period for which such contract is in effect, and (iii) the registered producer of such fuel provides to the taxpayer the certification described in paragraph (4). (B) Limitation The amount of blended renewable natural gas treated as renewable natural gas under subparagraph (A) for any period shall not exceed the number of gallons of renewable natural gas specified under subparagraph (A)(ii) and certified by the producer under paragraph (4) for such period. (C) Blended renewable natural gas For purposes of this subsection, the term blended renewable natural gas means compressed or liquefied natural gas which consists of both renewable natural gas and other compressed or liquefied natural gas. (4) Certification A certification is described in this subparagraph if such certification— (A) identifies the product produced and the gallon equivalent of fuel acquired by the taxpayer for a purpose described in paragraph (1), and (B) is provided such form and manner as prescribed by the Secretary. (5) Gasoline gallon equivalent For purposes of this subsection, the term gasoline gallon equivalent means, with respect to any nonliquid renewable natural gas, the amount of such fuel having a Btu content of 124,800 (higher heating value). (6) Termination This subsection shall not apply to any sale or use for any period after December 31, 2033. . (b) Application of other rules (1) Registration The last sentence of section 6426(a) of the Internal Revenue Code of 1986 is amended by striking subsections (d) and (e) and inserting subsections (d), (e), and (l) . (2) Denial of double benefit Section 6426(h) of such Code is amended by striking subsection (d) or (e) and inserting subsection (d), (e), or (l) . (3) Fuel must be connected to the United States Section 6426(i) of such Code is amended by inserting after paragraph (2) the following new paragraph: (3) Renewable natural gas No credit shall be determined under this section with respect to any renewable natural gas which is produced outside the United States for use as a fuel