; and (ii) increase the standards by regulation if the Secretary determines that additional cost-effective energy efficiency potential is achievable, taking into account the requirements described in paragraph (3)(C). (B) Lead time If the Secretary revises standards under this paragraph, the regulations shall provide adequate lead time to ensure that compliance with the increased standards is feasible. (5) Delay of submission for first reporting period (A) In general Notwithstanding paragraphs (1) and (2), for the 2019 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 2020–2021 reporting period. (6) 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 future years. (e) Transfers of electricity or natural gas savings (1) Bilateral contracts for savings transfers Subject to the limitations of this subsection, a retail electricity supplier or retail natural gas supplier may use electricity savings or natural gas savings purchased pursuant to a bilateral contract from another retail electricity supplier or retail natural gas supplier, a State, or a third-party efficiency provider to meet the applicable performance standard under subsection (d). (2) Requirements Electricity savings or natural gas savings purchased and used for compliance under this subsection shall be— (A) measured and verified in accordance with subsection (f); (B) reported in accordance with subsection (d)