; and (ii) not more than 2 Federal renewable electricity credits for each megawatt hour of renewable electricity generated on Indian land. (B) Adjustment Except as provided in subparagraph (C), not later than January 1, 2023, and not less frequently than every 4 years thereafter, the Commission shall review the effect on the aggregate quantity of renewable electricity generated as a result of providing credit multipliers under this paragraph and shall, as necessary and after providing 1 year of notice, reduce the number of Federal renewable electricity credits issued under this paragraph per megawatt hour of renewable electricity generated by any given energy source or facility, but not below one, to ensure that the number is no higher than the Commission determines is necessary to incentivize incremental renewable energy generation in impacted communities and on Indian land. (C) Facilities placed in service after enactment (i) In general For any renewable electricity generation facility placed in service after the date of enactment of this section, subparagraph (B) shall not apply for the first 10 years after the date on which the facility is placed in service. (ii) Initial period For each year during the 10-year period described in clause (i), the Commission shall issue to the facility the same number of Federal renewable electricity credits per megawatt hour generated as are issued to that facility in the year in which the facility is placed in service. (iii) Subsequent period After the 10-year period described in clause (i), the Commission shall issue Federal renewable electricity credits to the facility in accordance with subparagraph (B). (5) Credits based on qualified hydropower For purposes of this subsection, the number of megawatt hours of renewable electricity generation from qualified hydropower shall be calculated— (A) based solely on the increase in average annual generation directly resulting from the efficiency improvements or capacity additions described in subsection (a)(5)(A)