On June 6, 2026, the U.S. District Court for the District of Columbia vacated IRS Notice 2025-42 in full, ruling it "arbitrary and capricious" under the Administrative Procedure Act (APA). The decision in Oregon Environmental Council v. IRS, Civil Action No. 1:25-cv-04400 (CKK) (D.D.C. June 6, 2026), restored a beginning-of-construction framework just weeks before the OBBBA's July 4, 2026 beginning-of-construction deadline.
Quick Summary/Timeline
- The Inflation Reduction Act (IRA) of 2022 created the Section 45Y clean electricity production tax credit and Section 48E clean electricity investment tax credit as technology-neutral incentives for zero-emission electricity generation.
- The One Big Beautiful Bill Act (OBBBA), enacted July 4, 2025, accelerated the phase-out of these credits for wind and solar, requiring projects to begin construction by July 4, 2026 (or be placed in service by December 31, 2027) to preserve credit eligibility.
- Since 2013, "beginning of construction" has generally been established through one of two methods: the Physical Work Test or the Five Percent Safe Harbor.
- In August 2025, the IRS issued Notice 2025-42, eliminating the Five Percent Safe Harbor for wind projects and most solar projects (over 1.5 MW), leaving the Physical Work Test as the sole method for those facilities.
- On June 6, 2026, the court vacated Notice 2025-42 in full, restoring the Five Percent Safe Harbor as an available method ahead of the deadline.
- As of this writing, no appeal or stay has been publicly confirmed, though one remains widely expected among firms tracking the case. The July 4, 2026 beginning-of-construction deadline has now passed.
What does this mean for firms? For the roughly nine-month window between the ruling and the July 4, 2026 deadline, developers had two paths to establish beginning of construction rather than one. Projects that didn't lock in a beginning-of-construction position by that date now proceed on the December 31, 2027 placed-in-service pathway instead. Either way, prevailing wage and apprenticeship (PWA) compliance remains a separate, ongoing requirement regardless of which beginning-of-construction method a project used.
Full Background
What Are Sections 45Y and 48E?
The Inflation Reduction Act of 2022 (Pub. L. 117-169) added Sections 45Y and 48E to the Internal Revenue Code as technology-neutral successors to the older Section 45 production tax credit and Section 48 investment tax credit. Section 45Y provides a production tax credit for electricity generated at a "qualified facility" with a greenhouse gas emissions rate of zero or below; Section 48E provides an investment tax credit based on a taxpayer's qualified investment in such a facility. Both credits apply to facilities placed in service after December 31, 2024.
What Is "Beginning of Construction," and Why Does It Matter?
Neither the IRA nor the OBBBA defines "beginning of construction" in the statutory text. Instead, the IRS has filled that gap through a long series of sub-regulatory notices dating back to Notice 2013-29, which first established the two methods described below. That framework was reaffirmed and extended across more than a decade of subsequent guidance, including Notice 2022-61, which applied the same principles to Sections 45Y and 48E, and, importantly, to the prevailing wage and apprenticeship (PWA) rules discussed later in this post.
"Beginning of construction" matters because it is the trigger date used throughout federal energy tax credit law to determine which set of rules, and which deadlines, apply to a given project.
The Two Tests: Physical Work Test and Five Percent Safe Harbor
Physical Work Test. Construction begins when "physical work of a significant nature" starts. This is a qualitative, facts-and-circumstances test. It focuses on the nature of the work, not its cost or quantity, and covers both on-site work (e.g., excavating a foundation, setting anchor bolts, installing racking) and off-site work performed under a binding written contract (e.g., manufacturing of components, mounting equipment, transformers). Preliminary activities, like planning, permitting, site clearing, and geotechnical testing do not count.
Five Percent Safe Harbor. Construction is deemed to have begun once a taxpayer pays or incurs 5% or more of the total cost of the facility. This is a quantitative, bright-line test that lets developers establish eligibility through early-stage spending, such as procurement or deposits, without needing to show that physical construction activity has actually started on-site.
Both methods have historically been subject to a Continuity Requirement: the taxpayer must maintain continuous progress toward completion, which is generally deemed satisfied under a Continuity Safe Harbor if the facility is placed in service within four calendar years of the year construction began.
The Executive Order Behind It
On July 7, 2025, President Trump issued Executive Order 14315, Ending Market Distorting Subsidies for Unreliable, Foreign-Controlled Energy Sources (90 Fed. Reg. 30,821). The order directed the Treasury Department, within 45 days of the OBBBA's enactment, to issue guidance ensuring that the OBBBA's credit termination provisions for wind and solar were "strictly" enforced, including guidance to prevent taxpayers from using broad safe harbors to establish beginning-of-construction status without having actually built a substantial portion of the facility.
What the Notice Did
In response, the IRS issued Notice 2025-42 on August 15, 2025. The notice:
- Eliminated the Five Percent Safe Harbor for all wind facilities and solar facilities exceeding 1.5 MW (AC), leaving the Physical Work Test as the sole method available to establish beginning of construction for those projects ahead of the July 4, 2026 deadline.
- Preserved the Five Percent Safe Harbor only for "low output" solar facilities — those with a maximum net output of 1.5 MW or less.
- Applied retroactively to any applicable wind or solar facility whose construction had not already begun (under prior guidance) before September 2, 2025.
- Left the four-year Continuity Safe Harbor in place but effectively required continuity to be shown through actual physical work rather than through the broader "continuous efforts" concept available to Five Percent Safe Harbor projects under prior guidance.
Source: IRS Notice 2025-42, 2025-36 I.R.B. 351 (full text, IRS.gov).
