President Donald Trump is again seeking to boost the struggling U.S. coal industry, with an announcement expected Thursday to spend nearly $700 million to support coal-fired power plants and coal exports.

The Trump administration is putting nearly $700 million toward coal, one of the president’s favorite energy sources. President Trump announced the move during Thursday remarks in the Oval Office, saying his administration is “taking historic action to bring down the price of energy and the cost of living for all Americans with the power of...