Smart Export Guarantee (SEG) for Commercial Solar Carports

What SEG is

Smart Export Guarantee — introduced January 2020 to replace the closed Feed-in Tariff (FIT) — requires electricity suppliers with over 150,000 domestic customers to offer a SEG tariff for surplus electricity exported from sub-5MW generation. Suppliers set their own tariffs; rates vary widely.

Current SEG rates

Octopus Energy Outgoing Fixed: 15.0p/kWh (best fixed). Octopus Outgoing Agile: variable, tracking wholesale prices (often 4-25p/kWh). EDF Energy Export+: 5.5p/kWh fixed. OVO Energy SEG: 4.0p/kWh fixed. British Gas Export and Earn: 4.5p/kWh fixed. Smaller suppliers (Good Energy, Octopus, So Energy) routinely offer better rates than Big 6.

Eligibility

Solar PV under 5 MW (which covers all commercial carports in the UK). MCS-certified installation. Export meter installed (smart meter or dedicated export meter). DNO G99 connection in place. SEG application made to chosen supplier — typically a 1-2 week process.

Export volume in practice

UK commercial carports: typical 75-85% self-consumption; 15-25% export. A 300 kWp carport generating 255,000 kWh/yr exports ~38,000-64,000 kWh/yr. At 15p/kWh SEG (Octopus Outgoing Fixed), that's £5,700-£9,600/yr export revenue.

How to maximise SEG revenue

(1) Choose the highest-paying SEG supplier — currently Octopus Outgoing Fixed at 15p/kWh; (2) Use Octopus Outgoing Agile for sites that can shift load to off-peak (export at premium times); (3) Add battery storage to time-shift export to peak SEG hours (4-7pm typically pays best); (4) Switch supplier annually if SEG rates change; (5) Consider corporate PPA off-takers — some pay 10-13p/kWh fixed for direct PPA, vs SEG variable.

SEG vs PPA: which is better?

SEG (Octopus Outgoing Fixed at 15p/kWh): simple, no contract commitment, can switch supplier. Corporate PPA: 10-14p/kWh typical, locked-in for 5-15 years, requires sleeving via Octopus or REGO certificates. Most commercial carports take SEG for simplicity unless export volume exceeds 200,000 kWh/yr (where PPA economics improve).