What is the Home Energy Storage trial from OVO Energy?

What is the Home Energy Storage trial from OVO Energy?
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Updated on 14/06/21 by Jess_OVO


As part of our journey to Plan Zero we’re keen to see how Home Energy Storage can help to make our homes smarter and our grid greener. As we’re in the next phase of our trials, we’re no longer looking for new participants but you can find out more about what we’re hoping to find out on our Powervault trial page or our Sonnen battery trial page.


Think of them as a large battery which can store up power you generate at home, through solar panels or other micro-generation sources. This can then be used at times when the sun goes in or when your usage peaks. What’s more the energy stored can even be fed back into the grid at times it’s needed most.


Heard about Home Energy Storage before or just discovered it and excited by it’s possibilities? Comment below, we’d love to start a Home battery conversation!


OVO member but not got a smart meter yet? - Book today!


Interested but not yet an OVO member? - Check out our plans!


76 replies

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Although I don’t work in the energy-sector, someone who does has thoughtfully sent me an internal news-sheet from Western Power concerning the Kaluza Storage Trial near Lincoln. Here’s the top of the front-page for your interest:



When we post to this Forum we should be aware that OVO’s Kaluza Division is right at the forefront of what’s happening in the energy industry. These storage trials have countrywide implications beyond what we perceive in our own homes.

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Yes I noticed this too @Stevie_G.

This choice may have much to do with the characteristics of the Electricity Grid in that area. It is very close to a major confluence of National Grid lines. Thus Lincoln’s electricity supply parameters have more to do with National Grid data than the Distribution Grid from which our houses actually get fed.

Kaluza’s software is using National Grid data to identify when storage should be charged and discharged.

So in my area of the Westcountry, Kaluza’s Platform would be more likely to deduce the incorrect charge-times. We have a surplus of renewable energy. There is low correlation between what the National Grid supplies into Devon & Cornwall and the actual sources of the electricity supplied to my home (which I can tell from data for my local Bulk Supply Point).

At this stage of development of Kaluza’s software they’re probably just interested in designing systems to import data rather than dealing with such discrepancies.

That’s why there is currently an odd situation on the V2G Trial. The data-stream from the local sub-station is being obtained from the Distribution Grid near Newquay in Cornwall, but the V2G car charging data is being tested on a Nissan Leaf based in Wiltshire!

The North Cornwall coast enjoys a wealth of renewable energy resources, but little of this can be fed back to Wiltshire via the National Grid because there’s a long-standing capacity constraint which prevents it.

Kaluza may not mind in the case of V2G.

But I would understand it if they now wished to avoid such anomalies occurring in the Storage Trial.

I’m just tagging the Moderators @Darran_OVO and @Tim_OVO to ensure they see what I’ve posted here. They may wish it to be linked to the Forum Topics on the V2G Trial.


Pity this trial is only for people in Lincoln but I suppose it has to start somewhere. Hope it can be widened to Bristol!

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Sorry I've taken a few days to respond here.

I don't think any of the current strategies for Home Storage Batteries or EV's (with or without V2G) can yet be assessed for viability.

Until these devices can be used on a genuine Time Of Use Tariff, we are simply trying to assess lengthy pay-back times whilst constrained by vastly over-simplified National import/export rates.

How can customers know which technology to invest in when they can only count on their existing (12 month?) tariff to which a few pence get added per kWh exported?

Who knows what tariffs will exist in just 6 months time?
Userlevel 2
just caught up on >1 year of posts on this subject. Lots of interesting and useful information - thank you.

The way I see it there are 4 key components and the tricks are sequencing, technology maturity/cost, taking offers/opportunities (like FITs - fail), and cost.

the 4 components we are all juggling are:

  • SMETS2 - no brainier to pursue this path.
  • micro generation - mainly solar so mainly on when we are mainly not using
  • EV - a massive battery - mainly not there when solar wants to store (assuming a traditional work life model) but it should be back connected just in time for the evening solar off/oven & tv on cycle.
  • Dedicated batteries. Always there for solar and acting like a balancing pond for both EV and the local grid.

SMETS2 is free, solar is relatively cheap but is limited value to society without storage and balancing.

EV is a big investment and one where tech will / is improving quickly and cost will go down. Ditto batteries.

Here are the questions:

EV or battery first? given that we have solar.

how long do we wait? When is the next cycle/jump happening in cost /technology for these two?

