Solar Panels UK - is it worth it?

[ElectricPolice]

Another on cost... bird proofing.
That or a pressure washer to send baby pigeons to the middle of next week.

Do it ASAP, it wasn’t even mentioned when I got mine installed. Spent the next year listening to the f**kers scratching around underneath making their nests.
Our house was the only one in the street with a parade on the roof, like a local youth club!
Paid another stack of cash to get scaffolding back and fitted it myself. Not a fun job
On the plus side I did a bit or pointing at the same time

 

[WannabeOwner]

I think we're possibly saying the same thing

Indeed

once you have the scaffolding up so it can be cost effective (although woudl you be able to access the west roof if you put scaffolding up on the east? maybe more expensive than that

Yes, I'd assumed 2x as much scaffolding would be needed - bonus if they can access both sides of the roof from one side - but I doubt it would cost 2x the price - they have still got to come out for the quote, and to put the scaffolding up, and take it down, and the the Admin for the invoice etc.

There's also a point that having generation earlier and later in the day is more useable than having massive generation in the middle, I suspect this is only an effect for a month or so however.

IME its several Summer months. When I have a mo. I'll have a look at the "start" time for my East array during last Summer. I also have a South array, but I only have combined data logged, not for each of them independently unfortunately.

I had a full-sun day yesterday, the East was producing 1kW at 08:10 and the South at 09:25 - its an isolated reading though and might have been impacted by passing clouds etc. (my recollection is that the lead-time of East (and the lag-time of West) is less than that)

It's all not really relevant as most won't choose

Yes, and that was the point which I wanted to make - but did so badly. Either way, we are stuck with the roof alignment, and don't have a choice!

If my neighbour has a South roof, and I have an East West roof, then if he covers his South roof and I only cover my East (or my West) I'll get 15% less electricity than him (for the same sized roof area and same installation cost, let's assume)

But if I cover both my East and West I'll get 70% more than him ... and my guess is that it would cost 70% more, and not double.

I think that folk often think that South is inherently better, whereas East / West provides the opportunity of twice the roof area. Mid day peak is better on South, but 2x as much PV on an East / West roof provides the opportunity to generate 70% more electricity - assuming that the home owner has the ability to use it.


Good point made about shading of East / West side in Winter - the sun is so blinking low on a winter's morning / evening that anything in the way is going to cast a shadow. I'm fortunate to have nothing to the East of me...

... although PC generates so little in Mid Winter (only 10% of Mid Summer) so one could take the view that even a roof which is shaded (only) in Winter is not much loss so long as it will generate well in Summer.

 

[DaveNN]

Do it ASAP, it wasn’t even mentioned when I got mine installed. Spent the next year listening to the f**kers scratching around underneath making their nests.
Our house was the only one in the street with a parade on the roof, like a local youth club!
Paid another stack of cash to get scaffolding back and fitted it myself. Not a fun job
On the plus side I did a bit or pointing at the same time
View attachment 901746

Yep.
Ordering and expect in a few days.
Will look at spikes for the apex.

 

[SimonV]

can anyone recommend a PV installer in Bristol/South West? I’m struggling to even get quotes in…

 

[Stranger Dings]

can anyone recommend a PV installer in Bristol/South West? I’m struggling to even get quotes in…

I’m also in Bristol, so await responses with interest. With day rates at 46p KWh now, the business case for solar is very strong.

 

[Steerpike]

I have West and South facing panels and I'm now considering the East roof.
There is limited space and I have been quoted £7,590 for 6 x 410W panels + SolarEdge 2200W inverter.
Given what I paid in the past, this is rather more than I was expecting, however, perhaps prices have risen and this is reasonable?

 

[Avendit]

what does PVWatts say about it? (looking at current generation curve and what the new total would be could be useful) and how does that compare to your usage pattern? Also, how east is east? A few degrees north or south could have quite an impact I think? And what are you adding this set to?

While more is more is always more, to some extent that is reliant on your ability to consume more! The biggest difference for me would be around the shoulder seasons (which we are starting to approach) and the ability to survive on battery + solar extra days a year and more % of each day into the winter. But we are pure electric and can always use more. If you are on a gas boiler still, where do you put those extra 2kw through the summer? Selling them back to the grid is a pretty shonky solution unfortunately. Would the early morning power be particularly useful (breakfast or getting a battery a head start, whatever).

In your quote, there is probably only £1000 to £1500 of panel costs . Rest is overheads, skaffold etc. If the business case isn't making a huge amount of sense, you might be better waiting until you need skafolding or roof work done anyway? Not sure prices will ever go down for the hardware, so you could just view it as doing as much to futureproof as possible and treat it as a sunk cost to mitigate an unknown future.

Tough decision.

