I need to do is stop looking at all the graphs the mesmerising 😂
Almost generated 17KWh today with best 24kw when it was crazy hot last week. View attachment 177184View attachment 177185
They look fantastic! Nice house as well!!! I have similar look on mine with the red brick and blue tiles, panels do actually look quite cool deffo not an eye sore like I thought they might be.

Took about 6 weeks for octopus to sort my export tariff. They don’t back date it sadly :(

How does this night time force charge at 7.5p work? Sounds like a great deal and something that would really benefit me as well. Do you need to be on a certain tariff with them?

Also weather is starting to look pretty nice next week so hopefully you can max it out :)
 
@AlanJ , I would have thought a 6kW array, facing pure south, should do 5000kWh to 5200kWh in a year based on experience. This depends on a fair few thing but if south facing and no shade, that should be achievable.

Price cap unit price is currently 0.29, so £1450 for 5000 if you can use it all. A battery will maximises your use but add to the spend. £14,500 saving over 10 years.

Based on estimates, I believe they are predicting 0.50 from October. So £2500 for 5000.
£25,000 if those prices stay for 10 years. Maybe the average will be less. The system will likely still be making money after it has paid itself off. We can look to the folks who have 10 year old systems still making money, there is a lot of them.

Seeing all the graphs changes behaviours. Reduces your excess use where you are motivated to chase the zombie energy use now you can see it on a graph. So you win by using less too.
thanks @Calimori - this is now starting to look a bit more convincing. I did some research about the next price cap rise, and 36p -49p seems to be the expected range. The announcement is 26th Aug, so we will all know soon enough.

Really impressed with the Global Solar website, it has tons of info that has opened up a whole new world to me, you can just plug your postcode in, and then configure up an intended system:
1659580976762.png

1659581027375.png
1659581057550.png
1659581089355.png
1659581133709.png

I spoke to 3 suppliers of systems yesterday (chosen at random), only one would give me a quote over the phone, but I did manage to glean a few bits of useful info from talking to all 3:

1. The price of storage batteries has zoomed up this year due to shortage of stock.
2. The batteries are zero rated for VAT if you buy initially with a system, but if you buy as an add-on, then you will pay 20% VAT
3. Li-ION batteries typically have a 6,000 cycle lifespan, and this equates to over 10 years use, but they say it's probably 10 years and you'd need to change them, or supplement them with brand new
4. The supplier that game me a quote, calculated the system would have a max capacity of 5,330kwh per year, but then they told me they took 80% of that value when calculating the electricity saving? I've assumed it is due to losses in the system? Anyhow, I've built that figure into my model.
5. quote £10,995 for 6kw system 15 X 400w panels, 2X 2.4kwh li-ion batteries. or £9,250 for one battery and £7,500 for zero battery system. So a battery is £1750. Found same battery on-line for ~£1.2k (incl VAT), but seems to be no stock in the UK - all quoting Nov/Dec delivery. The quoting company said this is common ploy and by time they have the batteries in stock their price will have risen again.
6. Reluctant to quote on >6kw, and told me there is a limit to how much you can put back into the grid, over 3.6kw, you need to apply to local DNO (District Network Operator) which costs £500 and takes months. I can understand the latter but not sure why they wont spec a bigger set of panels? is it limits within the invertor?
7. Dual or single MPPT Invertors? Another rabbit hole I've fallen down!

I now have more questions than I started with!

Anyhow - plugged everything I have learnt so far, into a spreadsheet. first on current price cap:
1659584090838.png
break even year 8

then with 36p unit cost:
1659584146322.png
b/e year 7

then with 49p / kwh:
1659584215017.png
b/e year 5
 
Morning Snapshot bright start but overcast with 100% cloud cover.
Woke up this morning with 10% battery left but remember only half my battery’s here ATM so things will be a lot better when I have 11.25 KWh setup.

Bear in mind @AlanJ im further north than you up not so sunny Sunderland!