@Transparent caused me to pause with his comment on Tesla battery. What we don’t want to do is jump in on a £8k investment that solves our personal storage but doesn’t help with the wider 33kv grid.

Rather than publicity promotion from OVO for specific hardware (although everyone likes a tech announcement ) what I really want to hear what their vision or strategy is that is coherent with the national strategies and infrastructure plans / challenges that @Transparent talks about.

how about it @Nancy_OVO ? Looks like You’ve got an enthusiastic, informed and engaged audience here. Tell us what you’d like to do and where you’d like to take it. Then we can all align our individual decisions to a common aspiration and make every battery, EV and solar panel purchase count for even more!
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Hi @rajan It's still a live project. The Storage Battery is one of three OVO products being developed by Indra Renewable Technologies. This now falls within the Kaluza Division of OVO, which is basically everything except the selling of energy to domestic customers.

With hindsight I would suggest that the Press Launch a year ago was significantly premature.

There's a whole heap more work required to allow this technology to be connected to the Grid beyond just designing a box into which you put some batteries, a charger and an inverter.

Firstly there needs to be a new G-standard for grid-connected batteries on single-phase supplies. The present three (G59, G83 and G100) all limit export to 16A.

This is OK if you want to connect a source of renewable energy to the grid, but nowhere near enough if the Storage Battery is to be used "on demand" by the Distributed Network Operator to smooth out peaks and balance phases at the sub-station:-

This graph shows the current on one feed from a substation at the end of February. Not only can you see the "peakyness" of demand, but also the imbalance between the three phases. That equals losses at the sub-station, which simply generates heat.

The advertised spec for the Storage Battery says it has an output capability of 40-45A. That's not covered by any G-standard yet available. But less than this would have little affect on the sub-station variations in demand.

Secondly, OVO need to offer a half-hour variable tariff. Without this, customers could only charge the Battery during an Economy-7 period, and release the energy during the other hours of the day. This is of no use to the DNO. They too need to be part of the variable-tariff structure, buying back electricity when required.

The Regulatory Framework is in place for this Time-Of-Use Tariff, and it is supported within the SMETS commands in Smart Meters. But it isn't yet being offered to customers.
Userlevel 4
What ever happened to this? Looks like the links to the OVO site have all mysteriously disappeared....

Take it that means it didn't work well and it's not going to roll out further?

@Darran_OVO @Nancy_OVO
Only just joined OVO's forums, and delighted to find such enthusiasm for home energy storage, and V2G. But I have been watching this area on and off since having solar panels on my roof in 2011, and thought the technology is there, I'm not convinced the economics are. My rule of thumb is that the total power you can get out of a rechargable batter is the number of kW hours stored, times depth of discharge (without shortening battery life), times cycle life (for that depth of discharge). For lead acid, using 80% and 400 cycles, that is about 320 times the battery capacity. The cost per kWh is the cost per kWh of the battery divided by this metric, eg for lead acid, about £100/320, or just over 30p/hour, even if it is free to charge, and there is no difference between the charge power and the discharge power. For lithium cobalt, the number is about 0.8 x 1,000=800, for LiFePO4 about 0.8 x 2,000 = 1,600. It seems the latest Lithium NMC batteries are claiming 1,000 - 2,000 hours cycle life (but not the NCA's that Tesla use, which are still reckoned at 1000 cycles). At present, on Simple Energy Variable, with Economy 7, I pay OVO 10.038p/kWh (incl VAT) at night, and 17.493p/kWh during the day. So for every kWh stored at night and used during the day (I'm not presuming that OVO would buy my electricity during the day at the same price they sell it), I would save 7.455p. A home storage battery or V2G system has to cost less than £24/kWh (Lead Acid), £60/kWh (Lithium Cobalt or NCA), £120 (LiFePO4 or NMC - if NMC really lasts that long), or its just money down the drain. (BTW that is assuming the chargers and inverters cost nothing, or have infinite life).

The economy is a bit better if I can charge with solar power and discharge to house loads, because I always have surplus power during the day during the summer, and use power charged at daytime rates in the evening - potentially saving 17.493/kWh. However, altering the DC side of my solar system would invalidate my installation certificate and lose the FiT. If you have an electric car and are thinking of V2G, check the cost per kWh of battery before engaging with this. We're all used to mobile phone batteries dying after 3 years, but when you think about it, charging once per day, it is 365 x 3 cycles = 1095 cycles. For some time I was puzzled how Tesla owners expected 8+ years of battery life. Then it dawned on me that at 10,000 miles/year, the car only used 37 full discharges/year (Model 3 with 75kWh battery, using 270 miles EPA range). In practice, charging once per week from 20%-100% (or better practice, charging far less daily), 1,000 cycles should last about 20 years.
So, sorry just jump on the bandwagon late....

