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⚡ SEG Earnings Calculator

Smart Export Guarantee rates compared

kWh
%
What % of solar you use yourself (typical: 40% without battery, 80% with battery)
Exported kWh (what you sell)
Generation × (1 − Self-consumption)

SEG Rate Comparison

Provider Rate Annual 25-Year
💡 Octopus Outgoing offers the best SEG rate at 15p/kWh. 25-year projections assume 2% annual rate increase. Rates correct as of 2025 — check provider websites for current rates.

Annual Earnings by Provider

Deemed vs Actual Export

Deemed Export: Some SEG providers calculate your export based on a fixed assumption — typically 50% of your generation. This comes from the old MPAN-based system used before smart meters were widespread. You get paid on this "deemed" amount regardless of how much you actually export.

Actual Metered Export: With a smart meter (SMETS2), your export is measured precisely. You get paid only for what you actually send to the grid.

Which is better? If you use most of your solar yourself (high self-consumption), deemed is usually better — you get paid for 50% even if you only export 30%. If you export most of your solar (low self-consumption), actual metered export benefits you more.

kWh
%
p

Comparison

Deemed (50%)
Actual Metered
🟢 Deemed export wins — you earn £ more per year because your self-consumption is above 50%. 🟢 Actual metered wins — you earn £ more per year because you export more than 50%. ⚖️ It's a tie — your self-consumption is exactly 50%.
💡 Old FIT installations often use deemed export. If you have a smart meter and high self-consumption (e.g. with a battery), you may earn more on deemed. But most new SEG tariffs require a smart meter and pay on actual readings.
kWh
%
%
£
p
p

Battery Impact on SEG Earnings

No Battery
With Battery
Self-Consumed
Exported
SEG Earnings
Import Savings
Total Annual
💡 Battery increases total annual savings by , but reduces SEG earnings by because you export less. The extra import savings more than compensate.
🔋 Battery payback from additional savings:
⚠️ For illustration only, not financial advice. SEG rates change regularly — check provider websites for current rates. Actual earnings depend on your system, tariff and usage patterns.
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How to Use the SEG Earnings Calculator

  1. Enter your solar system size The kWp rating of your panels.
  2. Estimate your export percentage How much of your generated electricity goes to the grid? Typically 50–70% without a battery, 20–30% with one.
  3. Compare SEG rates See earnings at different supplier rates side by side.
  4. See annual earnings The calculator shows how much you'd earn per year from exporting surplus solar.

Use Cases

Choosing the best SEG tariff. SEG rates vary wildly between suppliers. from 1p/kWh to over 15p/kWh. This calculator compares the main providers so you can see which one pays the most for your export. Switching SEG provider can add hundreds of pounds to your annual earnings.

Deciding whether to get a battery. A battery reduces the amount you export (because you store and use more yourself). Whether this saves money depends on the difference between your import price and the SEG rate. If you pay 28p to import but only earn 5p from exporting, every kWh you keep is worth 23p. The calculator shows the break-even point.

Understanding Octopus export tariffs. Octopus offers the highest export rates, including variable tariffs that pay more at peak times. This calculator helps you understand what you'd actually earn versus the headline rate.

Frequently Asked Questions

What is the Smart Export Guarantee?

The SEG is a government-backed scheme that requires licensed electricity suppliers to offer tariffs for small-scale low-carbon generators (like solar panels) who export electricity to the grid. It replaced the Feed-in Tariff scheme for new installations from January 2020.

Do I need a smart meter for SEG?

Yes. all SEG tariffs require a smart meter that can measure export (half-hourly metering). If you don't have a smart meter, you may still qualify but would receive a deemed (estimated) export payment, which is usually much lower.

Can I switch SEG provider?

Yes. you don't have to use the SEG tariff from your electricity supplier. You can have your import from one supplier and your SEG from another. Octopus is currently the most popular SEG provider due to its higher rates.

How much could I earn from SEG?

For a typical 4 kWp system exporting 60% of generation, annual SEG earnings range from about £80 (at 4p/kWh) to £300+ (at Octopus variable rates). The difference between the cheapest and best SEG tariff could be £200+ per year.

Is my data private?

Yes. All calculations run in your browser.

Why Use This SEG Calculator?

Most solar calculators lump SEG earnings into an annual savings figure without showing you the breakdown. This one focuses purely on export income and lets you compare actual SEG rates from different suppliers. It's the tool you need after you've decided on solar. to make sure you're getting paid properly for what you generate.

Works offline, no sign-up, no tracking, and no installer will call you after using it.

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