Mercury and Air Toxics Standard for
Power Plants
Marney Hoefer
January 26, 2012
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Overview
 Background on mercury air toxics rule
 Overview of the new standards to regulate
mercury and air toxics for power plants
 Compliance dates and flexibility
 How the final rule differs from the proposed rule
 Interaction with Wisconsin’s Mercury Rule (ch.
NR 446)
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How did we get here?
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December 2000: EPA made a determination that it was appropriate and
necessary to regulate EGUs under s. 112 of the CAA
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January 2004: EPA proposed section 112 standards for mercury emissions from
coal-fired EGUs and nickel emissions from oil-fired EGUs. Also proposed in the
alternative to remove EGUs from the section 112 list and regulate under section
111.
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March 2005: EPA issued a final revision of the appropriate and necessary finding
for coal and oil-fired EGUs and removed such units from s. 112 list. EPA never
finalized s. 112 standards for mercury or nickel but did finalize the regulation
under s. 111 to reduce mercury emissions from coal-fired EGUs (Clean Air
Mercury Rule).
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February 2008: The D.C. Circuit vacated both the 2005 action to remove EGUs
from the s. 112 list and the section 111 rule to limit mercury emissions. As a
result, EGUs remain a s. 112 listed source category.

March 2011: EPA proposed section 112 air toxics standards for all coal- and oilfired EGUs that reflect the application of maximum achievable control technology
(MACT).
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December 2011: EPA makes a finding that it is appropriate and necessary to
regulate EGUs and finalized section 112 air toxic standards for coal and oil-fired
EGUs
Federal Rule -- applicability
 Applies to EGUs larger than 25 MW that burn
coal or oil for the purpose of generating electricity
for sale and distribution through the national
electric grid to the public
 Includes investor-owned units, as well as units
owned by the Federal government, municipalities
and cooperatives that provide electricity for
commercial, industrial and residential uses.
 In Wisconsin, applies to approximately 15
sources (50 units)
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Wisconsin Sources
(as identified by EPA)
 Alma
 Pleasant Prairie
 Blount Street
 Pulliam
 Columbia
 Rock River
 Edgewater
 South Oak Creek
 Elm Road
 Valley
 Genoa
 Weston
 John P. Madgett
 Manitowoc
 Nelson Dewey
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Federal Rule Summary
 For all existing and new coal-fired EGUs, the rule
establishes numeric emission limits for
 Mercury (reducing emissions by approximately 90%)
 Particulate matter (as a surrogate for toxic non-mercury
metals)
 Hydrochloric acid (as a surrogate for all toxic acid gases)
 For existing and new oil-fired EGUs, the rule
established numeric emission limits for
 Particulate matter (as a surrogate for toxic metals)
 Hydrochloric acid
 Hydrofluoric acid
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Emission Limits – coal & solid fired
Subcategory
Filterable PM
Hydrogen
Chloride
Mercury
Existing coal fired
unit*
0.3 lb/MWh
0.02 lb/MWh
0.013 lb/GWh
Existing IGCC
0.4 lb/MWh
0.005 lb/MWh
0.03 lb/GWh
Existing solid oil
derived unit
0.09 lb/MWh
0.08 lb/MWh
0.002 lb/ GWh
New coal fired unit*
0.007 lb/MWh
0.0004 lb/MWh
0.0002 lb/ GWh
New IGCC
0.07 lb/ MWh** or
0.09 lb/MWh***
0.002 lb/ MWh
0.003 lb/ GWh
New solid oil derived
0.02 lb/ MWh
0.0004 lb/MWh
0.002 lb/GWh
* Limits are for units that do not burn low rank virgin coal.
** Limit is for duct burners on syngas.
*** Limit is for duct burners on natural gas.
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Alternative Numeric Emission
Standards
 The rule establishes alternative numeric emission
standards for:
 Sulfur Dioxide (as alternate to HCl)
 Individual non-mercury metal air toxics (as an
alternate to PM)
 Total non-mercury metal air toxics (as an alternate
to PM)
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Limits on Organic Air Toxics
 Instead of numeric limits, the standards set work
practices to limit emissions of organic air toxics,
including dioxin and furan, from existing and new
coal and oil-fired power plants.
 The work practice standards require an annual
performance test program for each unit including
an inspection, adjustment, and/or maintenance
and repairs to ensure optimal combustion.