I've been playing around with low voltage applications and currently my house lighting is all 12v running from 2x leisure batteries along with all the control gear for my automation etc. Ive been using a mains charger to maintain the batteries for now, but wish to move to wind/solar and increase the battery capacity to be able to use an inverter and run some 240v for the UFH pumps.

I'm really interested in this technology and have just resigned back up to OVO for another 2 years, so how do I get started? what do I need?

The plan is to be at a point where we are off grid sufficient and if we can feed back and make a few ££ so much the better.

Back on point, The home battery technology is a really smart idea.
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Hey @TCndaHouse welcome to the forum, great to see you getting stuck in and posting!

Make sure you have registered interest here.

In regards to which EV to buy, yes the V2G charger technology we are working on, is for Nissan Leaf's only right now, however that will change in the future as this technology develops.

You might want to check out this area of the forum. We have a load of EV customers that have shared their experiences with their EV's so far, so feel free to have look and ask them any questions you like, they are a super helpful bunch!!


We have been with Ovo for just over a year now and everything seems to be going well.

I'm interested in this storage because we have solar panels that came with the house when we bought it and I would like to be able to store some of the energy to use to charge up my current plug-in hybrid and my future electric vehicle.

I know some of your offerings are for Nissan Leaf but I don't believe my electric vehicle will be a Leaf purely because of the range on the Leaf does NOT provide what I would be looking for. I need a vehicle that will get me 250+ miles on a full charge. I wouldn't use that each day but I would be using that during the week when I'm commuting to clients.

I would love to be part of the trial
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Ironically I happen to also meet all of those criteria as well so not sure if that's a good or bad thing!

Like you say hopefully they don't find enough people and have to extend this out further. I'm from South London where I'm pretty sure there would be a massive opportunity that OVO are missing out on here.
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Well @rajan , I passed the first selection stage for the (aborted) XStorage Battery Trial last year. That meant I got to read the criteria for the on-site survey. There are quite a lot of things to be considered:

  • Type of Consumer Unit
  • Spare (physical) capacity in Consumer Unit
  • Spare electrical capacity within the building
  • Possible overheating of unit if placed in a heated room
  • Possible noise intrusion from the battery-unit's cooling system
  • Proximity of the Consumer Unit to battery location
  • Availability of WiFi within range
  • House ownership (or landlord's agreement)
  • Pre-existing grid-connected generation
  • Time left on existing OVO Contract
  • Unrelated nearby fire risks
  • Material the wall is constructed with (for wall-mounted units)
  • Smart Meter
  • Adequate earthing to the property

So I still think there would be difficulty finding suitable sites for the Trial, even if OVO took applicants from across the country.

Goodness knows how they're going to find a cluster of suitable houses fed by the limited number of sub-stations in Rugby which are now part of the Trial. :?
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Maybe for you but the message I have always got when I've contacted them is you should be included and it's going to be going live by the end of the summer and you just need to wait for more updates. Have contacted them a few times.

Again just hope it's not the same excuse with the car charger!
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I don't think OVO have misled us, @rajan. They originally expected to select suitable sites from across the country. And a high proportion of us would've been rejected anyway for technical and contractual reasons.

However, the opportunity to work alongside a DNO is probably a recent development which came about long after we'd already put our names forward.

DNOs can apply for grant funding from Ofgem's Network Innovation Competition (NIC) and the Low Carbon Networks (LCN) Fund to undertake trials which assist them in achieving their RIIO-ED1 cost-controls targets. I suspect they applied for one jointly with OVO and have only just heard they've been successful.

We should note that these RIIO targets require new technology to be designed which straddles responsibilities shared across a number of companies. Some Trials will fail. So it makes sense for OVO to do their first Trial of the new Home Storage Battery from Indra with the costs underwritten by Ofgem.
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Another one who's disappointed from waiting and being told it'll arrive by summer but now it looks like it's not going to arrive for me at all.

