Solar quote confusion

Cranberryberry

Martyn1981 said:

Hiya. I can certainly see your frustration, that's quite an eclectic mix of systems.

Do you have a rough idea of many panels can fit on your roof(s)? And will they all have the same orientation?

The Solaredge system concerns me slightly, as it's pushing the kWp to inverter size to the limit, and possibly starting to get wasteful regarding capping. Also, if you don't have shading and are using one roof, then Solaredge may be overkill - but please note, Solaredge is brilliant, I have two systems using it, so if needed, and/or the PV is across two different orientations, then I can understand it.

I think what jumps out at me the most is the difference between a 6kW inverter in one quote, and a 3.68kW inverter in another. It would make a lot more sense to know if you can (hopefully) exceed the 3.68kW cap, or not, otherwise it's hard to judge what might be best.

Thanks. Yes, if only they would all quote for the same system!

All systems use the main (south-ish) facing roof and, apart from the 2.9kw one they use the West facing roof. The West roof has a chimney hence, I think, the solar edge for dealing with shading (I guess??)

The systems all estimate generation above 3.68kW (except the 2.9kWh system of course) - Quote 1 Usable: 5447w, Quote 3 Usable: 4910 usable.

Martyn1981

Cheers, that helps. So if the system is split across two rooves, and tehre may be some shading, then I can see why Solaredge would be considered. The same can be done by a 'normal' inverter that has two MPPT's, one effectively for each roof, though Solaredge will most likely squeeze out a bit more generation, especially if there is some shading. Also explains the 3.68kW to 5.4kWp difference, as the panels won't all be peaking at the same time.

South facing is obviously best for annual generation, but west is really useful for lengthening the generation into the evening in the 6 months with longer days, so not to be sniffed at. Also the way PV costings go, the extra PV on the west, which will generate ~20% less pa than south facing, will most likely add less than +80% v's the south PV (pro rata).

If I recall correctly, panels of even 400Wp are now down to about £115 + VAT, so if you are getting PV installed, with all the fixed costs of cabling, inverter etc etc, then maxing out the kWp makes sense ...... within reason.

Best of luck hunting for cheaper deals.

Hexane

It's probably worth phoning Red Electrical in Chorley. It sounds like you're not in their usual area of business, but if you explain what you're after and that other quotes have come out as expensive and confusing, they might find it worth a visit to offer a quote. The limited space on the south-facing roof makes it a complicated one. They might recommend something similar to Quote 2 but cheaper, or they might recommend a SolarEdge solution in which case if there's really space for 17 panels and a DNO application is successful, then I would expect they could easily beat the price per kWp in Quote 3. (Unless the various shipping crises have pushed prices though the roof?)

Incidentally, your Quote3 mentions "Connection agreement application & processing" which sounds like a DNO agreement but then mentions a "SE 3680 Inverter" which sounds like something you wouldn't need a DNO agreement for. And the Quote3 supplier also mentioned something about 4.9kW useable? Seems fishy.

Cranberryberry

Thanks Hexane - I’ll see if they’re up for it!

Yes, the various permutations make it really confusing. A £1/watt flat quote where I can stretch my budget would suit fine but I’m dreaming!

[Deleted User]

Cranberryberry said:

QrizB said:

I don't know where in the country you are but even at the cheaper end of the scale, £1.26/watt seems a little high. How many quotes have you got? Can you post brief details here?

As a rule of thumb, higher wattage systems should be cheaper per watt, will have better economics and no-one ever complains of having too much solar power.

Do keep in mind that any system capable of producing more than 3.68kW will need prior permission from your DNO and this might include a fee.

I'm in the North West/North Wales border area so we should have lots of suppliers but I've managed to get a few quotes, three of which are (just realised I messed up some numbers in my original post so they don't quite match!).

Quote 1: £11,000 / 6035w/ £1.82 per watt (INCLUDES BATTERY)

17x 335 W Monocrystalline Panels (not specified)
1x 6kw inverter (not specified
1x 9.6kwh battery
software etc
scaffolding

Quote 2: £4200 / 2920w/ £1.44 per watt 

Solaris 3Kw inverter
8x JA Solar 365KW Panels
Renusol mounting system
Tigo TS4 Optimisers
Install, Scaffold etc

Quote 3: £6500 / 5400 watt/ £1.20 per watt

15 x Longi Black frame 360W solar panels,
15 x SolarEdge P401 Optimisers.
Mounting equipment for roof installation with cable flashings.

1 x SE 3680 Inverter.
1 x Generation Meter. Connection agreement application & processing.
Scaffolding etc

Try GenFit Solar Chester or Hafod Energy - both are local and good companies to deal with. I eventually went for GenFit Solar and I am very happy with the PV solar and PW2 that they installed last year. I also have SolarEdge and an in roof mounting system. The other advantage of using a local company is that they are known to the DNO (SPEN). I ended up with no export limit and no DNO witness visit as the documentation provided by GenFit was excellent. In theory, I could export 10kWs to the Grid.

Cranberryberry

[Deleted User] said:

Try GenFit Solar Chester or Hafod Energy - both are local and good companies to deal with. I eventually went for GenFit Solar and I am very happy with the PV solar and PW2 that they installed last year. I also have SolarEdge and an in roof mounting system. The other advantage of using a local company is that they are known to the DNO (SPEN). I ended up with no export limit and no DNO witness visit as the documentation provided by GenFit was excellent. In theory, I could export 10kWs to the Grid.

Thanks. I’ll look in to those! Re you willing to share your system size and the cost at all?