President Trump has backed up his vow to revive coal by toppling Obama-era environmental rules, by attempting a coal rescue plan and by promising to yank the United States out of the Paris climate accord.

Yet more than a year into Trump's presidency, there remains deep pessimism in the energy industry about the chances of a coal comeback in the near-term -- or even in the long run.

Hurt by booming renewable energy and cheap natural gas, coal's share of U.S. power generation slipped to an all-time low of 30% in 2017, according to the Department of Energy's Energy Information Administration. That's down from more than half the electric grid in 2001.

A dozen coal-fired power plants are slated for closure in 2018, rivaling the record-high of 15 that shuttered in 2015, according to Bloomberg New Energy Finance. Thirty-three coal plants closed during President Obama's second term.

Trump has attempted to resuscitate the coal industry by gutting the Clean Power Plan, Obama's signature effort to slash power plant carbon emissions. The Trump administration also tried -- and failed -- to enact a plan that would have subsidized slumping coal power plants.

Although the pace of coal plant closures slowed in 2017, the outlook looks bleak.

Even without the Clean Power Plan, the EIA expects coal-fired electric generating capacity in the United States to decrease through 2030 because natural gas is cheap and renewable energy costs are declining.

Forecasters anticipate a greater amount of coal power capacity to vanish between 2017 and 2030 than what disappeared between 2011 and 2016.

"I don't think there's one coal plant being built in the country. Whatever Trump tries to do doesn't really matter because it's driven by economics," said Andy Smith, an Edward Jones analyst who covers power companies.

Related: Trump hasn't killed the renewable energy boom

Coal's demise has been caused by the shale boom, which made natural gas cheap and abundant. If natural gas stays cheap, the EIA expects coal-fired power generation to decline through 2050.

In other words, not even Trump's own Energy Department is predicting a coal turnaround.

Contrast that with the extreme optimism around renewable energy. New technology and a wave of investment has made solar and wind increasingly-competitive with fossil fuels.

Renewable energy has doubled its foothold in U.S. power generation over the past decade and now contributes as much electricity as nuclear, according to Bloomberg New Energy Finance. The rise of solar and wind power has helped the United States produce the least greenhouse gas emissions since 1991.

The clean energy surge isn't over. The EIA expects renewable power to soar by 139% by 2050, led by wind and solar. Renewable power is expected to grow dramatically under all scenarios envisioned by the EIA -- even if natural gas prices stay low.

The global picture for renewable energy also looks bright.

BP predicted in its annual energy outlook on Tuesday that renewable energy will account for about half of the global increase in power generation through 2040, boosting its share of the pie from 7% today to about a quarter.

BP anticipates renewables will gain market share "faster than any other energy source over a similar period."

Meanwhile, coal is set to account for just 13% of the increase in power, compared with 40% over the past quarter-century.

"The main loser is coal," the BP report said.

Related: Mine closing wipes out many of Trump's coal job gains

To be sure, coal won't disappear completely.

U.S. coal production rose in 2017. Coal exports grew, and a wave of bankruptcies led to lower production costs.

The United States still relies on coal for about one-third of its power. Coal is also a major source of employment in parts of Appalachia. About 52,000 people work as coal miners and others support the industry as truck drivers and in other roles.

"Coal's not going away. It's still the backbone of the system. But we certainly don't see it growing," said Smith.

Globally, BP expects coal to remain the largest source of energy for power in 2040, however its share of the pie is set to drop below 30% from around 40% today.

The saving grace for the U.S. coal industry in recent years has been exports, which soared 48% in 2017. Shipments of U.S. coal to Asia nearly doubled last year thanks largely to strong demand from China.

But China's appetite for coal is likely to wane as the country transitions from an energy-intensive industrial powerhouse to a service-oriented economy. BP expects that shift, along with pollution concerns, will cause China's coal use to decline.

"It seems increasingly likely that China's consumption of coal has peaked," BP wrote.