; and (B) the increase in CHP system savings from upgrading or replacing, after the date of enactment of this section, a combined heat and power system that commenced operation on or before the date of enactment of this section. (5) CHP system savings The term CHP system savings means the electric output, and the electricity saved due to the mechanical output, of a combined heat and power system, adjusted to reflect any increase in fuel consumption by that system as compared to the fuel that would have been required to produce an equivalent useful thermal energy output in a separate thermal-only system, as determined in accordance with regulations promulgated by the Secretary. (6) Codes and standards savings (A) In general The term codes and standards savings means a reduction in end-use electricity or natural gas consumption by a retail electricity supplier or in the service territory of a retail natural gas supplier as a result of the adoption and implementation, after the date of enactment of this section, of new or revised appliance and equipment efficiency standards or building energy codes. (B) Baselines In calculating codes and standards savings under subparagraph (A)— (i) the baseline for calculating savings from building codes shall be the more stringent of— (I) (aa) the 2015 International Energy Conservation Code for residential buildings; or (bb) the ASHRAE/ANSI/IESNA Standard 90.1–2013 for commercial buildings; or (II) the applicable State building code in effect on the date of enactment of this section