AsianFin—Solar manufacturers are asking the Biden administration to slap duties on $12.5 billion of imported equipment from Southeast Asia, setting the stage for a sweeping trade probe that threatens to make power projects more expensive.

In petitions filed Wednesday, seven U.S. panel makers and polysilicon producers seek trade help to counteract what they say are unfair practices by overseas rivals. Their requests raise the prospect of tariffs as high as 271.5% later this year.

These companies mainly focus on solar cell imports from Cambodia, Malaysia, Thailand and Vietnam, accounting for about 80% of total U.S. photovoltaic imports.