2016 and inserting December 31, 2021 . (3) Phasedown (A) Alternative fuel credit Paragraph (1) of section 6426(d) of such Code is amended by inserting (37.5 cents for fuel sold or used in 2019 and 25 cents for fuel sold or used after 2019) after 50 cents . (B) Alternative fuel mixture credit Paragraph (1) of section 6426(e) of such Code is amended by inserting (37.5 cents for fuel sold or used in 2019 and 25 cents for fuel sold or used after 2019) after 50 cents . (b) Effective date The amendments made by this section shall apply to fuel sold or used after December 31, 2016.