is not the generation of electricity. (B) Capacity limitation The term waste energy recovery property shall not include any property which has a capacity in excess of 50 megawatts. (C) No double benefit Any waste energy recovery property (determined without regard to this subparagraph) which is part of a system which is a combined heat and power system property shall not be treated as waste energy recovery property for purposes of this section unless the taxpayer elects to not treat such system as a combined heat and power system property for purposes of this section. (D) Termination The term waste energy recovery property shall not include any property the construction of which does not begin before January 1, 2027. . (e) Effective date The amendments made by this section shall apply to periods after December 31, 2019, under rules similar to the rules of section 48(m) as in effect on the day before the date of the enactment of the Revenue Reconciliation Act of 1990.