GHG BACT Analysis Case StudyRussell City Energy CenterNovember 2009Updated February 3, 20101Project Description•612 megawatt natural gas fired combinedcycle power plant in Hayward, CA.•GHG emission sources-2 Siemens Westinghouse 501FD3 combustion turbines – natural gas fired-2 Heat Recovery Steam Generators with supplemental firing – natural gas fired-1 Emergency Fire Pump – diesel fired-5 Circuit breakers – SF6•Emission controls-Dry Low NOx Combustors-Selective Catalytic Reduction-Oxidation catalyst•Power purchase agreement with PG&E•Permits required from California Energy Commission and Bay Area Air Quality ManagementDistrict2Project Description3Air Permit History•Bay Area Air Quality Management District issued combined Authority to Construct andPSD Permit on November 1, 2007-Appeal to Air District Hearing Board denied-Petition to EAB resulted in remand of PSD Permit on July 29, 2008-EAB Deseret decision issued November 13, 2008-Johnson Memo December 18, 2008•Draft PSD Permit issued December 8, 2008.-Public hearing held January 21, 2009-Public comment period extended until February 6, 2009-EPA approved Petition for Reconsideration February 19, 2009•Revised Draft PSD Permit and AdditionalStatement of Basis Issued August 3, 2009-Included GHG BACT and voluntary GHGlimits to address Deseret uncertainty-Public hearing held September 2, 2009-Public comment period closed September 16, 2009-Awaiting final permit•http://www.baaqmd.gov/Divisions/Engineering/Public-Notices-on-Permits/2009/080309-15487/Russell-City-Energy-Center.aspx4General Approach•Followed the 5 Step Approach•Initial BACT Analysis in December 2008•BACT Analysis modified in August 2009-Responses to comments•Resulted in voluntary federally-enforceable GHG limits5Step 1 – Identify Control Technologies•Combustion controls-No way to alter the chemical reaction (CH4 + 2O2= CO2+ 2H20)-Thermal efficiency was the onlycombustion control identified•Post-combustion controls-Carbon capture and storage-Nothing else•Response to comments-Evaluation of non-fossil electricity generation-BAAQMD sympathetic but deferred to California Energy Commission-BAAQMD states “... the federal BACT framework is clear that it does not requireconsideration ... of non-fossil-fuel-fired alternatives ...”6Step 2 – Eliminate Technically Infeasible Options•Combustion controls-Energy efficiency is feasible and proven•Post combustion controls-CCS not commercially available-DOE expects commercial deployment in 2025 (73 FR 44370)-Appropriate sequestration sites in bay area not demonstrated-Need further evaluation ofenvironmental impacts of CCS•Conclusion that high-efficiency power generation technology is the only available andfeasible control technology•Since top control technology chosen no further analysis required per EPA top-down BACTapproach7BACT Emission Limit•High efficiency power generation the only option-CEC data indicated CCGT can achieve 56% efficiency-Original project featured 501FD2 turbines achieving 55.8% efficiency-Project revised to FD3 achieving 56.45 efficiency•Comparable projects8BACT Emission Limit•BAAQMD determined CO2 emissions achievable for the level of efficiency•CDC data showed CCGT power plants with emission rates ranging from 794 to 1058 lb/mwh•BAAQMD cites EPA guidance that BACT limitsshould not necessarily reflect the maximumpossible emissions control efficiency under themost favorable conditions but rather atlevels that will allow facilities to achieve compliance consistently over time under alloperating conditions•Factors reducing CCGT efficiency:-Hot weather-Starting up or shutting down-Loads below 100 percent-Duct firing-Air cooling•In December 2008 BAAQMD ProposedBACT Limit for CO2 of 1100 lb/mwh-Lowest regulatory limit at the time (CA SB 1368)-Enforced through heat input limit9Revised BACT Limit – Comments on December 2008 BACT•More efficient CCGT configurationsexist - “G” and “H” turbine technology-G technology would be less efficient at 612 mw configuration-H technology not yet demonstrated at60 Hz (Inland Empire just starting)-BAAQMD concluded FD3 was mostefficient for this project•BACT limit issues-BACT was established as thermal efficiency (%) but expressed as mass emissions per unit of poweroutput (lb/mwh)-The permit limit of 1100 lb/mwh was developed toaccommodate older, higher emitting facilitiesand should be considered a floor-Data shows achievable emission from new CCGT power plants as low as 800 lb/mwh-There was no justification for the compliance margin-Heat input limit justification was 35% higher than the rated maximum for the turbines-Heat input limit should instead be an outputbased limit – emissions could rise as efficiencydeclines yet heat input would remain the same•BAAQMD legal counsel worked with Calpine andcounsel for key commenters to revise limits-Absolute based on heat input-Efficiency based on heat rate-Monitoring and testing provisions10GHG BACT – Mass Emissions Limits•Based on permitted heat input limits•Expanded to include other GHGs•Monitored real time-Fuel flow more accurate than CO2 CEMS•Based on common emission factors (EPA and CARB)•Most permits contain heat input limits11•Heat Rates (no duct firing)•Factors affecting heat rate-Gas pressure variability-Gas quality variability-Cooling water quality variability-Turbine exhaust flow degradation-Steam turbine performance degradation-Gas turbine performance degradation-Parasitic load (water treatment)GHG BACT– Output Based Efficiency Limits7,730Degraded Base (degradationbetween major overhauls andcompliance margin)7,080Installed Design Base (3.3% design margin)6,852Net Design Base (new and clean)Heat Rate (Btu/kwh)Condition12Miscellaneous•Fire pump BACT was limiting operation totesting and emergencies to achieve annual limitof 7.6 metric tons CO2E•Circuit Breakers-Each breaker contains about 145 pounds SF6-No direct emissions – potential for fugitive emissions from leaks•5 Step BACT for breakers-Step 1: Identified SF6 alternatives (oil or air-blast) and SF6 breakers with leakdetection-Step 2: SF6 alternatives eliminateddue to space/safety considerations-Step 3: SF6 breakers with leak detectionranked highest but alternatives evaluated-Step 4: SF6 alternatives would require moreland, generate more noise, and increasethe risk of dielectric fluid release-Step 5: SF6 breakers with leak detection selected to maintain emissions below 39.3metric tons CO2E per year13GHG BACT Permit Conditions•Mass limits per previous table measured continuously•Efficiency limit of 7,730 Btu/kwh-Initial compliance test within90 days of commissioning-Annual compliance tests thereafter-ASME Performance Test Code on Overall Plant Performance (ASME PTC 46-1996)-BAAQMD concluded continuous monitoring not possible-Efficiency limit measured during baseload operation•No substantive comments on GHG BACT ofthe 140 plus comment letters received14Lessons Learned•Project configuration will drive the efficiency determinations-Simple cycle vs. combined cycle-Turbine scale (larger is more efficient but not always marketable)-Customer defines project configuration-Size (megawatts)-Characteristics (ramp rate, peaking capacity)•Companies should be amenable to reasonable GHG limits based on efficiency-Important to maintain realistic estimate of heat rate degradation-Vendor heat rate projections cover first 48K hours•Difficult to define efficiency except wheredesign bases and heatrate guarantees exist-Many factors degrade efficiency