 

[ItsNotAboutTheMoney]

can anyone recommend a PV installer in Bristol/South West? I’m struggling to even get quotes in…

Not surprising you're struggling.
Total installed capacity for systems <= 10kW has gone from~10MW/mo late 2020/early 2021 to over 41MW/mo since August 2022.
For 10kW-50kW it's gone from ~3MW/mo to over 6MW/mo.
Those are dominating PV installs.

Solar photovoltaics deployment

Monthly deployment of all solar photovoltaic capacity in the United Kingdom.

www.gov.uk

 

[phil4]

I had solar installed mid Jan... here's what I've learned:

• You generate a surprising amount of power when foggy.
• On a good clear day (eg. earlier this week), you'll generate quite a lot of power, eg. 20kWh from my 5kW array.
• On a good day, using the zappi is easy, as the surplus goes over the threshold it'll use it, until the sun starts to set and it dips below, eg 16% extra on a MYLR
• On a variable day, the zappi might blip on or off but a lot doesn't go into the car, as it's not high enough for long enough.
• Get a battery. As above, on a variable day, sometimes you'll be generating 400W and not able to charge the car, then 3.8kW and you are, then not. Let the battery soak up the spare below 1.4kW, as sending it to the grid, even if you're paid is wasteful.
• Make sure you get the MCS cert. I'm not sure how, as the installer will want paying first, but if they then don't send it you've not got their money. But you really do need it.

 

[Avendit]

I had solar installed mid Jan... here's what I've learned:

- You generate a surprising amount of power when foggy.
- on a good clear day (eg. earlier this week), you'll generate quite a lot of power, eg. 20kWh from my 5kW array.
- On a good day, using the zappi is easy, as the surplus goes over the threshold it'll use it, until the sun starts to set and it dips below, eg 16% extra on a MYLR
- On a variable day, the zappi might blip on or off but a lot doesn't go into the car, as it's not high enough for long enough.
- Get a battery. As above, on a variable day, sometimes you'll be generating 400W and not able to charge the car, then 3.8kW and you are, then not. Let the battery soak up the spare below 1.4kW, as sending it to the grid, even if you're paid is wasteful.
- Make sure you get the MCS cert. I'm not sure how, as the installer will want paying first, but if they then don't send it you've not got their money. But you really do need it.

Oh to be down south! My split array has the east facing NE so its only in the last few days its starting to see the sun. Which leaves the 4kw SE array doing all the heavy lifting. Haven't seen over 8.5kwh yet this year, so 20 in a day is really impressive!

But that 8.5 + a 10kw battery is enough to see me through to ~2pm without touching the grid, then its kinda break even through to 5pm with background load covered by solar and any extra demand coming from the grid. Then its fully grid through to midnight and we start the cycle again. Another few weeks and we should have the sunny days covering our needs through to sundown, then another month and the battery will carry us into the evening. At some point we have to be brave and flip to charging the battery from solar rather than over night, but then we should see ~5 months of no grid use other than charging the car.

 

[phil4]

Oh to be down south! My split array has the east facing NE so its only in the last few days its starting to see the sun. Which leaves the 4kw SE array doing all the heavy lifting. Haven't seen over 8.5kwh yet this year, so 20 in a day is really impressive!

But too even things up, you've got a battery. It's all well and good having 20kWh, but the first part of the day and last part under that more or less go to waste (they actually do), and while the car getting charge it good, it's only saving me 7.5p/kWh. Whereas you're able to offset some/all of your expensive evening use, which I can't. So I think you probably win.

 

[SimonV]

I’m also in Bristol, so await responses with interest. With day rates at 46p KWh now, the business case for solar is very strong.

Hi. I’ve now had 3 quotes ranging from 13-10k. One company based in Hampshire, one local and one sort of local. That’s for 8/9 panels, 3.6ish kWh capacity, 4/5k inverter and similar battery

 

[ringi]

After seeing the solar modeling in the Loop app using my half hourly meter reading I am totally convinced about having a battery as even at this time of year it nearly doubles the self use from the small PV array they assume.

Looking at live usage data, my washing machine goes from nearly 1kw when it is spinning to very little every few minutes while rinsing, so without a battery it would import most of the power from the grid even if the PV had enough output for the total half hour usage. Likewise with cooking at lunch time.

It easy to get higher payments for sending power to the grid if a battery is used so power is sent mostly between 5pm and 7pm, likewise electricity cost for import is highest between 5pm and 7pm. So I would size a battery so in winter using a overnight charge we did not need to import before 9pm on all but the lowerest PV days. Interesting a heatpump only seems to work for us if we have a large battery to run the heatpump on cheap rate electricity.

Its disappointing how little automatic integration with Octopus Agile is fully supported by inverter vendors.

