Natural gas generation first surpassed coal generation on a monthly basis in April 2015, and the generation shares for coal and natural gas were nearly identical in 2015, each providing about a third of all electricity generation.

US law firm Blank Rome’s petrochemical and natural resources practice group leader Michael Krancer, a former secretary of the Pennsylvania Department of Environmental Protection, warned President Barack Obama’s Clean Power Plan which was purportedly targeting the coal industry was much more than just a “mad dash for renewable energy”

He said the CPP actually “takes a page from the Soviet-style planned economy – in this case, a national electricity economy”

Both Obama and his wannabe successor Hillary Clinton once touted natural gas as an essential clean bridge fuel to wean the US off dirtier fossil fuels and reduce the country’s reliance on foreign players.

However, political newspaper The Hill cited a dangerous shift from the draft CPP which focused on coal to the final CPP, which it said would “accommodate a large transition from coal power directly to renewables like wind and solar, skipping over natural gas altogether.

The CPP is currently on ice after the US Supreme Court stayed the plan on February 9, sending it to a lower court for a ruling and undermining Obama’s signature environmental policy after critics had argued it was federal overreach.

It was the first time the Supreme Court halted a regulation even before the lower court ruled.

Krancer said that if the courts eventually judge that the White House overstepped its authority, that could be good news for the natural gas industry.

While coal was significantly less expensive than natural gas between 2000 and 2008, supplying about half of the US’ total generation, in 2009 the gap between coal and natural gas prices started narrowing as large amounts of natural gas produced from shale formations changed the balance between supply and demand in US natural gas markets.

The EIA said Obama’s environmental regulations affecting power plants have played a “secondary role” in driving coal's declining generation share over the past decade, although plant owners in some states have made investments to shift generation toward natural gas at least partly for environmental reasons.

“Looking forward, environmental regulations may play a larger role in conjunction with market forces,” the EIA said in yesterday’s Short-Term Energy Outlook.

“Owners of some coal plants will face decisions to either retire units or reduce their utilisation rate to comply with requirements to reduce carbon dioxide emissions from existing fossil fuel-fired power plants under the Clean Power Plan, which is scheduled to take effect in 2022 but has recently been stayed by the Supreme Court pending the outcome of ongoing litigation.”

Beyond the growing market share for natural gas-fired generation over the past decade, the EIA said coal's generation share has also been reduced by the growing market share of renewables other than hydroelectric power, especially wind and solar.

“Unlike the growth of natural gas-fired generation, which has largely been market-driven, increased use of non-hydro renewables has largely been driven by a combination of state and federal policies,” the EIA said.

“The use of renewable energy sources such as wind and solar has also grown rapidly in recent years so that generation from these types of renewables is now surpassing generation from hydropower.”

The EIA’s March 2016 STEO expects that the combination of market forces and government policies will continue to stimulate the use of natural gas and non-hydro renewables for power generation.

In the EIA's forecast, natural gas provides 33% of generation in 2016 while coal's share falls to 32%.

The expected share of non-hydro renewables increases to 8% in 2016, with hydropower's share at 6%.