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:
|Technology and band||Deployment (MW)||Corridor||Degression rate|
|Solar PV||1st May to end Jul 2012 - official||from 1st Nov 2012|
|Solar PV||1st Aug to end Oct 2012 - official||from 1st Feb 2013|
|Solar PV||1st Nov to end Jan 2013 - official||from 1st May 2013|
|>50kW||40.867||Low [A]||3.5% [A]|
|Solar PV||1st Feb to end Mar 2013 [B] - official||from 1st Jul 2013|
|<=10kW||44.213||Low [A]||3.5% [A]|
|>10kW<=50kW||12.395||Low [A]||3.5% [A]|
|Solar PV||1st Apr to end Jun 2013 - official||from 1st Oct 2013|
|Solar PV||1st Jul to end Sep 2013 - official||from 1st Jan 2014|
|>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]|
|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%|
|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.
[B] The government set a short 2-month degression period here, to bring PV dates into line with other, annually degressed, technologies.
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.