UK Home Battery Storage

Thinking allowed and wondering if anyone has experience or idea on this stuff, I'm living in the NE of Scotland and have full electric heating, soon to be 2 electric cars and trying to figure out if getting home battery storage would be beneficial (cheaper home running costs) for me.

As my heating is electric and mostly storage I have an economy 10 type tariff, my thinking is, to get smart battery storage, charge up over night and use the electricity through the day, charging up cars, lighting, top up heating when needed etc. I don't have solar and not planning on installing.

For info.

15,000Kwh/year on heating @ 7.560p / kwh
5,000Kwh/year on day rate @ 19.5p / kwh (cost of charging cars not currently included, took this estimate from bill but would try and do as much overnight as possible)

I would essentially be looking to offset the day rate usage and wondering if it was worth it or does anyone have any other alternative ideas?

Bern

Historically, the cost of the battery plus the cycle count/lifespan kills this approach, but what product were you considering?

Are you talking lead/acid battery or something else?

I heard of places doing this on a massive scale years ago (hotel somewhere) but I've not heard of anyone doing it at home. Seems expensive initially and no one here wants to lose space to batteries. Safety aspects to consider, etc.

Why can't you charge your cars overnight on the cheaper tariff?

The main appeal for domestic batteries is people with lots of installed solar who have electricity "for free" due to low feed in rates. I've not hard of anyone trying to arbitrage day and night rates like this.

Swapping the storage heaters for an air source heat pump would likely greatly reduce your electricity consumption, although the capital cost could mean it takes a long time to recoup. But the same goes for batteries.

Are you talking lead/acid battery or something else?

LifePo4 is pretty much at price parity with lead acid for the same nominal capacity, with much greater usable capacity and longevity. And denser too.

Are IKEA offering their solar/battery systems in the UK? Could you get enough power off them in the NE of Scotland? They're very reasonable priced and quality looks very good from what I've seen...

This is very much early days back of fag pack stuff but I'm essentially a tight arse and trying to save some pennies so airing my thoughts to see if they hold water.

@JonoMarshall, so yeah, state of health of batteries will have to be considered, haven't done enough research to be considering anything in particular but will drop examples in here once I've had more of a look.

@lynx, will likely be lithium, would have to be a smart setup as well which will likely add to the cost

@hippy more things to consider but think I have the space for it, the fact not many folk have considered it also intrigues me and makes me wonder if there is a reason for it.

@grams cars will be charged overnight and heaters will be charged up also on the cheap rate, I'm looking to fill a battery with juice and use it for everything else through the day. There would not be enough capacity for heating and car charging but should be enough to cover day time usage.

Looked at solar, and the payback wasn't great but the battery side interested me, specifically loading it up with cheap electric. Especially as it may also protect against power cuts as well.

Have looked briefly at air source but can't face having my house ripped up for all the piping and the cost is pretty high to say the least. With batteries, the initial cost should be lower, but then so would the payback, still lots of thinking and research to do.

I know they had something a while back, will look again, if I could latch solar on at the same time that would work quite well, but loading up on cheap electricity on the night rate would actually make it more viable I think.

I looked into it very recently, we don't use enough power to make it viable ATM but once we move over to an EV I'll be straight onto it... Different meteorological conditions in Oz to where you are, obvs, but good luck!

We looked into lots of PV/overnight electricity storage options before settling on a sunamp unit. More than 50k cycles with the restriction of only using it for heating/DHW was a decent tradeoff. If you can use all the overnight electricity into a car/TS then you might get equivalent gains, but generally electric batteries (outside of an existing car) couldn't pay for themselves compared to a daytime tariff and a TS has standing losses and the added space requirements.

Had to look that up but looks interesting, have full electrics heating so don't believe that would work there.

For cost wise, if I can use my 5000kwh a year from the battery, that would be over £500 per year saving, in theory, just based on all day time electricity usage being from the battery. Not sure how likely that is

No idea, have not kept up with the tech developing. Then the health and safety issues of lithium.

@bernhard It would also depend what kind of space you had, and how much money you had to invest and if there are any grants. Depending on how much work was needed would the savings on VAT make it viable to complete a new build.

