What is Home Energy Storage from OVO Energy?

I've registered for my interest and have my fingers crossed with excitement I am in the trial! Currently an owner of a Nissan leaf with my partner driving a Renault Zoe. We are both enthusiastic for a greener world!

Interesting... but I'd like to know a lot more about this product.

It doesn't seem to be derived from the Eaton XStorage, as was the OVO Home Battery product announced last year. And when I checked the twitter-feed from this morning's OVO Launch Event, there's a picture of a display saying that this new product is available in 5kWh and 10kWh versions.

That's a better than the Home Battery (4.2kWh), but still a long way short of the capacity of a typical EV (Nissan Leaf 2018 = 40kWh).

The financial viability of this is going to come down to the tariff and software controls... both of which can be altered by OVO as they learn more about customer usage.

It all looks very exciting!

Bumblebee :)

I've moved your question over here as we already had a topic and its might help others looking at this thread!

Darran

Follow-up to what I've written above:

I have a few more details on the new Home Energy Storage unit, which I've been sent and am permitted to share on the open public forum:

Capacity: 4.2kWh to 10kWh options
Power: 5 kW continuous, 10 kW peak
Dimensions: 650mm wide x 300mm deep x 1080mm high
Weight: 96 kg -122 kg

Unlike the OVO Solar Store, this new unit is floor-mounted, not hung from a wall, and is suitable to be sited externally.

I don't know a lot more than this (yet) so please don't badger me!

That's excellent feedback @SparkySi!

My own solar-thermal panel clocked 141degC today too. :)

You will be unsurprised to hear that the Home Energy Storage Project Managers (PMs) are reading this thread.

What you say is very important. A typical domestic solar-PV installation is going to be 4kW due to the single-phase Grid-connection being limited to 16A (G83 Standard). So on a day like today, this would fill the largest 10Kw Home Energy Storage in 2½hrs

Remember this is a newly announced product. We don't yet know -

• if it has a solarPV input at all
• if it can have extra slave-units added like the Tesla Powerwall

In the meantime I think it's important that the Forum continues to generate useful feedback, like you have by providing your Generation Graph for today. Thanks.

@Transparent I run a dual inverter SolarEdge system, the 16A limit is not really a big issue anymore, the metering kit that I fitted to give the graphs above also allows export limitation if needed and is acceptable to the DNO as a means of control. It also allows me to run the immersion controller (also SolarEdge). I've attached the graph from today's immersion input, you can see its fully heated the cylinder (250 litres) very early in the day and maintains all day no problem. This is fairly typical behaviour for my system. I have a number of systems with a similar setup including one with a 5kWp input, Tesla Powerwall 1 and immersion control, that site has run grid free most of this month.

The Powerwall 1 was DC controlled battery, which is more efficient but can affect system total output, quite important for some FiT registered systems. The current trend is towards AC coupled batteries, so they effectively monitor for export energy and charge the battery with the same amount. Its basically the same as the Immersion control.

Immersion control input

5kWp solar PV with Tesla Powerwall 1 and immersion control

Hi @f0rbesy,

Interesting comments. So do you have your own PV solar panels, or is there a surfit of renewable energy available in Nottinghamshire?

I can foresee other ways in which your son can be brought up fossil-free, but I'm just trying to learn a bit more about how you expect to achieve that please.

Can I point out two matters raised by what you've written?

1. OVO haven't (yet) told us whether the new Home Energy Storage Unit has any solar connection. Currently all we know is that it can be charged and discharged from the Mains Grid.
2. OVO haven't given any indication that the energy in a Home Energy Storage Unit can be transferred directly to either of the new EV Chargers. It may seem logical to you & I that it does so, but the announcements thus far only declare that both a Grid-connected. There are both cost and technical considerations here.

You are first household I know of with two Leafs. Does that mean you already have two separate Chargers?
If so, what power rating are they?

The critical limitation factor here is that a standard domestic dwelling has a single-phase supply via a 100A "Board" Fuse. The four most hungry electrical circuits which you might have would be these:

• Electric shower 45A (10½kW)
• Cooker circuit 30A or 45A
• EV Charger 30A (7kW)
• Power-ring 30A

Clearly the potential to "blow" the Mains Fuse is quite high!

In future the solution will be technological. Items like the EV Charger and those which are not time-critical (eg washing machine & Freezer) will be connected via Smart Switches (ALCS). ALCS devices will communicate with the forthcoming SMETS2 Smart Meters, and are actually controlled by your Energy Supplier such as OVO.

Somehow we have to move from the present reality to the brave new Smart World. It's possible that the new OVO Home Energy Storage Unit is the missing link. It also might be a Smart (ALCS) device. But again, OVO have yet to announce that.

I'm hopeful that the Project Managers reading this will allow us to know a bit more soon. But in the meantime, I just wanted to point out that we can't infer functionality that OVO hasn't told us about!

That was a stunningly fast response, @f0rbesy!

Everything you're saying makes sense to me. I'm a member of a local Transition Towns Group where we often discuss these issues.

So the new Leaf Charger sounds good for you.

Assuming it is run via the forthcoming SMETS2 Smart Meter protocols, you could not only charge at twice the rate of your existing units, but also ditch the restrictive time-frame of E7.

Hi @NoPoke,

I can clarify that point. The Trial of the OVO Home Battery (Mk I) which didn't actually occur in 2017 was specifically for homes that had no other grid connection.

