If you’re weighing up a solar quote in 2026, the Smart Export Guarantee (SEG) rate you’re offered can move your payback period by a year or more — yet most homeowners still accept whatever their installer’s default tariff happens to be. There’s no fixed national export rate in the UK, which means the difference between a mediocre SEG tariff and a genuinely good one is entirely down to which supplier you sign up with, and whether you understand what you’re comparing.
What the Smart Export Guarantee actually is
SEG replaced the old Feed-in Tariff in 2020. Any licensed electricity supplier with more than 150,000 customers must offer at least one export tariff to small-scale generators (solar, wind, hydro, battery storage) below 5MW capacity — but the law only obliges them to offer something above zero pence. It does not set a minimum rate. That’s why rates offered across the market currently span from token amounts around 3-4p/kWh up to headline tariffs at the top end of roughly 12-20p/kWh, depending on the supplier, tariff type and whether you’re also on their import tariff.
To qualify at all, your system needs MCS certification — this isn’t optional paperwork, it’s the gatekeeper for every SEG application. An uncertified DIY install, or one done by a non-MCS installer, simply won’t be eligible, no matter how well it performs. If you’re choosing an installer, confirming MCS accreditation should be step one of due diligence, alongside checking their NIC or NAPIT electrical registration.
Fixed vs variable SEG tariffs — what’s the real difference
SEG tariffs split into two broad types, and conflating them is the single most common mistake in export-rate comparisons.
Fixed-rate SEG tariffs pay a flat pence-per-kWh rate for every unit exported, usually locked in for 12 months. You know exactly what you’re earning regardless of when the export happens — 3am or 3pm, it’s the same rate. These suit households without a battery, or anyone who wants predictable numbers for a payback calculation.
Variable/half-hourly SEG tariffs pay a rate that tracks wholesale electricity prices in real time, sometimes swinging from near-zero (or occasionally negative) during oversupply, up to well over 20-30p/kWh during evening peak demand. These only make sense if you have a smart meter capable of half-hourly export readings and, ideally, a battery so you can choose when you release stored solar power to the grid rather than exporting the moment the sun produces it. Get this wrong — exporting flat through the day on a variable tariff with no battery to shift it — and you can end up worse off than a mediocre fixed rate.
The practical rule: no battery, no smart export shifting capability, or you just want simplicity — go fixed. Got a battery and are willing to actively (or automatically, via an app) time your exports around peak pricing — a variable tariff can meaningfully beat a fixed one, but only if you engage with it.
Who’s paying what in 2026 (illustrative comparison)
Exact rates change frequently and differ by region, meter type and whether you’re a new or existing customer, so always check the live tariff on the supplier’s own SEG page before signing. As a rough shape of the market in 2026:
| Tariff type | Typical range | Best suited to |
|---|---|---|
| Standard/legacy SEG (smaller suppliers) | ~3-8p/kWh | Anyone not actively comparing — usually the weakest deal |
| Mid-market fixed SEG | ~8-15p/kWh | No-battery households wanting predictable income |
| Premium fixed SEG (often tied to their import tariff) | ~15-20p/kWh | Households happy to bundle import + export with one supplier |
| Variable/agile-style SEG | Can spike above 20-30p/kWh at peak, drop near zero off-peak | Battery owners actively time-shifting exports |
Octopus Energy has run some of the more widely discussed SEG offerings — including variable, half-hourly tariffs aimed at battery owners — but it is not alone; several suppliers now compete at the top end, and the “best” tariff for any household depends on their own consumption pattern, battery presence and whether they’re prepared to switch supplier purely for the export rate (which is allowed — your SEG supplier doesn’t have to be your import supplier). Treat any “best rate” headline as a snapshot, not a fixed fact, and re-check every 12 months when your tariff renews.
How much does the SEG rate actually change your payback?
Take a typical 4kW residential system in southern England generating roughly 3,400-4,000 kWh/year (using the ~850-1,050 kWh per kWp/yr range typical across the UK). If a household self-consumes around 40% of that and exports the remaining 60%, that’s roughly 2,000-2,400 kWh exported annually.
- At a weak 4p/kWh SEG rate: that’s £80-£96/year in export income.
- At a strong 15p/kWh fixed rate: £300-£360/year.
- At a well-timed variable tariff averaging, say, 18-20p/kWh across exported units (achievable only with a battery shifting exports to peak windows): £360-£480/year.
