RALEIGH, North Carolina (Reuters) - U.S. Treasury Secretary Janet Yellen on Thursday warned that any attempts to roll back the Biden administration's clean energy tax credits would raise costs for families and jeopardize new investments in U.S. manufacturing that are creating jobs.

Yellen told an audience at North Carolina's Wake Tech Community College that families across the country had claimed $8.4 billion in energy tax credits that would help them lower their energy bills long-term.

Republican presidential candidate Donald Trump has pledged to rescind many of President Joe Biden's clean energy rules for power plants and electric vehicles. Trump has also said he would end hundreds of billions of dollars in tax subsidies enacted in the 2022 Inflation Reduction Act (IRA), saying he would halt the "green new scam" and redirect funds toward building roads and bridges.

Without mentioning Trump, Yellen said that eliminating the IRA's clean energy tax credits "would be a historic mistake."

"Rolling them back could raise costs for working families at a moment when it's imperative that we continue to take action to lower prices," Yellen said in excerpted remarks. 

"It could jeopardize the significant investments in manufacturing we're seeing here and across the country, along with the jobs that come with them, many of which don't require a college degree."

She also said a roll-back could "give a leg up to China" which is investing heavily in clean energy industries. The Biden administration is expected to soon announce its final implementation plans for steeply increased tariffs on Chinese electric vehicles, batteries, solar cells and other goods to protect the development of a domestic clean energy supply chain.

Recent polling ahead of the Nov. 5 presidential election shows that Vice President Kamala Harris, the Democratic nominee, has gained ground and is now virtually tied with Trump in North Carolina, giving Democrats the chance to flip a state that Trump narrowly won in 2020 in his defeat against Biden.

Yellen's remarks emphasized the consumer savings from IRA tax credits, in line with Harris' economic proposals aimed at stemming rising living costs for Americans, which Harris also unveiled in Raleigh. Previous Yellen remarks have emphasized the economic growth and job creation benefits of such investments.

Yellen said a historic U.S. recovery was still underway with second-quarter U.S. growth at 3%, inflation declining and unemployment still near historic lows.

"But our administration knows that prices for key household expenses like healthcare, housing, and energy are still too high. Bringing down the costs of these essentials is our administration's top economic priority," she said.

Yellen said Treasury data shows that 90,000 families in North Carolina have claimed over $100 million in residential clean energy tax credits for installations like solar panels and energy storage batteries, with an average claim of $5,000. North Carolina families claimed $60 million in energy efficiency tax credits for heat pumps, efficient air conditioning and insulation for an average of $880.

At the Wake Tech campus, which trains workers for the electric vehicle and efficient building technologies industries, Yellen took a drive in a Mustang Mach E, an EV that no longer qualifies for a $7,500 U.S. tax credit under the IRA because of Chinese content in its battery.