Solar export tariffs: compare the whole bill before switching

Understand what is being paid for

Export tariffs pay for eligible electricity sent to the grid. They do not pay the same amount for all the electricity your panels generate, because some may be used at home or stored. Use metered exports, not the inverter’s total generation figure, when estimating export income.

Ofgem’s Smart Export Guarantee information explains the framework and participating-supplier obligations. Individual suppliers set their offers and terms. Check the generation, metering and documentation requirements for the tariff you are considering.

Build a whole-bill comparison

Record annual grid imports, annual exports, the import unit rate, export rate and daily standing charge for each offer. Add exit fees and any equipment or account restrictions separately.

For a hypothetical home importing 3,000 kWh and exporting 1,500 kWh, Offer A at 27p import, 12p export and 50p per day has a modelled annual net cost of £812.50. Offer B at 29p import, 16p export and 55p per day costs £830.75. The higher export rate still produces a bill £18.25 higher in this example.

These are fictional offers. Enter real offers in the tariff comparison tool.

Fixed and time-varying rates answer different questions

A flat export rate makes the arithmetic straightforward. A time-varying rate needs the amount exported in each interval. Multiplying every exported unit by the best evening rate exaggerates earnings if much of the solar leaves the home at midday.

A controlled battery may change that pattern, but account for losses, charging costs, reserve, export limits and the amount the system can discharge during the paid period. Keep an unmanaged base case beside the proposed strategy.

Check compatibility before comparing numbers

• Must the supplier also provide your imported electricity?
• Is your EV import tariff compatible with the selected export product?
• What meter and generation documentation are required?
• Are battery exports treated differently from solar exports?
• Are there equipment, control or availability restrictions?
• When does payment start and how is it calculated?

Supplier rules can change. Octopus publishes an export overview and compatibility guidance, which are useful examples of the details to check. Do not rely on an old comparison table as proof of today’s offer.

Keep a dated record of the offer

Save the tariff terms and quote date with your assumptions. For a variable product, test more than one rate scenario. If you are on an existing Feed-in Tariff arrangement, understand the effect of changing export arrangements before agreeing a switch.

Our time-of-use guide explains weighted rates, and the Flux versus Intelligent Go guide looks at two different approaches to managing a home’s electricity.