Solar panel quote review please

woolgar.c

We've recently started looking in to solar panel systems & getting quotes. The more we've looked in to it the more confused we feel. 
Can anyone offer any advice or a service / person we can speak with for some impartial advice. 

Our aims were
- to offset our energy bills so they are reduced as much as possible (& the money that would have gone to energy bills will instead go to paying off the solar system we get installed). 
- a simple system that can hopefully automate charge & discharge from the grid at optimum times

We have a fully south facing roof, a slightly south west facing roof and a south facing garage roof. No shade across any of it. The house roofs can fit approx 10 or 11 panels, if we include the garage we could fit about 14.
I work from home 5 days per week, toddler is also home 1 day in week, all 3 of us home weekends. We have a hot tub too. 3 bed house end terrace to give an idea of size. House roofs are 40 degree pitch.

Our average daily consumption is 23 kWh. I think we actually use less energy in winter when the hot tub isn't out. Last year our average monthly summer use (without hot tub) was about 270kWh, this year (with hot tub) it's about 855kWh. Last winter average monthly use was about 495kWh. Average annual use was 532kWh

We have a smart meter & currently are with Octopus, although we'd want to switch to the Flux tariff once the solar system is installed.

We're struggling to figure out what system combination is best to reduce our bills without spending more than needed on the system itself. It's also hard to figure out how much real difference there would be between things like type & quality of panels, inverters, batteries. We can't seem to actually figure out what system size is best. Some of our quotes were 11 panels and as we learnt more we thought the largest possible array is probably best so 14 panels would be better (by including the garage roof). 

The battery seems to be the more significant cost. I'm unsure how much we would benefit from adding one, or perhaps just opting for a small one. My husband is more keen & likes the idea of a larger one, utilising Octopus Flux and forced charge / discharge at key times. We may get an electric or hybrid car in the next 3 or 4 years.

we've looked in to & had quotes for panels ranging from 430 to 455W, batteries from 5 to 13.5Kw, inverters & microinverters. 

Also unsure if a DNO99 application (to go beyond the 3.6 limit) would be worth it. 

We've watched endless videos from Gary does Solar & tried various combinations in his online solar modelling calculator but we've ended even more confused. 

I feel like we need to get back in contact with some companies to amend our quotes in terms of panel size but as a guide this is what we have so far. Any input on quality & things to consider would be great. So far it seems each company has good reviews, I think the equipment is more variable.

1. Greenscape
(this was via a scheme currently running in Kent which in theory should make it cheaper but also seems to have the worst equipment of the quotes)
11 x 430W Longi LR5 panels (system size 4.73kW), Fox ESS H1 Series Inverter, Fox ESS EP5 5 kWh battery. Includes optimizers, bird guarding, scaffolding to the 2 roofs. Someone has been to the house to check pitch of roof etc. £8,895

2. Nano Protech
11 x 455W Aiko panels (system size 5.05kW), Tesla Powerwall 3 13.5kWh battery (I believe this is also the inverter). Includes scaffolding to 2 roofs, DNO application (not sure if this is for the 3.6 limit or beyond), gateway. £13,752

3. Soly
They suggested 13 panels on the 2 house roofs but everyone else has suggested 10 to 11 would fit.
13 x 455 Aiko panels (system size 5.92kW), Giv Energy battery 13.5 kWh, Enphase microinverters. Includes scaffolding to the 2 roofs.  £12,594
 
4. Bliss
They suggested it would be easy enough to add another 5kWh battery. The below price is discounted. They suggested the microinverter they use is one spec up from the one in the Soly quote.
14 x 455 Aiko panels (system size 6.37kW), Enphase battery 5kWh, Enphase microinverters. Includes scaffolding to the 3 roofs. someone has been to the house to speak with us but didn't measure the roof or pitch. £12,675
(same quote but for 10 panels on 2 roofs with no discount was £11,541)

5. Cahill
I think this is the point at which my husband has been trying to figure out the different battery options. We have 3 quotes from Cahill for the same panel set up but with different batteries & hence different inverters. 
10 x 440 DMEGC panels (system size 4.4 kW). 
a) with Fox ESS EP5 (5.1kW) battery and Fox ESS H1 Series inverter
b) with Tesla Powerwall 3 (13.5kW)
c) with Giv Energy All in One (13.5kW) battery and Fox ESS F Series inverter

6. Light Renewables
Awaiting a more specific quote but first suggestion is as follows. Seen some varied reviews of this company with suggestions their admin may have improved but we don't want to end up waiting an age for the certification and export ability. It's been suggested these panels may be better quality than those in the other quotes although they are the lower end of the power amount.
13 X Sharp 435W bifacial panels + Tesla PW3 + Gateway 2 fully installed for £11.7K.

