; but (ii) return to customers the revenue associated with fixed costs collected in excess of the authorized amount under clause (i); and (C) earn a performance-based incentive for shareholders for the achievement of energy efficiency standards. (6) Evaluation, measurement, and verification incentives The Secretary shall encourage States that have delegated authority to administer this section to provide incentives to retail electricity suppliers, retail natural gas suppliers, and third-party efficiency providers to use randomized control trials and other experimental or quasi-experimental approaches to evaluate energy efficiency measures and programs within the State. (g) Information and reports In accordance with section 13 of the Federal Energy Administration Act of 1974 ( 15 U.S.C. 772 ), the Secretary may require any retail electricity supplier, retail natural gas supplier, third-party efficiency provider, or any other entity that the Secretary determines appropriate, to provide any information the Secretary determines appropriate to carry out this section. (h) State law Nothing in this section diminishes or qualifies any authority of a State or political subdivision of a State to adopt or enforce any law or regulation respecting electricity savings or natural gas savings, including any law or regulation establishing energy efficiency requirements that are more stringent than those under this section, except that no State law or regulation shall relieve any person of any requirement otherwise applicable under this section. . (b) Conforming amendment The table of contents of the Public Utility Regulatory Policies Act of 1978 (16 U.S.C. prec. 2601) is amended by adding at the end of the items relating to title VI the following: Sec. 609. Rural and remote communities electrification grants. Sec. 610. Federal energy efficiency resource standard for retail electricity and natural gas suppliers. .