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Averaging
 Averaging allowed only between individual existing
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units at a single stationary source
Would only be permitted between individual units in
the same subcategory in the Final EGU NESHAP
(i.e., coal-fired EGUs)
Would not be permitted between two or more different
affected sources
New affected sources would not be able to use
averaging
Required to submit an emission averaging plan
Existing sources subject to EGU NSPS would be
required to continue to meet the PM emission
standard of that NSPS regardless of whether or not
they are using emissions averaging
Start-up and Shut-down
 Rule sets work practice standards instead of
numeric emission limits during periods of start-up
and shut-down
 These standards require units to burn fuels such
as natural gas or distillate oil during start-up and
shut-down
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Compliance Options
 The EPA anticipates that the following
technologies, practices and compliance strategies
can be used to comply with the new standards:
 Wet and dry scrubbers
 Dry sorbent injection systems
 Activated carbon injection systems
 Fabric filters
 Extended compliance option from state and
enforcement discretion to help with
implementation timelines
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Compliance dates
 Without extensions, compliance with the new
standard will be required by approximately April
2015 (depending on when the rule is published)
 States given discretion to extend compliance date
by one year (likely to be broadly applied)
 Reliability critical unit determination (likely to be
narrowly applied)
 Enforcement discretion – Dec. 16, 2011 Giles
Memo
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Compliance Flexibility
 Facilities can use a longer averaging time for
mercury – 90 days instead of 30 days – but if they
choose this option, they will have to meet a
tighter standard (1.0 lbs/TBtu)
 State ability to grant an additional year as needed
for technology installation
 Pathway for reliability critical units to obtain a
schedule with up to an additional year to achieve
compliance
 Enforcement discretion
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How does the final standard differ from
the proposed standard?
 Using filterable PM as a surrogate for the metal
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toxics limit
Monitoring and reporting requirements
Provided an alternative compliance option for
sources that plan to comply by averaging across
multiple units
Revised definitions of coal subcategories
Added subcategories for non-continental oil-fired
units and limited use oil-fired units (use work
practice standards)
Filterable PM
 EPA had proposed an emission limit for total PM,
which includes both filterable PM and
condensable PM.
 The filterable PM limit was finalized instead of
condensable.
 The EPA determined that this was appropriate
because “most of the metallic air toxics consist of
filterable PM and the one that is not – selenium –
is well controlled by the limit on acid gases.”
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Monitoring and recordkeeping
 EPA adjusted several monitoring and
recordkeeping
 Final rule simplifies the procedures for
demonstrating continuous compliance to two
options: continuous monitoring or periodic
quarterly testing
 Rule clarified that sources are only required to do
testing for the form of the limit they choose to
meet
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Sustainability of MATS rule?
 Challenge of the appropriate and necessary finding which
based the finding on the benefits from the reduction of
particulate matter and that the benefits from reducing
mercury were not quantified in such a way to justify a
finding that regulation of mercury was necessary and
appropriate
 Sen. Inhofe has indicated that he will file a petition under
the Congressional Review Act to block the regulation
 Sen. Inhofe has also sought an Inspector General study
into the EPA’s scientific review procedure of its mercury
risk assessment
 Questions about whether EPA failed to properly consult
FERC on the impact of the rule on the energy supply
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Summary of Wisconsin Rule
 Required the state’s four major utilities (Alliant, Dairyland,
We Energies and Wis. Public Service Corporation) to
reduce their mercury emissions by 40 percent by 2010
 Requires large (150 MW and greater) coal-fired power
plants to reduce mercury using one of two approaches:
 Achieve a 90 percent reduction in mercury emissions by the
year 2015 (0.0080 lbs/GWh)
 Reduce multiple pollutants, including NOx and SO2 and
achieve 90 percent reduction in mercury emissions by 2021
 Requires small (>25 MW and < 150 MW) coal-fired power
plants to reduce their mercury emissions using best
available control technology
 Allows for averaging across system units
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Wisconsin Sources
 Majority of EGUs in Wisconsin have opted to comply
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with the 90% reduction by 2015, averaged across the
utility’s fleet
Many facilities have opted to have their small units
subject to the 90% reduction in order to be able to
average across their fleets
MG&E – Blount has converted to natural gas and
probably will not be subject to the rule
We Energies opted for the multi-pollutant option with
the 2021 compliance date for 90% reduction
Some utilities have already stated publicly that they
are set to comply with the limits
New Source Performance Standard
Revision
 In addition to the standards for mercury and air
toxics, the EPA revised the new source
performance standards for fossil-fuel-fired EGUs.
 These revisions include numeric emission limits
for PM, SO2 and NOx.
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Questions?
Marney Hoefer
[email protected]
608-259-2685
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