Table of Contents
- Introduction
- Prior IRS Guidance: Beginning of Construction – A Quick Overview
- The OBBBA’s Changes – Notice 2025-42
- The OBBBA Update’s Effects on You
Introduction
The Inflation Reduction Act (IRA) introduced transformative clean energy tax incentives, including bonus credits for projects that meet specific labor standards. Among these, the prevailing wage and apprenticeship requirements have become central to maximizing certain tax benefits. Recently, the One Big Beautiful Bill Act (OBBBA) introduced new updates (Notice 2025-42) on August 15, 2025 that reshape how these labor rules apply, specifically under Sections 45Y and 48E. This blog explores the original IRA framework, its impact on taxpayers, and the nuanced changes brought by Notice 2025-42.
Prior IRS Guidance: Beginning of Construction – A Quick Overview
Under the IRA, prevailing wage and apprenticeship requirements must be met to qualify for enhanced tax credits. Failure to comply may result in penalties and the loss of bonus credit eligibility. For a full debrief on how this affects projects, visit our YouTube series.
The credits directly addressed in the OBBBA BOC notice include:
- Clean Electricity Production Credit (§45Y)
- Clean Electricity Investment Credit (§48E)
The prevailing wage requirement mandates that workers be paid at least the wage rates set by the U.S. Department of Labor.
Under the proposed IRS guidance, the beginning of construction date determines if prevailing wage and apprenticeship (PWA) requirements apply to the construction of a qualified facility. Under the Beginning of Construction (BOC) Exception, a qualified facility which began construction prior to January 29, 2023 is eligible for the increased credit amounts without meeting PWA requirements.
The IRA initial guidance (87 FR 73580) specified that the BOC date could be determined under the following methods:
- The Physical Work Test
- Verifies that “physical work of a significant nature” has begun. This takes into account work performed by the taxpayer or subcontractors prior to the manufacture, construction, or production of the applicable wind or solar facility. The test focuses on the type of work, not its cost or volume. This includes both off-site and on-site work, such as:
- Manufacturing of components, mounting equipment, support structures (e.g., racks, rails, inverters, transformers), and other power conditioning equipment
- Excavation for foundations, setting anchor bolts, pouring concrete, etc. (see Page 7 Section 3 of notice 2025-42)
- Verifies that “physical work of a significant nature” has begun. This takes into account work performed by the taxpayer or subcontractors prior to the manufacture, construction, or production of the applicable wind or solar facility. The test focuses on the type of work, not its cost or volume. This includes both off-site and on-site work, such as:
- The Five Percent Safe Harbor
- Defines beginning of construction as the period when:
- (i) A taxpayer pays or incurs (within the meaning of § 1.461-1(a)(1) and (2)) five percent or more of the total cost of the facility
- (ii) Thereafter, the taxpayer makes continuous efforts to advance towards completion (see section 2.02(2)(ii) of Notice 2022-61)
- Defines beginning of construction as the period when:
- The Continuity Requirement and Continuity Safe Harbor
- Under the Physical Work Test and Five Percent Safe Harbor, taxpayers must demonstrate continuous construction or continuous efforts regardless of which method was used to establish the beginning of construction (see section 2.02(3) of Notice 2022-61).
- The Continuity Safe Harbor provides that the continuity requirement will be considered met if the facility is placed in service within a certain time frame, outlined in the applicable tax credit.
The OBBBA’s Changes – Notice 2025-42
The following rules set forth by the OBBBA have an effective date of September 2, 2025 for applicable wind and solar facilities. Thus, projects that began before this date are not subject to this update.
Wind and solar projects that begin construction within 12 months of the OBBBA’s enactment (prior to July 5, 2026), can still qualify for the full credit with no placed-in-service deadline. For any wind and solar projects that fall outside of this one-year safe harbor, the OBBBA shortens the timeline for these projects to qualify for the credits, requiring these facilities to be placed in service by December 31, 2027.
The OBBBA modifies the beginning of construction regulations for the §45Y and §48E tax credits to prevent artificial manipulation or acceleration of eligibility. Key changes include:
- Restricting the “Beginning of Construction” determination to the Physical Work Test only
- The “Five Percent Safe Harbor” is not applicable to most facilities for this purpose and may only be used for low-output solar facilities (1.5 megawatts or less).
- Maintaining the Continuity Requirement, which is satisfied if continuous physical work is performed.
- There are specified excusable disruptions to a continuous program of construction, such as weather delays, permitting issues, or supply shortages (see section 4.02 of Notice 2025-42).
Exception: Continuity Safe Harbor
A taxpayer is deemed to satisfy the continuity requirement if the facility is placed in service by the end of the calendar year that is no more than four years after the year construction began.
If the facility is not placed in service within that four-year window, whether the continuity requirement is met will be determined based on facts and circumstances.
Example from Notice 2025-42:
- If construction begins on August 20, 2025, and the facility is placed in service by December 31, 2029, the Continuity Safe Harbor is satisfied.
- If the facility is placed in service after January 1, 2030, the IRS will evaluate whether the continuity requirement was met. July 5, 2026, marks the cut-off for beginning construction to claim the §45Y and §48E tax credits, so taxpayers seeking to earn these credits must do so before the termination date. This termination applies to applicable wind and solar facilities.
The OBBBA Update’s Effects on You
The new BOC rules under Notice 2025-42 apply to wind and solar projects that do not begin construction before September 2, 2025, under prior IRS guidance. Projects that begin construction before that date, including those relying on the 5% Safe Harbor, will remain governed by the prior IRS guidance on BOC.
For projects starting after September 2, 2025, taxpayers and developers must rely solely on the Physical Work Test as outlined in Notice 2025-42 to establish construction start dates (aside from low-output solar facilities) and must meet continuity requirements to retain eligibility for §45Y and §48E credits.
The July 5, 2026, cutoff is another critical milestone: projects that begin construction after this date and are placed in service after December 31, 2027, will no longer qualify for enhanced tax credits. Therefore, many taxpayers and developers will be pushing to get their project’s BOC date established prior to July 5, 2026, and must be aware of these new guidelines. Projects that start after July 5, 2026, will need to ensure that they are well-planned and on track to be placed in service prior to December 31, 2027.
Understanding these changes and planning accordingly is essential for maximizing incentives and avoiding disqualification, especially when it comes to the newly established deadlines. As the regulatory landscape evolves, staying informed and proactive will be key to successful clean energy project development. Alliant is here to assist you with all things prevailing wage to help you maximize your credit.
Need assistance? Feel free to contact us for solutions catered your projects.


















