Smart Export Guarantee UK 2026: The Tied vs Untied Trap Explained

SEG export rates range from 1p to 29p per kWh, and the difference between picking a tied versus an untied tariff is not just a few quid. It can cost you £200+ a year. Most comparison sites gloss over the tied/untied distinction, and that is where people get stung. Here is every rate compared, with worked examples so you can see what it actually means for your bill.

What is the Smart Export Guarantee?

The Smart Export Guarantee, or SEG, is a government scheme that forces large electricity suppliers to pay you for the solar electricity you send to the grid. It replaced the old Feed-in Tariff in January 2020, and unlike the FiT (which paid a flat rate set by the government), SEG rates are set by the suppliers themselves. Some pay 16p. Some pay 1p. Both are technically compliant with the law.

To qualify, you need three things: MCS-certified solar panels (or equivalent certification), a smart meter that can measure export, and an export tariff with a licensed supplier. You do not need to have installed your panels through that supplier. You do not even need to import electricity from them, though whether that is a good idea depends on the tariff.

That last point is the whole game. Let us explain why.

The tied vs untied trap: the bit most guides skip

SEG tariffs come in two flavours: tied and untied. A tied tariff means you must get your import electricity from the same supplier that pays your export. An untied tariff, sometimes called "no-strings", lets you export to one supplier and import from a different one.

This distinction matters because import rates vary by £200-£300 a year between suppliers. If you sign up for a shiny 16p/kWh export rate that ties you to a supplier charging 30p/kWh for import, you might be worse off than taking a 12p/kWh untied rate and buying import from someone cheaper.

The trap is this: a supplier might advertise a great export rate to get you in the door, knowing you will then pay above-average import rates for the next 12 months. The 3p/kWh difference between a 15p tied rate and a 12p untied rate on your export is £57 a year. If the tied supplier charges 2p/kWh more on your import across 3,500kWh of annual usage, that costs you £70. Net loss: £13. You are paying for the privilege of a higher export number that sounds better in the brochure.

Worked example: tied looks better, untied actually wins

Take a typical 3-bedroom house with a 4kWp solar system generating 3,800kWh per year, using 1,900kWh themselves and exporting 1,900kWh. They import another 2,500kWh from the grid (winter, evenings). Here is how two real-world options stack up:

In this example, where import rates happen to be similar, the tied tariff wins by £38/year. But now assume the tied supplier charges 27p/kWh for import instead of 25p - that adds £50 to your bill and flips the result. The point is not that one is always better. The point is you have to check both sides.

Every SEG tariff compared (August 2026)

Here is the full table of current SEG rates, ranked by what a typical household would net after combining import and export. Tied tariffs are marked with a check; untied tariffs have no import requirement.

Rates sourced from supplier websites and SunSave monitoring, verified August 2026. Intelligent Octopus Flux has been closed to new customers since April 2026 and is not listed. Standard Octopus Flux returned after a brief suspension and is included.

The "Annual Saving" column is the combined import-plus-export saving for a typical solar household, based on SunSave methodology. It is the best single number for comparing tariffs because it accounts for both sides of the meter.

Installer-only tariffs: the higher rates you only get if they fit the panels

Several suppliers offer premium export rates that are only available if that same supplier installs your solar system. These are the highest headline rates on the market, but they lock you into one installer, which limits your ability to shop around for the best installation price.

These rates look great on paper. Good Energy's 25p/kWh is nearly double the best open-market rate. But here is the catch: if Good Energy charges £2,000 more for the installation than a local MCS installer, you have just pre-paid eight years of the export premium upfront. Always get quotes from independent installers first so you know the baseline installation cost. Our solar costs guide has the numbers.

Time-of-use export: Octopus Flux explained

Octopus Flux is the only widely-available time-of-use export tariff, and it is the most misunderstood rate in UK solar. Here are the actual numbers:

The 29.32p headline rate only applies between 4pm and 7pm. Outside that window you get 4.99-10.11p. If you do not have a battery, almost none of your solar generation falls in the 4pm-7pm peak in winter, and only a bit does in summer. Most of your export will be at 10.11p, which is worse than Octopus's own flat 12p Outgoing tariff.

With a battery, the maths flips. You can charge the battery during the cheap overnight period (or from solar during the day) and export it all during the 4pm-7pm window at 29.32p. That is where the real money is. But it requires a battery, and batteries cost £3,000-£4,500 installed.

Recent rate changes you need to know about

How to pick the right SEG tariff: a checklist

Do not just sort by export rate and pick the highest number. Here is the order of operations:

1. Do you already have solar panels? If yes, installer-only tariffs are closed to you. Skip that whole table. Your best open-market options are Ecotricity 16p (tied), EDF 15p (tied), or Fuse 13p (untied).
2. Do you have a battery? If yes, Octopus Flux's 29.32p peak window becomes usable. If no, avoid time-of-use tariffs entirely - you will earn less than a flat 12-15p rate.
3. What is your current import rate? If you are on a cheap fixed import deal (below 24p/kWh), an untied 13p export rate from Fuse might beat a tied 16p rate that forces you onto a 27p import tariff. Do the maths on both sides.
4. How long is the fix? Tied tariffs often lock you into 12-month fixed import deals with exit fees of £25-£150 per fuel. If rates drop in six months, you are stuck. Untied tariffs let you switch import whenever you want.
5. What equipment do you have? Some tariffs require specific inverter brands or battery types. Check the small print before signing up.

If in doubt, run your numbers through our solar savings calculator. It accounts for your system size, usage pattern, and location to give you a personalised estimate including export income.

The 10x gap between best and worst

The difference between the best and worst SEG tariff is roughly 10x on export alone. Ecotricity at 16p versus Outfox Energy at 1.05p. On 1,900kWh of annual export, that is £304 versus £20. Three hundred quid a year, just for picking the right supplier.

But the real gap is bigger when you factor in import. A Good Energy Solar Savings Exclusive customer earning 25p/kWh on export and paying 14p/kWh overnight import through the Heat Pump tariff could net £1,431 in combined annual savings. The same household on Utility Warehouse's 2p SEG and a standard import tariff might net £838. That is a £593 difference every year.

For more on how solar savings stack up against current electricity prices, see our energy price cap and solar payback guide. If you are looking at the grants side, our solar grants guide covers ECO4, the Warm Homes Plan, and the 0% VAT deadline.