Maryland Department of the EnvironmentMichael Woodman/Tad AburnStakeholder Meeting # 3Draft Power Plant Regulations – February 12, 2014SO2 Regulatory SupportModelingWhat Emission Rates Are Needed to ComplyWith the 1-Hour SO2 Standard?Topics Covered•Background•Role of modeling in 1-hour SO2compliance•Modeling completed by Maryland•Modeling completed by Sierra Club•Summary of results•Emission rates from the modelingBackground•EPA guidance sets up aprocess that allows states toachieve early compliance withthe 1-hour SO2 standard–Can avoid being designated“nonattainment” altogether•Must use models to establishemission limits for sourcesthat guarantee that 1-hourstandard will not be exceeded•Not the usual process tocomply with federal standards–Appropriate because peak 1-hour SO2 levels are almostalways associated withindividual ... or closelylocated – stationary sourcesof SO2The Model•EPA has approved regulatorymodel that must be used toperform this kind of modeling•The model use severaldifferent types of data–Physical data from the source•Stack height, exit velocity, exittemperatures, etc.–Emissions data–Meteorological data–Topographical dataWho Has Modeled?•Maryland has performedmodeling for all of the Raven andNRG plants–Modeling for Warrior Run is inthe works–The Maryland modeling wascompleted by MDE and theDepartment of NaturalResources (DNR) PowerPlant Research Program(PPRP)•Sierra Club has performedmodeling for the Raven and NRGplants•Raven and NRG may also beperforming modeling to look atthis issueModel Set-Up•MDE/PPRP–AERMOD(v12345) Model–Raven Power:•BWI Met data (2008-2012)•Essex Background (2010-2012)–NRG Power•Met Data (2008-2012)–Washington National(Chalk Point & Morgantown)–Dulles(Dickerson)•Beltsville Background (2010-2012)•Sierra Club–Raven Power:•AERMOD (v11103) Model•BWI Met data (2006-2010)•No Background–NRG Power•AERMOD (v12345) Model•Met Data (2007-2011)–Washington National(Chalk Point)–Dulles(Dickerson)–Dulles (2008 – 2012)(Morgantown)•Beltsville Background (2009-2011)Modeling Raven Power•Three of the Raven plantsare located fairly close toeach other–Brandon Shores–Wagner–Crane•This requires that all three ofthe plants be modeledtogether to insure that thepotential concentrations inthat area are modeledaccuratelyCrane Modeling ResultsSierra Club“Stand Alone”MDE/PPRP“Stand Alone”MDE/PPRP“Cumulative”Unit #1Not Completed1,501 lbs/hr1,436 lbs/hrUnit #21,501 lbs/hr1,436 lbs/hrPlant Total(Units #1 & #2)3,482 lbs/hr3,002 lbs/hrModeledConcentration<196.2 ug/m3195.6 ug/m3Allowable Rates From the ModelingLimits in the Regulation1,400 lbs/hr foreach unitWagner Modeling ResultsSierra Club“Stand Alone”MDE/PPRP“Stand Alone”MDE/PPRP“Cumulative”Unit #2Not Completed987 lbs/hr493 lbs/hrUnit #32,023 lbs/hr1,011 lbs/hrPlant Total(Units #2 & #3)3,115 lbs/hr3,010 lbs/hrModeledConcentration<196.2 ug/m3194.6 ug/m3Allowable Rates From the ModelingLimits in the RegulationUnit #2 – 500 lbs/hrUnit #3 – 1,000 lbs/hrBrandon Shores Modeling ResultsSierra Club“Stand Alone”MDE/PPRP“Stand Alone”MDE/PPRP“Cumulative”Unit #1Not Completed1,797 lbs/hr1,026 lbs/hrUnit #21,797 lbs/hr1,026 lbs/hrPlant Total(Units #1 & #2)2,182 lbs/hr3,594 lbs/hrModeledConcentration196 ug/m3194 ug/m3Allowable Rates From the ModelingLimits in the Regulation1,000 lbs/hr foreach unitModeling NRG Energy•In designing their scrubbersystems, for all three of theirplants, NRG vents to tall “bypass” stacks when thescrubber or the continuousemission monitors are beingrepaired or tested–Emissions may also vent to theby-pass stacks duringemergencies•Because of this, the modelingmust look at operations whenthe scrubbers are running andalso when emissions vent toby-pass stacksChalk Point Modeling ResultsBy-Pass Stack (729 feet) ResultsSierra ClubMDE/PPRPFacilityEmissions(Total of 2 units)Not Completed11,705.8 lbs/hrModeledConcentration__196.0 ug/m3Scrubber Stack (400feet) ResultsSierra ClubMDE/PPRPFacilityEmissions(Total of 2 units)2,300.22,430.9 lbs/hrModeledConcentration<196.2 ug/m3195.6 ug/m3Allowable Rates From the ModelingLimits in the RegulationScrubber - 2,400 lbs/hr forall units – one stackBy-Pass – 11,500 lbs/hr forall units – one stackMorgantown Modeling ResultsBy-Pass Stack (700 feet) ResultsSierra ClubMDE/PPRPFacilityEmissions(Total of 2 units)Not Completed7,551.6 lbs/hrModeledConcentration__195.8 ug/m3Scrubber Stack (400feet) ResultsSierra ClubMDE/PPRPFacilityEmissions(Total of 2 units)2,615.5 lbs/hr3,126.2 lbs/hrModeledConcentration<196.2 ug/m3195.0 ug/m3Allowable Rates From the ModelingLimits in the RegulationScrubber - 1,500 lbs/hr foreach unitBy-Pass – 7,500 lbs/hr forfor both unitsDickerson Modeling ResultsBy-Pass Stack (703 feet) ResultsSierra ClubMDE/PPRPFacilityEmissions(Total of 3 units)Not Completed8,909.8 lbs/hrModeledConcentration__195.9 ug/m3Scrubber Stack (400feet) ResultsSierra ClubMDE/PPRPFacilityEmissions(Total of 3 units)360 lbs/hr1,043.3 lbs/hrModeledConcentration<196.2 ug/m3195.6 ug/m3__Allowable Rates From the ModelingLimits in the RegulationScrubber - 1,000 lbs/hr forall units – one stackBy-Pass – 8,900 lbs/hr forAll units – one stack