Windmill farm cad design software displayed on monitors

5% safe harbor for wind and solar project construction eliminated


The 5% safe harbor method is eliminated for projects on which construction has not begun before September 2, 2025.


In Notice 2025-42, the IRS updated the rule for determining when construction has begun for wind and solar projects for purposes of qualifying for tax credits under IRC Sections 45Y (clean energy production credit) and 48E (clean electricity investment credit). The "5% safe harbor" test is generally eliminated, leaving the "physical work" test as the only way to establish that construction has begun on the project. The notice is effective for applicable wind and solar projects for which construction has not begun before September 2, 2025.

The "One Big Beautiful Bill Act" (P.L. No. 119-21, OBBBA) eliminated the IRC Section 45Y and 48E credits for wind and solar projects placed in service after December 31, 2027, except for projects for which construction begins within 12 months of July 4, 2025.

 

Following the legislation's enactment, President Trump issued an Executive Order on July 7, 2025, in which the Department of Treasury was directed, within 45 days of the OBBBA's enactment, to issue guidance to assure policies around the "beginning of construction" are not circumvented and to restrict the use of broad safe harbors unless a "substantial portion of a subject facility has been built." 

 

Previously, to establish the beginning of construction, taxpayers could demonstrate that construction has begun by either: (1) starting "physical work of a significant nature" (the physical work test) or (2) paying or incurring 5% or more of the total cost of the facility (the 5% safe harbor test). In addition, taxpayers had to demonstrate either continuous construction or continuous efforts (the continuity requirement).

 

Read the full article.

Summary 

Responding to an Executive Order, the IRS outlined in Notice 2025-42 when construction of a wind or solar facility has begun for purposes of determining whether the facility is subject to the credit termination provisions added to IRC Section 45Y and 48E.

About this article

Related articles

September 30 funding deadline looms as Congress returns to session

Fall 2025 Washington outlook: government funding, tax policy, health care, trade, and financial services shaping year-end legislation.