Tucked inside Republicans' massive domestic policy bill is an excise tax for wind and solar projects, a provision that came as a surprise not just to the renewable energy industry, but to numerous senators who are crafting the legislation.

Wind and solar companies were already bracing for Congress to end federal subsidies. But the Senate bill goes even further and penalizes those industries.

The latest version of the Senate’s massive budget bill that is being raced through for a vote as soon as Saturday deals a fatal blow to the use of tax credits in place since 2005 to spur more wind and solar energy and would set a new tax on those projects for the first time, renewable energy proponents said on Saturday.