Best day so far (in the life of my array – Dec 22 > now) was 18kWh.
And this is why people should qualify some statements with a description of their array, because this ^ could lead people, who are thinking about spending money on PV, to believe that they can fit a standard 4kWp system and generate more than enough power all year, when the reality is probably very different.
@daffy I’m way below that with 6kw array, split 50/50 se/sw facing. Managed a measly 1.4kw so far today.
Ours is a 5.5kWp array which is almost south facing (SSSW) at an inclination of 30deg. We're in the SW. cThe lower half of the array is in shade during the very first part of the morning at this time of year due to the neighbours house being slighty up the hill from us and having a higher pitch to their roof.
Since December we've generated just over 550kWh.
Looking at joining the solar party, it seems like a no brainer based on quotes so far, but let me know if I'm missing something.
One point to note is we're in a conservation area (Edinburgh) with about 50% flat roof which is partially shaded by cupola and chimney so those do limit system design somewhat so we'll max out at 3kwh tops I reckon.
Regardless of limitations if seems like a no brainer, £12k for a 3kwh system and battery, of which home energy Scotland will give £2500 grant and the remainder as a 12 year interest free loan.
Payback period on the system is only 8 years and savings over the lifetime are around £20k so seems like a no brainer, if you pay for it all as grant and loan then you only repay £70 a month on the loan and are saving more than that a month of the electricity bill. Even accounting for payback not as estimated for any reason, it's quite clearly a good cost saving as well as right thing environmentally.
Am I missing anything?
What's the size of the battery being offered?
One point to note is we’re in a conservation area (Edinburgh) with about 50% flat roof which is partially shaded by cupola and chimney
Planning? A flat roof would require a ground mount style frame to mount the panels - that's going to stand out somewhat! Is the shading going to encroach on a 3kW array or is 3kW the size that will be completely unshaded?
I have an unshaded S facing 3kWp system in N Wales and for 5 months of the year it produces less than £70 worth of electricity per month @ 35p/kWh.
(Annual production averages 3MWh)
Have you factored that in?
Recently had 4.8kWp Solar and 7.1kWh Storage. Lux hybrid inverter allows import and export settings. Paid £9.9K
On a dull feb day I am putting a couple of kWh in the battery at night on Octopus Go, so 15p, and the rest of the day is self sufficient. Generating 3.7kWh so far today has even topped up the battery
Very happy, I have only imported peak rate electricity 2 or 3 times in the last month
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What’s the size of the battery being offered?
10kw
Planning? A flat roof would require a ground mount style frame to mount the panels – that’s going to stand out somewhat!
Should be fine, tall narrow townhouses with a fairly narrow street means it's impossible to see any of the panels on the neighbours, ours would be the same. The guidance on what is acceptable or not is whether it's visible on the front elevation, which it isn't.
Is the shading going to encroach on a 3kW array or is 3kW the size that will be completely unshaded?
3kw is the unshaded section.
I have an unshaded S facing 3kWp system in N Wales and for 5 months of the year it produces less than £70 worth of electricity per month @ 35p/kWh.
(Annual production averages 3MWh)
Have you factored that in?
Awaiting the final proposal and drawings through but from what we went through yesterday, yes all of this is factored in. I've also got neighbours very similar system to compare against that should give me a good idea of real world generation versus theoretical.
I’ve also got neighbours very similar system to compare against that should give me a good idea of real world generation versus theoretical.
PVGIS shows an annual generation of about 2650kWh for your location (if you haven't looked already) and it tends to be really quite accurate.
Well Wales seems to be the solar power capital at the moment 😉 My 6.0 KW array was pushing almost 5.1 kw for quite some time earlier. It is a intermittewntly cloudy day here but am on 10 kWhs already generated. Yesterday was 16 KWh total. 218 LWh for February so far and 421 for the year. That is used and stored since I have no export capability. To be fair there has only been a few days of over generation and hence wasted output. A guess would be no more than 20 KWh lost
606kwh in aberdeen for the yr so far on a 5.3 array
@welshfarmer that's impressive. I would only get that percentage of the installed power on a sunny day in May - but my installation is 12 years old and I think the technology has improved significantly.
...... and the panels will perform better in the current low temperatures compared to warm summer temps.
Certainly wondering if my panel setup is fubar with those generation numbers. Possibly too much resistance on the cable run or other gremlin.
Having had a battery staying at high soc, noticed it’s at the other extreme now- 3 pct which feels too low!
