Yes, you can install a home battery with no solar panels and charge it from the grid on a cheap night rate. Four things make it harder than it looks. It is taxed differently: a battery fitted alongside solar panels is zero-rated for VAT, a battery fitted on its own carries the standard 23%, so identical kit costs more than €1,000 extra. The grant is small: SEAI's €1,800 solar grant is paid per kWp of panels, so a battery-only job gets none of it; the only grant is SEAI's separate €600 battery grant, open since 6 October 2026. There is no export payment: the Clean Export Guarantee pays for renewable electricity, and grid electricity you stored is not renewable generation. And the round trip costs you: you buy more kWh than you get back. On Electric Ireland's own published rates we make the payback 9.5 to 15.5 years on a €6,150 install, or about 8.6 to 14 years after the €600 grant, against a 10-year product warranty.
Every rate on this page was read from the supplier's, the regulator's or the manufacturer's own published page on 19 August 2026 and includes VAT at 9% on electricity unless stated otherwise. Where a number is our own arithmetic rather than a published figure, it says so.
This is the no-panels case. If you already have solar, or you are pricing a battery as part of a solar install, start with battery storage in Ireland and what a 10 kWh battery costs instead. Those pages assume a battery that soaks up your own generation. This one assumes it has nothing to soak up.
What You Are Actually Buying
Without panels, a home battery does one job: it moves the time at which you buy electricity. You import cheap units overnight, store them, and draw them back out when the rate is high. Nothing is generated. Nothing is saved on consumption. You are trading on the gap between two prices, which is why the size of that gap decides everything.
Electric Ireland publishes these rates for new electricity customers. They include VAT and, where the plan carries one, the standard discount.
| Plan | Day | Night | Other band |
|---|---|---|---|
| 24 hour flat smart rate (the cheapest flat rate on the list) | 29.81c, all hours | ||
| Home Electric+ Night Boost | 37.60c 08:00–23:00 | 18.54c 23:00–08:00 | 10.88c boost, 02:00–04:00 |
| Home Electric+ SST | 32.43c | 17.04c | 34.60c peak, 17:00–19:00 |
| NightSaver (day/night meter, no smart meter) | 34.12c | 16.83c | – |
The 2am to 4am boost band is the whole prize. At 10.88c against a 37.60c day rate, the raw gap is 26.72c a unit. Nothing else on the Irish market comes close to that spread for a household with no generation of its own.
The VAT Trap Nobody Quotes You On
This is the single biggest difference between a battery bought with panels and the same battery bought alone, and it is not a grey area.
Revenue's tax and duty manual on the supply and installation of solar panels sets out that from 1 May 2023 the zero rate applies to supplying and installing solar panels on private dwellings. Section 3.1 then extends that zero rate to “ancillary equipment supplied and installed with the solar panels as part of the same supply and install contract for the solar panels, such as the wiring, the controller, the combiner box, the batteries”.
Read the condition rather than the list. The battery is zero-rated because it is ancillary to a solar panel contract. Take the panels out and there is no solar panel contract for it to be ancillary to. Revenue's own page on the standard rate of VAT then removes any doubt about where that leaves you: the examples it gives of goods at the standard rate are solicitor services, furniture, batteries, motor vehicles, consultancy services and tyres. The standard rate has been 23% since 1 March 2021.
| Job value before VAT | Fitted with solar panels (0%) | Fitted on its own (23%) | The difference |
|---|---|---|---|
| €4,000 | €4,000 | €4,920 | €920 |
| €5,000 | €5,000 | €6,150 | €1,150 |
| €6,500 | €6,500 | €7,995 | €1,495 |
Teagasc's battery storage factsheet tells readers to factor VAT in, and says “installing a battery with a solar PV system incurs 13.5% VAT, while retro-fitting a battery attracts 23%”. The retrofit half is correct and matches Revenue. The with-solar half is two VAT regimes out of date: 13.5% was the position before 1 May 2023, and the rate on that side is now zero. The structural point stands and the gap it describes is now wider, not narrower, than the factsheet says.
A €600 Grant at Most, and No Export Payment
SEAI's Solar PV Scheme pays €700 per kWp up to 2 kWp and €200 for every additional kWp to a maximum of €1,800. Every euro of it is calculated on installed panel capacity. None of that €1,800 is available for a battery on its own. Since 6 October 2026 SEAI pays a separate flat €600 towards a battery of 5 kWh or more (the Battery Energy Storage System grant), installed by an SEAI-registered solar PV company after you get the grant offer, in a home built and occupied before 2025. SEAI's criteria don't require panels, and the post-works BER is only required where the home has solar PV, so a battery-only job of 5 kWh or more can claim it (seai.ie, read 7 October 2026). On the €6,150 install below, that brings the cost to €5,550.
