(a)(1)(B), the kilowatt hours of electricity produced by a taxpayer at a qualified facility shall include any production in the form of useful thermal energy by any combined heat and power system property within such facility. (B) Combined heat and power system property For purposes of this paragraph, the term combined heat and power system property has the same meaning given such term by section 48(c)(3) (without regard to subparagraphs (A)(iv), (B), and (D) thereof). (C) Conversion from BTU to KWh (i) In general For purposes of subparagraph (A), the amount of kilowatt hours of electricity produced in the form of useful thermal energy shall be equal to the quotient of— (I) the total useful thermal energy produced by the combined heat and power system property within the qualified facility, divided by (II) the heat rate for such facility. (ii) Heat rate For purposes of this subparagraph, the term heat rate means the amount of energy used by the qualified facility to generate 1 kilowatt hour of electricity, expressed as British thermal units per net kilowatt hour generated. (3) Production attributable to the taxpayer In the case of a qualified facility in which more than 1 person has an ownership interest, except to the extent provided in regulations prescribed by the Secretary, production from the facility shall be allocated among such persons in proportion to their respective ownership interests in the gross sales from such facility. (4) Related persons Persons shall be treated as related to each other if such persons would be treated as a single employer under the regulations prescribed under section 52(b). In the case of a corporation which is a member of an affiliated group of corporations filing a consolidated return, such corporation shall be treated as selling electricity to an unrelated person if such electricity is sold to such a person by another member of such group. (5) Pass-thru in the case of estates and trusts Under regulations prescribed by the Secretary, rules similar to the rules of subsection