Smart Export Guarantee (SEG)

If you have solar panels and you are still on a 4p flat-rate export tariff with the same company that supplies your gas, you are likely losing £80-£250 a year on the export side. The good news: switching SEG is a five-minute online form, and you do not have to switch import to do it.

This is a snapshot of the SEG market as of May 2026, with the headline rates and the catches.

What SEG is

The Smart Export Guarantee is a regulated scheme under the Smart Export Guarantee Order 2019. It replaced the Feed-in Tariff (FiT) for new installations from 1 January 2020.

The mechanics: any electricity supplier with more than 150,000 domestic customers must offer a SEG tariff. The tariff must pay above zero for every kWh exported to the grid. Suppliers can set the rate, the structure (flat or time-of-use), and the contract length.

The household must have a smart meter that supports half-hourly export readings (SMETS2 or SMETS1 with the right firmware). Without that, no export tariff is payable.

SEG is funded entirely by suppliers — there is no government subsidy. Suppliers buy the exported electricity at their SEG rate and resell it on the wholesale market. Suppliers with strong renewable generation portfolios (Octopus, Good Energy) tend to offer higher rates because the export aligns with their commercial strategy.

Why SEG matters more than most homeowners think

A typical 4kWp solar array on a south-facing UK roof generates around 3,800 kWh per year. Of that:

• ~30-50% is consumed in the home directly (depending on occupancy pattern and battery).
• ~50-70% is exported to the grid.

For a home exporting 2,000 kWh per year:

Over a 25-year solar panel lifetime, the difference between the worst and best tariff is £6,000+. SEG is one of the few areas of the energy market where switching genuinely makes a meaningful difference.

The SEG market in 2026 — full comparison

Rates change frequently. This is a May 2026 snapshot. Always check the supplier's current published rate before switching.

For households without a battery, the practical best-in-market rates are Octopus Outgoing (15p, requires Octopus import), E.ON Next Exclusive (16.5p, requires E.ON Next import), and Octopus Outgoing Lite (8p, no import requirement).

For households with a battery, time-of-use tariffs change the maths entirely — see below.

Octopus Outgoing vs Outgoing Lite — the key distinction

The most common SEG question is the difference between these two Octopus tariffs.

Outgoing Lite is the right choice if you are happy with your current import supplier and just want a better export rate. The 8p rate is the highest open-market SEG rate available to non-import customers.

Outgoing Fixed is materially better, but the cost of switching import to Octopus has to be set against your current import rate. For most households the Octopus standard tariff is competitive enough that the switch pays for itself; for households on a deep fixed deal with another supplier it may not.

Time-of-use tariffs and batteries

Time-of-use SEG tariffs only make sense with a battery. The economics work like this:

• Charge the battery from the grid in the off-peak window (typically 02:00-05:00) at 5-7p/kWh.
• Discharge to the grid during the peak window (typically 16:00-19:00) at 28-30p/kWh.
• The "round-trip" arbitrage profit is roughly 20-22p/kWh per cycle, less battery wear.

For a 10 kWh battery, a single full cycle a day at this spread is around £700/year before solar. Combine with solar export at peak rates and a well-tuned system can earn £1,000+/year on top of bill savings.

The catch: only certain batteries are supported by Octopus Flux (the dominant TOU export tariff). Currently supported: Tesla Powerwall, GivEnergy, Solax, Sunsynk, Solis, and a growing list of others. The full list is published on the Octopus help pages.

Households considering a battery purchase specifically for arbitrage should run the numbers on payback. Battery costs in 2026 are around £350-£500 per kWh installed; round-trip degradation is around 60% capacity over 10 years. The payback at current spreads is typically 6-9 years before warranty expiry, which is the right side of viable but not the slam-dunk it would be at lower battery prices.

How to switch SEG without switching import

This is the part most homeowners do not realise: SEG is a separate contract from your import tariff. You can be on British Gas for import and Octopus Outgoing Lite for export at the same time.

1. Confirm your smart meter is sending half-hourly export readings. Check this on your in-home display or by asking your current supplier.
2. Choose the SEG supplier and tariff. For most homes without a battery, Octopus Outgoing Lite at 8p is the best open-market rate.
3. Apply on the SEG supplier's website. You will need your MPAN (top of your last electricity bill), your installation MCS certificate (or a copy of your FiT statement if you have one), and the technical specification of the system (panel size in kWp, inverter, battery if any).
4. The new SEG supplier requests a meter readings transfer from your current supplier. This typically takes 4-8 weeks via the industry data network.
5. Once the transfer completes, you receive monthly export earnings from the new SEG supplier, while your import tariff remains unchanged.

If you are also on the legacy Feed-in Tariff (FiT closed to new entrants in 2019), you can keep the FiT generation payments and switch only the export side to SEG. FiT and SEG can run in parallel.

Common reasons SEG applications get rejected or delayed

• No smart meter. Without a SMETS2 or compatible SMETS1, half-hourly export readings are not available. Book a smart meter install with your import supplier first — they are obliged to fit one free.
• MCS certificate missing. Most suppliers require an MCS certificate from the original install. If lost, ask the original installer for a duplicate; if the installer is no longer trading, the MCS database can re-issue.
• Multi-occupancy property. SEG payments go to the meter holder. If the panels were funded by a third party (rent-a-roof schemes from 2010-2014), the third party usually retains the export rights.
• Tariff closed to new entrants. Suppliers can withdraw a tariff at short notice. Octopus Outgoing has been temporarily closed to new sign-ups during high-volume periods.
• Pending import switch. Some SEG sign-ups are blocked while an import switch is in flight. Wait for the import switch to complete before applying.
• System over 5 MW. SEG only applies to systems up to 5 MW. Domestic systems are well below this.

What about FiT — is it still better than SEG?

The Feed-in Tariff closed to new entrants on 31 March 2019. Existing FiT contracts run for 20 to 25 years from the original install date and pay generation tariff (for every kWh produced, including consumed at home) plus a deemed export tariff (typically 50% of generation, paid at a flat rate).

For a 2012-era FiT contract, the generation tariff can be 25-50p/kWh — far above any SEG rate. For households with FiT, the rule is:

• Keep the FiT generation tariff. It is locked for the contract term.
• Switch the export side to SEG if your FiT export rate is below current SEG rates. FiT deemed export at 5.5p/kWh in 2026 is below Octopus Outgoing Lite at 8p — so a switch usually pays.

FiT customers should check with their current FiT administrator before switching the export side, because some FiT contracts treat the deemed export as part of the bundled package.

SEG is the most movable lever in domestic solar economics. Switching from a 4p flat tariff to an 8p flat tariff with no other changes earns a typical UK household an extra £80-£100/year on a 4kWp system. The full picture — including time-of-use tariffs and battery arbitrage — can move the dial by £500+/year for the right household.

The mechanics are five minutes of admin and a 4-8 week wait. The hardest part is comparing the rates honestly against your own export pattern.

For a tariff comparison run against your specific export readings and battery setup, run the Green Home Grants eligibility checker and select the SEG path. If you want a deeper analysis with an independent assessor reviewing your export profile and recommending the right tariff, the directory at Healthy Homes Network lists qualified solar and storage assessors.