The export side closes off too, and the reason is worth reading carefully. The CRU's microgeneration page defines what earns the Clean Export Guarantee: electricity generated from renewable sources, and it adds that electricity “generated from renewable sources and is then stored in a battery to be used or exported at a later time is still regarded as renewable energy”. The qualifier is doing the work. Renewable electricity that passed through a battery still counts. Grid electricity that passed through a battery was never renewable generation in the first place, so there is nothing for a supplier to remunerate.
In practice that means a grid-charged battery should be set to self-consumption only. You are not going to be paid for exporting units you bought a few hours earlier at the night rate. See our page on Clean Export Guarantee rates for what the scheme does pay, and to whom.
You Still Have to Tell ESB Networks
People assume that with no generation there is nothing to register. That is not how the rules are framed. ESB Networks defines micro-generation by the rating of the inverter connecting to the network, not by what sits behind it. Its standard says the inverter capacity “facilitates combinations of energy sources such as storage and generation, behind the inverter”, and its definitions section is explicit that Energy Source Capacity covers “Generation and energy storage”. Its published list of micro-generator types includes combined renewable micro-generators and storage systems.
So the test is whether your battery inverter can push power onto the network, not whether a panel is attached. If it can, the installation sits inside the micro-generation notification regime and the NC6 form applies, with the inverter type-tested to I.S. EN 50549-1 and installed by a Safe Electric registered contractor. If your installer intends to configure it as zero-export so it never energises the network, get that in writing along with the type test certificate. Our guide to the NC6 form covers what the notification involves.
The Round Trip Is Where the Argument Is Won or Lost
A battery gives back less than you put in. How much less is genuinely contested, and the two most quotable Irish and manufacturer sources sit a long way apart.
Tesla's own Powerwall 3 datasheet for this region lists two separate figures: solar to battery to home or grid at 89%, and solar to home or grid at 97.5%. The second is the pass-through number for electricity that never enters the battery, measured on EU weighted efficiency methodology. It is not a round-trip figure, and any page quoting “97.5% round-trip efficiency” has taken the wrong row. Note too that even the 89% is the solar path, where the electricity arrives as DC. Charging from the grid adds a conversion that path avoids, so 89% is a ceiling for what we are doing here, not an estimate of it.
Teagasc goes the other way, and specifically about this exact practice. Its factsheet warns that with batteries recharging overnight on night-rate electricity, “the efficiency losses changing AC current to DC current to store it, and then converting DC back to AC to use it, mean that as much as 25-30% of the night rate electricity is wasted in efficiency losses, making the exercise unviable”. That is a round trip of 70 to 75%. The same page also says each conversion loses 6 to 8%, which would put the round trip near 84 to 88% and closer to Tesla. Both numbers are on the one page and they do not agree with each other.
Rather than pick a winner, everything below is run at both ends. If your real system lands at 89% you get the good column. If Teagasc's warning is nearer the mark, you get the other one.
| Charged at | At 89% round trip | At 80% | At 70% |
|---|---|---|---|
| Night Boost, 2am–4am, 10.88c | 12.22c | 13.60c | 15.54c |
| Night Boost, night band, 18.54c | 20.83c | 23.18c | 26.49c |
| SST night, 17.04c | 19.15c | 21.30c | 24.34c |
| NightSaver night, 16.83c | 18.91c | 21.04c | 24.04c |
| Compare against | 29.81c, the cheapest flat smart rate you could have stayed on | ||
Read the bottom row before the rest. The usual mistake is to compare a battery kWh against the 37.60c day rate, but that day rate is only on your bill because you moved to a night plan. The honest comparison is against the flat plan you would otherwise be sitting on. On that basis, charging in the night band at 70% efficiency saves 3.32c a unit, which is not a business case. Charging in the boost window at 89% saves 17.59c, which is.
The Tariff Alone Loses You Money
Here is the part that catches people out. A night plan is a trade, not a gift. Moving to Night Boost adds the cheap band and, in the same move, raises the price of everything you use between 8am and 11pm from 29.81c to 37.60c. That is 7.79c more on every unshifted daytime unit.
Take the regulator's benchmark household. The CRU sets 4,200 kWh a year for an average home, a figure Electric Ireland uses in its own estimated annual bill calculation. Assume 65% of it falls outside the 23:00 to 08:00 window, which is our assumption, not a published one, and works out at 7.48 kWh a day.
| Setup | Annual cost | Versus the flat plan |
|---|---|---|
| Flat smart plan at 29.81c, no battery | €1,252.02 | – |
| Night Boost, no battery | €1,299.02 | €47.00 worse |
| Night Boost + battery, charged in the night band, 89% | €841.24 | €410.78 better |
| Night Boost + battery, charged in the night band, 70% | €995.60 | €256.42 better |
| Night Boost + battery, all charging at 2am–4am, 89% | €606.27 | €645.75 better |
| Night Boost + battery, all charging at 2am–4am, 70% | €696.86 | €555.16 better |
The second row is the finding. Switch to a Night Boost tariff without a battery, at the regulator's own benchmark usage, and you are €47 a year worse off. Every cent of the gain in the rows underneath is produced by the battery, not by the tariff. If the battery is out of service for a month, you are paying 37.60c for your teatime electricity with nothing offsetting it.
