This section defines the net Northern Ireland emissions account as the aggregate amount of net Northern Ireland emissions of each greenhouse gas for that year, minus any carbon units credited to the account for the period plus any carbon units debited from the account for the period. This clarifies how emissions are to be determined for the purposes of comparing the amount of emissions for a year against the emission reduction targets in the Act and any carbon budgets set under section 23. The section similarly sets out how to determine the net Northern Ireland emissions account for carbon dioxide and methane. Section 11 sets out requirements relating to the crediting and debiting of carbon units to the net Northern Ireland emissions account.