Almost harvested 3KWh before 9 and battery starting to get topped up slowly so on way up at 11%
C0A07E1B-594A-47C1-A96F-5F29FCA82E7F.png


This shows quite a lot of data but until the job finished I’m not signed off for the feed in tariff however you can see when the wife gets up how the battery supply’s our power.
C73411EB-8A72-4CF6-9B3D-4EB2BF2E58E2.png

To answer @russdx1 as my system not signed off and on the feed in tariff I won’t change over to Octopus GO but project solar force charge my battery remotely during the period 12:30-4:30 and I’ll schedule my car to do the same so pretty much free electric and fuel to my car as it’s only 7.5p per KWh
However bear in mind the daytime rate is approximately 9p per KWh more taking it up to 38.57p at todays price.
This is negated by using both my solar panels and the battery of course which in the last 3 days since the battery was fitted I’ve been almost totally off grid with a couple of blips here and there.
 
Answering your questions
1. The price of storage batteries has zoomed up this year due to shortage of stock.
Yes, I have seen the price rise since the start of 2021. My Tesla PowerWall went up by £500 in 6 months. I don't think the bubble will burst until production increases significantly

3. Li-ION batteries typically have a 6,000 cycle lifespan, and this equates to over 10 years use, but they say it's probably 10 years and you'd need to change them, or supplement them with brand new
The PowerWall has a 10 year guarantee, and I would expect it to still function at 11 years but with degraded storage. I also think battery tech will have moved on significantly allowing for greater storage sizes. In other words, I expect to want to upgrade this in 10 years

4. The supplier that game me a quote, calculated the system would have a max capacity of 5,330kwh per year, but then they told me they took 80% of that value when calculating the electricity saving? I've assumed it is due to losses in the system? Anyhow, I've built that figure into my model.
There are losses, plus variations due to being in the UK with unpredictable weather. We all get caught out when we have had a glorious hot sunny day and then realise it isn't as good for generation because the panels are less efficient when really hot.

5. quote £10,995 for 6kw system 15 X 400w panels, 2X 2.4kwh li-ion batteries. or £9,250 for one battery and £7,500 for zero battery system. So a battery is £1750. Found same battery on-line for ~£1.2k (incl VAT), but seems to be no stock in the UK - all quoting Nov/Dec delivery. The quoting company said this is common ploy and by time they have the batteries in stock their price will have risen again.
£7500 for the solar array is very good based on fitted quotes I have seen.
Calculate how much you will use from when the system is generating less, say 6pm and when it starts at 10:00 the next day. I have used 4.8kW since midnight. You may find you want more storage.


6. Reluctant to quote on >6kw, and told me there is a limit to how much you can put back into the grid, over 3.6kw, you need to apply to local DNO (District Network Operator) which costs £500 and takes months. I can understand the latter but not sure why they wont spec a bigger set of panels? is it limits within the invertor?
They don't want the hassle of an on site visit. Most want to do the simple option where the DNO just sign it off on paper.
It is measured on what the inverter can kick out in AC. The inverter can take a higher amount of DC from the panels but the output will be limited. The reality is that there are fewer occasions where the system would be able to generate the maximum amount. I saw a few times in May where the sun was glorious but not too hot and I hit the limit of my inverter, for less than 10 minutes.
More panels is better but then the returns of investments do not look so good. They should be aiming for the best value set up


7. Dual or single MPPT Invertors? Another rabbit hole I've fallen down!
I have microinverters, each panel has a device that balances it independently, they then feed into one main invertor. This makes each one more efficient and not effected by shade, like a standard string setup. The disadvantage of dual invertors is more cost, if the increased efficiencies appear to pay off, then I would look into it. But how it aggregates back into your house for the approved certification, might be a reason the fitters would prefer not to bother. They want simple setups so they can move on to the next job.
 
thanks @Calimori - this is now starting to look a bit more convincing. I did some research about the next price cap rise, and 36p -49p seems to be the expected range. The announcement is 26th Aug, so we will all know soon enough.

