Smart Export Guarantee vs Export-Only Solar in 2026

Export-only solar: when it pays

An export-only solar installation generates kWh and sells them all back to the grid at the Smart Export Guarantee tariff — there is no self-consumption. The economics are simpler than self-consumption solar, but the rates of return are lower. In 2026, with the best SEG fixed rates at 15-16.5p/kWh and capital costs unchanged from self-consumption installs, export-only solar pays back in 12-18 years depending on system size and tariff.

Who should consider export-only

Three scenarios where export-only makes sense:

• Empty barns or farm buildings with no on-site demand — common in retired or hobby agricultural sites. The roof generates revenue passively.
• Brownfield commercial sites awaiting tenants — landlords install solar before letting; the export income covers carrying costs until a tenant arrives.
• Owner-occupiers planning to be away long-term — second homes, properties owned by retirees who travel for half the year. Self-consumption is low, so export-only economics may be similar to self-consumption.

Tariff comparison

The headline 15-16.5p SEG rates are export-only tariffs requiring no specific import contract. If you take a paired import-export tariff like Octopus Outgoing Fixed (15p export, requires Octopus import at standard rate), the trade-off depends entirely on your import unit rate. For a property with no occupancy, take the highest-paying export-only tariff regardless of import rate.

Tax position

SEG income is taxable at your marginal rate but most domestic installations stay well under the £1,000 annual trading allowance — meaning no tax actually due. Commercial export income is taxable trading income, but the Annual Investment Allowance on the system usually gives a much larger deduction in year 1.