What the Smart Export Guarantee actually is
The Smart Export Guarantee (SEG) is the Ofgem-mandated scheme that replaced the Feed-in Tariff in 2020. Every licensed UK electricity supplier with over 150,000 customers must offer a tariff that pays solar homes for every kWh of electricity they export to the grid. Unlike the old FiT, the rate is not set by government — each supplier prices its own, and rates vary from a token 1p/kWh to over 30p/kWh at peak times on smart tariffs.
To claim SEG payments you need an MCS-accredited install, a smart meter capable of half-hourly export readings (SMETS2), and a signed export tariff with your chosen supplier. You can be on any import tariff — most SEG tariffs are export-only, so you keep your existing import deal.
Octopus Flux: how it works
Octopus Flux is a time-of-use import and export tariff aimed at homes with solar + battery. It splits every 24-hour period into three windows. Off-peak (02:00-05:00) imports at a low rate — typically 15-19p/kWh — perfect for charging the battery overnight. Peak (16:00-19:00) exports at a high rate — typically 24-32p/kWh — so the battery discharges into the grid during the evening spike. The rest of the day sits at a flat middle rate for both import and export (around 22-28p/kWh import, 15-19p/kWh export).
Flux is genuinely powerful for solar + battery homes because you can arbitrage: import cheap overnight, self-consume during the day from solar, then export stored solar (and even imported overnight cheap) into the peak-price evening window. Well-set-up 10 kWh systems on Flux routinely add £200-£450/year on top of their normal solar savings.
Intelligent Octopus Flux (2026)
Intelligent Flux is Octopus's newer smart-controlled variant, launched in beta in 2025 and now open to most GivEnergy, Fox ESS and Tesla Powerwall 3 owners. Instead of fixed three-window pricing, Octopus's platform actively controls charge and discharge based on live wholesale prices — pushing you extra earnings on days when grid prices spike (typically winter cold snaps).
Real-world reports from 2025 users show Intelligent Flux edging fixed Flux by roughly £80-£150/year on a 10 kWh Powerwall 3, at the cost of handing scheduling control to Octopus. Homes on manual Flux keep tighter control (useful for very-large batteries or EV-heavy homes); most typical households do better on Intelligent.
The main SEG tariffs compared
Octopus Outgoing Fixed: 15p/kWh flat, no time-of-use complexity. Best for solar-only homes or households that don't want to think about it.
Octopus Flux: 15-32p/kWh depending on time band. Best for solar + battery homes willing to configure schedules.
Intelligent Octopus Flux: dynamic, typically 5-10% higher earnings than fixed Flux. Best for compatible battery brands.
EDF Export+: 5.6p/kWh flat, but bundled with competitive import deals — worth checking if you're already an EDF import customer.
British Gas Export & Earn Plus: 6.4p/kWh flat, existing BG import customers only.
E.ON Next Export: 16.5p/kWh flat, no import-tie required — Octopus Outgoing's main rival for solar-only homes.
Scottish Power SmartGen+: 15p/kWh flat, existing customers only.
OVO SEG Tariff: 4p/kWh flat — one of the lowest, only worth it if you're already an OVO customer and don't want to switch export supplier.
Good Energy SEG: 5.5p/kWh flat, appeals to buyers who want a green-only import + export supplier.
Worked example: a Sussex 5 kWp + 10 kWh system
Assume 4,750 kWh/year generation on a well-oriented Sussex roof, a 10 kWh battery, and 5,200 kWh household consumption. With no battery on Octopus Outgoing Fixed at 15p, exporting roughly 3,000 kWh nets £450/year in export income plus £480/year in bill savings from the 1,750 kWh self-consumed.
Add the battery and move to Octopus Flux. Self-consumption rises to about 4,000 kWh — cutting the bill by £1,200/year at 30p/kWh. Remaining 750 kWh exported through the peak window at ~28p averages £210/year. Overnight battery arbitrage (charge 10 kWh at 17p, discharge to grid at 28p) on ~200 winter days adds a further £220/year. Total: £1,630/year — roughly £400/year more than the same household on Outgoing Fixed.
Intelligent Flux typically adds another £100-£150 on top by capturing wholesale price spikes automatically.
How to choose the right SEG tariff
If you have solar only (no battery): go for the highest flat export rate you can get. E.ON Next Export at 16.5p and Octopus Outgoing at 15p lead the market. Don't bother with Flux — you have nothing stored to shift into the peak window.
If you have solar + battery and want maximum earnings: Octopus Flux (manual) or Intelligent Flux. The uplift over flat-rate tariffs is £200-£450/year on a 10 kWh system.
If you have an EV: Intelligent Octopus Go (import) + Octopus Outgoing (export) is often better than Flux, because Intelligent Go's 7p overnight EV window is lower than Flux off-peak, and your export earnings from solar are already good on Outgoing at 15p flat.
If you're loyal to your current supplier: check their SEG rate before shopping. Being on a low-rate SEG tariff can cost £150-£400/year on a 5 kWp system — usually more than the hassle of switching export supplier saves.
Common SEG pitfalls to avoid
Not signing up: over 100,000 UK solar homes never claim SEG at all — pure lost income. If your smart meter is fitted, you're eligible.
Staying on the installer-default SEG: many installers auto-enrol you with their default supplier at 5-6p/kWh. Always compare before your first bill cycle.
Import + export bundling: some suppliers only offer their best export rate if you also take their import tariff. Model the combined bill — a great export rate can be wiped out by an above-market import rate.
Battery brand compatibility with Intelligent Flux: check Octopus's supported list before you buy a battery. Tesla Powerwall 3, GivEnergy AIO, and Fox ESS ECS are all currently supported; some older SolaX, LG and Pylontech systems are not.
How SEG interacts with 0% VAT and MCS certification
SEG eligibility requires an MCS certificate — one more reason to insist on an MCS-accredited installer. The 0% VAT rate on solar (in place until at least March 2027) is unaffected by which SEG tariff you pick; the two schemes run independently. You do not lose SEG income if you later add a battery, an EV charger or an extension — you just re-submit the MCS certificate to your export supplier.
Where SEG is heading
Ofgem's 2025 review of the SEG confirmed the scheme will continue at least through 2028, with a stronger push toward time-of-use pricing (which suits Flux-style tariffs). Wholesale evening prices remain volatile, so expect Intelligent-style dynamic tariffs to spread across other suppliers over the next 12-24 months. The direction of travel is clear: batteries and smart tariffs are the way to maximise solar ROI in 2026 and beyond.