President Donald Trump just dealt his biggest blow to the renewable energy industry yet. On Monday, Trump approved duties of as much as 30% on solar equipment made abroad, a move that threatens to handicap a $28 billion industry that relies on parts made abroad for 80% of its supply. The Solar Energy Industries Association has projected 23,000 job losses this year in a sector that employed 260,000. The tariffs are just the latest action Trump has taken that undermine the economics of renewable energy. The administration has already decided to pull the U.S. out of the international Paris climate agreement, rolled back Obama-era regulations on power plant-emissions and passed sweeping tax reforms that constrained financing for solar and wind. The import taxes, however, will prove to be the most targeted strike on the industry yet and may have larger consequences for the energy world. Trump approved four years of tariffs that start at 30% in the first year and gradually drop to 15%. The first 2.5 gigawatts of imported solar cells are exempt for each year, the president said in an emailed statement. China and neighbors including South Korea may opt to challenge the decision at the World Trade Organization - which has rebuffed prior U.S.-imposed tariffs that appeared before it. Lewis Leibowitz, a Washington-based trade lawyer, expects the matter will wind up with the WTO. The Solar Energy Industries Association warned the tariffs will delay or kill billions of dollars of solar investments.