; and (ii) estimate the impact of the standards on current and future electricity and natural gas use in the service territories of the suppliers; and (C) establishing requirements governing applications for, and implementation of, delegated State administration under subsection (h). (2) Coordination with State programs In establishing and implementing this section, the Secretary shall, to the maximum extent practicable, preserve the integrity and incorporate best practices of existing State energy efficiency programs. (d) Performance standards (1) Compliance obligation Not later than May 1 of the calendar year immediately following each reporting period— (A) each retail electricity supplier shall submit to the Secretary a report, in accordance with regulations promulgated by the Secretary, demonstrating that the retail electricity supplier has achieved cumulative electricity savings (adjusted to account for any attrition of savings measures implemented in prior years) in each calendar year that are equal to the applicable percentage, established under paragraph (2), (3), or (4), of the base quantity of the retail electricity supplier