Battery only vs alternatives

cheesesarnie

Hi
As a reasonably heavy electric user with an awkward (south,east and west facing) roof and no pv etc,  I've long had the opinion that a battery only install could be the best solution for us. The 13.5kwh of a givenergy AIO would cover 1 days usage most days charged up from IO or Agile depending when we get on the EV bandwagon.

With the cost of panels dropping and the improvements in export rates I'm starting to have 2nd thoughts but running the numbers is hurting my head.

For us a 4kw solar install would need to be installed to 3 aspects and need 3 sets of scaffolding.

I know the numbers are unique to each set of circumstances but what are peoples opinions on the viability of a 10kwh+ battery only install (assuming all consumed within the house) vs. a non standard 4kw solar install?

Thanks Tony

Netexporter

The saving in VAT on the battery, if installed with solar, would make a good contribution towards the panels.

I see having panels in three orientations as a possible advantage, as you'll be getting a "boost" at times when you are most likely to be using electricity. Do you know that you roof will only carry 4kWp of panels? Worth going for the maximum, as most of the fixed costs are much the same and panels are cheap.

cheesesarnie

Thanks, yes have been speaking to an installer about a tiny max 4 panel install on a garage roof on top of the battery to avoid the vat basically.

On the actual house, a couple of historic quotes have told us max 4kw on the actual house due to annoying aspect shapes and a velux with a conservatory clogging up scaffolding access. There was talk of at least £2k worth of scaffolding once upon a time which made the full solar angle seem a dead end.

Its sounding like a givenergy AIO plus a couple of panels on a garage might be only  £1k more than 4kw panels only on the main roof.

Netexporter

have been speaking to an installer about a tiny max 4 panel install on a garage roof on top of the battery to avoid the vat basically.

Sounds like a good plan. Might be worth considering ground mount, if you have a large garden. You need to get planning permission for that, though.

cheesesarnie

Considered ground mounted but thought for vat avoidance the garage roof looks fair game.
Tbh I'm also wondering if vat on batteries might get dropped in the next budget...that would make the decision slightly easier.l I think

QrizB

There was a thread in mid-2021 on the Energy forum from someone who had a battery-only install in a flat.

With pre-crisis E7 prices, he was looking at something like an 8-year payback. His sums held together and he was happy with them but he got a lot of stick from a certain type of forum members who poo-poohed the idea.

Sadly the thread seems to have been deleted (at least, I've not been able to find it again) but I imagine he did very well over the last couple of years, where the E7 differentials have been much wider.

Petriix

I always say it's important to do your own sums. But don't just assume you'll use x amount per day, run a simulation using your real usage data in a spreadsheet to see how much a battery would have actually saved you. When I ran the numbers I cancelled my battery installation because the savings were much lower than the theoretical maximum; that was when energy prices were much lower though. 

If you don't already have a smart meter recording 30 minute data then that's the first thing you need to sort out. 

cheesesarnie

Yeah got the SMETS2 and on Agile. It's a good shout running the number on past data!