1. For the purpose of monitoring emissions and determining the minimum requirements for tiers, each operator shall determine the category of its installation pursuant to paragraph 2, and, where relevant, of each source stream pursuant to paragraph 3 and of each emission source pursuant to paragraph 4.

2. The operator shall classify each installation in one of the following categories:

(a) a category A installation, where the average verified annual emissions in the trading period immediately preceding the current trading period, with the exclusion of CO₂ stemming from zero-rated carbon and before subtraction of transferred CO₂, are equal to or less than 50 000 tonnes of CO_2(e);

(b) a category B installation, where the average verified annual emissions of the trading period immediately preceding the current trading period, with the exclusion of CO₂ stemming from zero-rated carbon and before subtraction of transferred CO₂, are more than 50 000 tonnes of CO_2(e) and equal to or less than 500 000 tonnes of CO_2(e);