Last reviewed: 5 September 2026. This page covers what physically
happens to plug-in solar generation you do not use, and what your meter does with it. It is about the
electricity, not the paperwork — the export payment question is answered separately and the answer is
no. Electricity figures use the Ofgem price cap for 1 October to 31 December 2026.
Yes. A plug-in solar device exports to the grid, and it does so constantly, without asking you and
without any way to switch it off. What it does not do is earn you a penny for it. Those two facts sit
uncomfortably together, and understanding why is the difference between buying a plug-in kit with your
eyes open and buying one on the strength of a product photo.
What actually happens at the socket
A plug-in microgenerator is a grid-tied inverter in a box. It synchronises with the mains waveform
at your socket and pushes current into the ring. Electricity, having no opinion about ownership, then
flows to whatever is drawing it — nearest load first, electrically speaking.
So the order of events at any given second is:
- Your appliances draw whatever they need.
- The inverter supplies as much of that as the panels are producing at that moment, up to its
800 W ceiling. - Any shortfall is imported from the grid through your meter, and you pay for it.
- Any surplus flows outward through your meter, onto the network, and into your neighbours’ houses.
You are paid nothing.
There is no storage step in that list, and there cannot be. SI
2026/848 defines a plug-in microgenerator as a device that is not designed to import electricity
from the household installation in order to store it for later supply. A kit that could hold back the
surplus would not be a legal plug-in kit. Export is not a failure mode of the design; it is a
structural consequence of it.
What your smart meter sees
This is the part people worry about most, and the worry is misplaced. A modern SMETS2 smart meter
measures import and export as two separate registers. Surplus flowing outwards increments the export
register and does nothing to the import register. You are not billed for it. You are also not credited
for it, because nobody is reading that register for the purpose of paying you.
What you will notice, if you watch your in-home display on a bright Sunday afternoon with the house
empty, is your consumption reading dropping to zero and staying there. Some displays show a negative
figure or a distinct export state; many simply show zero and give no hint that anything is leaving the
building. That is a display limitation, not a metering one.
| Meter | What it does with export | Are you billed for it? | Are you paid for it? |
|---|---|---|---|
| SMETS2 smart meter | Records it on a separate export register | No | No — no export MPAN exists against which to settle it |
| SMETS1 smart meter | Behaviour varies by make and by whether it has been migrated to the DCC | No, in normal operation | No |
| Modern digital (non-smart) meter | Usually registers zero consumption while exporting; some models hold the last reading | No | No |
| Old electromechanical disc meter | Can in principle run backwards; these are essentially gone from the domestic estate | No — the reading would fall | No, and deliberately engineering this would be dishonest |
[VERIFICAR: the SMETS1 row is generalised from how DCC-migrated and unmigrated
first-generation meters behave in practice. We have not found a primary source that states SMETS1
export-register behaviour by manufacturer. If your meter is a SMETS1, ask your supplier directly what
it does with export.]
Why nobody pays you: the SEG wall
The Smart Export Guarantee is the mechanism by which domestic
generators are paid for export, and a self-installed plug-in kit cannot enter it. It requires an
installation certified under MCS or an accepted equivalent, an export meter capable of half-hourly
measurement, and an export MPAN. A plug-in kit fails the first test outright, and the first test is the
one that cannot be bought around: MCS certifies installations carried out by certified contractors, and
the entire premise of a plug-in kit is that you install it yourself.
The full argument, condition by condition, is in can you get SEG payments for plug-in solar. The
practical summary is that every exported unit is a gift to the network.
What the gift is worth
Here is the arithmetic that ought to be on the box. Take a 0.9 kWp kit generating roughly 800 kWh a
year — our own estimate, from a public UK yield range of about 750 to 1,050 kWh per kWp depending on
latitude and siting, not an MCS figure. What matters is not what it generates but what share of it
lands inside the house.
| Household pattern | Self-consumption | kWh used at home | Value kept per year | kWh exported free |
|---|---|---|---|---|
| Empty weekdays, 8 to 6 | 45% | 360 | £95 | 440 |
| Someone home part of the day | 60% | 480 | £126 | 320 |
| Home most days, loads shifted to midday | 75% | 600 | £158 | 200 |
| Home all day, hot water on a daytime timer | 90% | 720 | £190 | 80 |
The spread between the top and bottom rows is £95 a year — from the same panels, the same inverter
and the same weather. Nothing else you can do to a plug-in kit comes close to that. Moving the panels
from a west wall to a south-facing frame is worth less. Buying a bigger kit is worth less, and past
about 1 kWp behind an 800 W inverter it is worth almost nothing, because the extra units arrive at
midday when you were already exporting.
That is why using more of your solar at home
is the single most valuable page on this site for anyone who has already bought a kit.
Does exporting cause you any problem?
Three worries come up repeatedly, and two of them are unfounded.
- “Will my supplier object?” No. Suppliers are not party to your generation
arrangements; your network operator is, and it is notified under G98. See DNO notification. - “Am I stealing from the network?” No. You are giving electricity away without
compensation, which is the opposite complaint. - “Could my street’s voltage rise?” This one is real in principle, which is
precisely why G98 notification exists and why the limit is 800 W. Your DNO wants to know what is
connected on each feeder so it can manage voltage across the whole street. One 800 W device is
negligible; several thousand unrecorded ones on a weak rural feeder are not. Notifying is a 28-day
obligation from commissioning and one device per dwelling — see how to fill in a G98 notification.
Can you stop exporting?
Not with the device itself. There is no consumer-adjustable output limit on a compliant plug-in kit,
and there is no legal plug-in kit with a battery inside it. Your only levers are on the demand side:
move consumption into daylight, or size the kit closer to your daytime baseload so there is less
surplus to lose in the first place.
A separately installed home battery can absorb the surplus, but that is a different purchase with a
different justification. Spending several thousand pounds to recover £50 a year of gifted plug-in
generation makes no sense; buying a battery because your tariff has a wide overnight-to-peak spread may
well, and the solar becomes a bonus. That case is made in a home battery without solar panels and can I add a battery to plug-in solar.
Frequently asked questions
Where does the exported electricity actually go?
To the nearest load on your local low-voltage network — in practice, your neighbours. It does not
travel to a power station or into any kind of storage.
Could my meter run backwards and cut my bill?
Not on any meter installed in the last two decades. Import and export are counted separately.
Deliberately arranging otherwise would be meter tampering.
If I get rooftop solar later, does my plug-in kit’s export become eligible?
No. The rooftop system’s own generation can be registered for SEG through the certified installer;
the plug-in kit’s cannot, even sharing the same meter.
Should this change my buying decision?
It should change the size you buy and where you site it, more than whether you buy at all. Judge a
kit on what it is worth with zero export income, because that is what it is worth. See are plug-in solar panels worth it in the UK and the payback period.
Sources.
SI
2026/848 ·
Ofgem, Smart Export Guarantee ·
Ofgem, price cap unit rates and standing charges ·
Energy Networks Association, find my network operator.
Generation and self-consumption figures are our own estimates from a public UK yield range; see
editorial methodology.