Court Ruling Overturns Notice 2025-42
The Case
Seven governmental, tribal, and private organizations, including the Oregon Environmental Council, sued the IRS, arguing that Notice 2025-42 was arbitrary and capricious under the APA. Seventeen states and the District of Columbia also filed an amicus brief in support of the plaintiffs, arguing the notice would raise electricity costs and disrupt state energy planning.
Source: Amicus Curiae Brief of Oregon et al., Case No. 1:25-cv-04400-CKK, Doc. 29 (D.D.C. Feb. 20, 2026) (full text).
The Holding
On June 6, 2026, Judge Colleen Kollar-Kotelly of the U.S. District Court for the District of Columbia granted the plaintiffs' motion for summary judgment and vacated Notice 2025-42 in full, remanding the matter to the IRS. The court held that the IRS had failed to satisfy the "reasoned decision-making" standard required of federal agencies under Motor Vehicle Manufacturers Association v. State Farm Mutual Automobile Insurance Co., 463 U.S. 29 (1983).
The Practical Effect
With Notice 2025-42 vacated, the pre-existing framework under Notice 2022-61 and its predecessor notices is restored. Wind and large-scale solar developers may once again use either the Physical Work Test or the Five Percent Safe Harbor to establish beginning of construction ahead of the July 4, 2026 deadline.
Two deadlines remain unchanged by the ruling and are worth keeping straight:
- July 4, 2026: The statutory beginning-of-construction deadline under the OBBBA. Projects that begin construction on or before this date lock in the original phase-out schedule for the 45Y/48E credits.
- December 31, 2027: The fallback placed-in-service deadline. Projects that do not meet the July 4, 2026 beginning-of-construction deadline are not automatically ineligible for the credits, but they must instead be placed in service by December 31, 2027 to qualify.
Ongoing Developments
As of this writing (July 13, 2026), the July 4 deadline has passed, and this remains a live legal question rather than settled law:
- No appeal or stay has been publicly confirmed as of this writing, though industry counsel widely expects the government to appeal or seek a stay. The court itself acknowledged in its opinion that there was "almost zero chance" appellate proceedings would conclude before the July 4, 2026 deadline — a prediction that has held true, since the deadline passed with no appellate resolution.
- This ruling is specific to Sections 45Y and 48E beginning-of-construction timing. It does not address other requirements tied to different guidance or deadlines, such as the "Foreign Entity of Concern" (FEOC) / Prohibited Foreign Entity beginning-of-construction rules, which are anchored by statute to a different, fixed set of pre-2025 notices and are unaffected by this decision.
- PWA requirements are untouched. The prevailing wage and apprenticeship rules, and the beginning-of-construction concept used to assess whether a project is exempt from them, derive independently from Notice 2022-61 and are not the subject of this litigation.
Given this, several firms tracking the case advised developers not to abandon Physical Work Test documentation even if they qualified under the Five Percent Safe Harbor in the run-up to the deadline, since a later reversal on appeal could still leave safe-harbor-only projects exposed retroactively.
Best Practices — Especially for Prevailing Wage Compliance
Whichever beginning-of-construction method your project ultimately relies on, prevailing wage and apprenticeship compliance is a separate, independent requirement that determines whether you receive the base credit rate or the enhanced rate — generally five times higher — under Sections 45Y and 48E. That determination is not affected by Oregon Environmental Council v. IRS. With that in mind, firms should consider the following:
- Don't let the safe harbor question distract from PWA documentation. Whether your project qualifies under the Physical Work Test or the Five Percent Safe Harbor, you still need contemporaneous records establishing that laborers and mechanics were paid at least the applicable prevailing wage rates, and that the required percentage of total labor hours was performed by registered apprentices (generally 15% for projects that began construction after December 31, 2023).
- Document both begin-construction pathways where feasible. If your project can support both a Physical Work Test position and a Five Percent Safe Harbor position, maintain records for both. This creates a fallback if the safe harbor is stayed or reversed on appeal.
- Track prevailing wage determinations by classification and geography. Rely on published Department of Labor wage determinations (available via SAM.gov), and request supplemental wage determinations promptly if a classification isn't listed for your project's location.
- Maintain "good faith effort" documentation for apprenticeship requirements. If registered apprenticeship programs deny your request or fail to respond within the required window, keep the request and denial (or non-response) on file — this is what substantiates the good-faith exception.
- Prepare for Form 7220. Compliance (or correction of a prior failure) is reported using IRS Form 7220, Prevailing Wage and Apprenticeship (PWA) Verification and Corrections. Build your recordkeeping process now so you aren't reconstructing payroll and apprenticeship data under time pressure later.
- Consult legal counsel before finalizing your beginning-of-construction strategy. With the July 4, 2026 deadline now passed, firms should confirm with legal counsel which beginning-of-construction method their project ultimately relied on and whether that position is well-documented enough to withstand IRS scrutiny or a later reversal on appeal.
Conclusion
The vacatur of Notice 2025-42 is a meaningful change for wind and solar developers racing toward the July 4, 2026 beginning-of-construction deadline. It restores optionality that many projects were built around, but the government's potential for evolution in the legal landscape means rulings could still shift past the deadline.
What remains applicable is the importance of rigorous, well-documented prevailing wage and apprenticeship compliance. Building the foundation for securing the full value of the 45Y and 48E credits is key, regardless of how the begin-construction question is ultimately resolved.
Have questions about how this affects your project's compliance strategy? Connect with our team to make sure your prevailing wage and apprenticeship documentation is airtight, regardless of which safe harbor you rely on to establish beginning of construction.