I signed up to the vehicle charger as well so hopefully I can at least get that! If not then I'll probably be switching supplier sometime soon as there's really no point in holding out any more hope for these.
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You mentioned looking into getting Tesla Powerwalls, @shadowfixer.

Can I point out that these have only internal micro-controllers to take in electricity (during cheap periods). The point about OVO's Home Storage Battery is that they also have the VCharge software, which operates externally - across the whole nation!

Without any wide-area Storage Network Management, the Powerwall is effectively 1st-generation storage technology. It's job is simply to try to save money for the customer. It will have no positive effect on phase imbalances, and if it's being charged overnight (like an EV), then it will not only increase substation losses but also prevent overnight cooling of underground feeds.

I have no idea if Powerwalls can be upgraded to act as an Auxilliary Load Control Switch once Half-hour Variable Tariffs are available. If not, then they are effectively dumb-devices, operating outside of the forthcoming SMETS2 Smart Meter control system.

They key to OVO's technology is the interlink between the storage devices (incl their new V2G charger) and the overall management provided by their VCharge software.

This will allow OVO to introduce variable-rate tariff systems which allow reselling of energy back to the grid at higher rates because the DNOs can call on that power to balance substation loads. It is far more valuable to them than a Powerwall, over which they have no control.

Assuming the OpenLV trials are successful, all 230,000 ground-based substations could have LV-CAP monitoring fitted. These will have the capability to inform VCharge when and where stored charge needs to be released. For example energy in Home Batteries could be sequentially released within the Westcountry as clouds move across Cornwall & Devon, momentarily causing drop-outs in PV solar-generation.

Please remember, I'm not an OVO Employee. I'm only stating what could happen, and I have no insight into the thinking of the team that devise OVO's Tariff system!

Nor do I know how OVO arrange their energy buy-in system. But I'd hope they will in future be negotiating lucrative price reductions from DNOs who want to call on their Stored Charge network.... and hence share the profits with us customers. :)

But I doubt that the OVO Board would be buying up companies like Indra and VCharge if they were intending to do little more than become a competitor to the Tesla Powerwall!
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@shadowfixer totally agree, but we only found out about the changes very recently and were then working out how best to communicate it to everyone. As I said the trial has taken many twists and turns along the way, so we were trying to get the right balance of "keeping everyone in the loop". Definitely some good learnings here.

We don't have a date yet, as we need to now find people in that specific area, then it will take time to get people through eligibility and then to install. I will do my best to check in with you all more regularly on this to keep you as updated on progress as I can. Phase 2, no dates at all yet. We need to focus on getting this first trial up and running. As and when we have any indication on a phase 2, again I will do my best to keep you all posted!

Great feedback for @Transparent 🙂 He is super knowledgeable so we are glad to have him on board for topics like this!!
@Darran_OVO Thanks for the update. It would have been nice to have had this information sooner in the forums as I am guessing that there are many more people disappointed to not be in the initial pilot than are happy to be in it... Do you know how long the initial pilot is scheduled for, and when we might see some movement towards a phase 2?

@Transparent Thank you also for your very detailed reply - you went to great lengths to explain the situation so that even a numskull like me understands!

That being said, im only 20 miles from Rugby and also supplied by WPD - although way out in the sticks - so am highly unlikely to be involved in any pilot if the idea is to stress test the existing infrastructure.....

Maybe i had better look at financing some powerwalls myself....

Thanks again.

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Hi @shadowfixer; I too am not in the Home Storage Trial area that's been selected. :(

However, from a technical viewpoint, OVO have made an excellent decision to work with Western Power on this. They are at the forefront of implementing the RIIO-ED1 strategy imposed on all DNOs by Ofgem.

The DNOs are required to reduce losses on the Distribution Network (below 33kV). Western Power's website has a good description of the technical losses issue and further pages stating how they are tackling it.

Modern technology like PV solar panels and Electric Vehicles connected to the 240v single-phase domestic supply are increasing network losses significantly, with some substations now exhibiting around 10%. This is unsustainable.

In a nutshell the electricity transmission and distribution networks were designed about 100 years ago, when they looked like this:

But at the start of the 21st century, this is how it now appears:

As a consequence, the phase imbalances cause transformers to overheat. And the underground feed-cables are no longer cooling down overnight because of homes charging EV's on Economy-7 tariffs.

