Soldato
- Joined
- 7 Sep 2020
- Posts
- 3,752
- Location
- Gods Country
3 today……was cloudy and snowing
Solar panel production figures
- Thread starter Ron-ski
- Start date
Soldato
- Joined
- 4 Aug 2007
- Posts
- 22,041
- Location
- Wilds of suffolk
2.8, was looking at second half of Jan 23, most days 6-8 so hopefully the two upcoming sunny days will be in that kinda region!
Soldato
- Joined
- 25 Mar 2004
- Posts
- 15,992
- Location
- Fareham
What was your maths for working out the ROI period to be 4 years?
We had very similar systems installed, and very similar costs I think.
Mine is all GE kit, 5kW Hybrid inverter, 8.2kWh battery, 4.4kW of panels, £8.5K installed.
Installation was September 2022, so had the system for about 15 months. I did work out my full annual util costs when I'd had the system for a year, repeating this for the next year could be interesting.
This didn't include some exceptional items such as the Gov rebates (£400 back) + Saving sessions last year (about £100 I think). Had a few Octopus refs as well so I think I worked out I was in theory paying negative for the months shown.
Consumption for the year was 6329 kWh, if I was on the SVR rates this would have been close to £1.9K cost for electric, and gas was as shown, £421 for the year, so my total cost would have been say £2.3K, but actual wound up at £700, a saving of £1.6K, which does nicely offset the £8.5K install costs in y1.
I think I worked out my repayment was more like 5 years, as there are some extra benefits beyond those shown, such as the saving sessions. I can't really count the £400 gov rebates though.
Last edited:
I worked out our full year costs for 2023 today, minus £405, that includes referrals, FITS, export and saving sessions. The first three months was on standard variable rate as well, and our Feb 2023 bill estimated annual costs for electric at £1730 and gas at £960, so a saving of around £3k.
Payback will be about 7 years
actually a bit less, as 3 months last year was on SVR.
@john_smith Did you move to another country today? Perfect graph and nearly 20 kWh, very nice.
Payback will be about 7 years
actually a bit less, as 3 months last year was on SVR.@john_smith Did you move to another country today? Perfect graph and nearly 20 kWh, very nice.
Last edited:
So compared to you I looks like I use more (about 1000KWH more) my average import is a bit lower than yours as 95% of my import is off peek.
I also paid about £1k less for my system.
So I would say our sums are closer than it looks.
I justified my system on a 10 year payback, so 4 or 5 is impressive. However this does requires SVT to stay high and it could drift to more like 4.5-6 years if products like go get more expensive and SVT get cheeper.
I think I got in at just the right time as the same system now would be a lot more expensive.
Edit: shows how people saying solar isn’t worth it are barking up the wrong tree.
Last edited:
Soldato
- Joined
- 19 Oct 2010
- Posts
- 2,935
@Ron-ski Ha. Not moved….but I agree. It’s probably the nicest graph I’ve produced.
If today is a sign of this years energy it’s going to be a good one.
32.7 in @ 7.5p and 28.2 out at 15p.
I’ve just started charging my battery again and it will dump again before midnight. So add maybe 7/8 onto both the ins and outs. £1.50 profit after the sc.
If today is a sign of this years energy it’s going to be a good one.
32.7 in @ 7.5p and 28.2 out at 15p.
I’ve just started charging my battery again and it will dump again before midnight. So add maybe 7/8 onto both the ins and outs. £1.50 profit after the sc.
Last edited:
Soldato
- Joined
- 25 Mar 2004
- Posts
- 15,992
- Location
- Fareham
I made a simplified view of what I've actually been billed, minus any solar stats, but it's so cheap due to solar.
I also added my Saving Session data from 2022 - 2023, looks like I made £73.19. Not sure if I should attribute that to 2022 or 2023 though, or even both 50/50. Maybe to keep it simple I would just call it 2023, and the current one we're in could be 2024.
This would take that total cost from £633.88 down to £560.69, so a good cost for 2023, this doesn't include any Octopus refs or anything either.
I also added my Saving Session data from 2022 - 2023, looks like I made £73.19. Not sure if I should attribute that to 2022 or 2023 though, or even both 50/50. Maybe to keep it simple I would just call it 2023, and the current one we're in could be 2024.
This would take that total cost from £633.88 down to £560.69, so a good cost for 2023, this doesn't include any Octopus refs or anything either.
Soldato
- Joined
- 25 Mar 2004
- Posts
- 15,992
- Location
- Fareham
Yeah just not sure how using more saves you a lot, in summer I never run out of power really (I actually generated 4,444 kWh for the year so more than you!).
Do you have an EV? Most of Nov/Dec I've had to import a few peak units per day because my usage is spread across the day, if your average use is higher than mine, it must mean you're filling an EV overnight but using less on house load than me.
Did you have any working out done for your 4 year thing, or was it eyeballing it?
