Mercury Emission Standards for Power Plants

Most Recent Action

On April 15, the U.S. Court of Appeals for the D.C. Circuit upheld the Environmental Protection Agency’s (EPA) regulation of mercury and air toxics from coal- and oil-fired power plants (commonly referred to as MATS). This article provides background information about the rule and D.C. Circuit Court’s decision.

The EPA has released a proposal to revise the Mercury and Air Toxics Standards rule (also known as the MATS or Utility MACT) for new coal and oil plants. The proposal does not change the final emission limits for existing power plants.

The EPA is delaying implementation of the Mercury and Air Toxics Standards (MATS also known as Utility MACT) for new power plants based on new information provided by industry stakeholders after the rule was finalized. This reconsideration does not cover the standards set for existing power plants.

The EPA’s stated goal for this reconsideration is providing greater certainty for five planned future facilities, in Georgia, Kansas, Texas, and Utah, that would be covered by the standards. The EPA will review new information related to monitoring issues at new power plants and will address other technical issues on the acid gas and particle pollution standards for these plants. The agency’s review will not change the types of state-of-the-art pollution controls new power plants are expected to use to reduce this harmful pollution.

The agency will complete the rulemaking by March 2013, and in the meantime will stay the final standards for new power plants for three months.

Background

The 1990 Clean Air Act (CAA) Amendments authorized the EPA to issue standards to reduce toxic air emissions from many sources, and to study whether to do so for power plants. On December 20, 2000, the EPA made the determination that it was appropriate and necessary to regulate coal- and oil-fired electric generating units (EGUs) under CAA section 112, and added such units to the CAA section 112(c) list of sources that must be regulated.

On January 30, 2004, the EPA proposed section 112 standards for mercury (Hg) emissions from coal-fired EGUs and nickel (Ni) emissions from oil-fired EGUs, and, in the alternative, proposed to remove EGUs from the 112 list based on a finding that it was neither appropriate nor necessary to regulate EGUs under this section of the CAA.

On March 29, 2005, the EPA issued a final revision of the appropriate and necessary finding for coal- and oil-fired EGUs and removed such units from the 112 list. The EPA never finalized the proposed section 112 standards for Hg and Ni. The removal of EGUs from the 112 list was challenged in court, and on February 8, 2008, the D.C. Circuit Court, in State of New Jersey v. EPA, determined that the EPA violated the CAA by removing EGUs from the 112 list. As a result of the ruling, EGUs remain a CAA section 112(c) listed source category. In accordance with a consent decree stemming from another court action, the EPA Administrator was required to sign a final section 112 rule by November 16, 2011.

The EPA finalized the court-ordered Mercury and Air Toxics Standards (MATS) for power plants in February 2012.

It is the intention of the EPA that this rule force companies to make a decision between controlling emissions or retiring older EGUs and shifting to more modern methods of generation. This rule is part of a group of rules known as the EPA’s Regulatory Train Wreck.

Authority

This proposed rule is developed under the authority of section 112 of the Clean Air Act (CAA).

Standards

The final MATS rule regulates units at both major and area sources. The mercury and air toxics standards will affect Electric Generating Units (EGUs) that burn coal or oil for the purpose of generating electricity for sale and distribution through the national electric grid to the public. These include investor-owned units as well as units owned by the Federal government, municipalities, and cooperatives that provide electricity for commercial, industrial, and residential uses.

The final rule identifies two subcategories of coal-fired EGUs, four subcategories of oil-fired EGUs, and a subcategory for units that combust gasified coal or solid oil (integrated gasification combined cycle (IGCC) units) based on the design, utilization, and/or location of the various types of boilers at different power plants. The rule includes emission standards and/or other requirements for each subcategory.

The EPA also signed revisions to the new source performance standards (NSPS) for fossil-fuel-fired EGUs. This NSPS revises the standards that new coal- and oil-fired power plants must meet for particulate matter (PM), sulfur dioxide (SO2), and nitrogen oxides (NOx).

