Solar Panels UK - is it worth it?

[ACarneiro]

Yeah, December sucks.
119 kwh vs a peak of 1.4MWh in May (I think it was a sunnier May than usual this year, to be fair)

 

[MrT3]

61 kWh for Dec, 891 kWh in June.

 

[WannabeOwner]

230kWh for December, 2,200kWh in June.

I think that's right - as my rule-of-thumb is that we get 90% less solar in December than "peak"

Maybe having quite a lot of panels means mine turn-on more often, when overcast? 2/3rd of mine are East facing, so might be that morning sun in December is better ...

 

[GRiLLA]

64.9 kWh generated in Dec from 6.48 kWp. 637kWh in August, wasn't installed in July.

96% of electricity bought offpeak, I'm pleased that I didn't over-buy more battery than I really needed for the darkest month.

 

[PITA]

905 kWh in June 2023
70 kWh in December 2023

SolarEdge price tracking shows £1,913 of free Solar electricity generated in 2023

Octopus SEG credits were £74.94

Octopus Saving Sessions were £114.86

HM Government Discount Scheme was £201.00

Total : £2,303.80 in 2023

2024 will be a lot more than that now we're on 15p export rates.

 

[PITA]

I'm pleased that I didn't over-buy more battery than I really needed for the darkest month.

Yes, same here.

What made the difference for us, was Octopus extending cheap rate for 6 hours, instead of the previous 4 hours.

Makes a big difference for our two Powerwalls to stay powered up on cheap electric.

Perfect actually, for us.

 

[Pete UK]

883.6kWh in July
77.6kWh in December.

2,600kWh generated in 6 months.

1,442kWh exported (after change in export prices, previously sent to car or batteries)
500kWh given to the grid for free in first 2 months (awaiting export MPAN set up)

Octopus Savings sessions £97. (5 out of 8 sessions).

Octopus SEG credits £147 (4 months sept—>Dec)

99% off-peak usage this month and something like 97% off peak for the 6 months of operation. (Faults and lots of calibrations, plus Octo-Aid not recognising my API key for some reason as of today so can’t see exact figure!)

I’m pretty sure I’m going to be positive on the electricity bill also, plus a good contribution towards the gas bill!)

Roll on the longer days….

 

[PITA]

Here we go again...

Gentlethems... start your inverters.

Good luck and may all your photons be big ones

 

[Mrklaw]

64.9 kWh generated in Dec from 6.48 kWp. 637kWh in August, wasn't installed in July.

96% of electricity bought offpeak, I'm pleased that I didn't over-buy more battery than I really needed for the darkest month.

I’m surprised we have mostly been ok with a 9.5 even when my wife puts on a double tumble dry session and we’re cooking (we moved to induction). I think even limited solar helps extend in those cases in winter too, to slow your discharge (plus that 9.5kwh is only covering 18 hours)

 

[WannabeOwner]

What made the difference for us, was Octopus extending cheap rate for 6 hours, instead of the previous 4 hours.

Subjectively I think that makes sense. Grid consumption must be low between, what?, 11PM and 6AM? That will lead to North Sea Wind curtailment ... so might as well shift all you can, and that will favour battery owners. For anyone well insulated they could put heat-pump on and overheat the house by a degree or two.

I looked at EnergyDashboard for the last week

and for a week in June that had good Solar

I think even limited solar helps extend in those cases in winter too

Does for me too. On a lousy overcast winter day I am on grid for 4 Peak hours. On a reasonably sunny day I don't need any Peak, and a really sunny day I finish the day on positive so less Off Peak charge overnight ....

... well, back when the aim was to minimise exporting. But I still think on that basis, in case we lose export-benefits.

 

[GRiLLA]

I’m surprised we have mostly been ok with a 9.5 even when my wife puts on a double tumble dry session and we’re cooking (we moved to induction). I think even limited solar helps extend in those cases in winter too, to slow your discharge (plus that 9.5kwh is only covering 18 hours)

We use more or less the same, 10.64kWh with a 90% DoD. Also the same as @PITA the extra hours of cheap rate make the most difference. Good days for solar in December tend to be a bit of a waste as we just end up with excess when the next charge cycle begins so it earns us 7.5p savings. While I try to pick my days for washing based on the forecast generation, Mrs Grilla uses more of a 'its all dirty right now' approach.

Once my youngest goes back to school and eldest to University then demand will be lower on average.

 

[PITA]

I’m surprised we have mostly been ok with a 9.5 even when my wife puts on a double tumble dry session and we’re cooking (we moved to induction). I think even limited solar helps extend in those cases in winter too, to slow your discharge (plus that 9.5kwh is only covering 18 hours)

We have a setup at home which works really well. It's a bit bonkers, but it works.

Our house has an Energy Performance Certificate of A+ ... so it's fairly well insulated. But we kept our Gas Boiler central heating system. Our house is very toasty in Winter and we use a lot less Gas, as wet central heating is the only use for Gas now. Moved to induction cooking.

