Overview

• Treasury issued guidance to meet the 45-day deadline from President Trump’s executive order, redefining when wind and solar projects start construction under tax credit rules.
• The rules narrow “physical work of a significant nature” to specific on-site activities such as excavating turbine foundations and installing solar support racks.
• Off-site activities like manufacturing components, mounting equipment and transformer work may no longer count toward the beginning-of-construction test.
• Developers are stalling projects or rushing safe-harbor actions—buying transformers and American-made panels—to protect existing subsidies.
• Clean Energy Associates warns the tighter definition could wipe out roughly 60 GW of planned U.S. solar capacity through 2030, risking billions in investment.