Solar and battery proposal feedback

chile_paul2

Hi all,

I'd love any thoughts and feedback from the wise folks on this forum on the solar + battery proposals we've had from a local installer.

The installer in question has very positive feedback, has recently completed an install for some friends of ours and really impressed me with their professionalism when they came around to quote - so I'm fairly sold on them unless there are any red flags that you can spot.

They have provided 3 separate proposals and I'm just trying to weigh up the pro's and con's of each - currently I'm leaning towards the EcoFlow battery and inverter.

We currently use 6,000kWh per annum and have high day-time usage as both my wife and I are at home during the day. We have 1 EV and when the next car is up for replacement we will replace that with an EV as well, so consumption will rise in the future. We're limited to a max of 8 panels - other installers have said they wouldn't be able to fit that many (based on Google Earth / online assessments) but this company have attended the property, sent a drone up to take pictures and believe they can fit 8.

We have asked about Tesla Powerwall as I've seen these are recommended on the forum. The installer has said they can install them but don't recommend it as believe SigEnergy and EcoFlow give better value for money.

Thanks in advance for any comments or feedback!

Screwdriva

A couple concerns:

1) Sigenergy and Fox are inexpensive Chinese owned brands that have spotty reputations. Both haven't been around for more than a few years. Neither can compare to the ownership experience of a Powerwall 3, no matter what the installer may claim. Tesla are considered best in class and are the only brand to offer a 10 year unit replacement warranty - if something goes wrong, they replace the entire unit with their latest generation offering.

(Same goes for AIKO btw, their panels have been marketed for < 3 years). Installers love these brands because they are cheap to purchase wholesale.

2) Eurener panels have been made in Valencia since 1997, have a superior fire rating and are ethically manufactured. They come with a 30 year warranty as standard and will produce more power in real world conditions.

The PW3 offers 13.5kW of storage, which is ~30% + more than what's on offer.

The installers I use to help other forum members offer 8 X Eurener 515W (4.1 kWp) bifacial panels paired to a Tesla PW3 for ~£10K installed. Less an additional £375 rebate to you from Tesla. Includes a 10 year workmanship warranty and bird netting, both essential for peace of mind.

That's less £ for more power generated and for more storage, all from established brands. Should be clear that you can do better than what's been quoted to you. Hope this helps!

QrizB

I agree with Screwdriva; you've been quoted a premium price for budget equipment.

Newbie_John

And also in your quote the estimated savings of nearly £1200 are exaggerated.

If you use 6000kWh then savings will be close to £700.

If you put £11k to 4.5% savings account you will make £500 - so your actual savings will be much lower - £200 a year.

chile_paul2

https://forums.moneysavingexpert.com/discussion/comment/81963554#Comment_81963554

out of interest what’s your basis for thinking the savings are over-stated?

The savings interest rate would also in my circumstances be taxed heavily which factors into the calculations

Screwdriva

@Reed_Richards does a good job comparing both options here. Your exact mileage may vary slightly.

QrizB

out of interest what’s your basis for thinking the savings are over-stated?

I'm not the poster you're replying to but I agree they seem to have over-egged the savings.

They've quoted for a ~4kWp PV system. I don't know where you are in the UK but if you're in "the south" a realistic upper generation estimate from such a system would be 4000 kWh/yr.

If you managed to consume all of that as a replacement for mains electricity, on the 25p/kWh standard variable tariff it would save you £1000/yr.

But you're unlikely to self-consume all of it. Even in a 6000 kWh/yr household there will be summer days when you generate more electricity than you can usefully use. So perhaps you'll self-consume 3000 kWh/yr and export 1000 kWh at 12p/kWh. That would give combined earnings and savings of £870/yr.

With a simple model like that, saving £1200 a year seems optimistic.

There are ways to use the battery with a time-of-use tariff (I see you have an EV so you might already be on a suitable tariff) and reduce the average price of the 3000 kWh/yr that you'll still be buying from the grid. As a guess you might be able to bring your average import price down from 25p/kWh to 15p/kWh which would be a further £300/yr saving. £870 then becomes £1170 which is similar to the installer's estimate. However there's no detail in the screenshot you've shared to explain how they got their numbers, and I can't say whether they've assumed creative use of ToU tariffs, or not.

(Also note that if you're currently on an EV tariff and a good proportion of your 6000 kWh/yr is already purchased off-peak at a discount, your current average import price is hopefully less than 25p/kWh and the savings from replacing some of it with solar PV could be rather less than I've assumed.)

chile_paul2

The assumptions in their calculation is that we would consume 1778 kWh direct from the panels and that this would increase to 2935 kWh through use of the battery

Im anticipating a significant portion of the savings to come through use of time of use tariffs to charge the battery overnight.

I had a visit from the installers that @Screwdriva recommended yesterday and will wait for them to come back to me with a quote.

Newbie_John

https://forums.moneysavingexpert.com/discussion/comment/81968990#Comment_81968990

The idea with saving account was very simple, there's plenty of other savings instruments like ISA, LISA, JISA, GIA utilizing tax free thresholds for CGT, dividends.. I don't know your circumstances but there is a lot of options - and let's just use £400 income from that to make it simple.

You already have an EV so there's chance to lock in very cheap ToU tarrif - and if your savings are compared to 25p rate - EV tarrifs offer rates as low as 3.5p although now due to war realistic are closer to 10p. So with your use of 6000kWh a year lets say 2000 goes towards a car 2000*(25-10)=£300, (possibly another £300 when you buy another EV) and some household usage that runs at the same time maybe another £100. So by not having anything installed - you could save £800.

Regarding your set up - due to low number of panels your export amount will be low impacting £ you earn - £1200 is very optimistic, closer to £800.

Sure there are other aspects to consider like price stability - you'll be better of if prices go up (wars etc) but worse if price of electricity drops a lot (decoupling from gas prices etc.), you get more out by considering heat pump, you'll be more green, house value may go up..

My entire point is that before you decide to go with this set up - try to consider some of the points that were raised above.