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Why your feed-in tariff rate changes every April
If you have ever compared your statement with the rate you were quoted when the panels went up and found they do not match, this is why. The rate was never a fixed number of pence.
The short answer. Your rate is index-linked. Generation and export tariffs are adjusted every financial year by the Retail Price Index movement over the previous calendar year. The figure you were quoted was the figure for the year you joined, and it has been revised every year since.
What is indexed, and to what
Both payments are indexed: the generation tariff on everything the system produces, and the export tariff. The index is RPI, not CPI, and the adjustment uses the RPI increase or decrease over the previous calendar year, applied for the financial year ahead.
That is the mechanism behind an otherwise odd-looking number. Early rates were set at round figures, and almost nobody is on a round figure now, because fifteen years of indexation have moved them. The current table is the one for 2026-27, and your band's figure is on the rates page.
It moves your rate, not your band
This is the part worth being clear about, because the two get conflated. Indexation revises the rate attached to your own band and eligibility date. It does not reassign you to a different band.
That matters because the bands moved in one direction over the life of the scheme, and it was downwards. Tariffs for installations accredited in 2010 and 2011 are multiples of the ones set in the final years before closure. Being moved to a newer band would be a cut, not a rise. Nobody is moved, but it is worth understanding that the annual increase is the only upward movement in the system.
Which band you are in was decided by your eligibility date and your declared capacity, and it was decided once. The rate finder takes both and returns the 2026-27 figure, and every band is published so you can see where yours sits among the rest.
It can go down
The rule is symmetrical. It is an adjustment by the RPI increase or decrease, so a calendar year in which RPI fell would produce a lower rate for the following financial year. For most of the life of this scheme RPI has been positive and the practical experience has been a rise each April, but the mechanism does not guarantee one, and a guide that told you the rate only ever goes up would be wrong about how it works.
What this does not protect you from
Indexation keeps the tariff roughly level in real terms. It does nothing about the end of the term, when both payments stop altogether rather than being adjusted. Of the 869,807 installations on the register, the oldest terms are the ones on the highest rates, which is what makes that ending sharp. See what happens when your feed-in tariff ends.
Indexation rule as published by Ofgem in its Feed-in Tariffs guidance for generators: generation and export tariffs are adjusted every financial year by the RPI percentage increase or decrease over the previous calendar year. Rates from the Ofgem FIT tariff table for 2026-27, installation counts from the installation report of 2025-12-31. Information only, and not financial advice.