A federal judge has dealt a legal blow to the Trump administration's push to tighten renewable energy tax credits, striking down Internal Revenue Service guidance that limited how wind and solar projects could qualify for the incentives. The ruling, issued Saturday by U.S. District Judge Colleen Kollar-Kotelly, a Clinton appointee, found that the Treasury Department's new definition of "begin construction" was arbitrary and capricious.
At the heart of the dispute is the IRS's long-standing interpretation of what constitutes starting construction for clean energy projects. Since 2013, the agency had recognized two pathways: beginning physical work of a significant nature, or incurring at least five percent of a project's total cost—known as the Five Percent Safe Harbor. The Trump administration's guidance, released after President Trump signed the One Big Beautiful Bill Act, eliminated the five percent option, requiring developers to show physical work had begun.
Kollar-Kotelly wrote that the change was a "significant shift" without adequate explanation. "Because neither the Notice nor the administrative record provides an explanation from which 'the agency's path may reasonably be discerned' in light of all the facts and circumstances, the Notice is arbitrary and capricious," she stated in her opinion.
Still, the judge acknowledged the ruling may provide only temporary relief. The Big Beautiful Bill, one of the administration's most aggressive moves to curb renewable energy, phases out tax credits for solar and wind projects entirely unless they start construction before July 5, 2026, or are placed in service by 2028. That looming deadline means developers still face significant uncertainty. "It is likely that market participants will need to await the outcome of an appeal before they will have certainty about the legal effect of the Notice," Kollar-Kotelly noted.
The Trump administration has pursued multiple avenues to hamper renewable energy, including permit revocations and procedural delays. The Treasury Department guidance was specifically designed to narrow safe harbors, as Trump directed the agency to restrict credits unless a "substantial portion" of a facility had been built.
An IRS spokesperson declined to comment on whether the agency would now allow projects to use the Five Percent Safe Harbor, citing ongoing litigation.
Renewable energy advocates celebrated the ruling. "This is a huge win for clean energy development, and for everyone already feeling the impacts of rising electricity costs," said Jana Gastellum, executive director of the Oregon Environmental Council, one of the groups that sued. "The IRS guidance that hindered these technologies was just another example of the federal administration causing energy market chaos. Saturday's decision removes that barrier," she added in a statement.
The legal battle comes amid broader political fights over energy policy. In a related development, GOP Rep. Bacon urged Trump to drop his intelligence pick to save surveillance law, while Democrats have blocked FISA renewal over the same nomination. The administration's energy agenda also intersects with international tensions, as Iran's calculus suggests it believes it can outlast Trump in ongoing conflicts.
For now, the ruling restores the five percent safe harbor, but the clock is ticking. With the July 2026 construction deadline fast approaching, developers must weigh whether to proceed with projects that may lose tax credit eligibility under the Republican-backed phaseout. The case is likely to be appealed, leaving the industry in a state of limbo.
