Plug in solar panels and the meter

[ericmark]

The new proposed amendment says the installer can be the customer, with a simplified form.

Can you link to the simplified form? Does not affect me, as already have a second MPAN number, but for those who don't, this form filled in correctly could double what they get from the panels.

Also, how the smart meter records import and export, my solar software produces a line graph, but my smart meter seems to produce a bar graph, each bar is ½ an hour.

So is that bar an average, or minute by minute? So if for example, between 12:00 and 12:30 I export 0.2 kWh and import 0.2 kWh will it show export and import or zero? I have looked on my app And it does seem for same ½ hour period it can show both import and export. So a solar panel may produce 400 watt/hour, and you may use 300 watt/hour, but because a cloud went over, you are still changed for 50 watt/hour.

The supplier is laughing all the way to the bank, unless you get the second MPAN number.

 

[denso13]

But it seems the limit is 800 watt per circuit,

It is still one per household currently until/if the G98 recommendations change.

 

[denso13]

Can you link to the simplified form?

It's from a zipped word document here, https://dcode.org.uk/assets/2026/dcrp-26-02-consultation-pack.zip, which downloads automatically.

Here is a screenshot if you rather not click on the link,

 

[camerart]

No. Why would I? You want me (and others) to read something specific post it in plain text and add the source as a link should I desire to follow that...

And the world is flat, too!

The modern Smets2 measure Import and Export separately.
They won't count down the Import Register when Exporting current from a solar (or battery) system to the Grid.

Don't believe all you read on the internet.

Hi R,
Ok, thanks.

I don't believe all I read on the internet, and that's why I asked you experts, here on the internet.
C

 

[camerart]

Smart meters record exporting separately, they don't reverse.

Hi D,
This is kind of what I meant, thanks.
C

 

[camerart]

Only very very very old mechanical spinning disc / analogue dial meters (sometimes called Ferranti meters) could ever run backwards... AIUI.

Plenty of anecdotal reports of such meters running backwards with early solar installs.

Modern smart meters might record solar export in a separate register (but that register might need enabling via a supplier?).

Hi R,
Yes, it does say, that it has to be enabled.
C

 

[camerart]

Hi All.
Thanks for all of the input. I'll consider buying one when they arrive, and experiment.
My questions have been answered, so cheers.
C

 

[ericmark]

One per household seems sensible, but the bit you show says limit 16 amps per phase, and I tried the link, and my LibreOffice corrupted the document.

But it asks for MPAN number, and you don't get the second MPAN number until you submit the form, so confused.

Thanks for all of the input. I'll consider buying one when they arrive, and experiment.

Please do tell us all how you get on.

 

[denso13]

But it asks for MPAN number, and you don't get the second MPAN number until you submit the form, so confused.

It's asking for any existing MPAN's. The form is only to notify the installation of plug in solar.

 

[camerart]

One per household seems sensible, but the bit you show says limit 16 amps per phase, and I tried the link, and my LibreOffice corrupted the document.

But it asks for MPAN number, and you don't get the second MPAN number until you submit the form, so confused.

Please do tell us all how you get on.

Hi E,
If you mean the link I posted, here's the full page, hopefully.
C
☀
pluggedin.solar

CalculatorSolar ReportFind your kitBlogFAQAboutCalculate savings

Home/Blog/Smart Meters & Solar: Complete UK Guide
Getting Started4 May 20265 min read

Smart Meters & Solar: Complete UK Guide​

Smart meters and solar panels UK guide. SMETS1 vs SMETS2, export tracking, plug-in solar compatibility, and SEG payments.

This article is relevant for the UK market

Why Smart Meters Matter for Solar Owners​

If you're generating your own electricity — whether from a rooftop array or a plug-in solar kit — your smart meter is the single most important piece of infrastructure in the chain. It's what determines whether your supplier knows you're exporting, whether you get paid for it, and whether your bills actually reflect what you're using.

Most guides on this topic were written for traditional rooftop solar. This one covers plug-in solar too, because the smart meter considerations are slightly different when you're feeding 400–800W through a standard socket.

SMETS1 vs SMETS2: Which One Have You Got?​

There are two generations of smart meter in the UK. The difference matters enormously for solar.

SMETS1 meters were the early rollout (roughly 2013–2018). They communicate via the supplier's own network, which means they often "go dumb" if you switch supplier. More importantly for solar, many SMETS1 meters cannot record export — they only measure import. If you're generating solar and pushing surplus to the grid, a SMETS1 meter simply won't see it.

SMETS2 meters use the national DCC (Data Communications Company) network. They work across all suppliers, and critically, they have two registers: one for import, one for export. This is what you need for solar.

To check which you have: look at the meter itself for a label, or log into your supplier's app. If your in-home display (IHD) stopped working after a supplier switch, you almost certainly have a SMETS1.

What to do if you have a SMETS1: Request an upgrade from your supplier. It's free — suppliers are obligated to offer SMETS2 replacements. Do this before installing plug-in solar, not after. The process typically takes 2–4 weeks.

How Solar Generation Interacts with Your Smart Meter​

When your plug-in solar panels are generating electricity, three things can happen:

1. You use it directly — the panel output feeds into your home circuit and offsets what you'd otherwise draw from the grid. Your smart meter sees reduced import.
2. You export surplus — if your panels generate more than you're currently consuming, the excess flows back through the meter to the grid. A SMETS2 meter records this on the export register.
3. You store it — if you have a battery like the EcoFlow Delta 2, surplus energy charges the battery instead of exporting. Your meter sees neither import nor export for that energy.

