EIA details pollution controls installed in response to mercury rule

The U.S. Energy Information Administration (EIA) recently released preliminary data from its annual survey of electric generators, detailing the capacity of coal-fired power plants with installed pollution control equipment due to the U.S. Environmental Protection Agency's Mercury and Air Toxics Standards, or MATS, rule.

MATS established emissions limits for hazardous air pollutants associated with coal combustion such as mercury, arsenic, and heavy metals. It required all coal fired power plants that sell power and have capacity greater than 25 megawatts to comply with specific emission limits by April 2015, although some units received extensions, EIA noted in a July 7 "Today in Energy" report.

EIA, which is part of the Department of Energy, said that coal-fired generating capacity in the U.S. dropped from 299 gigawatts at the end of 2014 to 276 GW as of April 2016. Coal-fired generation's share of total electricity generation fell from 39% in 2014 to 28% in the first four months of 2016.

"These changes can be attributed to a mix of competitive pressure from low natural gas prices and the costs and technical challenges of environmental compliance measures," the agency said.

87 GW of coal plants installed pollution control equipment

Between January 2015 and April 2016, about 87 GW of coal-fired plants installed pollution control equipment and nearly 20 GW of coal capacity retired. Twenty-six percent of those retirements occurred in April 2015, the MATS rule's initial compliance date, EIA said.

Some power plants began installing controls prior to this timeframe. The final MATS rule became effective in 2012.

Most remaining coal plants applied for and received a one-year extensions that allowed them to operate until April 2016 while developing compliance strategies, EIA said. "If a coal unit did not meet MATS requirements by then, it had to either retire, switch to another fuel, or cease operation, the federal agency noted.

A few plants, totaling 2.3 GW, received additional one-year extensions, giving them until April 2017 to comply. The additional fifth year was to allow coal plants to operate due to reliability concerns. About 5.6 GW of coal capacity fuel switched primarily to natural gas.

Of the 87 GW of coal capacity that installed pollution control equipment to comply with MATS, activated carbon injection was the dominant compliance strategy. More than 73 GW of coal-fired capacity installed activated carbon injection systems in 2015 and 2016,
effectively doubling the amount of coal capacity with activated carbon injection.

Other compliance strategies include the optimization of existing emissions control equipment, the addition of new equipment or capabilities, or some combination of operational changes and new investments to improve mercury capture or to achieve other environmental control objectives, such as reducing emissions of particulate matter, nitrogen oxide and sulfur dioxide. Many generators have opted for a multipollutant approach to mercury control by installing more than one type of equipment. Overall, plant owners have invested at least $6.1 billion from 2014 to 2016 to comply with MATS or other environmental regulations.

EIA said that although its data is preliminary, 98% of coal capacity status is reported to EIA on a monthly basis, meaning the uncertainty associated with the values presented in the July 7 report is relatively small.

Full-year 2016 information will be reported to EIA in 2017 and made available later that year.

EPA issued finding tied to MATS in April

In April, the EPA issued a final finding that it is appropriate and necessary to set standards for emissions of air toxics from coal- and oil-fired power plants.

The finding responded to the U.S. Court of Appeals for the District of Columbia Circuit's remand of the MATS rule in wake of the Supreme Court's decision in Michigan v. EPA. In the Michigan case, the court held that EPA "must consider cost —including, most importantly, cost of compliance before deciding whether regulations is appropriate and necessary."

Fifteen states lead by Michigan have filed suit challenging EPA's April 25, 2016 "Supplemental Finding that it is Appropriate and Necessary to Regulate Hazardous Air Pollutants from Coal- and Oil-Fired Electric Utility Steam Generating Units.