I would suggest that WPD have chosen the specific area in Rugby for particular technical reasons. It is a town with a lot of industry, old substations, heaps of underground cables and very little in the way of commercial (3-phase) renewable energy.

It's possible that they may already be using switched-links between substations within Rugby in an attempt to share the loads. This strategy is called Network Meshing, and is based on the LV-CAP monitoring system which I have described here on the Forum in the OpenLV Topic. There are 40 LV-CAP equipped substations owned by WPD which are trialling the new Network Meshing technology.

Let's remember that we all pay a %age of our electricity bills to the DNOs. It is very much in our interest to assist Western Power in turning around the distribution losses. A decade ago they were less than 5%. If we adopt the right strategies, I see no reason why we can't get them back there again, or even lower.

OVO's Home Storage battery has great potential to reduce phase imbalance and harmonics, and hence lower the substation losses. With relevant inputs to the VCharge controlling software, the batteries can release stored charge rapidly into heavily-loaded feeds, restoring the phase balance.

Well, that's the theory. Now we need the Trial to see if it can actually work!
Userlevel 7
Hi all, some of you will no doubt have received an email today advising of some changes to the first round of the trial for our Home Battery Storage (HES). Whilst disappointing for some of you, the nature of a trial is that things can change.

To confirm for anyone that hadn't registered interest but still wants the latest, we are working with WPD, the DNO for the Rugby area, to use HES to enable the provision of flexible power to a very specific set of postcode to really put the battery technology through its paces. This will allow us to really prove that the technology works and measure the impact on the grid and the benefits to those customers in that one area. This will then help us shape phase 2 of the trial when we get to that.

We've been trying our best to keep everyone updated, but the trial (behind the scenes) has taken many different turns along the way so we wanted to ensure the updates we sent were correct and useful rather than constantly sending updates, changing the parameters or the direction we were heading.

Appreciate its been frustrating for those of you so keen to get your hands on this technology and we are so pleased to see the level of interest this has driven. Please keep an eye on the forum and the website for any future updates.

Just got an email from OVO, slightly gutted to be honest - not in the pilot, despite being located "in the Midlands" (Warwickshire to be exact). Waited all summer with no updates, to the very last 2 days of summer (it was "Coming in Summer 2018) to find out more...

Am guessing it is because i am not in a town somewhere..... Would have been nice if they had told us the selection parameters up front....

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Don't get me wrong, the support guys that are here doing their best to support the community and on easy support requests they do great. But seemingly as soon as they need more details from the techys or in this case product manager, they don't seem to be looped in. It should have just been announced and then the topic locked so that we know that we're just waiting and not expect any updates til they post them :)

Where is the fun in that to lock it down? Then they will not hear everyone's opinion and feedback on the product haha. Plus, they are able to provide that feedback to the people behind the project to hopefully give them an insight what everyone wants for the renewable battery storage.
Don't get me wrong, the support guys that are here doing their best to support the community and on easy support requests they do great. But seemingly as soon as they need more details from the techys or in this case product manager, they don't seem to be looped in. It should have just been announced and then the topic locked so that we know that we're just waiting and not expect any updates til they post them 🙂
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It's not like they have done anything wrong. It's not like EA or any game developers where they give a release date and push it back like three times before it's released haha! At least OVO have said this is coming summer. It's still summer and so they have not broken any promises to their customers. Until summer ends, then I guess people can then prompt OVO and ask what is happening.

True - but what is fairly bad form is opening topics on a forum and then not giving any more details or acknowledging peoples questions. I really don't see the point of forums if the people actually involved at OVO (product managers, etc) are going to bother showing up. I'm active on quite a few internet forums and the ones with the best customer bases are the ones who can be bothered to spend a bit of time chatting with users/customers and actually getting that valued feedback. When I moved to OVO I thought they'd be like that, but doesn't appear that way. The support guys seemingly try their best to help out but they don't appear to be supported by the 'doers' in the organisation to allow us to be informed. They should probably just lock topics like this and just keep it as an announcement to show its not going to be monitored.

I guess they are as excited as we are for their products and they wish to show us. Again, it's like game developers (Yes I am using game devs for being a huge gamer) when they reveal a trailer of their latest game. You only get so much little information until it gets closer to release or on release when they are ready to provide more information. I wouldn't worry about it, just look forward to the announcement, I know I am 🙂 Good things come to people who wait. So far from what I have seen on this forum, there have been a lot of OVO staff assisting customers as quickly as possible.