North Carolina Division of Air Quality - Mercury Regulations, Emissions, and

Deposition Modeling in North Carolina

Presented for

6th Annual Unifour Air Quality Conference Hickory, NC

June 15, 2012

By Steve Schliesser

Division of Air Quality (DAQ)

Environmental Engineer

BRUNSWICK

NEW HANOVER

COLUMBUS

PENDERBLADEN

RO BESON

SCOTLAND

DUPLINANSON

HO KERICHMONDSAMPSONUNION

CLAY JONESPAMLICO

CHEROKEE MACONTRANSYLVANIA

CLEVELANDLENOIRLENOIRMECKLENBU RG

CRAVENGASTON

JACKSON MOOREPOLK STANLY

GRAHAM HARNETTHENDERSONRUTHERFORD

GREENELEELINCOLN

PITT

SWAIN

HAYWOODHYDEJOHNSTON

WAYNE

BEAUFORTBUNCOMBE

CATAWBACHATHAM

MCDOWELLRANDOLPH

ROWAN

BURKEDARE

MARTIN WASHINGTON

WILSON

DAVIDSON TYRRELLWAKE

DAVIE EDGECOMBEMADISON YANCEY

ALEXA NDERCALDWELL

GUILFORD BERTIENASH

AVERY FORSYTHFRANKLIN

ORANGE

WATAUGAWILKES

YADKIN

HALIFAXHERTFORD

SURRY WARRENASHE

CASWELLGATESPERSONROCKINGHAMSTOKES

VANCE

ALLEGHANYNORTHAMPTON

DURHAM

Topics Covered

2002 NC Clean Smokestack Act

2012 EPA Electric Generating Unit (EGU) Rules

Statewide mercury emissions from 2002-2025

Principal mercury emission sources

Mercury deposition modeling results

Why Interest for Mercury in North Carolina back in 2002?

Mercury in fish tissue prompted NC fish advisories

Coal-fired power plants released 3,200 pounds of mercury for 2/3 of NC emissions

Limited data available on speciated mercury emissions

Mercury emission control varied from 0-90+% for U.S. power plants, questions as to why

Little known about relationship among emissions, deposition, and fish tissue level for mercury.

2002 North Carolina Clean Smokestack Act (CSA)

Officially Air Quality/Electric Utilities Act (SB 1078)

Require coal-fired power plant reductions of 73% for sulfur dioxide (SO2) & 77% nitrogen oxides (NOx)

SO2 and NOx controls also reduce mercury emissions

Requires DAQ to evaluate mercury emission control and recommend any development of standards and plans

Utilities Response to Clean Smokestack Act

From 2005-2010 NC utilities spent $2.9 billion installing:

- Selective catalytic reduction (SCR) or Selective non-catalytic reduction (SNCR) units for NOx control

- Flue gas desulfurization (FGD) scrubbers for SO2 control SCR/SNCRs reduce NOx by 80% and condition mercury

emissions to be more collectable FGDs collect 99% of SO2 emissions, and SCR/SNCR-ESP-FGD combination collect 90+%

mercury

EPA Electrical Generating Units (EGU) Mercury and Air Toxics Standards Rule

Maximum Achievable Control Technology Rule

(40 CFR part 63 subpart UUUUU)

aka EGU MATS (Mercury and Air Toxics Standards)

Compliance by April 2015 with 1-year extension option

Numerical emission limits Mercury Particulate matter / toxic metals Acid gases (SO2 or Hydrogen chloride)

NC Coal-Fired Utility Boilers EGU Pre-MATS 2010 Status

For 13 gigawatts (GW) of NC EGU capacity:

7 facilities with 10 GW capacity and 19 largest boilers

- Most well-positioned to meet EGU MATS standards

- All will continue to operate

7 facilities with 3 GW capacity and 26 smallest boilers

- None can meet any EGU MATS standards

- All retired by 2015

Pollutant NOx

PM/ Metals

HCl/ SO2

Mercury PM HCl SO2 Hg

  Emission Controls lb/MMBtu lb/TBtu

EGU MATS limits 0.03 0.002 0.2 1.2 Average of 19 largest boilers - CSA controls

SCR/ SNCR

ESP FGD All 3 0.03 0.001 0.19 0.8

Average of 26 smallest units – few/no CSA controls

No SCR/ SNCR

ESPNo

FGDESP 0.15 0.24 1.5 5.0

Emission Ratio smallest/largest  5 150 8 7

NC Coal-Fired EGU Pre-MATS 2010 Emission Performance

North Carolina Mercury Emissions from 2002-2025

2002 2005 2010 2015 2018 2023 20250

500

1,000

1,500

2,000

2,500

3,000

3,500

Reported to DAQ Projections by Utility Companies

Mercury Emissions,

lb/yr

EGU emission reductions from 2002:>70% by 2010

> 80% by 2025

EPA Airborne Mercury Deposition Modeling

EPA performed deposition modeling for EGU MATS

Used Community Multi-scale Air Quality (CMAQ) Model

Modeled with 3 scenarios:

1. Base year with 2005 emissions (Pre-rule)

2. Projected 2016 emission data (Post-rule)

3. Projected 2016 emissions without U.S. EGU emissions

EPA Modeling Observations for U.S. Nationwide Deposition

Patterns of total and US EGU-related mercury deposition differ considerably: Elevated deposition areas distributed, several in east close to EGUs.

US deposition dominated by sources other than EGUs;

-EGUs contribute 5% deposition for 2005, 2% for 2016.

In 2005, US EGUs contributed 5% deposition in US,

but up to 30% for certain watersheds.

DAQ Deposition Modeling Results for NC Scenarios

2005 with EGUs 2016 with EGUs 2016 without EGUs

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

Mercury Deposited in NC Mercury Emitted from NC sources

Mercury, lb/yr

Summary of Mercury Deposition Modeling

EPA modeling suggests deposition in NC should decrease by 10% between 2005 and 2016.

DAQ modeling indicates 16% of NC deposition comes from NC sources in 2005, down to 3% by 2016.

70% of mercury deposition in NC originates from outside the central and eastern United States.

Questions?

Steve SchliesserNC DAQ Environmental Engineer

919-707-8701 Steve.Schliesser@ncdenr.gov http://www.ncair.org

DAQ Clean Smokestack Act website: http://daq.state.nc.us/news/leg/

EPA EGU MATS website: http://www.epa.gov/airquality/powerplanttoxics/index.html