My experience of getting and running solar and battery

PGammage

About 3 years ago I started looking at getting solar panels and batteries installed. Like most I knew nothing about them and I was daunted at the prospect of spending thousands and being ripped off.

My annual grid consumption was around 3600kwh, with a daily average of around 8-10kwh per day. I spent over 6 months looking into it and eventually sized my own system, selected an installer and proceeded with my install in early 2022. I learnt a lot along the journey and there there were some bumps in the road - but I am very pleased with my system. I ended up choosing a company called Moixa (now closed down 🤦) as their solution was, in my view, good value for money. Key learning points

- Know your daily and annual consumption before getting any quotes

- Background check any installer before committing (companies house,m personal reviews etc)

- Only pay a small deposit and pay at least £100 on credit card for additional protection

- On the day of installation watch what the installers are doing and if you're uncomfortable with what their doing tell them to stop installation until you are

- Once the install is complete test everything (ie charge your EV if you have one to ensure it doesn't drain your batteries)

- Don't make final payment until you have all paperwork (MCS cert, DNO G98/G99, HIES guarantee, user guides)

- Check that what you were quoted is actually what was installed and what is on the paperwork

For the full 2024 year, excluding EV Charging and standing charge, my household electricity cost was £509. Without solar & battery that would have been closer to £980, so I've saved around £470 this year. If I also include export payments (Octopus Outgoing) of £160 - thats a total saving of over £630.

For reference my system is 5.2kwp of solar (JA Solar) & 7.2kwh of battery (Pylontech). The system is a Moixa Smart Battery, so needs no management from me. I don't have a PV Diverter or Solar EV charger - Hot Water heating and EV charging is done off-peak. I'm on Octopus Go and have chosen it over Flux as my Off-Peak EV charging would exceed any benefits of bigger flux export rates

I've written up my experience with some hints and tips to help anyone else doing an install avoid some of the challenges I had. If you're interested please ask

happyretiree

Thank you - that’s very helpful

QrizB

Thank you for the write-up!

I remember your previous thread from 2022:

https://forums.moneysavingexpert.com/discussion/6338376/sizing-solar-battery-requirements-and-selecting-a-supplier

Glad to know everything worked out and is performing as expected.

For anyone interested in "this sort of thing", it gets discussed fairly regularly over on the "green and ethical moneysaving" sub-forum, where the OP's original thread is hosted.

PGammage

QrizB said:

Thank you for the write-up!

I remember your previous thread from 2022:

https://forums.moneysavingexpert.com/discussion/6338376/sizing-solar-battery-requirements-and-selecting-a-supplier

Glad to know everything worked out and is performing as expected.

For anyone interested in "this sort of thing", it gets discussed fairly regularly over on the "green and ethical moneysaving" sub-forum, where the OP's original thread is hosted.

I did try and find a Solar or Renewables sub forum but couldn't find one 🤦. Happy for it to be moved to the other sub-forum if appropriate 

QrizB

PGammage said:

I did try and find a Solar or Renewables sub forum but couldn't find one 🤦. Happy for it to be moved to the other sub-forum if appropriate 

FWIW I think it should stay here, in Energy, at least for a few days. It'll get seen by folk beyond the sandals-and-lentils brigade

Swipe

How much did the installation cost back in 2022 and how much would it cost in 2025? When will you break even and begin to start saving money? I was looking into a battery for storage of off peak electricity but it seems the break even point for me comes after the guaranteed lifespan of the battery.

PGammage

Swipe said:

How much did the installation cost back in 2022 and how much would it cost in 2025? When will you break even and begin to start saving money? I was looking into a battery for storage of off peak electricity but it seems the break even point for me comes after the guaranteed lifespan of the battery.

It was around £9k and 2022 and now it would be closer to £8k. In terms of break even it just depends on how you use the system. In my case for the first two years I just let it do its thing. Now I am exporting more to the grid and being paid extra for it. I expect the roi to be around at eight years, but that's not my total motivation. Yes I wanted my utility costs to drop, environment. 

PGammage

Swipe said:

How much did the installation cost back in 2022 and how much would it cost in 2025? When will you break even and begin to start saving money? I was looking into a battery for storage of off peak electricity but it seems the break even point for me comes after the guaranteed lifespan of the battery.

I thought this might help with the ROI point. 

Baseline - Imagine a household with an average consumption of 10kwh per day and £8k in the bank. Each year the £8k will earn say £400 in interest (based on 5% return) and their electricity will cost just over £1k (based upon 27p/kWh) - that's a net loss of £600. So after around 13 years the £8k savings would be effectively gone and there would still be an annual bill of £1k. After 20 years they'd be down -£7k and getting worse by £1k every year 

Solar & battery - The market price for 5kwp of solar is around £4k, and a 10kwh battery is around £4k fully installed (I know it varies depending on complexity etc - but this is the market price). So a 4kwp array & 10kwh battery should cost around £8k

If sized correctly, the system would cover a proportion of the household consumption - let's say 50%. So the peak rate part of the annual bill will be say £500, with 1800kwh (5kwh/day) being off-peak via battery. So thats 45p/day (based on off-peak tariff at 9p/kWh) or £160 per year. So the total annual electricity bill would be £660.

We also know that 1kwp of solar will generate roughly 0.8-1Mwh per annum. Using the low end figure of 0.8Mwh, if this was all exported at 15p/kWh it would make £120. So a 5kwp system would return £600 per year if everything was exported. This would give you a net annual electricity bill of around £60. 

Think about that for a minute - that's £60 for the entire year!! 

After 9 years, you've recouped the £8k outlay. Years 10-20 you would be saving £1k per year by not having to pay your electricity bill, so you'd have £11k in the bank. After 20 years that's a net position of being almost £18k better off than the baseline position - and that's before you add interest on those savings.

And all the above doesn't take into account beneficial tariffs like Octopus Cosy where you can get 3 off-peak charges per day 🤯 - which would make this even better - especially if your consumption is driven by a heat pump

Now I know this is "man maths" and based on known knowns like export tariffs, and it doesn't factor in replacement kit over time, but neither does it factor in price rises in electricity costs or reducing costs of solar & battery. It also assumes only a 50% offset of peak rate consumption. If you increase this offset, say to 60% then £400 peak, £200 off-peak - net annual bill £0. Or 70% £300 peak £250 off-peak - net annual bill of £50 credit. 80% £200 peak, off peak £250 or roughly £150 credit on your annual electricity bill. 

Bottom line - if you want to reduce your household running costs it makes more sense to have solar & battery rather than money in the bank, and it only gets better the more you use it.

Oscarmax

Similar experience with our solar/battery system including charging up the PHEV (1658 kWh per year) and the standing charge our Octopus Energy bill this year is just under zero, 2023/2024 we paid around £100 per year.