EW split sucks in the winter unfortunately. It's only in the last week or so that our battery has been getting much charge. The worst days of january might only see 2 kWh. Last week the sun just seemed to suddenly get high enough for things to start working and we had a 22 kWh day. Will just about scrape 7 today and 300 for the month.
The summer is a different story as we can be generating from 0515 to 2115.
(Oxfordshire, 10kWp 35:65 E/W split, 50 degree angle on roof, 10 KWH battery)
Certainly wondering if my panel setup is fubar
Are you south facing or what? As @lodger said E/W is fairly crap in the winter but starting to get going now.
My set up is 3kw southwest and 3kw south east so not as bad as east and west. Was cloudy all day here with some rain and got approximately 2.5kwh for the day from 6kw panels.
PVGIS shows an annual generation of about 2650kWh for your location (if you haven’t looked already) and it tends to be really quite accurate.
Had not checked, thanks. This figure is almost on the nose of what our neighbours got last 12 months, and installer thinks he can squeeze a slightly bigger array onto our roof versus what they have (it's the same installer).
My set up is 3kw southwest and 3kw south east so not as bad as east and west. Was cloudy all day here with some rain and got approximately 2.5kwh for the day from 6kw panels.
Hmmm.
My 4kw E/W array produced 4.2kwh and it's been cloudy/rainy with a couple of bursts of short-lived sun.
Do you have micro-inverters or a single inverter, and if the latter is it dual mmpt?
You've probably just had more rain!
The s/w and s/e array are each meant to be on separate input to the inverter. each panel has got a tigo optimiser too.
The s/w and s/e array are each meant to be on separate input to the inverter
I take it they are? As I said before, it's tricky troubleshooting when the weather is not optimal - much easier when it's sunny and you know roughly what should be happening.
My money is still on crappy weather.
Managed a measly 1.4kw so far today.
Luxury - 0.35 here!
Was very murky all day, bar about one hour when we generated 0.2 kW.
@Footflaps where are you and how big is your array and what orientation?
The weather has been very patchy the last few days. We've been down in London; some times it's been glorious weather there while our panels back in Telford have been doing nothing, but at other times murky, damp weather there while our panels back home have been doing 5kw!
I can easily believe that the last day or so luck could be the difference between a couple of great solar days and a couple of terrible ones.
I put a 4.2kw array into a shop/flat I own (rented out) around 4 years ago. S/W facing roof. The whole building is electric only so I did it to help lower the tenants bills. I get the FIT which is somewhere around £130/year.
I’ve no remote access and have never bothered tracking how it’s doing apart from submitting quarterly meter readings to the FIT provider.
I recently put the figures I have from the FIT rebate remittances into a spreadsheet, looks like it’s performing reasonably well?
Just to bang on again about the PGVIS model. If you are thinking of solar it gives you a very good estimate of your possible gain. I have been surprised so far as to its accuracy.
Planning? A flat roof would require a ground mount style frame to mount the panels – that’s going to stand out somewhat!
Dug around on the Edinburgh planning portal last night. Neighbours with panels who did apply were told it did not need consent as it was not visible from ground level. So seems ok to crack on from that perspective.
Just out of interest how are the installers going to hold the frames down?
Just out of interest how are the installers going to hold the frames down?
Preferred (and likely) method is to drill through the roof to attach them, but they can use a ballast system if that is deemed not possible.
Preferred (and likely) method is to drill through the roof to attach them
As the son of an architect who's mantra was to never drill into a flat roof, that worries me. What do you think the chances are of all those holes remaining watertight over a period of 10 years?
(See also balustrades fitted onto flat roofs rather than onto the fascia)
Lovely day for generation, but to illustrate the difference between S facing arrays and E/W facing arrays this is the current state of play of my two setups:
4kW E/W Array:
Date - Time - [Total] Energy - Efficiency - [Current] Power
23/02/23 - 11:30AM - 3.200kWh - 0.801kWh/kW - 1,335W
3kW S Array:
Date - Time - [Total] Energy - Efficiency - [Current] Power
23/02/23 - 11:30AM - 6.713kWh - 2.238kWh/kW - 2,325W
!!
What do you think the chances are of all those holes remaining watertight over a period of 10 years?
Not an architect or engineer so to be honest, I've no idea.
Thus far just putting my trust in...
1. Both methods seemingly being established methods for fitting to flat roof.
2. Putting trust in a reputable company to guide me. Many cowboys out there but this one come well reviewed and personal recommendation from people I know.
