Smart Export Guarantee (SEG) is the mandatory UK regulatory framework that requires licensed electricity suppliers above 150,000 customers to offer at least one export tariff for solar PV generation exported to the grid. Replacing the Feed-in Tariff (FiT) scheme in January 2020, SEG is the income stream UK warehouse solar operators receive for excess generation beyond on-site self-consumption. For typical UK warehouse solar at 75-85% self-consumption, SEG income represents 8-15% of total project return. This guide compares the best SEG rates available in 2026, explains contract structures, and shows how to switch SEG suppliers without disrupting your main electricity supply.
Best SEG rates UK 2026 — by supplier
Current SEG rates for commercial warehouse solar in 2026, ordered by best fixed rate. Octopus Energy "Outgoing Octopus Fixed": 15p/kWh fixed (highest fixed SEG rate in UK 2026). Octopus "Outgoing Octopus Agile": variable, half-hourly tracking wholesale price, typical average 4-12p/kWh but can spike to 25-35p/kWh during peak periods. E.ON Next "Next Export": 4.5p/kWh fixed. EDF Energy "Export+Earn": 5.5p/kWh fixed. SSE / OVO Energy "SmartGen Export": 6p/kWh fixed. British Gas "Export & Earn Flex": 6.4p/kWh fixed. Bulb Energy (now Octopus subsidiary): 5p/kWh fixed. Drax Smart Export: 4.1p/kWh fixed. Scottish Power "SmartPower Export": 12p/kWh fixed (one of the highest after Octopus). For commercial customers (above 100 MWh/yr import), bespoke commercial SEG contracts are available from major suppliers — typically 4-8p/kWh negotiable. Switching SEG supplier is independent of import supplier and free to do once per 12 months.
Octopus Outgoing — why it is the best SEG tariff in 2026
Octopus Energy "Outgoing Octopus Fixed" at 15p/kWh is the highest fixed SEG rate available to UK warehouse solar operators in 2026. Three reasons it leads. (1) Octopus prioritises export tariffs as a customer acquisition lever — they offer market-leading rates to attract solar generators who often have low electricity import (Octopus benefits from grid balancing). (2) Octopus is the largest UK SEG aggregator, with operational scale to manage half-hourly settlement efficiently. (3) Octopus does not require you to be an Octopus import customer to receive Outgoing — you can keep your existing commercial electricity supplier and switch only SEG to Octopus. For a typical 1 MW warehouse solar with 75% self-consumption (225,000 kWh export annually), Octopus Outgoing at 15p/kWh generates £33,750/yr — compared to £6,750-£9,000/yr on the cheapest fixed SEG tariffs at 4.5-6p/kWh. The differential is £24,000+/yr — equivalent to a 3-4% improvement in IRR over the system lifetime.
Octopus Outgoing Agile — variable SEG tariff with peak-period opportunity
Octopus "Outgoing Octopus Agile" is the half-hourly variable tariff tracking wholesale electricity price. Agile pays you what Octopus earns on the wholesale market less their margin. Typical 2026 pattern. Off-peak (00:00-06:00): 2-6p/kWh — solar should be self-consuming (no export). Mid-day average: 4-8p/kWh — bulk of solar export period. Peak periods (16:00-19:00 weekdays): 18-25p/kWh routinely; up to 35p/kWh on capacity-constrained days. Negative pricing windows (occasional, mid-day on high renewable days): -2 to -8p/kWh — Octopus pays you to NOT export during these periods. For warehouses with battery storage that can shift solar generation to evening peak: Agile typically outperforms Outgoing Fixed 15p by 25-40%. Without battery, Outgoing Fixed 15p is the simpler choice. Switching between Fixed and Agile takes 4-6 weeks via Octopus Energy customer portal.