The reason for this is because the Approvals Certification for a domestic Grid-connection (which is G83) allows for a maximum of 16 Amps per phase. That's why most homes with solar-PV install the maximum possible 4kW using 16 panels.

The quick way for OVO to test their Home Battery control software (VCharge) would be for that battery to occupy the permitted G83 connection. This would only be possible if the home had nothing else already accounting for all or part of that 16A.

Since then, OVO reworked the Home Battery and released it as a dedicated Solar-Store device. Thus it sat between the solar panels and the Grid. This satisfied G83, but limited flexibility.

We don't yet know enough about the new Home Energy Storage Unit to know what configurations OVO might eventually release it in. There could be more than one "Product" based on the same device but operating differently.

Stage-1 is obviously to test the VCharge Distributed Storage Software algorithms, so it makes sense to do this using the simplistic configuration of having the Home Energy Storage Unit occupy the G83 slot - hence "no PV"!

This stage will presumably happen before we have SMETS2 meters available, so the Commands will have to be sent to the Trial Sites using the internet.

In its final iterations I would expect the Battery Unit to be refashioned to operate as an Auxiliary Load Control Switch (ALCS), synced to your SMETS2 meter. The Commands will then use the same encrypted data path currently employed for meter readings, thus making the Storage Network secure from being hacked by hostile foreign parties.

@SparkySi, I've had to read your posts here a couple of times to try and understand the points you're making. I think you're raising some really important issues.

So that others can follow, I'd like to adapt our discussion into a diagram:

This shows the configuration which I believe OVO are contemplating for the Home Battery Trial, on the assumption that no one (yet) has a SMETS2 meter.

The Smart Meter signals are handled by the Data Communications Company (DCC) and passed to/fro OVO using secure links.

To pick up your points I've added a PV Solar Panel and Inverter, although the Notes I've got from OVO state that these cannot be present in houses considered for the Trial.

I obviously haven't included your Powerwall!

With no Auxiliary Load Control Switch (ALCS) capability yet, I would expect the test to be undertaken with the VCharge "Stored Charge Management" Software Commands sent from OVO using the internet and the home's WiFi router.

Because the PV Inverter has no capability to be incorporated within the VCharge System, its output, added to that from the Home Energy Storage Unit, would exceed the maximum 16A permitted. And that's why OVO can't have it there.

Whether the PV panels themselves are rated greater than 4kW or whether their inverter has export limitation makes no difference at this stage. Correct?

Even after the Trial, when SMETS2 meters are available with ALCS capability, there are only two ways in which PV panels can be incorporated:

a. Change the Inverter for one with its own ALCS control
b. Use a modified Home Energy Storage Unit with a PV-panel input (DC)

Have I adequately described the situation?

If so, can I also point out that the final Home Energy Store probably won't be certified G83. It will be capable of putting out 10kW peak, and is not limited to 4kW/16A.

The reason is obvious... the Energy Store is designed to provide balance to the Grid during periods of high demand. It mustn't be constrained from carrying out the very job it's intended to do by being throttled back to 4kW!

... until you start getting charged?! Sheesh, @Asterix187!!

Perhaps OVO have to charge the customer if the "box" is delivered free of charge! 😛

Ah - speculation! That's one of my favourite subjects, @NoPoke!

It used to be called prophecy... but that's so fifteen hundreds (BC), don't you think? ;)
And then there was that slight problem when it transpired false prophets got stoned. Few of them had much of a career left after that!

So.... I like your thinking....
But:

a. if that's all there was to this venture, then it's not very attractive is it?
I mean, if it wasn't for this Trial, whoever would want to invest in a Home Battery. It's just not financially viable; the payback period would extend beyond my lifetime. And that's assuming I never had to pay for any maintenance or repairs.

b. I think we need to remember OVO's heritage. John Fitzpatrick wants to see a bright energetic future with lots of renewable generation that doesn't have to be backed up with nuclear-power to fill in the gaps.

c. These new Home batteries, EV Smart Chargers and V2G products (all announced simultaneously) are all designed to hang off Smart Meters. The Trial may well commence during the era of SMETS1, but I have little doubt that this technology has inbuilt protocols to operate as Auxiliary Load Control Switches (ALCS). Even before SMETS2 is released, that functionality could be mimicked using the internet during a Trial Period.

d. The days of Economy-7 are coming to an end. SMETS2 introduces 48 time-of-use (TOU) blocks throughout the day (ie half-hour tariff slots). OVO won't want to be Trialling concepts that are about to be superceded.

I live in an area which experiences gluts of renewable generation. Apart from a couple of local hydro-stations and an anaerobic digester, the rest isn't under manual control. When the wind blows or the sun shines, we have more electricity than the grid can cope with.

There's no point telling Western Power that they should export it to the Midlands or South East where it's needed to satisfy demand. We haven't got the infrastructure capacity to get it there!

If I was part of an OVO-managed (VCharge) distributed storage network, they would need to charge batteries in my area whenever we had renewables over-generation - not when it happened to be cheap during the small hours of the night.

So by all means, let's speculate... but we should be thinking much bigger than what we presently understand of electricity supply systems.

More speculation/ random opinion.

FWIW I think that distributed battery storage is a game changer for the grid. What is as clear as mud is the economics of such, though I expect with the rise of intermittent renewables, battery storage will become increasingly important. May require a change in regulation to reduce the minimum amount of thermal (inertial) capacity that the grid has to provide and large scale trials such as OVO's could provide data to enable that change.

Not speculation: There is a fairly new 1GW link between Hunterston Scotland and Liverpool , another 1GW to come online later.