SEG vs REGO sales: which export income route for commercial solar?
Two distinct income streams are available to UK commercial solar generators in 2026: the Smart Export Guarantee (paid for kWh exported) and REGO sales (paid for renewable origin certificates). They are not alternatives — you can claim both on the same generation. Here's how they work together.
Side-by-side comparison
| Feature | Smart Export Guarantee (SEG) | REGO sales |
|---|---|---|
| What you sell | Each kWh of electricity exported to the grid | Each MWh of renewable generation (as a certificate) |
| Buyer | Ofgem-licensed energy supplier you choose | Energy supplier (via broker) |
| Current 2026 rate | 3p-15p per kWh (Octopus Outgoing Fixed 15p best) | £8-£20 per certificate (0.8p-2p per kWh equivalent) |
| Eligibility threshold | Up to 50kWp requires MCS; above 50kWp engineering sign-off | From 50kWp typically — accreditation cost £375 + £30/year |
| Above 1MW? | Exit SEG — enter wholesale market via PPA | Continue REGO accreditation |
| Self-consumed generation | Not paid (only export) | REGO issued on all generation, including self-consumed |
| Combined revenue on 100kWp system (40% export) | £1,140-£5,700/year | £760-£1,900/year additional |
| Time to first payment | 4-6 weeks from commissioning | First REGO issued after first quarterly reporting period (3-6 months) |
| Switch cost | No charge to switch SEG supplier | Broker takes 5-15% margin on REGO sales |
| Stack with each other? | Yes — different mechanisms entirely | Yes — different mechanisms entirely |
Which one for your business? Real scenarios
Small commercial site under 50kWp
SEG only. REGO accreditation cost is uneconomic at this scale.
Medium commercial site 50-250kWp
SEG + REGO. Worth the £375 REGO accreditation cost. Additional £700-£3,000/year from REGO at 2026 prices.
Large commercial site 250kWp-1MW
SEG + REGO. REGO income often £3,000-£15,000/year. Combined with SEG, materially shifts payback.
Solar farm above 1MW
Wholesale PPA + REGO. Exit SEG (which doesn't apply above 1MW) and enter the wholesale electricity market. REGO sales become 10-20% of total revenue at scale.
Sites pursuing corporate Scope 2 disclosure
SEG with REGO retention. Don't sell the REGO — keep it for your own Scope 2 emissions reduction claim. This costs the REGO revenue but improves the carbon position.
Key deciding factors
- System size matters most — REGO accreditation breakeven is roughly 50kWp.
- Self-consumption rate doesn't affect REGO (paid on all generation) but affects SEG (paid only on export).
- Above 1MW you exit SEG entirely — different commercial structure (wholesale PPA).
- Corporate carbon disclosure can make REGO retention more valuable than REGO sale.
- REGO market prices are volatile — they moved from £0.50 to £30+ between 2017-2022.
Comparison FAQs
Can I claim SEG on a system above 1MW?
No. The Smart Export Guarantee applies only to systems up to 1MW (technically up to 5MW for some specific categories, but the 1MW limit is the practical ceiling). Above 1MW you operate in the wholesale electricity market via a PPA.
Do REGOs help with Scope 2 emissions?
Yes — if you retain them rather than sell them. Each REGO retained allows you to claim renewable origin for the electricity it represents in your Scope 2 emissions calculation. Selling the REGO transfers that claim to the buyer.
How are REGO market prices set?
By market supply and demand. Ofgem doesn't set the price. Brokers like ENGIE, Bryt Energy and ECOHZ make the market between renewable generators and energy suppliers needing renewable claims for their tariff fuel mix disclosure.
Can I sell SEG to one supplier and REGOs to another?
Yes — they are separate transactions. Many generators take SEG from Octopus Outgoing Fixed (15p/kWh) and sell REGOs through a specialist broker for additional 0.8-2p/kWh equivalent revenue.
Want a personalised comparison for your business?
Free 60-second eligibility check tells you which of these schemes apply to your specific business — and how they stack.
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