Solar#3: Supplier Selection

 

I contacted 4 companies for quotes with a bias for local companies:

 

Company	Local A	Local B	Octopus	Lovatts
Equipment proposed:  Panels  Inverter  Battery	14 x JA 405W Solis 5kW n/a (website shows Tesla)	14 x Tier-1 390W Solis / Solis hybrid	14x JAM 405W GivEnergy 3.6kW GivEnergy 9.5kWh	14 x Longi 400W GivEnergy 5kW GivEnergy 9.5kWh
Estimated annual production (kWh)	4,119	4,232	3,844	4,440
14 panels no battery	£9,665	£9,445	Not comparable	£10,047
14 panels with battery	Not offered	£16,656	£13,499	£13,647
14 panels with battery, in roof install / re-roof	Not offered	In current roof only - no re-roof option	Not offered	£16,220
Pre-quote visit	No - just Google maps	No  - just Google maps	No - Google maps & photos that I sent	Yes
Quote impression	Did not bother to visit Initially quoted for the wrong house! Errors in roof angle & house direction. Never bothered to ask if I wanted a battery. ROI very optimistic (eg based on 40p/kWh & no knowledge of our electricity consumption) No advice	Low headline price and then addons (eg scaffolding) Quote complex with lots of options (above price totals could be wrong) Would fix quote after £500 deposit & site survey. Limited advice from telephone call with salesperson.	Professional/ knowledgeable phone consultation and quote adapted with many options (battery size, number of panels, etc). Simple fixed price (small print has possibility of price change after site survey)	Professional quote with simple options and adapted over a couple of phone calls. Knowledgeable on solar generation AND roofs (eg inspected my current roof/attic).
Companies house  registration date  Number of registered Directors	2015   1	2010   1	2015   9	1962   8
Easy to get hold of before and after purchase & installation	No expert offered pre-quote. Seemed uninterested before the purchase; would this improve if any issues after installation?	No expert offered pre-quote.  No sense of depth to the business.	Large company. At the time I had a disputed £2,500 electricity bill; my sense was that this would be resolved & it was in the end, but it took a long time. Solar sales centre approx 250miles away.	HQ is 7miles away.
Reputation	Unknown, nice website.	Unknown	Enthusiastic about green energy.	Good local reputation as roofing contractor & now solar

 

Note: each quote was the result of a different discussion and so they are not always directly comparable. I have done my best to select pricing for similar configurations.

 

Considerations:

• My preference was always for a local company - someone who you can physically meet with if things are not working and also a professional company bothered about their reputation.
• Our house, and roof, is about 50 years old and, while the roof works (ie it does not leak), I am told (by a few people) that it is somewhere near the end of its life expectancy:
• It is a must that the supplier is knowledgeable about the roof and the installation does not lead to any roofing issues.
• Given that a re-roof will possibly be required during the life of the solar system then re-roofing and installing the solar panels seems a good way to kill two birds with one stone (note, the above re-roof price is just for the half of the roof with solar panels). My impression is that in roof installation is more elegant and, I feel, more robust (eg bird or wind damage), but I have no data to back up this latter point.

 

The two local companies, "A" & "B" ruled themselves out early by their approach to the quotation:

• One quoted for the wrong address and took some convincing that we live where we do!
• One had a very complex quote. It did sound like I would get a technical expert and a more thorough quote when I paid a deposit, but that seemed a bit risky to me when I am not familiar with the company.

 

The final decision was between:

• Octopus who almost won me over with their enthusiasm and professional approach. A key issue was an ongoing issue with an overcharge of £2,500 on my Octopus electricity bill (historic electricity charges); this was taking several months to resolve. Octopus were friendly and helpful about this and have since agreed with me that their billing was incorrect and refunded the money to my account (Octopus never chased payment of the £2,500, I just had a negative balance while they investigated). Resolution just took too long and happened at the wrong time for my solar supplier decision.
• Lovatts: a local (Bury) roofing contractor with a good reputation. They seem to be taking the newer solar side of their business seriously and the only company to offer an in roof install with a re-roof (ie replace roofing felt, batons and tiles). They were the only company to visit before quoting and appeared the most knowledgeable about both solar power, my roof & the installation process. Lovatts pass my 'local - someone I can get hold of' test also my 'knowledgeable about roofs' test.
  

 

It was reassuring to see that, barring the odd outlier the price and energy production estimates were similar, when comparing similar specifications. However, there was much more variability in ROI calculations, so I did my own - see below.

