How Export Meters Work — And What Goes Wrong

The short version

Your smart meter is doing two jobs simultaneously. It’s measuring the electricity coming into your home from the grid. And it’s measuring the electricity leaving your home and going back into the grid.

Most people only ever think about the first job. The second one — measuring your exports — is where things go wrong. And when it goes wrong, you stop getting paid.

Two directions. Two registers. One meter.

Electricity flows in two directions through your smart meter.

Import — electricity coming in from the grid to power your home. This is what your supplier bills you for.

Export — surplus electricity from your solar panels flowing back out to the grid. This is what your supplier pays you for under the Smart Export Guarantee.

Your smart meter has a separate counter — called a register — for each direction. Think of them like two separate odometers in the same dashboard. Both need to be working. Both need to be configured correctly. Both need to be actively sending data to your supplier.

The physical setup — what’s actually in your cupboard

When solar panels are installed, your electrical setup changes. Here’s what the chain looks like:

Solar panels → generate DC electricity → inverter converts it to AC → feeds into your home’s consumer unit → your home uses what it needs → surplus flows through your smart meter → out to the grid

Your smart meter sits at the boundary between your home and the grid. Everything that flows in either direction passes through it.

How export data gets from your meter to your supplier

Your smart meter doesn’t send data directly to your supplier. It goes through a chain:

Your meter → communicates via WAN (Wide Area Network) → to the DCC (Data Communications Company) → which distributes it to → your supplier’s systems

There are multiple points in that chain where things can break:

Your meter loses its WAN signal
The DCC fails to route data correctly
Your supplier’s systems fail to pick it up
The export register specifically isn’t included in what’s being requested

What half-hourly data actually is — and why it matters for export

Your smart meter records your import and export in half-hourly intervals — a snapshot every 30 minutes, 48 times a day.

Without it, your supplier is either estimating your exports — almost always lower than actuals — or not paying you at all.

A supplier can be receiving your import data perfectly and still have zero export data. The two registers are independent. Both have to be working. Both have to be requested by your supplier from the DCC.

The WAN signal problem

Your smart meter uses a built-in SIM card to communicate — similar to how a mobile phone connects to a network. If your meter is in a location with poor mobile signal, it may struggle to send data reliably or at all.

Signs of a WAN signal problem:

Your in-home display keeps losing connection to the meter
Your supplier’s app shows gaps or missing data
Your half-hourly data has frequent zeros or flat lines
An engineer visits and tells you your meter “isn’t communicating”

The HAN — the network inside your home

HAN stands for Home Area Network. This is the short-range wireless network that connects your smart meter to your in-home display (IHD). The HAN is separate from the WAN. Your meter can be communicating perfectly with the DCC via WAN while the HAN is down — which is why your IHD can go blank without it meaning your meter has stopped working entirely.

SMETS1 vs SMETS2 — what it means for your export payments

SMETS1 meters were the first generation, installed roughly between 2012 and 2019. When you switched supplier, your meter often lost its smart functionality entirely because the new supplier couldn’t communicate with it.

SMETS2 meters were built to a universal standard. They work with any supplier, and switching doesn’t break their smart functionality.

If you have a SMETS1 meter, ask your supplier specifically: “Has my meter been enrolled on the DCC network?” If it hasn’t, that’s your problem right there.

The commissioning process — what should happen when you switch

Your old supplier releases the meter on the DCC network
Your new supplier sends a commissioning request to the DCC
The DCC establishes communication with your meter
Your new supplier configures the import AND export registers
Half-hourly data starts flowing to your new supplier’s systems
Your SEG payments resume

In practice, steps 2 through 5 can take days, weeks, or in some cases months. Ofgem now requires suppliers to resolve smart meter issues within 90 days. If your meter still isn’t commissioned and sending export data 90 days after your switch, your supplier is in breach of their licence conditions.

The most common failure points

What can go wrong	What causes it	What fixes it
Export register not active	Missed during commissioning	Supplier configures register remotely
No half-hourly export data	DCC communication failure	Supplier raises DCC ticket
SMETS1 not enrolled on DCC	Migration not completed	Supplier enrolls meter on DCC
WAN signal too weak	Poor mobile coverage	Communications hub upgrade
HAN disconnected	Range or interference issue	Engineer visit to re-pair devices
SEG application incomplete	Missing MCS certificate	Complete application with supplier
Generation meter not linked	Installation setup error	Supplier updates meter serial numbers

What this means for you practically

The single most important thing to understand is this:

Export measurement is a separate system from import measurement. It has to be configured separately. It has to be requested separately from the DCC. And it’s the part that gets missed.

When you call your supplier about missing export payments, you’re not calling about a billing query. You’re calling about a technical metering failure. Ask for the smart meter technical team. Use the language in this article. Be specific.

Log everything. Every call. Every reference number. Every promise made. Your Problem Tracker is built for exactly this.

Coming up next

Written by a qualified UK smart meter installer. If your export payments are missing or wrong, start by logging your problem at tracker.smartmeterhelp.co.uk

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