Yes, you can add a battery to your solar panels without losing your Feed-in Tariff. The payments continue as long as your generation meter still records only the electricity your panels produce, and, if you are paid on metered export, the export meter still records only your solar. The risk is never the battery itself. It is where the battery sits in your wiring and what your generation meter ends up measuring.
Can you add a battery and keep your Feed-in Tariff?
The scheme neither bans storage nor specifically allows it, so adding a battery does not end your accreditation on its own. What decides the outcome is the metering you end up with. Keep the generation meter reading only your solar, protect any metered export, and report the completed change to your Feed-in Tariff licensee with the evidence it asks for. Get those three right and the tariff carries on paying exactly as before.
That is Ofgem’s position in its co-location guidance: where the requirements of the scheme continue to be met, storage can be added without affecting the accreditation of a Feed-in Tariff installation. The whole job comes down to protecting your meter readings and putting the change on record. The table below is the short version.
| Retrofit route | What it means | Feed-in Tariff risk |
|---|---|---|
| AC-coupled battery, fitted after the generation meter | The battery has its own inverter and connects downstream of your existing solar system | Low. Your certified PV system and its generation meter are left alone |
| Hybrid inverter replacement (DC-coupled) | Your solar inverter is swapped for one that also runs the battery | Depends on the metering. The generating side is re-wired, so the arrangement that isolates your solar generation has to be re-proven to the licensee |
| Battery fitted before the generation meter that can also charge from the grid | Grid electricity could pass through the generation meter | High. Without a single approved netting meter, payments can stop |
How your Feed-in Tariff actually pays you
You need to know this before you touch the wiring, because every risk below traces back to it. The Feed-in Tariff pays two separate things, and Ofgem sets both out in the co-location guidance.
- Generation payment. You are paid for every unit your panels generate, whether you use it, store it or export it. A generation meter sits close to the panels and records the gross amount they produce.
- Export payment. For solar PV of 30kW or less, this is normally deemed: the scheme assumes you export half of what you generate and pays you for 50% of the generation meter reading, without measuring actual export. Some installations instead have a real export meter and are paid on metered export.
Both payments are calculated from a meter reading. The generation payment reads the generation meter. Deemed export takes 50% of that same generation meter reading. Metered export reads the export meter. So protecting your Feed-in Tariff is really about keeping those meters measuring your solar and nothing else.
The scheme has been closed to new applicants since 1 April 2019, so this is entirely about installations that were already accredited. Existing systems keep their tariff for the rest of their eligibility period. Most installations have 20 years, but solar PV with an eligibility date before 1 August 2012 generally has 25 years. Check the eligibility date and the end date on your own Feed-in Tariff paperwork rather than assuming.
The one rule: keep the generation meter reading only your solar
A battery can be charged from your panels or from the grid. If grid electricity can pass through an ordinary generation meter, that reading is no longer only your solar, and it is not acceptable for payment. One exception exists: a single approved bi-directional meter that nets the flows and displays your solar generation only can still satisfy the rule. Everything else in this article is a consequence of that.
Ofgem is explicit that the generation meter must record only the electricity generated by the accredited installation, not from other sources, and that this matters most where the battery can be charged from imported grid electricity and sits before the generation meter. You also cannot satisfy the requirement by wiring up separate input and output meters and subtracting one from the other. The reading has to come from a single meter.
There are two clean ways to meet the rule:
- Put the battery after the generation meter, so whatever it charges from, the meter has already counted your solar. This is what an AC-coupled retrofit does naturally.
- Or, if the battery genuinely has to sit before the generation meter and can charge from the grid, fit a single bi-directional meter that measures import and export and displays a net value equal to your solar generation. It must be approved under the relevant metering rules and accepted by your licensee for payment, and be aware that netting can reduce the recorded generation, even to zero in a month when the battery draws more grid power than your panels make.
For most homes the first option is simpler, cheaper and far less likely to go wrong.
AC-coupled battery or a new hybrid inverter?
