The conservative House Freedom Caucus said on Friday that it would “not accept” changes that “water down” its cuts to green energy tax credits as the Senate weighs whether to alter the legislation.

The House version of the “big, beautiful bill” would make drastic changes to tax cuts for low-carbon energy sources passed in the Democrats’ 2022 Inflation Reduction Act (IRA).

Climate-friendly energy projects, including wind and solar, would only be able to qualify for the credits under the House bill if they begin construction within 60 days of the bill’s enactment. 

This brief window would likely make many projects ineligible for the credits, and is expected to significantly hamstring the development of new renewable power.

In a post on social media on Friday, the Freedom Caucus warned the Senate against loosening that restriction or others included in the bill.

“We want to be crystal clear: if the Senate attempts to water down, strip out, or walk back the hard-fought spending reductions and IRA Green New Scam rollbacks achieved in this legislation, we will not accept it,” said the post, which was attributed to the Freedom Caucus’s board. 

“The House Freedom Caucus Board will stand united holding the line. The American people didn’t send us here to cave to the swamp — they sent us here to change it,” they added.

The Senate has been widely expected to consider changes that could slow the rapid elimination of the tax credit passed under the House version of Trump’s “big beautiful bill.” 

Republican Sens. Lisa Murkowski (Alaska), Thom Tillis (N.C.), Jerry Moran (Kan.) and John Curtis (Utah) released a letter warning against a “full scale” repeal of the tax credits. Senate Republicans can only afford three defections and pass their bill.

On Friday, a group of 13 House GOP moderates released a letter calling on Senate leadership “to substantively and strategically improve clean energy tax credit provisions” in the legislation. 

“We believe the Senate now has a critical opportunity to restore common sense and deliver a truly pro-energy growth final bill that protects taxpayers while also unleashing the potential of U.S. energy producers, manufacturers, and workers,” said the letter, which was led by Reps. Jen Kiggans (R-Va.) and Brian Fitzpatrick (R-Pa.).

Altogether, the letters illustrate what could be a tough task ahead of the Republican leadership as they look to find a measure that will keep at least 50 senators on board and appease the House.

Emily Brooks contributed.