Section 48(a)(3)(A)(vii) is amended by striking periods ending before January 1, 2017 and inserting property the construction of which begins before January 1, 2022 . (g) Phaseout of 30 percent credit rate for fuel cell and small wind energy property Section 48(a) is amended by adding at the end the following new paragraph: (7) Phaseout for qualified fuel cell property and qualified small wind energy property (A) In general In the case of qualified fuel cell property or qualified small wind energy property, the construction of which begins before January 1, 2022, the energy percentage determined under paragraph (2) shall be equal to— (i) in the case of any property the construction of which begins after December 31, 2019, and before January 1, 2021, 26 percent, and (ii) in the case of any property the construction of which begins after December 31, 2020, and before January 1, 2022, 22 percent. (B) Placed in service deadline In the case of any qualified fuel cell property or qualified small wind energy property, the construction of which begins before January 1, 2022, and which is not placed in service before January 1, 2024, the energy percentage determined under paragraph (2) shall be equal to 10 percent. . (h) Phaseout for fiber-optic solar energy property Subparagraphs (A) and (B) of section 48(a)(6) are each amended by inserting or (3)(A)(ii) after paragraph (3)(A)(i) . (i) Termination of solar energy property Section 48(a)(3)(A)(i) is amended by inserting , the construction of which begins before January 1, 2028, and after equipment . (j) Termination of geothermal energy property Section 48(a)(3)(A)(iii) is amended by inserting , the construction of which begins before January 1, 2028, and after equipment . (k) Special rule for determination of beginning of construction Section 48(c) is amended by adding at the end the following new paragraph: (5) Special rule for determining beginning of construction The construction of any facility, modification, improvement, addition, or other property shall not be