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Controlling Power Plant Emissions: Overview
Information for...
Controlling Power Plant Emissions
On March 15, 2005, EPA issued the Clean Air Mercury Rule to permanently cap and reduce mercury emissions from coal-fired power plants for the first time ever. This rule, combined with EPA’s Clean Air Interstate Rule (CAIR), will significantly reduce emissions from the nation’s largest remaining source of human-caused mercury emissions.
Important progress on this issue began years ago. These pages cover this history; the proposed regulations to reduce mercury emissions in the power sector; the extensive comments received on these proposals; the process EPA pursued to best understand how to finalize these regulations, and information about existing and emerging technologies to reduce mercury emissions from power plants.
Together, the Clean Air Mercury Rule proposal and CAIR create a multi-pollutant strategy to improve air quality throughout the U.S. The landmark Clean Air Interstate Rule focuses on 28 eastern states having sulfur dioxide (SO 2) and nitrogen oxides (NOx) emissions that contribute significantly to fine particle and ozone pollution problems in downwind states.
President Bush’s Clear Skies legislation would establish a mandatory program to reduce and cap emissions of mercury, as well as emissions of sulfur dioxide (SO 2) and nitrogen oxides (NOx) from electric power generation to approximately 70% below 2000 emission levels. Clear Skies was first submitted as proposed legislation in the US House of Representatives on July 26, 2002 and in the US Senate on July 28, 2002. The legislation was reintroduced in both Houses of Congress as the Clear Skies Act of 2003 on February 27, 2003, and in the Senate as the Clear Skies Act of 2005 on January 24, 2005. EPA continues to believe this legislative approach is the preferred option to achieve these important reductions; however, since the Congress has yet to act, the Agency issued CAIR and the Clean Air Mercury Rule to provide communities with tools to solve the problem of pollution transported from other states.
Chronology of Actions to Date
Since the Clean Air Act was amended in 1990, EPA has researched mercury, including
how best to require reductions from power plants. This page provides a detailed
chronology of events that led up to the proposal in January 2004, EPA's issuance
of the final Clean Air Mercury Rule in March 2005, and of the reconsideration process that ended in May 2006.
Guiding Principles
Reducing mercury from power plants must be done right. The Agency took into account
relevant information about emissions, control technologies, health effects, and
the impacts on our electrical system and economic competitiveness. Given the
complexity surrounding all of these factors, EPA identified five principles for
providing context for additional inquiry and focus entering the decision phase
of the rulemaking. This page describes these principles and areas of additional
inquiry.
Applying Technology
Approximately 75 tons of mercury are found in the coal delivered to power
plants each year and about two thirds of this mercury is emitted to the air,
resulting in about 50 tons being emitted annually. This 25-ton reduction is
achieved in the power plant boilers and through existing pollution controls
such as fabric filters (for particulate matter), scrubbers (for SO 2) and SCRs
(for NOx). As more scrubbers and SCRs are installed to comply with the Clean
Air Interstate Rule and other regulations, mercury emissions are expected to
decrease. This multipollutant approach is central to the Agency's plan to reduce
mercury from power plants.
In addition to relying on existing technologies, several mercury-specific control technologies are in various stages of development, testing, and demonstration. Currently none of these technologies are in commercial operation on power plants in the U.S. but EPA expects these technologies to play a role as EPA and states require reductions in mercury emissions.
This page provides more information on technologies to reduce mercury from power plants.
Global Context
This page provides information about sources of mercury emissions
throughout the world, the global distribution of emissions, and how
U.S. mercury emissions fit into the global picture.
Public Comments
EPA received a record number of comments on its proposed mercury rule. This page
provides a summary of the comment process and information for people interested
in reviewing comments.
Where to find more information
Summary of the proposed Utility Mercury Reductions Rule - as well as a summary of the design of the program and the benefits it would provide.
Regulatory Actions - Links to proposed and final rules, fact sheets, and other rulemaking documents.
Technical Information - Technical support information and links to related information.