; (ii) opportunities for new State and local codes and standards savings; (iii) technology improvements; and (iv) other indicators of cost-effective energy efficiency potential including differences between States. (C) Minimum percentage In no case shall the applicable percentages for any calendar year be less than the applicable percentages for calendar year 2035. (4) Delay of submission for first reporting period (A) In general Notwithstanding paragraphs (1) and (2), for the 2021 reporting period, the Secretary may accept a request from a retail electricity supplier or a retail natural gas supplier to delay the required submission of documentation of all or part of the required savings for up to 2 years. (B) Plan for compliance The request for delay under subparagraph (A) shall include a plan for coming into full compliance by the end of the 2022–2023 reporting period. (5) Applying unused savings to future years If savings achieved in a year exceed the performance standards specified in this subsection, any savings in excess of the performance standards may be applied toward performance standards specified for the first 3 years following the year in which the excess savings are achieved. (d) Evaluation, measurement, and verification of savings (1) Regulations The regulations promulgated pursuant to subsection (b) shall— (A) be based on— (i) the Uniform Methods Project of the Department of Energy; (ii) the National Standard Practice Manual for Assessing the Cost-Effectiveness of Energy Efficiency Resources, developed by the National Efficiency Screening Project; and (iii) other best practices recognized in the energy efficiency industry; and (B) include— (i) procedures and standards for evaluating, measuring, and verifying electricity savings and natural gas savings that count towards the performance standards established under subsection (c) that— (I) specify the types of energy efficiency and energy conservation measures that may be counted