But... we also have an Air to Air Heat Pump with wall units in all strategic rooms, living rooms, bedrooms, office.

So in deep Winter we use Gas for a couple of months to heat the house. But in the transition months (Spring & Autumn) we use the Heat Pump only... and then Heat Pump only as Cool Air Conditioning throughout Summer.

In deep Winter... we also use rooms with Heat Pump wall units (on heating) through the night cheap rate to dry laundry (not in the bedrooms). For those clothing that can't use a Tumble Dryer and need to be Air dried.

In deep Summer... the air conditioning is on all night (using cheap rate) in all bedrooms which is lovely, ultra quiet and a good night's sleep.

We chose a Condenser Tumble Dryer because it's high energy use, and super fast drying. Which makes no difference at cheap rate periods, plus you get way more done through an early morning session. Rejected the heat pump Tumble dryer as too slow.

In the background, through the night, the cars are charging at full whack on 3 Phase while the Powerwalls are fully charged on Standby until 05:30

Then the whole house goes quiet and off-grid for the remaining 18 hours... except now in 2024 we'll be exporting everything...

 

[WannabeOwner]

fairly well insulated
...
in deep Summer... the air conditioning is on all night (using cheap rate) in all bedrooms which is lovely, ultra quiet and a good night's sleep

Are you well enough insulated that you cuold AirCon-cool the bedrooms during the day (i.e. from PV) and not run it (or run it "less") on Off Peak overnight?

Unless your bedroom(s) are West facing ...

 

[WannabeOwner]

Looking at the graph, from my earlier post, I wonder if I should re-think, and more seriously, having a wind turbine for Winter Months

IF?? wind and solar are roughly inverse Summer / Winter that would give consistent generation year round.

 

[WannabeOwner]

Looking at my PV generation, it is "sufficient" from April to September (PV in 2nd half of September is a bit "suspect")

Dunno if using national Wind generation is comparable, but looking at the Generation graph for 2023 the Wind seems to be good from 15-Sep to 01-Apr, which if relevant to a domestic turbine, sited in my garden, looks promising

 

[PITA]

Are you well enough insulated that you cuold AirCon-cool the bedrooms during the day (i.e. from PV) and not run it (or run it "less") on Off Peak overnight?

Unless your bedroom(s) are West facing ...

Yes you could do that...

We view the house as 'well insulated' but not hermetically sealed.

So in the mornings the house is already cool. Then as the day progresses the doors and windows get flung open at some point to enjoy the day.

Then we can set up 'cool rooms' usually bedrooms air conditioned to retreat to if it gets too warm.

My Wife is usually soaking in all the sunshine and heat in the garden or conservatory as she likes that.

But where it comes into effect, is on the evenings and night time. Close all the Windows & Doors, get the inside temps right down for a cool night's sleep.

I'm in the middle of installing a Mechanical Ventilation and Heat Recovery system this year... for filtered fresh air into the house. It'll remove pollen and contamination from outside air, and extract bad air from wet rooms. At this point... it'll be optional to ever open the windows again.

 

[PITA]

By the way... the idea is to be out and about... but come home to a better climate controlled environment (if and when you want it).

So far, so good.

 

[Js1977]

Seeing all these graphs I just realised another "shortcut" from the installer..... They didn't map my enphase array. How the hell am I supposed to know what each panel is doing which is one of me the main selling points of the system... its a bit annoying that |I have to be on to them yet again

 

[WannabeOwner]

I'm in the middle of installing a Mechanical Ventilation and Heat Recovery system this year... for filtered fresh air into the house. It'll remove pollen and contamination from outside air, and extract bad air from wet rooms. At this point... it'll be optional to ever open the windows again.

I have MVHR and we rarely open a window - that just lets in the flies (and bats / birds!), pollen and heat (summer) / cold (winter). Add to that the constant middle-range relative humidity - hanging washing dries faster, no moulds in winter (nor condensation inside windows), no winter coughs / colds, great for folk with respiratory ailments like Asthma. But the diameter of pipes for a retro fit is a challenge ... blinking builders putting up New Builds should be putting MVHR in as standard ... and PV on the roof, and an EV charger ... I whinge more and more like my Dad did when he was my age!

Be interested to hear what you think, once your installation is all done Best retro-fit we did to the old part of the house.

 

[PITA]

I have MVHR and we rarely open a window - that just lets in the flies (and bats / birds!), pollen and heat (summer) / cold (winter). Add to that the constant middle-range relative humidity - hanging washing dries faster, no moulds in winter (nor condensation inside windows), no winter coughs / colds, great for folk with respiratory ailments like Asthma. But the diameter of pipes for a retro fit is a challenge ... blinking builders putting up New Builds should be putting MVHR in as standard ... and PV on the roof, and an EV charger ... I whinge more and more like my Dad did when he was my age!

Be interested to hear what you think, once your installation is all done Best retro-fit we did to the old part of the house.

I agree 100%

New homes could be really bloody nice... and they don't have to be massive places either.