For most plug-in solar owners, the primary benefit is reduced import — your meter simply ticks up more slowly during the day. The export element only becomes meaningful if you're generating significantly more than you're consuming, which at 400–800W is less common than with a full rooftop system.

Do You Need a Smart Meter for Plug-in Solar?​

Strictly speaking, no. You can run a plug-in solar kit without a smart meter. The panels generate, your home uses the power, and your old-style meter spins more slowly. You'll still save money.

But a smart meter gives you two advantages:

Visibility — you can see exactly how much your import has dropped, half-hour by half-hour. This lets you shift usage (run the dishwasher at midday) to maximise self-consumption.

Export payments — if you're on the Smart Export Guarantee (SEG), you need a SMETS2 meter to receive payments for exported electricity. Without one, you're giving surplus power away for free.

For a typical 800W plug-in system, self-consumption is high enough that SEG payments are small (perhaps £20–40/year). But the visibility benefit alone is worth the free upgrade.

Smart Meter Settings to Check After Installing Solar​

Once your plug-in solar is running, check these settings with your supplier:

Export register enabled — some suppliers don't activate the export register by default. Call and ask them to enable it. This takes no physical visit; it's a remote configuration change.

Half-hourly settlement — if your supplier offers this (Octopus, OVO, and others do), enable it. It means your bills reflect actual usage patterns rather than estimated profiles, which benefits solar owners who import less during the day.

Time-of-use tariff compatibility — if you're on a tariff like Octopus Flux or Octopus Go, your smart meter needs to be recording at half-hourly granularity. Check this is active.

Smart Meter vs Energy Monitor: What's the Difference?​

Your smart meter measures total household import and export. It's the billing meter. But it doesn't tell you what individual appliances are doing, and it doesn't show you real-time solar generation.

An energy monitor — like the Emporia Vue 3, a Shelly Plus Plug, or the EcoFlow app — fills that gap. It shows you real-time generation from your panels, individual circuit consumption, and helps you optimise when you run high-draw appliances.

The ideal setup is both: a SMETS2 smart meter for billing and export, plus an energy monitor for real-time optimisation. For EcoFlow STREAM owners, the EcoFlow app already provides real-time generation data, so you may only need the smart meter side.

Best overall
EcoFlow PowerStream 800W Kit
~£799 estimated

• 800W dual-panel balcony or garden kit
• 600Wh plug-in battery included
• App with live monitoring & smart scheduling
• Balcony, garden & flat-roof mount options

View on EcoFlow →
BSI-compliant kits expected from July 2026. Prices are estimates.

Common Smart Meter Problems with Solar​

"My smart meter shows I'm importing even when the sun's out" — this is normal. Your panels might be generating 400W, but if your fridge, router, and standby loads total 500W, you're still importing 100W net. The meter measures the difference, not the solar output separately. See our troubleshooting guide for more.

"My IHD shows negative numbers" — this means you're exporting. Some IHDs display this clearly; others show it as zero or don't show export at all. The meter itself is still recording it — check your supplier app for accurate figures.

"My supplier says I don't have export data" — ask them to enable the export register. If they refuse or say your meter can't do it, request a SMETS2 upgrade. You're entitled to one.

 

[ericmark]

If you mean the link I posted, here's the full page, hopefully.

Very interesting, as I am sure you realise, I have had solar now for a few years. What would be handy, is a display showing state of charge of the battery, I have to boot the PC or phone to see that.

But we are looking at plug in solar, so no batteries, and the big problem with a small or no battery, is so many items use 2 to 3 KW, and very few under 800 watt.

So in the main, plug in solar will likely cover fridge, freezer etc.

In spite of many complaints from me, my wife still has two fridge/freezers and two freezers on the go, to my mind they would be better employed brewing my home brew. You can see when I made coffee and when the iboost+ started heating my DHW 09:00 to 10:30 approx, but can't see an iboost+ being worthwhile with plug in solar, in fact does very little to help with my 6 kW array, a simple time clock would be better.

But to gain by delaying any large power user to when the sun is shining is a hiding to nothing, as except for the unusual weather of last few weeks, working out when the sun will shine is near impossible, specially with a heat pump tumble drier which runs for 2½ hours.

So the big question, assuming you don't already have batteries, is solar panels into a battery pack and not connected to general home supply, or the plug and play?

The answer is mainly down to what control you have. So if for example I had a battery pack powering my fridge/freezer etc. So

= 637 watt/hours per day, and summer likely around 5200 watt/hours per day, so not enough to use it all in house. So we look at what can be close enough to the battery to be able to use it, without running a dedicated circuit around the house.

So it would seem looking at the kitchen, one need around a 4 kWh battery to be able to draw 3 kW, so step one is monitor kitchen items, so if your fridge/freezer uses 60 watts, what can you add and stay below the limit of the battery unit, air fryers, microwaves, kettles, mixers, running a second radial around one room is not that bad, maybe better living room, TV, AC etc, but each home will be different.

The battery pack method also gives you back-up with a power cut.

So the big question, plug and play or battery pack.

 

[morqthana]

Hi J,
I started reading your thread, but I don't want amateur guesswork and conspiracies, and it's too long for me to read, but thanks.
C

It shouldn't be too long.

And you're not going to get a different group of amateur guessers and conspiracy weeblers in this thread.