Relatively low electric usage - solar worth it?

Squint

My annual usage is 2200 kwh at just over 25.1p per kwh, the cost is £552.50 a year. Been quoted £7900. The quote indicates we can generate 4500kwh a year. As the quote is via my energy supplier I would sell back at 20p per kwh. In theory if that rate stayed the same it would take just under 8 years to pay back, ignoring the lost interest on the cash savings it will take, but that would be fine.

However, this is with Ovo who I understand will be taken over by Eon who have a lower payment. It isn't guaranteed anyway. For most energy suppliers it is a lot lower which could double the payback time. The trouble is that I would expect to move in 12 years so wouldn't get the pay back. Thoughts or advice?

QrizB

Welcome to Green and Ethical!

Been quoted £7900.

What exactly do you get for your money? The devil's in the detail.

The quote indicates we can generate 4500kwh a year.

Assuming you're not in the far North, that suggests to me that you've been quoted for ten 500-watt panels?

For a conventional installation, I'd expect that to be under £6k. Here's an example of an installer on eBay who's offering such a system for that price:

https://www.ebay.co.uk/itm/226356067773

I'm not recommending that installer or system, bit it's an example of what a "reasonable" price would be.

Squint

Thanks @QrizB you are right it is 10 panels and in the south with a south facing roof, I will get a few more quotes

Screwdriva

https://forums.moneysavingexpert.com/discussion/comment/82154491#Comment_82154491

Are you able to share:

1. Whereabouts in the country you are located?
2. An image of your roof? (Google Earth is better than nothing)
3. Any plans for a heat pump?

At ~2200 KWh per year, no decent battery will make financial sense as the consumption just isn't there to justify the spend. However, Solar on its own still does make sense without a battery.

Installers I use to help others offer 10 X 515W Eurener bifacial panels paired to SolarEdge optimizers + a SolarEdge 5KW inverter for ~£5500 all inclusive, including a 20 year warranty on the inverter, bird netting, G99 and a 10 year workmanship warranty on the entire system. Payback should occur in ~8 years without a battery. The more panels you can fit, the quicker this gets.

Hope this helps?

https://forums.moneysavingexpert.com/discussion/comment/82154485#Comment_82154485

I'm always cautious with these types of installers - this one in particular is peddling low end brands, a 20%+ oversized inverter and is openly stating that a G99 application could incur an additional cost. All backed by only a 5 year workmanship warranty, a limited coverage area and a higher price than above!

Squint

We are in the south and have now had a further slightly higher quote from Glow Green with 8 panels instead of 10 via the company directly referred by Ovo. Battery spec slightly lower too from Glow Green so the Ovo one seems better, but it is too reliant on the 20p back from Ovo for which there is no continued guarantee of payment at that level. I will ask what the savings are by not having a battery.

I think we can get 12 panels on the roof which is south facing.

No plans for a heat pump as our gas usage doesn't warrant it. No plans for an EV either at the moment.

I was surprised our usage was low as husband is retired and at home a lot and he likes electrical gadgets and never cares one iota about electric usage, unlike me. I normally work very long hours and not home much and other than my phone and e bike don't own anything that requires charging.

I have though realised that I was massively in credit with Ovo so getting a refund of £680 and reduced my direct debit to £125 a month for gas and electric. This is a win even though I think I may have somewhat wasted the solar companies time with this.

QrizB

Battery spec slightly lower too from Glow Green so the Ovo one seems better

You didn't mention a battery! If your quotes include a battery, that puts a different complexion on things.

Without a battery, you'll probably only use 600kWh of home-grown electricity each year and will export the rest. That makes your return heavily dependent on export tariffs. Here's a potential breakdown:

• Self-use saving: 600kWh @ 25p/kWh = £150/yr
• Export earning: 3900kWh @ 20p/kWh = £780/yr
• Total return: £930/yr

With a battery, even a small 5kWh one, you'll probably be able to use 12-1500kWh of your own electricity. This means more of your return is independent of your export tariff. It might be more like this:

• Self-use saving: 1400kWh @ 25p/kWh = £350/yr
• Export earning: 3100kWh @ 20p/kWh = £620/yr
• Total return: £970/yr

If your export tariff halved to 10p/kWh, in the no-battery case it would cost you £390/yr but in the second case it would only cost you £310/yr.

Screwdriva

^ I think that analysis highlights that you will struggle to recover the cost of the battery with such low consumption and no heat pump on the horizon.

I was curious and checked with one of the installers I use - A Fronius hybrid inverter based system will cost roughly the same and comes with best in class aftersales support. If I had to decide on one option, I would go with 12 X 515W Eurener bifacial panels and a 6KW Fronius inverter. No battery. Cost should be < £6K all inclusive.

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