Can Your Battery Actually Charge Fast Enough?
The 2am to 4am band is two hours long. To cover 7.48 kWh of daytime use you have to import 8.40 kWh at 89% efficiency, or 10.68 kWh at 70%. Squeezing that into two hours needs 4.20 kW or 5.34 kW of sustained charging power.
Teagasc puts the charge and discharge rate of the batteries typically installed here at 2.0 to 5.5 kW. Tesla's Powerwall 3 is configurable up to 5 kW of continuous AC charge power, rising to 8 kW with expansion units. So the top of the market can just about fill the boost window, and the middle of it cannot.
| Charge rate | Round trip | Annual saving | Payback |
|---|---|---|---|
| 2.5 kW | 89% | €550.58 | 11.2 years |
| 3.7 kW | 89% | €617.68 | 10.0 years |
| 5.0 kW | 89% | €645.75 | 9.5 years |
| 2.5 kW | 70% | €396.22 | 15.5 years |
| 3.7 kW | 70% | €463.32 | 13.3 years |
| 5.0 kW | 70% | €536.01 | 11.5 years |
Going from 2.5 kW to 5 kW is worth 1.7 years of payback at 89% efficiency and 4.0 years at 70%. Charge rate is the specification most quotes bury and most buyers never ask about, and on a battery-only install it matters more than capacity does.
Buy a Smaller Battery Than You Think
Your daytime consumption caps the useful size, not the other way round. At 4,200 kWh a year with 65% in day hours you have 7.48 kWh a day to displace. A battery with 13.5 kWh of usable capacity cannot cycle what is not there. The extra capacity sits idle, and you paid 23% VAT on it.
The exception is a household well above the benchmark: an electric car charged at home, storage heating, or a heat pump. Those push daytime and evening demand up and can genuinely use a bigger unit. Before buying on capacity, pull your own half-hourly data from the ESB Networks customer portal and count how many kWh you actually use between 8am and 11pm. That file, the HDF, holds up to two years of readings and follows you if you switch supplier.
One deep cycle a day for ten years is about 3,650 cycles. Teagasc puts current batteries at 6,000 to 10,000 warrantied cycles, with a product warranty normally of ten years. Tesla warranties the Powerwall 3 for ten years and requires it to stay connected to the internet to keep the full term. Daily arbitrage will reach the calendar end of the warranty long before it reaches the cycle limit, so the ten-year product warranty is the number to plan against, not the cycle count.
So Does It Pay?
On our figures, a €6,150 battery-only install pays back in 9.5 years at the very best and 15.5 years at the realistic worst, against a ten-year warranty. Take off SEAI's €600 battery grant and it is about 8.6 and 14 years. That is the honest verdict, and it is a narrower case than the marketing suggests.
It gets to the good end of that range only if three things are true at once. You are buying at the cheap end of the market. Your battery can take 5 kW so it can fill the 2am to 4am window. And you genuinely use 7 kWh or more between 8am and 11pm, so the thing gets cycled hard every single day. Miss any one of those and the payback drifts past the warranty.
There is also the comparison nobody makes on your behalf. Add panels to the job and you get the €1,800 SEAI grant, the whole contract including the battery drops to 0% VAT, and you become eligible for export payments. The same money spent on panels plus a battery is a different financial product entirely, not a more expensive version of this one. See our numbers on solar panels with a battery and on the battery grant question.
Where a battery-only install does stack up is when the payback is not the point: you want backup through a power cut, you have no roof worth putting panels on, or you are on a listed or shaded property. Those are good reasons. They are just not the same reason as saving money.
Price the version with panels before you buy the version without
Panels bring the €1,800 SEAI grant, 0% VAT on the battery too, and export payments. Get free, no-obligation quotes from SEAI-registered installers in your county and compare the two properly.
Get a Solar QuoteFrequently Asked Questions
Yes. A home battery can be charged from the grid rather than from panels, which lets you buy electricity on a cheap night band and use it during expensive day hours. It has to be installed by a Safe Electric registered contractor, and if the inverter is capable of exporting to the network it falls inside ESB Networks' micro-generation notification regime, so the NC6 form and an I.S. EN 50549-1 type test certificate apply. What changes without panels is the economics, not the legality: no solar grant (only the €600 battery grant), VAT at 23% instead of 0%, and no export payment.
