The coal-fired power industry again took a big hit last year, with total generation falling 6% by one group’s count.
But the industry’s emissions of two dangerous pollutants didn’t uniformly follow suit.
While there were fewer operating coal-fired power plants, they often spewed more sulfur dioxide and nitrogen oxides, according to recently released EPA data. Even as overall emissions of those pollutants fell across the country, releases from some large plants soared.
Nine of the top 10 emitters of sulfur dioxide (SO2) increased discharges last year, in several cases by double-digit percentages, the numbers show.
Topping the list: Martin Lake, a 2,250-megawatt facility in East Texas owned by Luminant Generation Co. Last year, the plant belched almost 56,200 tons of SO2, up 54% from 2017.
Other major polluters were the Gerald Gentleman Station in Nebraska, owned by the Nebraska Public Power District, and Entergy Corp.’s Independence facility in Arkansas. The Gentleman plant’s SO2 emissions jumped 31%; they rose 24% at the Independence facility.
Releases of nitrogen oxides (NOx) also increased at the Martin Lake and Gentleman plants, albeit by smaller margins. They dropped at the Independence facility.
With the Trump administration’s backing, all three power generators had previously skirted Obama-era attempts to require additional pollution controls on those plants.
In email exchanges this week, an EPA spokeswoman and representatives for the three providers attributed the added pollution primarily to increased electricity production.
The Gerald Gentleman plant, part of a regional power pool, "is one of the lowest-cost generating stations in the country and was called upon more frequently by the market in 2018 to generate, resulting in higher emissions," NPPD spokesman Mark Becker said.
While total SO2 releases at the Independence plant rose last year, its average annual emissions rate decreased, thanks to the use of low-sulfur coal, said Kerri Case, a spokeswoman for Entergy’s Arkansas operations. The company’s White Bluff facility, also located in Arkansas, was the only plant in the top 10 where overall SO2 releases dropped last year; NOx emissions fell at both plants as Entergy installed new controls, Case said.
At Luminant, a branch of Vistra Energy Corp., spokeswoman Meranda Cohn said the Martin Lake plant complies with all of its permits. SO2 emissions should decline significantly in the next few years as the company shifts from locally mined lignite to low-sulfur coal from Wyoming’s Powder River Basin as a fuel source, she said.
But since mid-2017, the opposite appears to have happened, said Dan Cohan, an associate professor of environmental engineering at Rice University. Luminant’s Martin Lake plant’s SO2 emissions rate shot up and has remained high, according to the EPA numbers, quietly posted on an agency website earlier this month.
SO2 contributes to atmospheric haze and acid rain; it can also help form fine particulates that are linked to a variety of heart and lung ailments, including a higher risk of premature death in some circumstances.
The spike is "very troubling," Cohan said.
Luminant’s Cohn didn’t respond to follow-up queries asking for the respective amounts of lignite and Powder River Basin coal burned in 2017 and 2018 at the Martin Lake plant. She also did not say when Luminant plans to complete the transition to Wyoming coal.
Rewriting an EPA success story
Under the Clean Air Act, SO2 and NOx are among a half-dozen pollutants for which EPA is required to set federal air standards. NOx, which can cause respiratory problems, is also one of the main ingredients in smog-forming ozone.
The coal-fired electricity sector has traditionally been a prime source of both pollutants.
The dramatic emission reductions that have occurred in recent decades are widely seen as an environmental success story. Since 1990, power sector releases of SO2 plunged from more than 15 million tons a year to 1.26 million tons last year. During the same time, NOx releases fell from 6.4 million tons to 1.03 million tons, according to EPA data.
Earlier this week, EPA Administrator Andrew Wheeler hailed the news that all six New England states now meet the 75 parts per billion hourly SO2 standard. That development "means cleaner air, improved health outcomes and greater economic opportunity," Wheeler said in a news release. It came after New Hampshire power plants installed new pollution controls, allowing central New Hampshire to be reclassified to attainment with the 75 ppb limit.
But in recent years, reductions in power industry pollution have also been driven by the continuing decline in coal-fired power production as utilities switch to cleaner-burning natural gas and renewable fuel sources.
Last year, an estimated 15.5 gigawatts of coal-fired generation dropped off the grid, according to the Institute for Energy Economics and Financial Analysis, a nonprofit research firm that supports the shift to renewables. That drop represented 6% of the roughly 257 GW in operation at the end of 2017, Seth Feaster, a data analyst with the firm, said in an email. Early last year, Luminant alone retired three plants accounting for more than 4 GW of coal-fueled electricity production, according to the company.
Nationally, total industry releases of SO2 dropped by about 6% last year from the 2017 total of 1.34 million tons, according to EPA. NOx emissions dipped almost 4% in comparison with the 2017 figure of 1.07 million tons.
But under President Trump, EPA has been loath to take any steps that would further imperil coal’s use as a fuel source. That attitude has been strikingly evident in the agency’s handling of its regional haze program, which aims to improve visibility in national parks and wilderness areas.
Under the Obama administration, EPA — sometimes forced to act by lawsuits brought by environmental groups — used haze reduction requirements to prod utilities into retooling older power plants with SO2 scrubbers and other pollution controls.
Under Trump, agency officials have repeatedly about-faced.
Days before President Obama left office in January 2017, for example, EPA released a proposed rule that would have required scrubbers on the Gerald Gentleman plant in Nebraska. That proposal was never published in the Federal Register and there is no sign that EPA has since pursued it.
Similarly, the Trump administration sided with Entergy and Arkansas regulators in rolling back another Obama-era plan that would have mandated scrubbers for the White Bluff and Independence plants (Greenwire, April 6, 2018).
While both facilities would cease coal-fired generation within the next decade or so under a proposed lawsuit settlement with environmental groups, that tentative deal would require Entergy to take only limited steps to reduce SO2 emissions in the meantime (Greenwire, Aug. 30).
In place of firm pollution control requirements for Martin Lake and other Texas plants tied to another Obama-era haze program, EPA now wants to substitute an in-state SO2 emissions trading program that critics say would do nothing to reduce actual releases (Greenwire, Aug. 24, 2018).
In 2016, moreover, EPA had declared parts of two counties around the Martin Lake site in nonattainment with the agency’s 75 ppb sulfur dioxide standard. In a proposed rule issued last month, agency officials branded that decision a mistake and said the area should instead be deemed "unclassifiable," a step that would take the onus off Texas regulators to come up with a cleanup plan for the plant.
In comments filed on the proposal Tuesday, the Environmental Protection Network, comprising mainly former EPA employees opposed to Trump administration policies, called the agency’s approach "improper." The group’s members include Janet McCabe, who was acting air chief in 2016.
"If finalized," McCabe said in a statement, "this action would put residents of the areas of Texas where the power plant continues to operate at risk for continued exposure to significant amounts of pollution."