; 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 The term codes and standards savings means a reduction in electricity or natural gas consumption 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. (7) Combined heat and power system The term combined heat and power system means a system that uses the same energy source both for the generation of electrical or mechanical power and the production of steam or another form of useful thermal energy, if— (A) the system meets any requirements relating to efficiency and other operating characteristics that the Secretary promulgates by regulation