 

[Avendit]

After seeing the solar modeling in the Loop app using my half hourly meter reading I am totally convinced about having a battery as even at this time of year it nearly doubles the self use from the small PV array they assume.

Looking at live usage data, my washing machine goes from nearly 1kw when it is spinning to very little every few minutes while rinsing, so without a battery it would import most of the power from the grid even if the PV had enough output for the total half hour usage. Likewise with cooking at lunch time.

It easy to get higher payments for sending power to the grid if a battery is used so power is sent mostly between 5pm and 7pm, likewise electricity cost for import is highest between 5pm and 7pm. So I would size a battery so in winter using a overnight charge we did not need to import before 9pm on all but the lowerest PV days. Interesting a heatpump only seems to work for us if we have a large battery to run the heatpump on cheap rate electricity.

Its disappointing how little automatic integration with Octopus Agile is fully supported by inverter vendors.

Solid logic, especially the averaging capability of a battery in addition to its time shifting capabilities.

But a heat pump isn't really a cost saving exercise. It's a carbon saving that should be approx break even cost wise with gas. Anything you do to improve on that could equally apply to a gas boiler.

 

[WannabeOwner]

It easy to get higher payments for sending power to the grid if a battery is used so power is sent mostly between 5pm and 7pm

"Easy"? I could do with knowing what that is please (so long as it doesn't involve giving over total control of my system)

 

[ringi]

But a heat pump isn't really a cost saving exercise. It's a carbon saving that should be approx break even cost wise with gas. Anything you do to improve on that could equally apply to a gas boiler

Being able to run the heatpump on cheap rate electricity all day is something a gas boiler can't do.

 

[ringi]

"Easy"? I could do with knowing what that is please (so long as it doesn't involve giving over total control of my system)

Set the battery to discharged between 5pm and 7pm down to the level of charge you need until the next days PV input. Use Octopus Outgoing Agile that tends to pay the most at these times.

 

[WannabeOwner]

Set the battery to discharged between 5pm and 7pm

How is that done? Do they do that (outside my control), or just pay me to export and penalise me to use during that time (i.e. incentivise me to do it, but under my control). Sorry, I know of Octopus Agile, but I don't know the details.

I've looked at Tesla option (Octopus collaboration I believe) but I'm not wanting to give over control as my system and requirements are complicated. Would be nice to get something for export, and I'd be very happy to be part of a "virtual battery" when the grid needs it.

PowerWall owners in California who joined the Tesla Virtual Powerplant apparently made up to $500 last year

Tesla Powerwall owners made up to $500 in the first year of the virtual power plant

Tesla Powerwall owners in the California virtual power plant report making up to $500 in the first year of the...

electrek.co

 

[Avendit]

I think this is what he's talking about, but I think you have to be on full agile, which is quite brave?

Octopus Outgoing East Midlands | Energy Stats UK

View Smart Meter tariff data and graphs that easily show how you could save money using Time of Use tariffs. Get £50 of free Octopus Energy credit.

www.energy-stats.uk

 

[WannabeOwner]

I think you have to be on full agile, which is quite brave?

Thanks. I have loads of data logged ... so I have the opportunity to run-the-numbers.

In Winter we have a period of Peak daytime usage if we are washing / baking and it is overcast / raining. I deliberately limit PowerWalls to 50% (from start of Peak until 6PM) 'coz with the Ukraine situation I thought I was being a good citizen by then using battery from 6PM onwards. On one hand it makes no difference if I drain the battery in the morning, and use Peak Grid thereafter, or if I stop at 50% by mid morning, use Peak until 6PM, and then drain battery some more ... except ... it means that I have more available if we get a power cut later on. For that reason I hold the last 10% and release that in time that it will be used-up (there-or-three-abouts) by start of Off Peak. On sunny Winter days, which augment battery, battery doesn't fall to near 0% by start of Off Peak

It is very rare that I have run out of battery, over winter, after 6PM, when I reduce reserve 50%-to10% and then 10%-0%, before start of Off Peak ... so I think I would be happy paying through-the-nose in the evening, if the need arose, so I think I just need to tot-up how often I am using Grid during winter days, and at what time, to see what Agile would cost

Just flicking back through the PowerWall stats: the last day we "held" at 50% and grid-imported at Peak was 30-Jan and that was 16:30 - 18:00 ... earlier in January the 50% was often reached by mid-day ... but I reckon that was only "some days" and only during December to late January (and the inverter on 1/3rd of my PV was bust during that period, so although not much insolation at that time my figures are worse than would be)

Now (mid February) even poor sun days are giving me enough battery-boost to mean that I get to Off Peak with no daytime grid use ... and Tesla AI?! is only charging PowerWall to 50%-ish on nights when strong sun is forecast for the following day