A court ruling restores the wind tax credit safe harbor deadline test
Wind and solar developers racing the wind tax credit safe harbor deadline just got a court ruling reopening their easiest path to qualify. On June 6, 2026, a federal court in Washington vacated the Internal Revenue Service notice that had eliminated the 5% safe harbor test for wind projects and solar projects larger than 1.5 megawatts, restoring that test weeks before the July 4, 2026 deadline it affects.
Under the One Big Beautiful Bill Act, enacted July 4, 2025, a wind or solar project must begin construction by July 4, 2026, to keep the federal tax credits in sections 45Y and 48E. There are 2 ways to prove that. The 5% safe harbor test only requires paying, or committing to pay, 5% of a project total cost. The physical work test requires actual construction activity, slower and harder to document against a deadline. In August 2025, the tax agency issued a notice removing the 5% test for every wind project and every solar project above 1.5 megawatts, leaving only the harder test for anyone not already locked in.
The 23 gigawatt total is the sum of the 2 figures Wood Mackenzie reported, 16 and 7, computed for this article and not a number Wood Mackenzie states directly.
Show the numbers
| Already safe harbored | 16 |
| In advanced development | 7 |
| Total pipeline racing the deadline | 23 |
Why the court says the notice cannot stand
The court found the tax agency never explained why wind and large scale solar needed a different construction test than every other technology in the same law. Utility Dive reported that the judge, Colleen Kollar Kotelly, found no reasoned decision that an earlier credit termination date for wind and solar alone justified a harder test for them alone. Vacating the notice restores the 5% test for any project that has not yet locked in the credit.
Before the ruling, California led 17 other states and the District of Columbia in a legal filing supporting the challenge, called an amicus brief, that lets outside governments argue a position in a case without being a party to it. California Attorney General Rob Bonta said of the fight, "At a time when the demand for energy is increasing, we should be ramping up clean energy projects, not slowing them down."
At a time when the demand for energy is increasing, we should be ramping up clean energy projects, not slowing them down.
Rob Bonta, Attorney General of California. Source 1.
Developers were already racing the deadline
The research firm Wood Mackenzie counted about 16 gigawatts of onshore wind capacity already safe harbored ahead of the deadline, plus another 7 gigawatts moving through advanced development, a combined 23 gigawatt pipeline this article calculates by adding those 2 figures. The same firm projected solar developers would safe harbor 216 to 240 gigawatts of solar by July 4, 2026, more than 13 times the wind total, a ratio calculated here from the 2 figures Wood Mackenzie reported. Andy Moon, chief executive and co founder of the developer Reunion Infrastructure, said, "We know developers that have safe-harbored 10 to 15 gigawatts apiece of pipeline."
We know developers that have safe-harbored 10 to 15 gigawatts apiece of pipeline.
Andy Moon, chief executive and co founder of the developer Reunion Infrastructure. Source 5.
Wood Mackenzie states this as a single range, not 2 disagreeing figures, so both ends are drawn from the same source. About 61% of that range had already reached safe harbor status before the notice existed.
Show the numbers
| Solar developers | 216 to 240 gigawatts |
The ruling may not be the final word
The ruling landed weeks before the deadline it affects, and does not settle the question. The government could still appeal, and the tax agency remains free to issue new guidance justifying the same restriction with better reasoning, neither of which had happened as of the most recent reporting for this article. A project that still misses the July 4, 2026 deadline is not automatically out. It can instead keep the credit by generating electricity, a status the law calls placed in service, by December 31, 2027.