Commercial SEG rates — bespoke tariffs for large warehouse generators
Commercial warehouse solar above 1 MW capacity / above 100 MWh/yr export typically qualifies for bespoke commercial SEG contracts (not the standard published tariff). Major commercial SEG providers in 2026. Octopus Business: bespoke commercial Outgoing rates, typically 8-13p/kWh fixed for 1-5 MW commercial generators. Power Purchase Agreement (PPA) structures with offtake commitment. EDF Business: bespoke export tariffs typically 5-9p/kWh fixed for commercial scale. SSE Business: 5-8p/kWh commercial export. British Gas Business: 5-7p/kWh commercial. Smartest Energy: specialist commercial PPA + SEG hybrid, typically 6-10p/kWh fixed with capacity payment option. SmartestEnergy can also bundle REGO certificates with export — useful for buyers wanting both SEG income and REGO certification simplicity. For large generators above 5 MW: corporate PPA route typically more attractive than SEG — sell to a corporate offtaker (Tesco, M&S, JLR etc.) at 8-13p/kWh fixed for 10-15 years.
How SEG income contributes to warehouse solar payback
For typical UK warehouse solar economics, SEG income is a meaningful but not dominant contributor to total return. Worked example for 1 MW warehouse solar (900,000 kWh/yr generation, 75% self-consumption). Self-consumption saving: 675,000 kWh × 22p/kWh grid retail rate = £148,500/yr. SEG export income at Octopus Outgoing 15p/kWh: 225,000 kWh × 15p = £33,750/yr. SEG export income at average UK SEG 6p/kWh: 225,000 kWh × 6p = £13,500/yr. Total at 15p SEG: £182,250/yr. Total at 6p SEG: £162,000/yr. Differential: £20,250/yr — 12% improvement in annual return. Over 25 years (undiscounted): £506,250 additional cumulative return on the best SEG tariff. SEG choice matters but should never override self-consumption optimisation — every kWh self-consumed at 22p saves more than every kWh exported at 15p.
How to switch SEG supplier without disrupting your import contract
SEG supplier is independent of your main electricity import supplier — you can have a different supplier for each. Switching SEG: Step 1 — register MPAN (Meter Point Administration Number) and MSID (Metering System ID Code) for your export meter. Your MCS installer provides these at commissioning. Step 2 — apply to chosen SEG supplier with: MCS certificate, G99 connection acceptance from DNO, half-hourly export meter readings (typically last 3-6 months), banking details. Step 3 — supplier processes application typically 4-8 weeks; backdating to MCS certificate date often possible. Step 4 — SEG payments begin, typically monthly bank transfer based on metered export. To switch SEG supplier later: 12-month minimum contract typical on fixed tariffs; 30-day notice on variable tariffs. Switching does not require any change to import contract — your import supplier remains separate. We help all our installs register for optimal SEG tariffs at commissioning as part of the standard delivery package.
SEG vs Power Purchase Agreement (PPA) — when to choose each
For commercial warehouse solar, SEG is one of three income routes from solar generation. The other two are direct self-consumption (highest value per kWh) and Power Purchase Agreement (PPA — sell to a corporate offtaker at agreed long-term rate). When SEG works best: warehouses with self-consumption above 70% and modest export volumes (under 500 MWh/yr export). Standard published SEG tariffs are administratively simple — no contract negotiation, free to switch, monthly settlement. When PPA works best: large warehouses with export above 500 MWh/yr OR low self-consumption (under 60%) requiring offtake guarantee. Corporate PPA structures typically pay 8-13p/kWh fixed for 10-15 years — providing revenue certainty for asset financing. PPA also bundles REGO certificate sales — convenient for installers wanting one income stream. Hybrid arrangements (PPA on a portion, SEG on the rest) are increasingly common for portfolio operators. Octopus Outgoing Fixed at 15p is bridging the gap between SEG and PPA — close to PPA economics with SEG administrative simplicity.