I agree, both your system and mine would be good investments here, and it's awesome you paid a bit less as well! Mine was split on two roof sections and slate tiles, so prob a bit more cost there.
I'm not calling you wrong, just interested in seeing how you calculated it all!
Yeah just not sure how using more saves you a lot, in summer I never run out of power really (I actually generated 4,444 kWh for the year so more than you!).
Do you have an EV? Most of Nov/Dec I've had to import a few peak units per day because my usage is spread across the day, if your average use is higher than mine, it must mean you're filling an EV overnight but using less on house load than me.
Did you have any working out done for your 4 year thing, or was it eyeballing it?
I agree, both your system and mine would be good investments here, and it's awesome you paid a bit less as well! Mine was split on two roof sections and slate tiles, so prob a bit more cost there.
I'm not calling you wrong, just interested in seeing how you calculated it all!
I have a PHEV that has a tiny battery, so may account for the delta of the additional load, I might be painting a bit of an optimistic picture but I’m looking at it from a holistic standpoint.
I do aggressively load shift as well in addition to the battery so that will probably help.
As for import, I average 95%+ off peek on octopus for (used to be 7.5p vs 9p now) for the year. November / December this is currently high 80s.
Edit: take your Dec 2022 import at 0.1448 va mine at 0.1042.
Last edited:
Last January one of the sunniest on record so this year will probably be worse. I only had my installation on the 26th so missed most of it, but averaged over 8kWh on those last 5 days.
This year is 22kWh so far for me in the first 7 days. Pretty much picking up where the dreadful December left off!
I guarantee it'll be sunny on Wednesday when its all turned off for my second array install though.
Soldato
- Joined
- 25 Mar 2004
- Posts
- 15,992
- Location
- Fareham
Your numbers are off somewhere I think, you can't typically use more than me, whilst also using less peak units very easily. December will usually run out of juice for me by the evening meaning will always need some peak units.
My actual data from December 2022 for elec import:
What does yours show?
This is aggressively load shifting, this is 86.3% off-peak usage, which is about the worst it gets due to the month and lack of solar. Something like June it was more like 96% off-peak, I can't totally avoid peak as the G1 inverter is capped and it can exceed the rate it can discharge sometimes.
Are you confusing my imported units with consumption?
I'm including Standing Charges in my costs here as well, you can see my actual usage average was 11.37p/kWh, the SC just kicks it up a bit.
25/12 for example you can see that poor solar meant I ran out of power pretty early so was importing from grid after 20:30.
Last edited:
Your numbers are off somewhere I think, you can't typically use more than me, whilst also using less peak units very easily. December will usually run out of juice for me by the evening meaning will always need some peak units.
My actual data from December 2022 for elec import:
What does yours show?
This is aggressively load shifting, this is 86.3% off-peak usage, which is about the worst it gets due to the month and lack of solar. Something like June it was more like 96% off-peak, I can't totally avoid peak as the G1 inverter is capped and it can exceed the rate it can discharge sometimes.
Are you confusing my imported units with consumption?
I'm including Standing Charges in my costs here as well, you can see my actual usage average was 11.37p/kWh, the SC just kicks it up a bit.
25/12 for example you can see that poor solar meant I ran out of power pretty early so was importing from grid after 20:30.
This was helped a lot by octopus Go faster with a 9:30 off peak start time. 92% cheep rate import.
As you can see I use a lot more at the cheep rate and quite a bit less a peak rate.
This year will be worse probably mid 80s and just over double the peak rate usage.
Edit: I also have a gen 1 inverter so limited to 2.6kw, however some clever timing and automation helps a lot
Edit 2: striping out the PHEV I used about 55kwh more off peak in Dec 2022 than you.
Last edited:
Soldato
- Joined
- 25 Mar 2004
- Posts
- 15,992
- Location
- Fareham
Yes was going to say PHEV is likely the cause of so much of your extra usage, I don't have things like tumble driers either, not really much additional I can add to overnight load here except for cooking dinner at midnight
What does your repayment look like without the EV? if you're including it in your solar repayment thing, it may explain why the timeframe is shorter, but then the additional cost of buying the EV in the first place should also come into the equation.
Last edited:
Yes was going to say PHEV is likely the cause of so much of your extra usage, I don't have things like tumble driers either, not really much additional I can add to overnight load here except for cooking dinner at midnight
What does your repayment look like without the EV? if you're including it in your solar repayment thing, it may explain why the timeframe is shorter, but then the additional cost of buying the EV in the first place should also come into the equation.
It’s not a full EV so a small 8kwh battery. It’s a company car so while not free (cost about £250 in tax and personal contribution)
When I get a full ev in 6months I will exclude it from the calc, but then I will so be playing with Octopus intelligent and charging at spot off peak times.
Yes 4 years is probably best case, 5 total is probably more realistic, however way better than 10.