FiT Export vs the Smart Export Guarantee: Should a FiT Site Switch?
Updated 23 October 2026 · SEO Dons Editorial
What changes when a FiT site moves its export to the SEG?
Only the export half of the payment moves. Ofgem says the Feed-in Tariff scheme, introduced on 1 April 2010 and closed to new applicants from 1 April 2019, "requires participating licensed electricity suppliers to make payments on electricity generated and exported by accredited installations". Support runs "between 10 and 25 years" depending on technology, capacity and commissioning date. A FiT site is therefore paid for generation and for export, and the Smart Export Guarantee covers export alone.
The two cannot overlap. Ofgem: "you cannot receive both SEG payments and FIT export payments for the same electricity. In order to register for the SEG, you must first opt out of FIT export payments". British Gas says a business that opts out of FiT export "will continue to receive FiT generation payments". Treat that as one licensee's statement and check it against your own statement of FiT terms, which this page does not interpret.
What is deemed export, and who gets it?
Ofgem says generators "may receive deemed export payments for installations with a capacity of 30 kilowatts or less if an export meter is not fitted". Export is estimated as a percentage of the generation meter reading, set each year by the Secretary of State. The FIT year 17 determination, signed on 25 February 2026 for 1 April 2026 to 31 March 2027, sets it at 50% of the generation meter reading for solar photovoltaic installations of that size, and 75% for hydro.
| Export basis | Applies to | Paid on |
|---|---|---|
| Deemed | Installations of 30 kW or less with no export meter | A fixed share of generation: 50% for solar PV in FIT year 17 |
| Metered | Installations with an export meter | The kWh the export meter records |
Ofgem describes deemed export only for 30 kW or less, so a larger commercial site taking export payments is paid on metered export. Fitting a smart or export meter also ends deemed export: Ofgem says deemed payments "will stop" and be replaced by payments for the amount the meter records, while "generation payments will not be affected".
When does switching pay? A worked example
A site of 30 kW or less on deemed export. The FiT licensee pays on 50% of generation whatever the site really exports. A SEG licensee pays only on metered export. Call the FiT export rate F and the SEG rate S. Per kWh generated, deemed FiT export earns 0.5 x F, and SEG earns the actual export share x S. SEG wins when S is greater than F x 0.5 divided by the actual share. The table works that out for illustrative export shares; the 50% is the only sourced input.
| Actual export share of generation | SEG rate must exceed |
|---|---|
| 20% | 2.5 times the FiT export rate |
| 30% | 1.7 times |
| 40% | 1.25 times |
| 50% | 1.0 times (equal) |
| 60% | 0.83 times |
A site that exports little is better off on deemed export, because it is paid for 50% it never sent. A site exporting more than half is underpaid by the deeming and can win even at a lower SEG rate. For the business tariffs on offer from suppliers, see SEG rates for businesses.
A site on metered FiT export. The comparison is simply the SEG rate against the FiT export rate, less any cost of the meter and MPAN. The FiT rate is index-linked: Ofgem says rates "will be adjusted each financial year in line with the Consumer Price Index (CPI)" from FIT year 17, and its tariff table for 1 April 2026 applied a CPI adjustment of 3.4 percent. Look up your own band in that table. A SEG rate is whatever the licensee sets, for the contract length it sets.
The way back is narrow. British Gas says you can opt out of FiT export only once every 12 months and that moving from deemed to metered export is permanent. EDF says that once you opt out you "cannot opt back in for 12 months" and cannot return to deemed export. Put your site's numbers through the savings calculator before committing.
What are the practical steps?
- Check the metering. Ofgem says most FiT installations are eligible for the SEG "provided they have a smart or export meter installed". A deemed-export site usually has none, so it needs an export meter and an export MPAN first; the Smart Export Guarantee guide covers both, and the Welsh Government notes that an export meter's benefits must be weighed against ongoing meter operator charges.
- Pick a licensee. Ofgem says a SEG licensee need not be your current energy supplier.
- Opt out of FiT export by contacting your FiT licensee, before the SEG tariff starts.
- Keep generation separately measured. Ofgem says you must measure generation "separately from all other sources" to receive generation payments. Tell your FiT licensee if a meter is replaced or removed, or begins measuring electricity the accredited installation did not generate.
- Tell Ofgem too, above 50 kW. Solar PV above 50kW is a ROO-FIT installation, and its generator must also update the Renewable Electricity Register for changes.
What if the site adds panels or a battery later?
Ofgem allows capacity changes up to 5 megawatts, but "you cannot receive FIT payments in respect of electricity generated from any additional capacity unless the extension was commissioned before 15 January 2016". Where meters record both accredited and non-accredited capacity, payments are prorated. Connecting a battery must be notified to the FiT licensee, and payments continue only while generation and metered export can still be accurately measured. EDF says battery export is eligible for the SEG if an eligible renewable installation is linked to the battery. Replacing or enlarging an array raises these questions in full, and repowering a commercial solar system covers them.
Sources and last checked
- Ofgem: Feed-in Tariffs (FIT); FIT generator guidance and FAQs; FIT payments and tariffs; FIT tariff table, 23 March 2026; SEG generators, checked 22 October 2026.
- Department for Energy Security and Net Zero: Feed in Tariffs (FITs) determinations, Year 17, updated 26 February 2026, checked 22 October 2026.
- Welsh Government: Connecting on-site generation to the grid (updated 11 September 2026), checked 22 October 2026.
- Licensee pages, used only for facts about that supplier: British Gas business; EDF, checked 22 October 2026.
Common questions
Will fitting an export meter change my generation payment?
Ofgem says no: generation payments are not affected by installing a smart meter. If you were on deemed export, those payments stop and are replaced by payments for the electricity the meter records as exported.
Can I go back to FiT export after joining the SEG?
Not quickly. British Gas and EDF both say you cannot opt back in to FiT export for 12 months after opting out, and EDF adds that you cannot return to deemed export. Your own FiT licensee's terms apply, so ask it before opting out.
Is the FiT export rate fixed?
It is index-linked rather than fixed. Ofgem says tariff rates are adjusted each financial year in line with the Consumer Price Index from FIT year 17, and the tariff table for 1 April 2026 applied a 3.4 percent adjustment.
Does the SEG licensee have to be my FiT licensee?
Ofgem says a SEG licensee does not need to be the same company as your current energy supplier, and a generator can apply to any SEG licensee. The FiT licensee only needs to hear about the opt-out and any meter changes.