Late last week, power company Vistra Energy announced that it would close two of its Texas coal plants by early 2018. In a press release, the company blamed "Sustained low wholesale power prices, an oversupplied renewable generation market, and low natural gas prices, along with other factors."

Just the week before, Vistra subsidiary Luminant had announced another Texas plant closure, according to Reuters. The three Texas coal plants reflect more than 4GW of capacity. The plants are only the latest in a string of announced retirements from power companies that find their coal units offline more and more often due to low electricity prices.

But these closures came at a surprising time: the Trump administration has been pushing some of the most aggressive policies aimed at helping out coal plants that we've seen yet. The US Environmental Protection Agency (EPA) moved to roll back the Clean Power Plan just last week, and, in late September, the Department of Energy proposed a rule that would increase compensation for facilities that can store 90 days of fuel onsite (i.e., coal and nuclear energy). Industry watchers expected the proposed lifelines would forestall exits from coal generation. (In Texas, the Clean Power Plan repeal is expected to help coal out considerably, although the Department of Energy proposed rule won't have too much of an effect because Texas' grid operator is exempt from Federal Energy Regulatory Commission rules.)

It seems that any expected help from the US government would not be enough to keep the older Texas plants economic. Bloomberg writes that, although demand for electricity has been growing in the Lone Star State (in contrast to much of the rest of the country, where demand is largely flat), wholesale prices for electricity have plummeted to $25 per megawatt-hour from a high of $49.3 per megawatt-hour in November 2014.

The Electric Reliability Council of Texas (ERCOT) announced in September that it expected to have a record-breaking winter, hitting 61,000MW of power demand. But supply would easily be able to meet that demand. "Nearly 86,000MW of total generation resource capacity is expected to be available for peak demand," ERCOT wrote. The council added that approximately 3,000MW of new generation capacity had been added between May and September 2017, including "two gas-fired combined-cycle units totaling 2,200MW."

Utility Dive also notes that 4GW of wind power is expected to come online in Texas in the coming years. That would mean installed wind capacity would exceed installed coal capacity in Texas if all coal retirements and all wind installations move forward as planned.

Mixed forecasts for coal

There's reason to think that this trend may continue. A new report (PDF) from the Union of Concerned Scientists (UCS), which advocates for environmental protection, puts the closure of coal plants into some context. According to the union, these closures aren't particularly novel. The report found that between 2008 and 2016, coal went from supplying 51 percent of the US’ power supply to just 31 percent of the mix.

Even now, with coal supplying one-third of the US’ power, UCS estimated more than 20 percent of existing coal power plants are “uneconomic” in today’s electricity market. They may face retirement before 2030. (That’s not including the 18 percent of the country’s existing coal capacity that is already announced for retirement or conversion to natural gas.)

A polluting neighbor Coal is the biggest source of carbon dioxide (CO 2 ) pollution in the US’ energy sector, and coal-burning plants, especially older ones, release particulates that are detrimental to health as well. Living near coal plants has been linked to Coal is the biggest source of carbon dioxide (CO) pollution in the US’ energy sector, and coal-burning plants, especially older ones, release particulates that are detrimental to health as well. Living near coal plants has been linked to lower birth weights as well as heightened incidences of cancer, heart disease, and respiratory disease . UCS’ report also estimated that, in 2008, 8.5 million people lived within 3 miles of a coal plant, but, by the end of 2016, only 3.3 million people did. Once all the announced coal retirements go into effect, that number is expected to drop to 1.9 million.

More coal plants may join the “uneconomic” group soon, too. The UCS wrote in its report that it found “a significant number of currently operating coal units that are just marginally economic, meaning that even a slight increase in costs would make them uncompetitive compared to alternatives.” That is, if the price of natural gas declines further or wind and solar continue to expand, those marginally economic plants will be threatened with closure. Additionally, if anything increases the cost of delivered coal, or if older coal plants start requiring more maintenance, that could threaten those plants, too.

The analysis assumes that demand for electricity won’t increase and that the government won’t increase subsidies to coal and cut subsidies for renewable energy. The Trump administration’s proposed rule to compensate power-generating plants for having 90 days' worth of fuel stored onsite would certainly help out those marginally economic coal plants. The Energy Information Administration (EIA) also predicts that US energy demand will rise in 2018 due to increased heating and cooling needs in the year to come. The EIA also predicts that coal will hold its 30-percent share of generation capacity through 2018 as natural gas demand increases, driving up the price for that fuel.

Still, barring a dramatic government bailout or some unforeseen shock in electricity markets, coal’s comeback doesn't seem like it’s on the horizon. The UCS naturally recommends that communities actively plan for retirements rather than try to stanch the bleeding. “Coal miners and coal-dependent communities need real action,” the organization says. “Attempts to roll back vital public health and environmental safeguards are not likely to change market factors driving out coal.”

But despite the economic implications of closures, eliminating coal plants will no doubt offer environmental benefits. The UCS wrote that as older, less-efficient coal plants started being retired in 2008, it “led to an 80-percent reduction in SO 2 emissions and a 64-percent reduction in NO X emissions, as well as a 34-percent reduction in global-warming carbon dioxide (CO 2 ) emissions.”

Update: This article was amended to reflect that ERCOT is exempt from FERC rules.