; and (ii) estimate the impact of the performance standards on current and future electricity and natural gas consumption in the service territories of the suppliers; and (C) establishing requirements governing applications for, and implementation of, State programs under subsection (g). (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. (c) 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 such retail electricity supplier has achieved cumulative electricity savings (adjusted to account for any attrition of savings from measures implemented in prior years) in each calendar year of such reporting period that are equal to or greater than the applicable performance standard