; and (2) for each million British thermal units of useful thermal energy output produced by the qualified cogeneration facility, a number of emission allowances (or fractions thereof) calculated in accordance with subsection (b). (d) Adjusted distribution for entering into certain agreements (1) In general If an existing facility or a newly constructed low-emission facility enters into an agreement described in paragraph (2), then over the period of the agreement the Administrator shall distribute emission allowances to such facility in accordance with this subsection in lieu of subsection (a), (b), or (c). (2) Agreement An agreement described in this paragraph is a 10-year or longer bilateral agreement signed after the date of enactment of this title between an existing qualified electric facility, an existing qualified thermal facility, or an existing qualified cogeneration facility, and a newly constructed low-emission facility for the annual purchase of a specified amount of emission allowances. (3) Definitions In this subsection: (A) The term existing means, with respect to a facility, in operation as of the date of entry into an agreement described in paragraph (2). (B) The term existing facility means an existing qualified electric facility, an existing qualified thermal facility, or an existing qualified cogeneration facility that is a party to an agreement described in paragraph (2). (C) The term newly constructed means that the facility involved did not produce electricity or useful thermal energy output prior to the date of entry into an agreement described in paragraph (2). (D) The term newly constructed low-emission facility means a newly constructed qualified electric facility, a newly constructed qualified thermal facility, or a newly constructed qualified cogeneration facility that would emit a lesser quantity of greenhouse gases per megawatt hour of electricity or per million British thermal units of useful thermal energy output, as applicable, than the Administrator distributes to covered