Adding a battery to a Feed-in Tariff system means fitting electricity storage alongside solar panels that are already accredited. Ofgem allows this. Its guidance says battery storage may be added to an installation without affecting its accreditation, as long as the installation still meets the metering rules.
The metering is the whole question. Your FIT generation payment is made on what your solar panels generate. Say a battery can be charged from the grid. If it sits on the wrong side of the generation meter, that meter may count grid electricity as generation. That is what the rules are there to prevent.
Key Points
- Ofgem says a battery or an electric vehicle charging point may be added without affecting accreditation, provided the installation still complies with the metering criteria.
- The basic rule has not changed: the meter must measure electricity generated by your installation separately from any other source.
- Ofgem sets out two ways a system with a battery can satisfy that rule. The first is the configuration. The second is the choice of meter.
- Configuration: the battery can only be charged by the solar installation, or it sits after the generation meter. Either way the meter reads only your solar.
- Meter choice: where the battery can also charge from the grid, use a bi-directional meter. It must measure input and output and display a net value.
- Ofgem is explicit that you cannot use two meters and subtract one from the other. The net calculation must be done by a single meter.
- Ofgem also warns that most smart meters are not bi-directional meters in this sense, because they do not produce a net value.
- You should report the battery to your FIT licensee, in line with your statement of FIT terms. Ofgem lists exactly what information to send.
- Deemed export can continue. Ofgem confirms deemed export payments can still be made for a FIT installation with storage, where the generation meter reads only the accredited installation.
- Ofgem recommends an MCS installer and the MCS Battery Standard for storage up to 50 kW.
Common Misconceptions
- A battery cancels my FIT. It does not. Ofgem allows storage alongside an accredited installation.
- I must have a bi-directional meter. Not necessarily. Ofgem accepts a configuration where the battery cannot draw from the grid, or sits after the generation meter.
- My smart meter will do the job. Ofgem says most smart meters are not bi-directional meters under its definition, because they do not calculate a net value.
- Two meters and a bit of arithmetic is fine. Ofgem specifically says using multiple meters to calculate a net value is not permitted.
- I lose deemed export if I fit a battery. Not automatically. Ofgem confirms deemed export can still be claimed where the generation meter measures only the accredited installation.
- A battery will increase my generation payments. It will not. It changes when you use your electricity, not how much the panels make. Battery losses can slightly reduce recorded generation.
Real-World Advice
Every battery project published on our work page is a new 2026 installation. In each one the battery went in on the same day as the panels. None of them is a battery retrofit onto a FIT era system.
UK-Specific Considerations
Where the battery sits decides most of it. Putting the battery after the generation meter is the simplest answer. The generation meter then only ever sees the solar. That is the first of Ofgem's two accepted routes and it needs no new meter.
A bi-directional meter is one option, not a rule. You will see it written that a bi-directional meter is always required. That is too strong. Ofgem accepts either an installation configuration that keeps the meter clean, or a suitable single meter that nets input and output.
Bi-directional meters read differently. Ofgem warns that readings from these meters are calculated on the difference between each month's import and export. If that difference is negative in a month, zero FIT payments could be claimed.
A battery loses a little on every cycle. Ofgem notes that set ups meeting the rules may record less generation, because batteries lose energy charging and discharging. FIT payments are then likely to be lower.
What to send your licensee. Ofgem lists three things.
- An updated single line or schematic diagram. It shows how electricity reaches the storage and how the metering is arranged.
- Details of the meter readings used to claim FIT payments.
- Details of the storage, including the date it was installed and commissioned, with supporting evidence.
Extra evidence for a bi-directional meter. Ofgem asks for more where one is fitted.
- The meter make, model and operator's manual.
- Confirmation of how the meter operates.
- Photographic evidence that it displays net renewable generation, without manual subtraction.
- A copy of the MID compliance certification.
- Whether the net function is set by the manufacturer or by the installer.
- Whether the battery can be charged from the grid.
Your network operator still has to be told. A battery with its own inverter is generation as far as the network is concerned. Under G98 the installer notifies within 28 days of commissioning. Where the total goes over 16 A per phase, the G99 process applies and the network operator must be consulted before the work.
Storage beside an existing micro generator. The Energy Networks Association points installers towards G99 in one case. It is where a battery inverter is added next to an existing G83 or G98 micro generator. G98 still applies where the combined total stays at or below 16 A per phase.
Three routes compared
| Route | What it looks like | What Ofgem needs to be satisfied | Effect on FIT payments |
|---|---|---|---|
| Battery after the generation meter | Battery wired downstream of the existing meter | Generation meter can only see the solar | Generation payments continue. Deemed export can continue |
| Battery that cannot charge from the grid | Solar only charging, no grid import to the battery | Configuration shows the meter reads only your installation | Generation payments continue. Deemed export can continue |
| Bi-directional meter | Single approved meter measuring input and output and showing a net value | Full evidence pack including photographs and MID certification | Generation paid on the net figure. A negative month means no claim that month |
When This Isn't Right For You
- Your generation meter cannot be isolated from a grid charged battery, and no acceptable meter can be fitted. Ofgem is clear that you would then not be entitled to generation payments.
- You already use nearly all your solar in the day, so there is little spare to store.
- Your eligibility period ends shortly and the decision hangs on FIT income rather than on bill savings.
- There is nowhere safe and ventilated to put the battery.
Before You Spend Money
- Ask the installer to draw the wiring before you order. Ofgem wants a single line or schematic diagram. If your installer cannot produce one, that is a warning sign.
- Ask your FIT licensee what they will accept. Requirements vary between licensees and are set in your statement of FIT terms. Ask before design, not after installation.
- Check whether the battery will be charged from the grid. That single decision drives the metering route. Cheap overnight charging is useful, but it changes the paperwork.
- Ask whether your existing meter can be reprogrammed. Ofgem specifically asks licensees to find out whether the installed meter can be reprogrammed to measure net generation.
- Confirm the network operator route. G98 notification and a G99 application take very different amounts of time.
- Use an MCS installer. Ofgem recommends it for storage up to 50 kW, along with the MCS Battery Standard.
Frequently Asked Questions
Q: Will adding a battery stop my Feed-in Tariff generation payments?
A: Not if the metering is right. Ofgem says storage may be added without affecting accreditation, as long as the installation continues to comply with the metering rules.
Q: Do I have to fit a bi-directional meter?
A: No. Ofgem accepts two routes. Either the configuration shows the generation meter reads only your solar, or a single approved bi-directional meter calculates and displays a net value.
Q: Can I keep deemed export payments with a battery?
A: Ofgem says deemed export can still be claimed for a FIT installation with storage, where the generation meter measures only the accredited installation.
Q: Will a battery reduce my FIT payments?
A: It can slightly. Ofgem notes that batteries lose energy through the charge and discharge cycle, so recorded generation, and therefore payments, may fall a little.
Q: Who do I have to tell?
A: Your FIT licensee, with a diagram and the details Ofgem lists. Your network operator too. If you are ROO-FIT accredited you also update your record with Ofgem.
Summary
A battery and a Feed-in Tariff can live together. The whole test is whether your generation meter still measures only the electricity your panels make. Ofgem gives you two ways to pass that test. Wire the battery so it cannot confuse the meter. Or fit a single meter that does the netting itself. Then tell your licensee, with a diagram and the evidence Ofgem lists, and tell your network operator. Do not let anyone fit a battery on a FIT system without settling the metering first.