The head of the biggest U.S. residential-solar company says the Commerce Department should issue a prompt preliminary decision into a tariff probe that it warns threatens to make panels more expensive.

“The planet’s on fire,” Mary Powell, chief executive officer of Sunrun Inc., said in an interview Wednesday. “We need to be thinking about ‘How do we radically collaborate to move faster?’ not ‘How do we slow things down? How do we make things more expensive?’”

The investigation into whether Chinese companies are circumventing decade-old tariffs by assembling cells and modules in Southeast Asia risks slowing U.S. solar installations, critics say. Boosting clean power is a key target of President Joe Biden, but so is spurring more domestic manufacturing.

Sunrun, which says the investigation is contrary to the Biden administration’s clean-power ambitions, thinks it’s in a solid inventory position despite the probe. The company has reached agreements for hundreds of megawatts of solar modules from manufacturers unaffected from the investigation, it said in its earnings statement Wednesday. Sunrun also expects to enter additional deals in the coming months.

The company boosted its full-year solar installation-growth guidance to at least 25%, up from 20% or greater. Shares were up 11% in after-market trading Wednesday.