Smart Meters and Solar Panels UK

If you have solar panels — or are planning to get them — your smart meter is not just a convenience. It is the gateway to getting paid for every unit of electricity you export to the grid under the best SEG export tariffs. Without the right meter, your supplier cannot verify how much you export, and your export earnings disappear. This guide explains exactly how smart meters and solar panels interact, what SMETS2 means for SEG payments, and what to do if your meter is old or incompatible.

Why your meter matters for solar exports

Solar panels generate more electricity than most homes can use on sunny days. That surplus flows back to the National Grid — and under the Smart Export Guarantee (SEG), your supplier is legally required to pay you for it, provided you have a qualifying installation and, critically, a meter that can prove what you exported.

The key requirement, set out in Ofgem's SEG rules, is a smart meter capable of recording half-hourly export readings. Without that granular data, your supplier cannot calculate your export payments — an estimate is not acceptable under SEG rules.

Under the Smart Export Guarantee Order 2019 and Conditions 57 and 58 of the Standard Conditions of the Electricity Supply Licence, any electricity supplier with more than 150,000 domestic customers must offer at least one SEG tariff to qualifying generators. But that obligation only activates for you if your meter feeds the right data.

SMETS1 vs SMETS2 — what is the difference?

SMETS stands for Smart Metering Equipment Technical Specification. There are two generations:

SMETS1 (first generation, installed roughly 2012–2018): These meters used a 3G SIM card to communicate with your supplier directly. They worked well — until you switched energy supplier, at which point many lost their smart functionality and reverted to sending manual reads. They were also installed before export metering became standard, so many SMETS1 units cannot record export data at all.
SMETS2 (second generation, mandatory for new installations from 2018): These meters connect through the Data Communications Company (DCC) — a government-mandated national smart meter network. Because every supplier speaks to the same DCC network, SMETS2 meters retain full smart functionality when you switch supplier. Crucially, SMETS2 units are designed to record both import and export in half-hourly intervals.

According to Smart DCC, every time energy is used or generated in a home with a SMETS2 meter, the data is encrypted and transmitted via the home communications hub to the DCC network, and from there to your supplier. For solar homes, this means export readings flow automatically to your SEG supplier without you lifting a finger.

How half-hourly settlement works for solar exports

Half-hourly settlement is the engine behind accurate export payments. Your SMETS2 meter logs how many kilowatt-hours cross the export boundary in each 30-minute window throughout the day. This granular data is what your SEG supplier uses to calculate your payment — whether you are on a simple flat-rate export tariff or a sophisticated time-of-use product.

Why does the 30-minute window matter? Solar generation is not uniform. On a clear summer day a 4 kWp system might export briskly between 10 am and 2 pm, then taper off as afternoon clouds arrive. Half-hourly metering captures exactly how much you exported and when, giving your supplier accurate data rather than a rough daily estimate.

For time-of-use export tariffs — such as Octopus Outgoing Agile, which pays a different rate every half-hour linked to the day-ahead wholesale electricity price — half-hourly data is not just useful, it is essential. Without it, the tariff simply cannot function. This is one reason why SMETS2 meters open the door to a wider range of export products than older meters can support.

If you are considering pairing solar with a home battery, the half-hourly data picture becomes even more important. Read our guide to home battery storage and smart metering to understand how batteries interact with smart meters and time-of-use tariffs to maximise your export earnings.

What happens with a SMETS1 meter?

SMETS1 meters can work with SEG, but there are important caveats. The government mandated a migration process to bring SMETS1 meters onto the DCC network — effectively upgrading them remotely to behave more like SMETS2 units. If your SMETS1 meter has been successfully enrolled on the DCC, your supplier may be able to receive half-hourly export data from it.

In practice, however, many SMETS1 meters were not fitted with export circuitry, meaning they can only record your total import. Even those enrolled on DCC may not transmit reliable export readings. If you have a SMETS1 meter and your SEG payments seem wrong or absent, contact your supplier and ask them to confirm that your meter is recording export data correctly. If it is not, request a free upgrade to SMETS2 — suppliers are required to fit smart meters at no cost to the customer.

What about old analogue meters?

Traditional analogue (non-smart) meters cannot support SEG payments. An analogue meter has no way to distinguish between electricity flowing into your home and electricity flowing out — it simply records total consumption. With an analogue meter, your solar panels will still work, and you will still benefit from every unit of self-generated electricity you consume directly (reducing your import bill), but you cannot receive export payments under SEG.

Under the old Feed-in Tariff (FIT) scheme, which closed to new applicants in 2019, many householders with analogue meters received a deemed export payment — typically calculated as 50% of their total generation reading, on the assumption that roughly half of all solar output was exported. This deemed-export approach does not apply under SEG; Ofgem requires metered export data, not estimates.

If you have solar panels and an analogue meter, contacting your supplier to request a free SMETS2 installation should be your first step. The government has a target for all homes to be offered smart meters, and suppliers are obligated to provide them. Once a SMETS2 is fitted, you can apply for a SEG tariff and start earning from your exports. The full picture of what you can earn — and which suppliers offer the best rates — is covered in our guide to the best SEG export tariffs.

Generation meters vs export meters — what does an MCS installer fit?

When an MCS-certified installer fits solar panels, the standard commissioning process includes a generation meter — a simple accumulation counter that measures total electricity produced by your panels in kilowatt-hours. This is separate from your property's main electricity meter and is typically mounted near the inverter.

The generation meter is useful for monitoring your system's total output, but it is not what your SEG supplier reads. Your supplier reads the export register on your main smart meter — the figure that records only the electricity that left your home and entered the grid. These two numbers are related (export = generation minus self-consumption) but are not the same.

Your property's export Meter Point Administration Number (MPAN), assigned by your Distribution Network Operator (DNO), is the identifier that links your property to export data on the national grid. When you register for SEG, you provide your MPAN alongside your MCS certificate number, and your supplier uses the MPAN to pull half-hourly export readings from the DCC.

Getting the most from your smart meter and solar

Once you have a functioning SMETS2 meter, the real work is choosing the right export tariff. A flat fixed-rate SEG tariff — typically 12–15p/kWh from major suppliers as of mid-2026, according to the Ofgem SEG Year 5 Annual Report (December 2025) — is the simplest option and well-suited to most solar-only households.

If you have a home battery, time-of-use export tariffs such as Octopus Intelligent Flux can unlock materially higher returns. According to Octopus Energy's Intelligent Flux FAQ, between June 2024 and May 2025, 34% of Intelligent Flux customers paid less for imported energy than they earned from exports — and the top 12% fully offset their electricity bill and standing charge, earning £314 or more in net credit on top. All of this is only possible because SMETS2 half-hourly export data lets the tariff settle accurately on every 30-minute window.

You also have rights under solar grants and SEG overview that include switching SEG supplier at any time — your export earnings do not lock you into a single supplier the way a Feed-in Tariff did. Monitor the market, and switch if a better rate appears.