WRAP Stationary Sources Forum Meeting November 14-15, 2006 BART Update WRAP Stationary Sources Forum Meeting November 14-15, 2006

BART update Q & A document BART Q & A – Oct. 2005 August 24, 2006 – has additional BART information Future Q & A’s

Exemptions from BART Modeled impact < contribution threshold (∆ dv) “Model Plant” SO2 + NOx < 500 TPY (PTE); facility > 50 km from Class I area SO2 + NOx < 1000 TPY (PTE); facility > 100 km from Class I area PM can be included with appropriate justification Permit limits < 250 TPY of visibility impairing pollutant Model plant Modeled impact less than threshold Limits must be made enforceable Install latest, greatest controls available

IMPROVE Equation Old Equation New Equation bext = 3((f(rh))[SO4] + 3((f(rh))[NO3] + 4(f’(rh))[OC] + 10[EC] + 1[IP] + 0.6[CM] + brayleigh New Equation [bext = 2.2 x fs(RH) x [Small Sulfate] + 4.8 x fL(RH) x [Large Sulfate] + 2.4 x fs(RH) x [Small Nitrate] + 5.1 x fL(RH) x [Large Nitrate] + 2.8 x {Small Organic Mass] + 6.1 x [Large Organic Mass] + 10 x [Elemental Carbon] + 1 x [Fine Soil] + 1.7 x fss(RH) x [Sea Salt] + 0.6 x [Coarse Mass] + Rayleigh Scattering (site specific) + 0.33 x [NO2 (ppb)] Use either; be consistent calculating natural, current, and future impacts BART and RP – changing equations & reconciling results Postprocessing with CALPUFF/CALPOST

UARG Settlement Letter and memo of July 19, 2006 International emissions Do not add to natural background or subtract from current conditions Explaining and assessing if implementation strategies are achieving RPGs Nonair quality impacts – no requirement to include collateral benefits of emission reductions in BART determinations Use 20% best days or annual average natural background

Deciview threshold State establishes the contribution threshold - should be no higher than 0.5 ∆ dv (e.g. ≥ 0.5 => subject to BART, < 0.5 => exempt) per the guidelines consideration for establishing the threshold should include the number of emission sources affecting the Class I areas at issue, the magnitude of the sources’ impacts, and the location of the sources. (See 70 FR 39161-39162, July 6, 2005.) Provide explanation in SIP

BART determination (five factors) BART analysis considers: Cost of compliance (BART and RP) $/ton; $/dv in addition to but not in place of Energy and nonair quality impacts (BART and RP) Existing controls in use at the source Remaining useful life (BART and RP) Degree of visibility improvement No prescription given to weighting

Intra-source trading (bubbling) BART-eligible units - “You should consider allowing sources to ‘‘average’’ emissions across any set of BART-eligible emission units within a fenceline, so long as the emission reductions from each pollutant being controlled for BART would be equal to those reductions that would be obtained by simply controlling each of the BART-eligible units that constitute the BART-eligible source”. (70 FR 39172) B-E and non-B-E units – permitted under the Trading Rule Emissions reductions are greater than case-by-case BART Geographic distribution of emissions is the same