 

Finally, my assumption was, that by picking a reputable installer, then they would have done the hard work of selecting good quality equipment, but I did do a few checks on GivEnergy:

• Trust pilot score of 4.3 with 70% at 5 star, but a decent number (16%) 1 star reviews - mixed stories on support.
• GivEnergy is a fast growing UK company, so potentially better for support than non-UK.
• Octopus (ie a large company with resources to assess properly) supply GivEnergy equipment and support it with their Intelligent Flux tariff (as of April 2024 GivEnergy is the only integration quoted by Octopus: https://octopus.energy/intelligent-flux-faqs/). This reinforced my impression of GivEnergy as a leading supplier.
• None of the inverter/battery supplier websites were very forthcoming on the effort required to set up and operate the system. My view is that I want a low effort system - 'set and forget' (just like my other pension investments). The GivEnergy website is reassuring in this respect: "For those who simply want to set and forget, the system’s default ECO mode will dynamically maximise your self-consumption. Meanwhile, inbuilt algorithms mean that your battery will charge and discharge intelligently – automatically taking advantage of cheap rates. This means that, if you choose, you can leave your solution to ‘just work’." https://givenergy.co.uk/solar-battery-storage/
• GivEnergy has an intriguing battery benefit statement on their website "Protect your energy supply from disruption" (https://givenergy.co.uk/products/home-battery-storage/). The implication sounds great - a power cut plunges the neighbourhood into darkness and our house remains lit up! I can see practical issues with this (eg what if our home consumption goes over the maximum battery output power?), but this would be a nice to have, even with some inevitable limitations.

 

Finally, the Lovatts pricing was in line with others. I decided to go with Lovatts in roof with GivEnergy battery, but does the ROI calculation still work?

 

My updated ROI calculation:

• Solar panels: I used the Energy Savings Trusts total solar production (3,400kWh), pro rated for 14 solar panels, as opposed to 12, but the same domestic usage from solar (ie 1,258kWh). I used the current (Nov '24) Octopus daytime export tariff (17.44p/kWh as opposed to the Energy Savings Trust 5p/kWh) and consumption tariff (28.44p/kWh). I also found a more realistic inverter replacement cost of £1,450.
• Battery: it was hard to estimate how much this would impact ROI from solar production (ie how much solar production that would have been exported at 17.44p/kWh would save importing from the grid at 28.44p/kWh and how much I could export in the evening at 28.82p/kWh (Octopus Flux peak export tariff) . In the end I decided to assume that I fill the battery at the Octopus Flux cheap rate and discharge fully at the peak rate every day of the year with no change to self-consumption estimate of the Energy Saving Trust. In the end I may work out a better approach, but at least this would be a baseline that I could calculate. I used a battery replacement cost, midway through the 25 years of £3,500.

 

This gives ROIs of:

• 8.3% without battery, on-roof installation
• 6.1% without battery, in-roof installation
• 7.7% with battery and in-roof installation

 

Taking the 'with battery and in-roof' case I repeated the ROI calculation from Solar Panels Investment Case. I pro-rated this to an initial investment of £7,000 to make it comparable to these original calculations. This gives:

 

 

• People's Pension Global Investments (up to 60% shares): £10,000
• Hargreaves Lansdown Fidelity World Index: £80,000
• Solar Panels (generic - my 1st calculation, based on generic Energy Saving Trust figures) : £15,000
• Solar Panels (my quote from Lovatts for in roof, with battery): £11,000

 

The solar panel investment case is less good than my original estimates. The main differences are:

• In roof return is ~£2,000 less, but I do get the comfort of knowing that half my roof is renewed.
• ~£2,000 less for additional mid-life equipment replacement allowance (battery and more expensive inverter)
• Octopus Flux export tariff is higher than the 5p/kWh assumed by the Energy Saving Trust.
• There was also a small reduction in import tariff with the Octopus winter 2023/24 electricity tariffs.
• Adding the battery makes a small improvement to my ROI calculation, but I think that this is where my assumptions on return are most flimsy and I could not find much published information on their operation (technical or financial).

 

My decision was to go ahead with Lovatts in roof with battery:

• ROI is in the ballpark/slightly better than a (typical?) 'medium risk' pension investment.
• Increase my investment diversity so reduced overall risk
• 'in-roof' removes worry that major roof work will be required (ie better than on roof or no solar) and looks better than 'on roof'
• Battery has slightly better ROI than no battery and the possibility of maintaining power during a power cut swings it.

 

Of course all the above is based on my own viewpoint and biases and I may have missed something; while it is now too late to change my mind, I would be interested in constructive comments.