This is the decision that shapes your risk. An AC-coupled battery keeps your original solar system intact and adds storage alongside it. A hybrid or DC-coupled retrofit replaces the inverter that your Feed-in Tariff accreditation was built around.
| AC-coupled retrofit | Hybrid inverter replacement | |
|---|---|---|
| What changes | A separate battery inverter is added downstream of the generation meter | The generating inverter itself is swapped, and the metering arrangement usually changes with it |
| Generation meter | Untouched. It keeps reading your panels exactly as before | The generating side is re-wired, so the reading arrangement has to be re-proven |
| Certified installation | The MCS-certified PV system that got you onto the tariff is left alone | You are modifying the generating part of a certified installation |
| Feed-in Tariff exposure | Lowest, because the meter and the accredited kit do not move | Higher, but not automatic loss. Keeps paying if the new metering still isolates your solar generation |
| When it still makes sense | Most retrofits, especially where the existing panels and inverter are healthy | When the old inverter is failing anyway and needs replacing regardless |
AC coupling usually makes the metering easier, because the existing generation meter can stay exactly where it is. A hybrid retrofit is not automatically a problem. It can also keep your Feed-in Tariff if the revised arrangement still isolates your eligible solar generation for the meter, with approved netting where grid charging could otherwise reach that meter. It simply changes more, so more has to be re-proven to your licensee. If your existing inverter still works, the AC-coupled route leaves the least to argue about.
Will a battery change your deemed export payment?
No, provided the generation meter stays clean. Deemed export is 50% of the generation meter reading for solar PV up to 30kW, and Ofgem confirms this stays true for installations with co-located storage. Add a battery after the generation meter and your deemed export keeps being calculated exactly as before.
This surprises people, because a battery means you actually export less. It does not matter. Deemed export is an assumption, not a measurement. You are paid for 50% of generation whether the electricity leaves the house or charges your battery. Storing more of your own solar to use in the evening therefore has no downside for a deemed-export household: you keep the same export payment and you buy less from the grid.
One point that trips people up: a smart meter does not, on its own, drag you off deemed export. Ofgem notes that most smart meters are not “bi-directional meters” in its sense, because they measure import and export separately without producing a single net value. Having a smart meter and a battery does not force you onto metered export or reduce a valid deemed payment.
Can you charge the battery from cheap grid electricity?
Yes, and for many people that is the whole point: fill the battery on a cheap overnight rate and run the house on it during the expensive day. Grid charging is allowed on a Feed-in Tariff installation. The condition is that the imported electricity must never be counted as your solar.
For an AC-coupled battery sitting after the generation meter, that is automatic. The generation meter has already recorded your panels before the battery charges from anything. The care is only needed on the export side if you take metered export, because exporting stored grid electricity and being paid for it as solar is exactly what the rules stop.
Ofgem is blunt about the failure case: where storage is co-located and it is not possible to tell whether the export meter is measuring your solar or stored grid electricity, the generator is not entitled to export payments. On a qualifying deemed-export account, your actual export is not used to calculate the export payment, so this does not arise.
What you must tell your Feed-in Tariff licensee
Notifying your licensee is a scheme requirement, not a courtesy. Your licensee is the supplier that pays your Feed-in Tariff, which is not always the supplier you buy electricity from. Contact them before the work if you can and ask for their current process, but the step the rules actually require is reporting the completed change with the evidence they ask for. A helpful reply beforehand is not a blanket guarantee that your eligibility continues. Ofgem assesses each change on its facts once it is made and reported, so keep everything in writing.
Ofgem’s guidance lists the kind of evidence a licensee may want. Ask your licensee for its current checklist, and be ready to provide:
- An updated single line or schematic diagram showing how electricity reaches the battery and where the meters sit.
- Whether the battery can be charged from the grid, and how the storage is operated.
- The storage details: make, model and capacity, and the operational date of the change.
- Which meter readings will be used for your Feed-in Tariff claims, and whether the existing meter needs reprogramming.
- Whether any netting is set by the manufacturer or programmed by the installer.
- A completed battery storage declaration. Appendix 1 of the co-location guidance is an example form, so use your licensee’s current declaration or an equivalent it accepts.
- If a bi-directional meter is involved, the meter make and model, its metering-approval certificate, and photographic proof that it displays a net generation value without manual subtraction.
If you have not looked at your generation meter since the panels went in, it is the small separate meter near your inverter or consumer unit with its own kWh total display, usually marked as generation. Note its make and its current reading before any work starts, so you can prove the count carried on cleanly across the change.
I put nothing on trust with a network operator or a scheme administrator that I have not also got in writing. When I dealt with my DNO over a system change, I emailed to confirm the requirement, kept the reply, and sent a clear single line diagram. Apply the same habit here. Here is a template you can adapt:
Subject: Battery storage added to my Feed-in Tariff installation FIT ID / account number: [your FIT ID] Installation address: [address] MPAN: [your MPAN] I have added battery storage to my accredited solar PV installation. Details: - Battery make, model and capacity: [ ] - Coupling: AC-coupled, fitted after the generation meter (or: hybrid inverter replacement) - Can the battery charge from the grid: yes / no - Generation meter: [make, serial, current reading] - unchanged (or: replaced with [make, serial, opening reading]) - Export basis: deemed / metered - Date of change: [ ] I attach an updated single line diagram. Please confirm the evidence you need and that my generation and export readings will continue to be paid as before. If a further declaration is required, please send it. [name, date]
Do you need to tell your DNO as well?