But still not committed to anything so open to other opinions.
What do you think the chances are of all those holes remaining watertight over a period of 10 years?
If it's done properly with proper seals and cowls then quite high.
A quick google suggest most flat roof system just sit on top and use ballast, which is a lot simpler...
https://www.valksolarsystems.com/en/solar-mounting-systems/kits/flat-roofs/solar-ramp/valktriple
We've always used ballast when installing antennas on flat roofs, but they have blown over in exceptionally windy conditions. Not sure how happy I'd be with a load of sails (solar panels) waiting to be lifted off the roof in the next gale....
We’ve always used ballast when installing antennas on flat roofs, but they have blown over in exceptionally windy conditions. Not sure how happy I’d be with a load of sails (solar panels) waiting to be lifted off the roof in the next gale….
Yeah, we are quite exposed, basically it's downhill for miles until it hits the Forth, and a single story property next door which means we have lovely clear views for miles from 2nd floor, but also really bloody exposed to the elements. I'm not sure I would be 100% on the use of ballast, but again I'd put trust in them. They did say that the ballast option is likely to be more expensive due to the amount that would be needed, it would be harder to get up and weight on the roof may be too much.
I was thinking that if we ever do a roof conversion we'd end up moving the solar panels to a flat roof, so I was thinking of making a frame which bolted into the walls at either end, had feet sat on the roof mid span and then bolt the solar panels to that, so they can lift off without ripping bolts out the walls....
Obvs be a bespoke frame, but fairly easy to make out of galvanised steel.
Not sure how happy I’d be with a load of sails (solar panels) waiting to be lifted off the roof in the next gale….
a wind load survey would quickly force you to use solar ballast buckets such as the renusol console
These enclose the back of the panel from the wind reducing sail effect
As Doug points out though cost and weight quickly mount
so I was thinking of making a frame which bolted into the walls at either end, had feet sat on the roof mid span and then bolt the solar panels to that, so they can lift off without ripping bolts out the walls….
quite sure Doug will want an mcs certificate which a home brew mounting system won’t get
quite sure Doug will want an mcs certificate which a home brew mounting system won’t get
It's not any different to how the installer we used mounts panels on gable ends etc, they just knock up bespoke frames out of square section steel tubing on site to mount the panels as required...
Plus in our case, which is what I was talking about, we already have all the certificates....
quite sure Doug will want an mcs certificate which a home brew mounting system won’t get
Yup and got to be supplied and installed by them to get the Home Energy Scotland grant and loan. Plus I hate heights so no chance I'm going up on the roof.
We've got a flat garage roof in Glasgow (approx 5.5m x 4m / 23m2) that gets sun most of the day, effectively our only potential for south facing. The house is E/W and North facing and is Victorian semi so wouldn't be appreciated by neighbours... Looking at option of putting 10/12 panels on the garage and rear extension, or 9 on garage and 3 on a frame next to the garage out of sight...
Would be going over a 2 year old sika liquid plastic roof - looking at the plastic trays for ballasting or else knock up a frame with pads to spread the load. There is a small ~300mm parapet upstand around the roof so shouldn't be "too" exposed to wind...
Is there a go to DIY package on the web, or a go to panel type that is considered the best value for money for this type of setup? There seem to be loads to choose from.
My facebook feed is now full of firm after firm offering 12 panels + inverter + battery deals from £5k to 13k... Plenty of DIY kits come up in google but it would be good to have a real recommendation from someone who has done something similar.
Electric company car coming in May will change our usage / might be looking at car charging point and a house battery setup too? Hard to know which way to go.
Sale of our existing car may provide some of the funds for this project. Looking for a bit of energy future proofing but will only do it if numbers work. I appreciate Glasgow and flat roof aren't perfect.
We consumed 7783kWh last year, = 21kWh per day. Expecting this to go up next year with car charging.
Any help would be greatly appreciated, thanks.
Any help would be greatly appreciated, thanks.
Run the numbers first to see what you could generate from the available area.
https://re.jrc.ec.europa.eu/pvg_tools/en/
Looking at option of putting 10/12 panels on the garage and rear extension
Again, check that you don't need planning as a panel on the garahe roof is going to add probably 1m to the height .
ideal thanks
If putting panels on a single storey building check they won't be shaded.
A home battery will pay for itself quite quickly if you make use of the Octopus Go tariff which you should consider anyway when the EV arrives.
