Power Generation, Transmission, and Use

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Maryland Power Plants and the Environment (CEIR-18)

4.1.4 Recent and Developing National Air Regulatory Drivers Affecting Power Plants 

Since power plants are a major source of air emissions, both federal and state policies and regulations continue to target power plants for additional pollutant control. These regulations not only address criteria pollutants and HAPs, but also GHGs and climate change. Recently, the federal Clean Power Plan (CPP) has established limitations on CO2 for both existing and new power plants. The CPP is summarized in detail in Section 5.2.3 of this CEIR. Other recent key regulations are addressed in this section.

Recent Maryland NOx Regulation

In April 2015, MDE petitioned the Administrative, Executive, and Legislative Review (AELR) Committee of the Maryland General Assembly requesting “emergency status” to reduce NOx emissions during the 2015 summertime ozone season. This emergency action was approved May 1, 2015 and was projected to reduce NOx emission by 10 tons on the worst “ozone days” each summer. Emergency regulations were effective for 180 days (in this case through October 28, 2015); therefore, a permanent rule was adopted in August 2015. On December 10, 2015, a final version of the emergency action was promulgated; the rule establishes NOx emission requirements beyond 2015 that will reduce ozone formation in the summer.

Utility Mercury and Air Toxics Standard (MATS)

On December 21, 2011, EPA promulgated a Maximum Achievable Control Technology (MACT) standard referred to as the Mercury and Air Toxics Standard, or the “Utility MATS.” MATS is intended to reduce emissions of HAPs from power plants. The rule established emission standards for new and existing fossil-fueled electric utility steam generating units with generating capacities greater than 25 MW. The rule is intended to reduce emissions of heavy metals (mercury, arsenic, chromium, nickel), acid gases (hydrogen chloride (HCl) and hydrogen fluoride (HF)), and organic HAPs (formaldehyde, benzene, and acetaldehyde) from coal- and oil-fired power plants. Subsequent to promulgation of the Utility MATS, in a 5–4 decision announced on June 29, 2015, the U.S. Supreme Court overturned MATS, ruling that the EPA did not properly consider the costs of emissions reductions in crafting the regulations; the Court did not take issue with the standard itself. On November 20, 2015, the EPA proposed a supplemental finding that included a consideration of the costs and benefits of the rule, concluding that taking “cost of control” into account does not change its previous determination that MATS is “appropriate and necessary” to regulate HAP emissions from coal- and oil- fired generating units. In December 2015, the Court of Appeals for the DC Circuit issued a ruling that allows EPA to enforce MATS while EPA addresses the issues raised by the U.S. Supreme Court in its June 2015 decision.  EPA’s final supplemental finding was published in the Federal Register on April 25, 2016.  At this time, MATS remains in place, and the EPA’s final supplemental finding completes its response to the U.S. Supreme Court; however, further litigation is expected.

For new and existing coal-fired generating units, the Utility MATS establishes numerical emission limits for mercury, PM (as a surrogate for toxic non-mercury metals), and HCl or SO2 (as surrogates for toxic acid gases). For new and existing oil-fired generating units, the rule establishes numerical emission limits for PM (surrogate for all toxic metals), HCl, and HF. Existing sources were required to meet emission limitations and implement work practice standards by April 16, 2015, but about 200 plants were granted extensions to install pollution control equipment; new affected sources are subject to the standards at start-up.

For affected power plant sources in Maryland, it is possible that add-on pollution control systems, such as wet FGD systems installed for HAA compliance, may be sufficient for compliance with the Utility MATS mercury and organic and metal HAPs standards. Both H.A. Wagner and C.P. Crane installed dry sorbent injection (DSI) systems in 2015 to meet the HCl emission limit.