section shall affect the application of any other provision of law to a covered entity (including the Clean Air Act), or the responsibility for a covered entity to comply with any such provision of law. Regional and State greenhouse gas initiatives are not preempted by this subtitle. (e) Regulations Not later than December 31, 2018, the Secretary shall promulgate regulations to carry out the provisions of this subtitle. 9903. Auctions (a) Periodic auctions The Secretary shall conduct periodic public auctions of carbon permits established under section 9902(a). The Secretary shall conduct at least 4 such auctions in each year for which carbon permits are established. (b) Auction rules The Secretary shall— (1) limit auction participation only to covered entities, (2) establish a limit on the amount of carbon permits that can be purchased by a single entity at each auction and an aggregate limit on the total amount of permits that can be held by a single entity at any one time that— (A) reflects anticipated sector and participant demand, (B) prevents speculation, manipulation, or hoarding of permits, and (C) does not interfere with normal market competition, and (3) have the authority to set a minimum permit price at auction. (c) Unsold permits Any carbon permit unsold at auction may be offered at the next quarterly auction in the calendar year. Any carbon permit unsold after the last auction for a calendar year shall be transferred to the reserve established under section 9908. 9904. Compliance obligation (a) In general Not later than April 1, 2019, and April 1 of each year thereafter, a covered entity shall surrender to the Secretary a quantity of carbon permits at least as great as the number of metric tons of carbon dioxide that the Secretary, in consultation with the Administrator, determines would be emitted by the combustion of covered fuels with respect to which the covered entity made the first sale in United States markets during the previous calendar year. (b) Use treated as sale For purposes of