(1) Ecology shall create GHG allowances as required to cover the annual allowance budgets determined in WAC 173-446-210.

(2) Ecology shall assign each GHG allowance a unique serial number that identifies the annual allowance budget from which the allowance originates.

(3) Each allowance is of the vintage year of the annual allowance budget from which it comes.

(4) Older vintage allowances must be retired before newer vintage allowances.

(5) Allowances do not expire and may be banked.

(6) Except as provided in this chapter, a covered or opt-in entity may not use an allowance from a future allowance vintage year to meet a current or past compliance obligation.