The US wind market and global supply chain were reeling Friday after Republicans in the House of Representatives unexpectedly proposed major changes to the production tax credit (PTC), sending shares of wind companies down – and leading analysts to dramatically rethink their projections for the market.

Although the wind industry has spent the past year expressing confidence about the fate of the PTC, the House Republicans’ 429-page tax bill published this week includes several changes to the PTC that would be enormously damaging to the wind market.