; and (III) requirements to account, in issuing zero-emission electricity credits under this section, for the risk that some fraction of the carbon dioxide intended for permanent storage or utilization may nevertheless be emitted into the atmosphere. (ii) Existing requirements In promulgating regulations pursuant to this subparagraph, the Secretary shall incorporate any existing requirements for the permanent geologic storage of carbon dioxide, including any requirements promulgated under section 45Q of the Internal Revenue Code of 1986. (f) Maximum quantity of credits Except as provided under subsection (e)(1), the total quantity of zero-emission electricity credits issued under this section to a generator for a calendar year shall not exceed the number of megawatt-hours of the qualified electricity generation of the generator for the calendar year. (g) No negative credits Notwithstanding any other provision of this title, the Secretary shall not issue a negative quantity of zero-emission electricity credits to any generator. (h) Facilities outside the United States With respect to electricity generated by a facility or generating unit that is located outside of the United States, a zero-emission electricity credit may be issued only with respect to electricity that is sold for resale in the United States. (i) Contracts A zero-emission electricity credit issued for electricity that is— (1) sold for resale under a contract in effect on the date of enactment of this title shall be issued to the purchasing retail electricity supplier in proportion to the zero-emission electricity purchased by such retail electricity supplier under the contract, unless otherwise provided by the contract