The NSPS will affect boilers that burn fuels, including coal, oil, or natural gas to produce steam to produce electricity or provide heat. This includes boilers used at industrial facilities (e.g., refineries, chemical and manufacturing plants, and paper mills), commercial establishments (e.g., stores/malls, laundries, apartments, restaurants, hotels/motels), and institutional facilities (e.g., medical centers, educational and religious facilities, and municipal buildings).
It is the intention of the EPA that this proposed rule force companies to make a decision between controlling emissions or retiring older EGUs and shifting to more modern methods of generation.

Requirements

For all existing and new coal-fired EGUs, the rule establishes numerical emission limits for mercury, PM (a surrogate for toxic non-mercury metals), and HCl (a surrogate for all toxic acid gases).
For existing and new oil-fired EGUs, the standards establish numerical emission limits for PM (a surrogate for all toxic metals), HCl, and HF. EGUs may also show compliance with the HCl and HF limits by limiting the moisture content of their oil.
The rule establishes alternative numeric emission standards, including SO2 (as an alternate to HCl), individual non-mercury metal air toxics (as an alternate to PM), and total non-mercury metal air toxics (as an alternate to PM) for certain subcategories of power plants.
The standards set work practices, instead of numerical limits, to limit emissions of organic air toxics, including dioxin/furan, from existing and new coal- and oil-fired power plants. Because dioxins and furans form as a result of inefficient combustion, the work practice standards require an annual performance test program for each unit that includes inspection, adjustment, and/or maintenance and repairs to ensure optimal combustion.
The standards also set work practices for limited-use oil-fired EGUs in the continental U.S.
A range of widely available and economically feasible technologies, practices and compliance strategies are available to power plants to meet the emission limits, including wet and dry scrubbers, dry sorbent injection systems, activated carbon injection systems, and fabric filters.
The revisions to the NSPS for fossil-fuel-fired EGUS include revised numerical emission limits for PM, SO2, and NOX.

The EPA estimates that there are approximately 1,400 units affected by this action. Approximately 1,100 existing coal-fired units and 300 oil fired units at about 600 power plants. The EPA expects that dozens of coal-fired plants already meet at least some part of the proposed standards, however, about 44 percent of all coal-fired plants lack advanced pollution control equipment.

Existing sources generally will have up to 4 years if they need it to comply with the rule. This includes the 3 years provided to all sources by the Clean Air Act. The EPA’s analysis continues to demonstrate that this will be sufficient time for most, if not all, sources to comply. Under the Clean Air Act, state permitting authorities can also grant an additional year as needed for technology installation. The EPA expects this option to be broadly available.

Reconsideration

The EPA is delaying implementation of the Mercury and Air Toxics Standards (MATS also known as Utility MACT) for new power plants based on new information provided by industry stakeholders after the rule was finalized. This reconsiderationdoes not cover the standards set for existing power plants.

The agency will complete the rulemaking by March 2013, and in the meantime will stay the final standards for new power plants for three months.

Revision

Additional Information

The EPA’s Regulatory Website for Power Plants

The EPA’s MATS Website

The EPA is delaying implementation of the Mercury and Air Toxics Standards (MATS also known as Utility MACT) for new power plants based on new information provided by industry stakeholders after the rule was finalized. This reconsiderationdoes not cover the standards set for existing power plants.

Final Rule (PDF), February 16, 2012

GLLF Summary of Public Reaction to the Final Rule, December 22, 2011

Presidential Memorandum – Flexible Implementation of the Mercury and Air Toxics Standards Rule, December 21, 2011

Fact Sheet Overview (PDF)

Fact Sheet: Summary of the Rule (PDF)

Fact Sheet: Clean Air and Reliable Electricity (PDF)

Fact Sheet: Benefits and Costs of Cleaning up Toxic Air Pollutants (PDF)

Fact Sheet: Adjustments from Proposal to Final (PDF)

Regulatory Impact Analysis

Integrated Planning Model (IPM) Analysis

Mercury Risk Assessment (PDF)

Emissions Overview Memorandum (PDF)