Every kWh of battery allows you to shift 1 kWh of usage to the night rate it saves you 12p a day, or £43 per year.

Current battery pricing is around £400-500 per kWh. I think you’d be lucky to break even within the lifespan of the battery.

Tbh your daily non-heating energy consumption seems rather high. A good look at what you’re using and whether it can be shifted to overnight might be more worthwhile.

Besides cycle life of batteries (which might well be the killer), remember you'll also have to budget for an inverter.

The grid is AC (as are most of your appliances) and batteries are DC.

So you'd buy cheap AC power at night and rectify to DC to charge your batteries. No issue there.
But you'll need to invert back to AC to run your appliances, requiring a beefy 4-5kW inverter which will add £550-700 to your system cost.

Also, losses.
Rectifiers, batteries and inverters each have efficiencies higher than 90% or even 95%, but when you stack these inefficiencies up together you might lose near 10% of your energy. (But the losses will be heat which is actually valuable/usable in the home, less valuable in a garage.)

This is what I needed to hear and hadn't properly considered, will look at this further, I would need usuable storage up to 13kwh (average usage, so probably higher in the winter) charged up each night to make this work which increases the costs significantly, back to the drawing board

Robert Llewelyn and his fully charged show has multiple you tube episodes on this subject .He’s got a couple of Tesla power walls and solar .. he got them free from a rewards program I think .
From what I’ve watched , without solar you’d be a long time , if ever , covering your outlay .

I'm in a similar situation, across in Moray and full electric on a THTC tariff.
As per the thoughts above, investing in batteries, charge controller, inverter doesn't make economic sense with the differential between rates.

My heating was storage heaters and water immersion switching on a few times per day wired into their own fuse box. Also some wall mounted dimplex convection heaters, towel rails which come off the same meter at the cheaper rate, but are always live and wired to a separate fuse box with breakers in it.

Last winter I started fitting IR panel heaters and smart thermostats in each area to replace the storage heaters, wired onto the always live supply. In mid winter, running costs seem the same as having the storage heaters cranked up, but the house is much warmer in the evening.

They have been good over spring/summer, as you feel the heat from them in a few minutes, so switch on if you feel cold.

I think Solar HW has been worthwhile overall. It doesn’t contribute much over winter, but heats the bulk of 2 to 3 showers worth on a reasonably bright day, with just a small top up of about 1KWh from the immersion before morning... my solar panel is now 15 years old and needs a new cover.
Adding an additional wrap around jacket to the foam clad HW cylinder must be making a saving as you can feel its toasty warm underneath.

Yeah, have priced up solar with battery as well showed a payback of 20 years, sod that, think I can now forget about this pipe dream :(

Can an air source heat pump generate electricity or will it just spit out heat? When I used to work on sustainable building magazines it was all ground source heat pumps, wind turbines and solar panels, batteries were still a pipe dream... There must be grants for this kind of stuff up in Scotland, no?

We have the renewable heat incentive up here but really not sure how it pays back, one of our neighbours in a very similar property is an architect, he has looked at it all and hasn't changed a thing so far. Heat pumps are just air conditioners in reverse so don't spit out any electricity but the coefficient of performance is always above 2 or 3 I think, meaning 1 unit of electricity will produce 2 - 3 units of heat but requires a plumbed in central heating system which we don't have.

but requires a plumbed in central heating system which we don't have.

Air to Air split systems are a thing and would be efficient most of the time in Scotland. There's probably several days per year when it's below 5ish degrees and damp air which will bring the COP down closer to 1

https://youtu.be/7J52mDjZzto

I like heat pumps, but we had below freezing for a month, now thinking, UFH ground floor and panel heaters upstairs but just need to make sure it is at least cost neutral and still warms the house properly.

Don't the cars have 2 big batteries in? charge cars over night, power home with cars during the day.

Is this a thing?

I think this is going to be a thing , not many cars can send charge back as I understand it .
That new Hyundai does though .
I’m sure I read some town in USA has the yellow school buses running as EV -
and they return the electricity to the grid once they have done the morning run