Electricity from renewable energy sources is also supported by a quota system in the form of a quota obligation with tradable certificates.

The Renewables Obligation Orders (ROO 2009, SCO 2009 ROO, ROO NI 2009) oblige electricity suppliers to demonstrate that a certain proportion of their supplies of electricity comes from renewable energy sources ("quota", Article 5 ROO 2009).

The evidence must be presented to the regulator Ofgem (for England, Scotland and Wales as well as collection point for NIROCs for the Northern Irish regulatory NIAUR) in the form of "Green Certificates" (ROCs, SROCs in Scotland, Northern Ireland NIROCs).

Under the quota system installations with a capacity of over 5 MW are promoted. Plants from 50 kW to 5 MW are entitled to choose between the feed-in tariff and the Renewables Obligation (Article 3.1.3 EA 1989, confirmed by Ofgem).