Across a 25-year panel lifespan, the difference between the weakest and strongest scenario above is roughly £7,000-£9,600 in export income alone — before accounting for the far bigger lever, which is import savings from self-consumption. That’s why SEG shopping is worth the twenty minutes it takes, but it’s also why it shouldn’t be the deciding factor in whether solar makes financial sense at all; it’s the icing, not the cake. For a fuller breakdown of how export income fits into total system economics, our own payback period guide walks through the maths against upfront cost, and thebritishsolarblog.co.uk’s consumer guide is a useful primer if you’re still at the “does this even work in the UK” stage.
Where a battery changes the equation
This is where SEG strategy gets genuinely interesting rather than just being a rate-shopping exercise. A home battery — typically £4,000-£8,000 installed (roughly £400-£700/kWh), with something like a Tesla Powerwall 3 (13.5kWh) landing around £8,500-£10,500 — lets you store midday solar generation and either use it yourself in the evening (avoiding ~25p/kWh import costs) or export it later at a higher variable SEG rate if your supplier’s peak export pricing beats your own evening usage value.
In practice, most battery owners on variable tariffs prioritise self-consumption first (each kWh you don’t import saves you the full ~25p import rate, which almost always beats even a strong SEG export rate) and only export genuine surplus. The battery essentially turns your SEG tariff from “whatever rate happens when the sun’s out” into “whatever rate you choose to export at,” which is the whole appeal of pairing storage with a variable export deal.
If you’re assessing whether a battery retrofit stacks up for your own roof, it’s worth getting a specific quote rather than working off national averages — installers such as Ecoaim in Livingston and Energy Concerns in Leicester both size battery capacity against actual half-hourly consumption data rather than rules of thumb, which matters more for the SEG-optimisation case than for a simple no-battery install.
Don’t forget the 0% VAT window
Both solar panels and battery storage (including retrofits added to an existing system) currently qualify for 0% VAT in Great Britain, a relief scheduled to run until 31 March 2027 before reverting to 5%. That’s a meaningful saving stacked on top of whatever SEG income you eventually earn — on a £7,000 system plus an £6,000 battery, the VAT relief alone is worth roughly £650 versus the scheduled 5% rate, let alone the old 20% rate. If you’re weighing up timing a purchase, the VAT deadline is arguably a bigger lever than chasing the last percentage point of SEG rate.
Practical steps before you switch or sign up
- Confirm MCS certification on your installation — no MCS, no SEG eligibility, full stop.
- Get your own supplier’s SEG rate in writing, not verbally quoted by an installer’s sales team — installers sometimes push a bundled deal with a partner supplier that isn’t actually the best available rate.
- Decide fixed vs variable based on whether you have a battery and are willing to actively manage export timing — don’t take a variable tariff on faith if you can’t shift when you export.
- You can switch your export supplier independently of your import supplier — shop the SEG market like you’d shop a mobile contract; loyalty rarely pays here.
- Re-check annually. SEG tariffs typically run 12-month terms and rates move — what was competitive last year may have slipped behind newer market entrants.
For homeowners in South Yorkshire, ElectriFusion Solutions and AMP Pro Electrical both handle the MCS paperwork and SEG registration as part of a standard install, which removes one common friction point — DIY SEG applications get rejected more often than installer-submitted ones simply through incomplete documentation.
The bigger picture: SEG is one line in a wider sum
Export income is real money, but it’s a fraction of what determines whether solar pays for itself. Self-consumption savings (avoiding ~25p/kWh import costs), the size and orientation of your system, local irradiance (the sunny south sees yields nearer 1,050 kWh/kWp/yr versus ~850 further north), and — for anyone running a business — the commercial-scale economics are all bigger factors. If you’re assessing a commercial roof or car park rather than a home, the arithmetic shifts considerably: commercial installed costs run roughly £900-£1,200/kWp, and export strategy interacts with far larger consumption profiles. Solar Car Parks and Solar Panels For Warehouses both cover the commercial export/self-consumption trade-off in more depth if that’s your situation, and solarweekly.co.uk’s 2026 industry overview has useful market-level context on where UK generation capacity (now around 21.6GW, roughly 6.4% of UK electricity) is heading.
The honest takeaway: don’t let a supplier’s default SEG offer sit unchallenged on your paperwork. Twenty minutes comparing fixed and variable rates against your own battery situation is one of the highest-value bits of admin you can do after a solar install — but treat it as optimisation on top of a sound underlying system, not the reason to go solar in the first place.