Notice 2025-42, page 351.

This notice provides guidance regarding beginning of construction for qualified wind and solar facilities under §§ 45Y and 48E, as amended by Public Law 119-21, 139 Stat. 72 (July 4, 2025), commonly known as the One, Big, Beautiful Bill Act (OBBBA). Sections 70512(a) and 70513(a) of the OBBBA add new §§ 45Y(d)(4) and 48E(e)(4), respectively, to the Code which terminate the § 45Y credit and § 48E credit, respectively, for applicable wind and solar facilities placed in service after December 31, 2027. Sections 70512(l)(4) and 70513(g)(5) of the OBBBA provide that the amendments made by §§ 70512(a) and 70513(a) of the OBBBA, respectively, apply to facilities the construction of which begins after the date which is 12 months after the date of enactment of the OBBBA (July 4, 2026). This notice provides new “beginning of construction” guidance, consistent with Executive Order 14315, 90 FR 30821 (July 7, 2025), to strictly enforce when construction of an “applicable wind facility” or “applicable solar facility” (each as defined in section 2.02(1) of the notice) has begun solely for purposes of determining whether such facility is subject to credit termination provisions added to §§ 45Y and 48E of the Code by §§ 70512 and 70513 of the OBBBA.