REGO certificates and bundling with SEG income
REGO (Renewable Energy Guarantees of Origin) certificates are Ofgem-issued certificates for verified renewable generation — one REGO per MWh. Two key questions for warehouse solar generators. (1) Sell REGOs OR retain for own GHG reporting? REGO market value in 2026: £4-£8/MWh. For 900,000 kWh/yr generation: £3,600-£7,200/yr if sold. For most commercial operators, retaining REGOs for customer Scope 3 audit purposes typically outweighs the open-market sale value (customer audit benefit can be £10,000+/yr in contract retention value). (2) Bundle REGOs with SEG export? Some SEG suppliers (notably Smartest Energy, EDF Business) bundle REGO certificate sales with SEG export tariffs — they pay an enhanced p/kWh rate in exchange for the REGO. Octopus standard SEG tariffs do NOT include REGO sale — you keep the REGO for your own use. If your priority is monetisation, REGO bundling can add 0.5-1p/kWh to effective export rate. If your priority is customer audit compliance, retain REGOs and accept standard SEG rate. We help structure the optimal split per project.
Common questions about best seg rates
What is the best SEG rate in the UK 2026?
Octopus Energy "Outgoing Octopus Fixed" at 15p/kWh is the highest fixed SEG rate available in 2026, significantly above the next-best Scottish Power SmartPower Export at 12p/kWh. For variable rates, Octopus "Outgoing Octopus Agile" can exceed 15p effective when paired with battery storage shifting generation to peak periods (peak rates reaching 18-25p/kWh during 16:00-19:00).
What is the best export tariff for commercial warehouse solar?
For warehouses under 1 MW: Octopus Outgoing Fixed at 15p/kWh is the best standard published tariff. For above 1 MW commercial generators: bespoke commercial SEG contracts at 8-13p/kWh fixed, typically negotiated with Octopus Business, Smartest Energy, EDF Business or SSE Business. For above 5 MW: corporate PPA structures with corporate offtakers (Tesco, M&S, JLR) typically deliver 8-13p/kWh fixed for 10-15 years.
Can I switch SEG supplier without changing import supplier?
Yes — SEG supplier is independent of import supplier. You can have your main electricity import contract with one supplier (e.g., British Gas Business) and your SEG export contract with another (e.g., Octopus Outgoing). Switching SEG does not affect import. Standard 12-month minimum contract on fixed SEG tariffs; 30-day notice on variable.
How much does SEG income contribute to warehouse solar payback?
For a typical 1 MW warehouse solar at 75% self-consumption: SEG income at Octopus 15p/kWh contributes £33,750/yr vs £148,500/yr from self-consumption (around 18% of total income). At average UK SEG 6p/kWh, SEG contributes £13,500/yr (around 8% of total). SEG choice can shift payback by 0.2-0.4 years; not dominant but meaningful.
Should I take the best SEG rate or a Power Purchase Agreement?
SEG works best for warehouses with above 70% self-consumption and under 500 MWh/yr export — administratively simple, free to switch, no long contract. PPA works best for large warehouses with export above 500 MWh/yr or low self-consumption — typically 8-13p/kWh fixed for 10-15 years providing revenue certainty for asset financing. Hybrid (PPA on portion, SEG on rest) is increasingly common.
How do I register for SEG after my warehouse solar is installed?
Apply to chosen SEG supplier with: MCS certificate (from your installer), G99 connection acceptance (from DNO), half-hourly export meter readings (last 3-6 months), MPAN/MSID export meter codes, banking details. Processing typically 4-8 weeks; backdating to MCS certificate date often possible. We register all our installs for optimal SEG tariff at commissioning as part of standard delivery.
Do all UK electricity suppliers offer SEG?
Suppliers with more than 150,000 customers are legally required to offer at least one SEG tariff. Major suppliers offering SEG in 2026: Octopus Energy (best rates), EDF Energy, SSE/OVO, British Gas, E.ON Next, Bulb (Octopus subsidiary), Scottish Power, Drax, Shell Energy. Smaller suppliers (under 150,000 customers) may or may not offer SEG — check on individual supplier websites.