“If you produce more gas in a static demand environment, you’re going to have a fuel fight between gas and coal,” said Kevin Book, an analyst with ClearView Energy Partners, a nonpartisan energy analysis firm.

It is also hard to see how Mr. Trump could use policy levers to expand production of natural gas. Over the last year, the historically high production levels of natural gas production glutted the market. Companies have idled fracking rigs as they wait for supply to tighten and prices to rise. Experts said that in a free market, the government cannot change that.

“No president controls the market. It’s pretty straightforward,” Mr. Book said.

Mr. Trump vowed to do so by ending regulations on fracking. “I think probably no other business has been affected by regulation than your business,” he told the gas executives. “Federal regulations remain a major restriction to shale production.”

That is largely false. The Obama administration has put forth regulations intended to govern the safety of fracking on public lands — a rule which would cover about 100,000 fracking wells, or about 10 percent of all fracking taking place in the United States. The vast majority of fracking occurs on state or private land and is governed by state and local regulations.

Still, in his appeal to both sides of the fossil fuel equation, Mr. Trump is distinguishing himself from Hillary Clinton, his Democratic opponent, who has put forward proposals to continue and increase environmental regulations on both coal and fracking.

In a debate in March, Mrs. Clinton said, “By the time we get through all of my conditions, I do not think there will be many places in America where fracking will continue to take place.”

She has also vowed to uphold President Obama’s climate change policy, the Clean Power Plan. The heart of the rule is a set of aggressive Environmental Protection Agency regulations intended to curb planet-warming carbon pollution, which comes mainly from coal-fired power plants. The rule has been temporarily suspended by a Supreme Court order, but if it is eventually upheld, it would most likely lead to the shutdown of hundreds of coal-fired plants — and an eventual freeze of the nation’s coal markets.