Please help!

charles_b_2

I had a quote from light renewables and they are very competitive on price. Usually recommended by @Screwdriva on this forum. That price seems very good.  My own system installed just 2 months ago (Solaredge with anti-islanding and 15 x 450w panels) was more expensive, prices are steadily declining.
I went with a local firm - check MCS and also Which trusted traders.  They were broadly similar on pricing and my preference was a local firm in the end. I have been very pleased with the final results and they were pretty quick at turning around the documentation.

MallyGirl

The argument for having a GivEnergy battery to take advantage of Intelligent Octopus Flux would seem to hold less sway with your usage figures. As a rule of thumb you need to be using less than 80% of what you generate for that to be the right tariff and your usage is high. On dull days in summer you may well not generate the daily 23kWh. That hot tub is a killer - I had no idea they were so expensive to run.
Our usage is more like 10kWh per day and we have 14 WSW facing panels, 13.5kWh AIO and we are making money with IOF.
We used Light Renewables and there were a few niggles through the process but our export permission didn't take long at all.

Screwdriva

Those Sharp bifacial panels should experience an average 10% albedo gain over the 435W rating, based on real world results seen with the same brand of panel here. 

If OP is okay with a white painted roof surface area behind the panels, peak performance of 475W+ should easily be achieved theoretically. With significant overperformance on most real world overcast days. This is why installers like Heatable have defaulted to bifacial panels.

I leverage 4 installers nationwide to help others with their PV installations and earn nothing from it  - LR is, by far, the most competitive on price, beating other installers who offer cheap Chinese brands like Aiko, DMEG and the like. The overwhelming majority of their end customers receive their documentation within 3 weeks (DNO delays being the exception) since 2022. I'm sure their recent Trustpilot scores would be terrible if end user experiences were poor. 

FlorayG

I know how you feel, I went through the same discussions. In the end I went with Project Solar because they are a national company well established ( a neighbour had his fitted by a local company now gone out of business so he has no backup) and their representative was able to answer all my questions, which other company reps weren't. The installation went very well and the after sales service excellent.
Was it the best choice for my circumstances? Well, the trouble is I will never know, because that's what I've got now and don't have anything to compare it with   so don't stress overmuch over which to choose - once you have chosen the deal's done

nologo

hi woolgar.c
I have just had a 5.9kW roof system installed by Light Renewables (last week) the install went very well, started at about 10am done by 7:15 pm,
no scaffolding (it's a bungalow), the installation is very neat & tidy no exposed cabling, meters in a cupboard, unfortunately the inverter was doa so waiting for replacement ( due Friday?)

Newbie_John

Hey, as you're talking more about reducing bills rather than being green, I will bring a very different point of view.

You pay about £1400 for electricity (532kWh x 12 months x 23p) so not sure what would be your actual saving - let's just say half of that a year? £700.
Average cost of your quotes.. about £12000.

If we look at rough estimates over 20 years (let's assume all prices and interests stay the same:
* Solar System:
20 years of £1400 electricty = £28k, half saved so only £14k cost and initial cost of £12k so total £26k cost.
* Saving Account 5%:
You will have £24k in your account, £28k electricity cost, so total £4k cost.

There are many unknown here, like what would be the price of electricity in 2045, as well as interest rates, inflation?
Will your system run for another 10 years or will you have to pay for its recycling/replacement?
Will you move out earlier and lose it?
Yes, I know 5% interest rate is quite optimistic - but there are other alternatives like Ripple etc. or stocks of green energy that give 7% in dividends etc.