Really impressed with the Global Solar website, it has tons of info that has opened up a whole new world to me, you can just plug your postcode in, and then configure up an intended system:
View attachment 177205

View attachment 177206
View attachment 177207
View attachment 177208
View attachment 177209

I spoke to 3 suppliers of systems yesterday (chosen at random), only one would give me a quote over the phone, but I did manage to glean a few bits of useful info from talking to all 3:

1. The price of storage batteries has zoomed up this year due to shortage of stock.
2. The batteries are zero rated for VAT if you buy initially with a system, but if you buy as an add-on, then you will pay 20% VAT
3. Li-ION batteries typically have a 6,000 cycle lifespan, and this equates to over 10 years use, but they say it's probably 10 years and you'd need to change them, or supplement them with brand new
4. The supplier that game me a quote, calculated the system would have a max capacity of 5,330kwh per year, but then they told me they took 80% of that value when calculating the electricity saving? I've assumed it is due to losses in the system? Anyhow, I've built that figure into my model.
5. quote £10,995 for 6kw system 15 X 400w panels, 2X 2.4kwh li-ion batteries. or £9,250 for one battery and £7,500 for zero battery system. So a battery is £1750. Found same battery on-line for ~£1.2k (incl VAT), but seems to be no stock in the UK - all quoting Nov/Dec delivery. The quoting company said this is common ploy and by time they have the batteries in stock their price will have risen again.
6. Reluctant to quote on >6kw, and told me there is a limit to how much you can put back into the grid, over 3.6kw, you need to apply to local DNO (District Network Operator) which costs £500 and takes months. I can understand the latter but not sure why they wont spec a bigger set of panels? is it limits within the invertor?
7. Dual or single MPPT Invertors? Another rabbit hole I've fallen down!

I now have more questions than I started with!

Anyhow - plugged everything I have learnt so far, into a spreadsheet. first on current price cap:
View attachment 177210
break even year 8

then with 36p unit cost:
View attachment 177211
b/e year 7

then with 49p / kwh:
View attachment 177212
b/e year 5
Great spreadsheet, but to be accurate it should consider the 'opportunity cost' - the amount you miss out on had you not invested. So what the £10,995 would have earned you in compound interest over the, for example, 10 year lifecycle of the hardware. As an aside, that assumes the initial capital to invest is on hand, not borrowed - that would need a different calculation.

Clearly there are many ways to invest, with various degrees of risk, but you can get a zero-risk 3.35% interest rate today for a 5 year investment of cash, even though the current Bank Of England base rate is 1.25%. The BoE interest rates are very likely to go up by 0.5% this week - bank interest rates to consumers will inevitably follow suit. They can continue to go up every month, and pretty much certainly will do in order to control inflation. Some forecasts yesterday estimated inflation will hit the low teens by next year, in which case, interest rates from banks for savings of between 5-10% will become feasible, so this is the kind of level of opportunity cost which should be factored in.
 
Last edited:
Great spreadsheet, but to be accurate it should consider the 'opportunity cost' - the amount you miss out on had you not invested. So what the £10,995 would have earned you in compound interest over the, for example, 10 year lifecycle of the hardware. As an aside, that assumes the initial capital to invest is on hand, not borrowed - that would need a different calculation.

Clearly there are many ways to invest, with various degrees of risk, but you can get a zero-risk 3.35% interest rate today for a 5 year investment of cash, even though the current Bank Of England base rate is 1.25%. The BoE interest rates are very likely to go up by 0.5% this week. They can continue to go up every month, and pretty much certainly will do in order to control inflation. Some forecasts yesterday estimated inflation will hit the low teens by next year - in which case, we can expect that interest rates will have followed suit - interest rates from banks for savings of between 5-10% will become feasible, so this is the kind of level of opportunity cost which should be factored in.
It's where do you stop the model, but I have added that in easy enough (Simple interest, just to get a feel) :
1659607098651.png

I take your point on rising return rates. Lets see what to BoE say in an hour!
 
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It's where do you stop the model, but I have added that in easy enough (Simple interest, just to get a feel) :
View attachment 177253

I take your point on rising return rates. Lets see what to BoE say in an hour!
I think your spreadsheet is really good, but agree knowing when to stop is hard - it's so much guesswork that in reality, by changing a couple of assumptions, you could make it either show that it's a no-brainer to invest, or the exact opposite. I find it very hard to know what is remotely realistic in terms of assumptions tbh.

Here's an example of opportunity cost over 10 years with fairly pessimistic (some economists would say realistic) future interest rates, taking into account compounding of interest. Column C is what would need subtracting from the values in your 'Saving' column to give a fair reflection of what was really saved per annum (assuming you agreed with my interest rate guesses).

Opportunity Cost Example.png
 
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