The Treasury Department’s latest safe-harbor guidance raises the domestic manufactured-product threshold for the Investment Tax Credit’s 10% domestic-content bonus, a change that will affect utility-scale developers more than residential installers.
For homeowners, the residential system side of the credit is untouched. The change targets the adder that developers claim on top of the base 30% credit, and mostly affects sourcing decisions for inverters and racking rather than panels themselves.
What actually changed
The prior safe harbor let developers count certain steel components toward the threshold using a simplified cost method. The new guidance requires more granular documentation of where that steel was melted and poured, not just fabricated.
Who’s affected
Utility-scale and community solar developers sourcing racking from mixed-origin supply chains will feel this first. Residential installers using standard rooftop hardware are largely unaffected for 2027 installations.