Obviosuly sales people say the typical that it pays itself in 10 years and then it's free money.. 

Martyn1981

That last quote looks pretty good. Probably worth you maxing out the PV, since it costs more to add bits later*, and nobody ever says they wish they had less.

Generation at a very loose guess, if southish facing and no shade, should exceed 5,000kWh pa. Normally it would be hard to use the higher summer generation figures, but your hot tub and battery would help (even if export rates from Octopus fall), so somewhere around £1k pa in savings might be possible.

*That said, a Powerwall 3 has direct PV inputs, so you could always add some ground mount panels, or even wall/fence mounted (planning permission no longer needed), directly. No need for DNO permission / notification as they'd sit behind the PW3 inverter and DNO permission/certification. 

Martyn1981

Newbie_John said:

Hey, as you're talking more about reducing bills rather than being green, I will bring a very different point of view.

You pay about £1400 for electricity (532kWh x 12 months x 23p) so not sure what would be your actual saving - let's just say half of that a year? £700.
Average cost of your quotes.. about £12000.

If we look at rough estimates over 20 years (let's assume all prices and interests stay the same:
* Solar System:
20 years of £1400 electricty = £28k, half saved so only £14k cost and initial cost of £12k so total £26k cost.
* Saving Account 5%:
You will have £24k in your account, £28k electricity cost, so total £4k cost.

There are many unknown here, like what would be the price of electricity in 2045, as well as interest rates, inflation?
Will your system run for another 10 years or will you have to pay for its recycling/replacement?
Will you move out earlier and lose it?
Yes, I know 5% interest rate is quite optimistic - but there are other alternatives like Ripple etc. or stocks of green energy that give 7% in dividends etc.

Obviosuly sales people say the typical that it pays itself in 10 years and then it's free money.. 

I'm genuinely struggling with that?

If we look at rough estimates over 20 years (let's assume all prices and interests stay the same:
* Solar System:
20 years of £1400 electricty = £28k, half saved so only £14k cost and initial cost of £12k so total £26k cost.
* Saving Account 5%:
You will have £24k in your account, £28k electricity cost, so total £4k cost.

Are you suggesting the leccy company waits 20yrs for you to earn interest, before paying them, whilst they charge you no interest?

Wouldn't you actually have to draw down your savings by £700 each year (the difference between the no PV, v's PV bill), leaving you with less each year?

Also you are adding annual savings interest, but ignoring annual inflation*. The PV savings hedge against inflation since 50% of a bill, is 50% of a bill, even if the price rises.

Lastly, you appear to be valuing the PV system at zero after 20yrs, but I've seen no production degradation after 13yrs, and there's no reason PV can't last 30-50yrs.

*I appreciate you mention inflation, but not including inflation in a calculation that includes annual interest fails to account for the falling value (in real terms) of the capital amount.

Newbie_John

@Martyn1981,

Yes there's many unknowns here, but let's comapre the case when we withdraw £700 every year from 5% savings of £12k towards electricity bill for 30 years vs solar system for £12k paid upfront:
(using this website: https://www.thecalculatorsite.com/finance/calculators/savings-calculators.php)
So in this scenario, solar system is not earning anything (bills are equal in both cases £700 instead of £1400).

a) solar set up -£12000k
b) savings: +£6000 remaining

There is too many unknowns, if electricty price drops to pre 2020 so close to 12p/kWh then this would work better towards savings. If savings/ISA/shares/Ripples (whatever you choose) average out to 1% then solar wins.

Not including inflation as this is a simplified case where we only pay for electricity - and even if know inflation will be above 0% for the next 5 years - that doesn't mean that electricty will be more expensive than it's now, it can be even cheaper.

Martyn1981

Hi @Newbie_John.

Shirley if a) the solar set up is -£12k, then b) the savings should be -£6k not +£6k?

Also I think your £700 figure is too low, which distorts your calculations. If we use £1,000 (based on ~20p/kWh (I believe you'd have to go back a further decade and ignore general inflation to get to ~12p/kWh)), then your bank balance is exhausted by the end of yr 19, whilst the PV asset still exists, and continues to generate/save.

Edit - I'm just trying to keep the calculations fair.