The degression factors used for calculating future tariffs were all changed (again) in the 2015 review
The principles adopted to calculate future tariff reductions have evolved from the simple annual percentage in the original legislation. The new approach which applies from 2016 onwards uses the principles of default and contingent degression from the pre-2016 system, but the figures have all changed.
There are now two elements taken into account.
The tariffs for each technology band have now be mapped (subject to adjustments for indexation and contingent degression - see below) to the end of the feed-in tariffs in 2019 as follows:Source: Government response to 2015 consultation Table 8
Tariffs will be furthermore be adjusted for RPI-indexation and for any:-
This element allows the degression rates to be adjusted depending on the actual levels of deployment under the FITs.
The tariffs will be reduced by 10% when the deployment in any technology band hits the caps set by the government.