In his first few weeks, President Trump has frozen climate spending, shaken up staffing at agencies like the E.P.A. and set off a wave of legal challenges.

About 80 percent of manufacturing investments spurred by a Biden-era climate law have flowed to Republican districts. Efforts to stop federal payments are already causing pain.

The pause affects billions of dollars and is delaying home repairs, factory construction and other projects, many in states that voted Republican.

Legal experts said the president was testing the boundaries of executive power with aggressive orders designed to stop the country from transitioning to renewable energy.

In a sweeping order, President Trump halted federal approvals for new wind farms, in a move that could affect projects on land and in the ocean.

The president said he’d declare an energy emergency, increase drilling and end support for electric cars. His pivot to oil and gas follows the hottest year in recorded history.

The fire at the Moss Landing plant, which stores electricity for the power grid, was unrelated to wildfires in Los Angeles.

The loan guarantees are one of the final attempts by the outgoing Biden administration to encourage power companies to cut emissions while trying to keep rates down.

Wright, the founder of a fracking firm, testified that he would back all forms of low-carbon energy as well as gas, oil and coal.

With a lucrative tax credit, the Biden administration is hoping to establish a new industry that might help fight climate change.