Presentation on theme: "North Carolina Division of Air Quality - Mercury Regulations, Emissions, and Deposition Modeling in North Carolina Presented for 6th Annual Unifour Air."— Presentation transcript:
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
Topics Covered 2002 NC Clean Smokestack Act 2012 EPA Electric Generating Unit (EGU) Rules Statewide mercury emissions from 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 (SO 2 ) & 77% nitrogen oxides (NO x ) SO 2 and NO x 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 NC utilities spent $2.9 billion installing: - Selective catalytic reduction (SCR) or Selective non- catalytic reduction (SNCR) units for NO x control - Flue gas desulfurization (FGD) scrubbers for SO 2 control SCR/SNCRs reduce NO x by 80% and condition mercury emissions to be more collectable FGDs collect 99% of SO 2 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
PollutantNOx PM/ Metals HCl/ SO 2 MercuryPMHCl SO 2 Hg Emission Controlslb/MMBtulb/TBtu EGU MATS limits Average of 19 largest boilers - CSA controls SCR/ SNCR ESPFGDAll Average of 26 smallest units – few/no CSA controls No SCR/ SNCR ESP No FGD ESP Emission Ratio smallest/largest NC Coal-Fired EGU Pre-MATS 2010 Emission Performance
North Carolina Mercury Emissions from
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 In 2005, US EGUs contributed 5% deposition in US, but up to 30% for certain watersheds.
DAQ Deposition Modeling Results for NC Scenarios
Summary of Mercury Deposition Modeling EPA modeling suggests deposition in NC should decrease by 10% between 2005 and DAQ modeling indicates 16% of NC deposition comes from NC sources in 2005, down to 3% by % of mercury deposition in NC originates from outside the central and eastern United States.