Yes, at the standard rate of 23%. Revenue's tax and duty manual zero-rates ancillary equipment including batteries only when it is supplied and installed with solar panels as part of the same supply and install contract. With no panels there is no such contract, and Revenue's own list of standard-rated goods names batteries explicitly. On a €5,000 job before VAT that is €1,150 you would not pay if panels were part of the same contract. Teagasc's factsheet still quotes 13.5% for the with-solar case, which was the rate before 1 May 2023.
Yes, since 6 October 2026, but only €600. SEAI's Solar PV Scheme pays €700 per kWp up to 2 kWp and €200 for each additional kWp, capped at €1,800, calculated entirely on panel capacity, so none of that applies. The separate Battery Energy Storage System grant pays a flat €600 for a battery of 5 kWh or more. SEAI's criteria don't require panels, but the battery must be installed by an SEAI-registered solar PV company after you get the grant offer, in a home built and occupied before 2025.
No. The CRU defines microgeneration as electricity generated from renewable sources, and states that renewable electricity stored in a battery for later use or export still counts as renewable. Electricity you imported from the grid was never renewable generation of yours, so it does not qualify for the Clean Export Guarantee. In practice a grid-charged battery should be configured for self-consumption only, and you should confirm that in writing with your installer.
On our arithmetic using Electric Ireland's published rates, a household at the regulator's 4,200 kWh benchmark with 65% of use in day hours saves €256 to €646 a year, depending on round-trip efficiency and how much charging lands in the 2am to 4am boost band. The wide range is not vagueness, it is the two variables that matter: charging entirely at 10.88c rather than 18.54c is worth about €235 a year at 89% efficiency, and dropping from an 89% to a 70% round trip costs about €154 a year if you charge in the night band, or about €91 if you charge in the boost band.
We make it 9.5 to 15.5 years on a €6,150 installed cost, which is a €5,000 job plus 23% VAT. The best case needs a 5 kW charge rate to fill the 2am to 4am window and an 89% round trip. The worst case is a 2.5 kW charge rate at 70%. Both ends sit at or beyond the ten-year product warranty, so a battery-only install rarely pays for itself inside the period it is guaranteed for. SEAI's €600 battery grant, open since 6 October 2026, brings the range to about 8.6 to 14 years. Adding panels changes the answer, because it brings a grant, zero-rated VAT and export income.
Tesla's Powerwall 3 datasheet publishes 89% for solar to battery to home or grid, and a separate 97.5% for solar to home or grid, which is the pass-through figure for electricity that never enters the battery. Sites quoting 97.5% as round-trip efficiency have taken the wrong row. Tesla's 89% is also measured on the solar path, where power arrives as DC, so grid charging adds a conversion and 89% is a ceiling. Teagasc warns that overnight grid charging can lose 25 to 30%, a 70 to 75% round trip, though elsewhere on the same page it puts each conversion at 6 to 8%. Plan on a range rather than a single number.
If the inverter can export to the network, yes. ESB Networks assesses micro-generation on inverter capacity rather than on the energy source, its standard states that this covers combinations of storage and generation behind the inverter, and its definition of Energy Source Capacity explicitly includes energy storage. Its own list of micro-generator types includes combined renewable micro-generators and storage systems. The route is the NC6 notification with a type test certificate to I.S. EN 50549-1 and installation by a Safe Electric registered contractor. If the system is to be configured so it can never energise the network, ask your installer to confirm that in writing.
Smaller than most quotes assume. Your daytime consumption sets the ceiling, because the battery can only displace electricity you were going to buy anyway. At the regulator's 4,200 kWh benchmark with 65% of use outside 23:00 to 08:00, that is 7.48 kWh a day, so capacity above roughly 7 to 8 kWh never gets cycled and you paid 23% VAT on it. Households with an EV, storage heating or a heat pump are well above the benchmark and can justify more. Check your own half-hourly data in the ESB Networks customer portal before choosing a size.
Sources: All figures read from the following pages on 19 August 2026. VAT treatment from Revenue's tax and duty manual on the supply and installation of solar panels, its standard rate of VAT page and its current VAT rates table. Grant values and scheme requirements from SEAI's solar electricity grant page. Export eligibility and the definition of microgeneration from the CRU's microgeneration page. Connection rules from ESB Networks' micro-generation page and its Conditions Governing the Connection and Operation of Micro-Generation. Plan rates from Electric Ireland's new customer electricity price plans, its smart meter plans and its Night Boost page. The 4,200 kWh regulator benchmark from Electric Ireland's estimated annual bill help page. Battery costs, charge rates, cycle warranties and the efficiency warning from Teagasc's battery storage factsheet. Efficiency, charge power and warranty specifications from the Tesla Powerwall 3 datasheet. Every annual cost, saving, payback and break-even on this page is our own arithmetic from those published figures, with the assumptions named beside each.
Published: 19 August 2026. Author: Neil Russell. Rates change and every house is different; check the figures against your own bill and your own quote before acting on them.