Possibly, and it is a separate question from the Feed-in Tariff. An AC-coupled battery has its own inverter, which adds capacity at your property. Your Distribution Network Operator cares about that under the G98 and G99 connection rules, whatever your tariff is.
The route is decided by capacity, not by a loose “total inverter” figure. G98 covers a connection where the aggregate Registered Capacity of all your generation and storage stays within 16A per phase, which is normally 3.68kW on a single phase, and it can allow notification after the work. Above that, or where the numbers are borderline, G99 applies. The G99 route then matters: some routes need the DNO to accept the application before you commission, while the current G99 also has a storage fast-track (route SGI-1) that can allow notification after connection. Your installer must assess the Registered Capacity, the Intrinsic Design Capacity and the applicable G99 route before any equipment is ordered.
Many battery and hybrid inverters are listed on the ENA Type Test Verification Register as fully type-tested, which can simplify the evidence. That is not permission to connect at your specific property, and it does not remove the application or notification. The duty to notify still sits with you or your installer, it is separate from your Feed-in Tariff licensee, and the two notifications go to different organisations for different reasons.
Your before-you-buy checklist
Work through this before you order a battery, not after.
- Find your Feed-in Tariff paperwork and note your licensee, your tariff rates, your eligibility end date, and whether your export is deemed or metered.
- Locate your generation meter and confirm where a battery would sit relative to it.
- Default to an AC-coupled battery fitted after the generation meter unless your inverter needs replacing anyway.
- If a hybrid inverter swap is unavoidable, treat the generation metering as something to design and prove, and involve an MCS installer.
- Decide whether the battery will charge from the grid, and confirm your metering keeps that electricity out of any reading you are paid on.
- Contact your licensee with the plan and wiring diagram, ask about its process, and report the completed change with the evidence it lists.
- Check separately whether the battery inverter needs a G98 notification or a G99 application to your DNO.
Questions homeowners ask
Does adding a battery invalidate my MCS certificate?
No. Adding a battery does not retrospectively cancel the certificate issued for your original solar installation; that certificate records the original job, it is not a live permit that a battery can void. An AC-coupled battery fitted after the generation meter leaves it alone, and your Feed-in Tariff does not depend on the battery itself being MCS-certified, so a competent electrician can carry out that retrofit. The new battery still carries its own certification, so ask the installer what will be issued for it, because MCS certification of the battery can matter for warranties and other schemes. If you replace the inverter instead, you are modifying the certified generating installation, so involve an MCS installer and tell your licensee. Continued eligibility depends on the resulting metering and scheme compliance, not on the old certificate.
Could I lose my Feed-in Tariff completely?
An unsuitable metering configuration can stop your payments and can put your accreditation at risk. In practice the danger is a battery wired before the generation meter, able to charge from the grid, without a proper netting bi-directional meter. Ofgem says there may be scope to reverse some changes and resume support, but the licensee and Ofgem assess each case on its own facts, so treat it as avoidable rather than easily undone. Fit the battery after the generation meter and this does not arise.
Will a battery reduce my generation payment?
Not with an AC-coupled battery after the generation meter, because the meter records your panels before any storage losses. The generation payment only shrinks where the meter is made to measure a net value that includes battery round-trip losses, which is another reason to keep storage downstream of the meter.
Can I take a Smart Export Guarantee payment as well?
No. You cannot be paid for the same exported units under both the Feed-in Tariff and the Smart Export Guarantee; they are alternatives, not a stack. If you already hold the old Feed-in Tariff export payment, deemed or metered, adding a battery does not push you onto the Smart Export Guarantee, and you keep the terms you have. Switching schemes is a separate decision to weigh on its own numbers, not something the battery forces.
The next move
Dig out your Feed-in Tariff statement and find two things: who your licensee is, and whether your export is deemed or metered. Then look at where your generation meter sits. If your inverter is healthy, ask installers for an AC-coupled battery fitted after that meter, send your licensee the plan, and report the finished change once it is done.
Do that and the battery becomes what it should be: more of your own solar used in the evening, a cheaper overnight top-up if you want it, and a Feed-in Tariff that keeps paying exactly as before. Ofgem’s co-location guidance and its guidance for FIT generators are the primary references to keep on file, alongside the annual deemed export determination that sets the methodology.
