SEG rates explained: fixed vs variable

What is a fixed SEG rate?

A fixed SEG rate pays the same amount for every kilowatt hour you export, whatever the time of day or the wholesale price. It is the simplest type of export tariff and makes income easy to predict. The rate may still change at the end of a contract term or with notice from the supplier.

What is a variable SEG rate?

A variable SEG rate moves with the wholesale electricity market, often changing every half hour. You may earn more when demand is high and much less when the grid has plenty of power, such as sunny afternoons. These tariffs need a smart meter that records half-hourly exports and suit people who actively manage when they export.

What is a time-of-use export tariff?

A time-of-use export tariff pays different set rates in different time bands, typically a higher rate during an evening peak and a lower rate at other times. It sits between fixed and fully variable tariffs. Time-of-use tariffs work best with a home battery that can store solar power and export it in the peak window.

Which type of SEG tariff is best for me?

If you have solar panels without a battery, a fixed rate is often the safest choice because most of your exports happen at midday. If you have a battery and are happy to automate charging and exporting, a time-of-use or variable tariff may pay more. Compare total yearly income, including your import costs.

• Solar only and you want predictable income: a fixed rate.
• Solar with a battery and you are happy to automate: time-of-use.
• Comfortable with price swings and actively managing exports: variable.
• Planning to add a battery later: choose a tariff you can leave without a penalty.

Can a variable SEG rate go down to zero?

No. Ofgem rules say every SEG tariff must pay more than zero at all times, so a variable rate cannot fall to zero or below. It can, however, drop very low when wholesale prices fall, which is why variable tariffs carry more risk than a fixed rate for households that cannot shift when they export.