Degression trigger history

This is the degression factors which have been applied, based on actual deployment levels and the regulatory contingent degression factors

Actual deployment levels and related degression %

The government publishes the relevant deployment figures here, and Ofgem uses them to calculate the revised tariffs, (as shown here), based on the degression policy and the corridors set for each technology band.

Relevant figures published to date, and future estimates where available, are:

Actual (and provisional) deployment figures and relevant contingent degression

Technology and band Deployment (MW) Corridor Degression rate
Solar PV 1st May to end Jul 2012 – official from 1st Nov 2012
<=10kW 163.769 Default 3.5%
>10kW<=50kW 57.091 Default 3.5%
>50kW 13.938 Low 0%
Solar PV 1st Aug to end Oct 2012 – official from 1st Feb 2013
<=10kW 61.048 Low 0%
>10kW<=50kW 12.563 Low 0%
>50kW 24.657 Low 0%
Solar PV 1st Nov to end Jan 2013 – official from 1st May 2013
<=10kW 50.268 Low 0%
>10kW<=50kW 8.641 Low 0%
>50kW 40.867 Low [A] 3.5% [A]
Solar PV 1st Feb to end Mar 2013 – official from 1st Jul 2013
<=10kW 44.213 Low [A] 3.5% [A]
>10kW<=50kW 12.395 Low [A] 3.5% [A]
>50kW 13.945 Low 0%
Solar PV 1st Apr to end Jun 2013 – official from 1st Oct 2013
<=10kW 93.416 Low 0%
>10kW<=50kW 42.654 Low 0%
>50kW 11.913 Low 0%
Solar PV 1st Jul to end Sep 2013 – official from 1st Jan 2014
<=10kW 66.605 Low 0%
>10kW<=50kW 17.716 Low 0%
>50kW 30,547 Low [A] 3.5% [A]
Solar PV 1st Oct to end Dec 2013 – official from 1st April 2014
<=10kW 88.621 Low [A] 3.5% [A]
>10kW<=50kW 22.224 Low [A] 3.5% [A]
>50kW 26.750 Low 0%
Non-solar technologies 1st Jan to end Dec 2013 – official from 1st April 2014
AD biogas <=500kW 14.442 Very high 20%
AD biogas >500kW 21.276 Low 0%
Hydro <=2MW 20.348 Default 5%
Hydro >2MW   Low 0%
Wind <=100kW 26.060 Very high 20%
Wind >100kW 109.917 Very high 20%
Sorry it all changes too fast! We can’t keep updating this helpful page after 2014- but you can get the data (in a less user-friendly format) here

[A] Sometimes default degression is applied even though deployment has been below the level where no degression should apply, because there can only be zero degression for two consecutive periods as detailed here.

The government set a short 2-month degression period here, to bring PV dates into line with other, annually degressed, technologies.

Provisional and estimated figures

Where provisional or estimated figures are quoted above, these are taken from the same sources that the government uses for its official figures:

  • The MCS register for systems up to 50kW
  • Ofgem’s ROO-FIT registrations for systems over 50kW

Estimated figures are derived before the quarter has ended based on published deployment figures for the first months of the quarter. The calculated totals take into account the fact that installations tend to increase towards the cut-off dates as shown by the weekly deployment graph.

Some statistics are added to the register late, so the provisional figures, which are derived from the first published data, may change.

Because the MCS figures are published weekly, there will be a small adjustment in reaching the official figures to allow for the partial weeks at the beginning and end of the period.

It is only when the final official figures are published by DECC that the degression percentages are finalised.