President Donald Trump pledged on Tuesday to revive America's coal industry by rolling back regulation, but energy experts expressed doubt his moves would significantly boost prospects for the controversial energy source.

Trump, flanked by coal miners and Environmental Protection Agency chief Scott Pruitt, a skeptic on climate science, vowed to end the "war on coal" as he signed an executive order to undo key measures implemented former President Barack Obama.

But the move comes at a time when utility companies decisively favor fuel sources other than coal for new power plants, especially cheap and abundant natural gas and renewable energy, favored by policies to promote wind and solar at the international, federal and state level.

"It's really symbolic," said Michael Webber, deputy director of the Energy Institute at the University of Texas at Austin. "This executive order is not going to save coal because coal loses to cheap natural gas."

Webber said the only way to really end the trend against coal would be with market-intervening policies that are virtually impossible to envision in the United States, such as a mandate to use coal or a tariff on natural gas "to make it falsely expensive."

And that would counter Pruitt's pledge Tuesday to not "pick winners and losers" but let the power industry pick the best fuel source for itself, the justification he used for rolling back the Obama era regulations.

Morningstar analyst Andrew Bischoff said Trump's move could give an incremental boost to coal in the short run by easing pressure to mothball coal-fired power plants.

But it will not be enough to counteract the roughly 40 percent greater efficiency of natural gas plants compared with coal.

"The real world impacts are that we continue to see renewable generation thrive under this administration," Bischoff said.

- Political support for renewables -

Trump, in a maiden trip to the EPA for the signing ceremony, ordered a review of emission limits for coal-fired power plants, an Obama policy that has been partly frozen in legal battles.

Trump also eased restrictions on leasing federal land for coal production and spiked an interagency group dedicated to assessing the social cost of greenhouse gases.

Environmentalists fear the steps may be a prelude to a US withdrawal from the landmark 2015 Paris climate accord and said the measures will make it difficult, if not impossible, for the US to meet its commitments under that agreement.

But even if their worst fears come to pass, the push for clean energy already has been heavily institutionalized and it would be difficult to completely stem the tide.

A report Tuesday from S&P Global Ratings said green finance "is coming of age" after the Paris agreement. The global green bond market doubled to almost $83 billion, led by China and corporate issuers, in the wake of Paris.

Even within the Trump administration some, key figures have a record of supporting renewable energy, including Energy Secretary Rick Perry, who oversaw huge expansion of wind energy in Texas while he was governor of the state.

"Apart from the EPA's Pruitt, who shares Trump's harsh environmental rhetoric, the heads of other key cabinet positions have more moderate views and are most likely to support growth opportunities for utilities," the Morningstar report said.

With the exception of a handful of states like West Virginia and Kentucky in coal country, the vast majority of US states have committed to renewable targets, some at 50 percent or more.

The push for renewable energy also has been boosted by federal tax credits promoting solar and wind, which have led to growing industries in states like Nevada and Iowa, home to senior lawmakers in Congress who are expected to resist a rollback.

Morningstar estimated that coal could constitute as little as 20 percent of US electric generation capacity by 2024, down from 50 percent in 2005 and 30 percent now.

Those figures in part depend on prices of natural gas, which will depend on whether the US shale boom that boosted American gas production persists.

The Trump administration has pledged to do what it can to keep US gas production high, a goal that analysts say will in itself limit coal's reach.

source: AFP