Estimate what your solar surplus earns through the Smart Export Guarantee — exported kWh and £ per year, by region, system size and SEG rate.
What is SEG?
The Smart Export Guarantee (SEG) is the UK scheme that pays you for the surplus electricity your solar panels export to the grid. Every licensed electricity supplier with over 150,000 customers must offer an export tariff, but each one sets its own rate — so the amount you earn varies by supplier.
How this is calculated
annual generation (kWh) = system size (kW) × regional sun hours
exported (kWh) = generation × (1 − self-consumption rate)
SEG income (£) = exported × SEG rate
Self-consumption is the share of your generation you use directly in the home — we use 45% without a battery and 75% with one, matching the site-wide methodology.
About SEG rates
- Default 6p/kWh — a typical supplier rate (our default).
- ~13p/kWh — the best widely-available fixed rate (Fuse Energy).
- 1p–15p — the realistic range, depending on supplier and tariff.
Compare every supplier's rate and learn how to switch in SEG explained.
How to earn more from your exports
- Pick a better SEG rate — switching suppliers is usually free and can double or triple your export income.
- Try a time-of-use export tariff — Octopus Agile or Flux can pay more at peak evening hours.
- Think about the battery trade-off — a battery raises self-consumption (cutting exported kWh), but self-used electricity is worth more than the SEG rate. See home battery ROI.
A typical Smart Export Guarantee rate is around 6p per kWh, but rates are set by each supplier and range from as low as 1p up to 15p. The best widely-available fixed rate is around 13p (Fuse Energy).
Switch to a supplier with a higher SEG rate, or pair your panels with a time-of-use export tariff such as Octopus Agile or Flux. Note that adding a battery increases self-consumption, which usually reduces exported kWh — the trade-off is that self-used electricity is worth more than the SEG rate.
On our default assumptions — a 4 kW system in London at 45% self-consumption — you export about 1,563 kWh a year. That earns roughly £94 at a 6p/kWh SEG rate, or about £203 at the best open fixed rate of 13p. Across UK regions the same system earns roughly £78–£103 at 6p. A battery raises self-consumption to 75%, cutting exports to about 710 kWh and income to about £43.
Estimates only — not financial advice. Sun hours from
PVGIS 5.2 (European Commission, 2026). SEG rates are supplier-set and change over time; 6p is a typical value and 13p is the best widely-available fixed rate as of late 2026. The 25-year figure assumes the SEG rate stays constant and does not account for panel degradation or tariff changes. Actual exported kWh vary by roof orientation, shading, installer and household usage. Always confirm current SEG rates with your supplier.