the complexities of nsr permitting ddix

2 Your environmental compliance is clearly our business.

Case Study Agenda

Identifying the Project

Identifying the Air Permitting Landscape

Identifying the Major Applicable Air Permitting Regulations

Unique Solutions to Air Permitting Issues

Schedule

Air Permit Received and Lessons Learned

Additional Lessons Learned on Similar Air Permitting Projects


Construction of 830 MW combined cycle natural gas-fired power block at existing 535 MW power plant facility

Proposed power block consisted of the following emissions sources

• Two (2) combustions turbines with heat recovery steam generators

• Natural gas-fired auxiliary boiler

• 12-cell evaporative cooling tower

• Ultra low sulfur diesel (ULSD) fuel as backup




Source: www.powermag.com

http://www.powermag.com/


Located in area classified as in attainment with all of the national ambient air quality standards (NAAQS) except the following:

• Located in ozone transport region (OTR) therefore ozone precursors, nitrogen oxides (NOX) and volatile organic compounds (VOCs) regulated as nonattainment area

• During application development fine particulate (PM2.5) NAAQS for the county was undergoing attainment redesignation from nonattainment to attainment

Identifying the Air Permitting Landscape


New Source Review (NSR) air permitting regulations determined the following pollutants were major based on applicable significant emissions rate (SER) increases due to block 2

• Nonattainment New Source Review (NNSR)▪ Ozone Precursors (NOX & VOC), PM2.5

• Prevention of Significant Deterioration (PSD)▪ Nitrogen Dioxide (NO2), Particulate Matter less than 10 microns (PM10),

Carbon Monoxide (CO), & PM2.5

PM2.5 evaluated under both NNSR and PSD due to uncertainty with attainment redesignation timeline and issuance of final permit

Identifying the Major Applicable Air Permitting Regulations


Lowest Achievable Emissions Rate (LAER) determinations

Purchase of Emissions Reduction Credits (ERCs)

Well established marketplace for VOC and NOX ERCs due to OTR

• Ability to purchase VOC and NOX ERCs anywhere within OTR with reciprocity agreements

• Although current demand for VOC and NOX ERCs increasing in area driving prices up

Major issue in TX area and further exacerbated by recent reduction of 8-hour ozone NAAQS from 75 ppb to 70 ppb effective December 28, 2015

NNSR Air Permitting Process


PM2.5 ERCs very limited

Purchasing PM2.5 ERCs outside of Air Quality Control Region (AQCR) requires an air quality modeling study to show that the location from which PM2.5 ERCs are purchased is contributing to the nonattainment status of area where ERCs are required

U.S. EPA preferred air dispersion model for < 50 km AERMOD and for >50 km long range transport air dispersion model

Potentially ERCs identified 70 km from project site



Long range transport air quality modeling analysis used the CALPUFF air dispersion model, pre 40 CFR Part 51 Appendix W proposed revisions

Use of existing meteorological dataset from Regional Haze Best Available Retrofit Technology (BART) permitting process utilized to cut cost of long range transport air quality modeling analysis and to decrease air permitting timeline

Ambient air quality monitoring guidance utilized to justify level of modeled concentrations required to demonstrate “significant impact” 0.01 micrograms per meter cubed (mg/m3)



Best Available Control Technology (BACT) analysis

Air quality modeling analysis

• U.S. EPA preferred nearfield air dispersion model (AERMOD) utilized

PSD Air Permitting Process


• Local meteorological data utilized from existing nuclear power plant 100 m tall multi-level meteorological monitoring system located 4 km away (purchased for $500)

• Major hurdles with air quality modeling analysis

▪ 1-Hour NO2 NAAQS (100 ppb) and combustion turbine startup emissions

▪ PM2.5 NAAQS and low headroom with current PM2.5 ambient monitoring concentrations (required to be added to modeled impacts)



Solutions for PM2.5 NAAQS air quality modeling demonstration

• Air quality modeling analysis is a two step process

• Model project-related emissions for comparison to the Significant Impact Levels (SILs) and if predicted concentrations are less than the SILs no further analysis is required

• If predicted concentrations are greater than the SILs then NAAQS and PSD increment evaluations required

• Strategy was to remain below PM2.5 SILs for the annual average due to existing NAAQS levels and utilize U.S. EPA guidance for using SILs



Solutions for PM2.5 NAAQS air quality modeling demonstration – (Continued)

PSD Air Permitting ProcessP

M2

.5A

nn

ual

Co

nce

ntr

atio

n (m

g/m

3) NAAQS

Level

Monitored Background

Value

0.4 mg/m3 available for modeling

12

11.6


Solutions for PM2.5 NAAQS air quality modeling demonstration – (Continued)

• Remaining below the PM2.5 Annual SIL critical because NAAQS analysis would require the addition of local sources to the analysis and inclusion of background concentration from representative ambient monitoring station

• Since area was currently going through PM2.5 redesignationprocess existing monitoring levels where 11.6 mg/m3 which left 0.4 mg/m3 of headroom for permitted facility and local sources

• To remain below PM2.5 annual SIL, air quality modeling iterations were performed to determine the maximum amount of hours per year ULSD could be utilized and still provide flexibility to the facility (~500 hours)



Solutions for NO2 NAAQS air quality modeling demonstration

• Required to evaluate periods of start-up NOX emissions due to 1-Hour averaging period of NAAQS

• Virtually impossible to remain below NO2 1-Hour SIL (7.5 mg/m3)

• Utilized non-default option in AERMOD that modifies the equilibrium ratio for the atmospheric chemical reaction between NO2 and ozone

• Currently non-default options require U.S. EPA regional approval

• Currently proposed amendments to 40 CFR Part 51 Appendix W – Guideline on Air Quality Models would remove regional approval requirement



Solutions for NO2 NAAQS air quality modeling demonstration – (Continued)

• U.S. EPA places high level of scrutiny on selected in-stack NOX/NO2 ratio which is a key input to AERMOD Tier III options

▪ Ozone Limiting Method (OLM) – Utilized for this project

▪ Plume Volume Molar Ratio Method (PVMRM) – Evaluated for this project

• Ultimately U.S. EPA region required one (1) of three (3) options for justifying in-stack NOX/NO2 ratio

▪ Stack test results from similar unit under similar operating loads

▪ Vendor guarantee from turbine provider

▪ Use of U.S. EPA default in-stack NOX/NO2 ratio (0.5)




• No test data available since this was a newly designed combustion turbine

• Vendor did not have enough data to justify in-stack NOX/NO2

ratio less than U.S. EPA default

• Ultimately U.S. EPA in-stack NOX/NO2 default utilized




• 1-Hour NO2 NAAQS air quality modeling identified a local source that when combined with facility showed an exceedance

• Two key factors led to demonstrating compliance with 1-Hour NO2 NAAQS

▪ Detailed review of local source uncovered that there was an existing Federal Energy Regulatory Commission (FERC) permit to convert two gas fired compressors to electric compressors (no air permit required to install electric engine)

▪ U.S. EPA guidance memorandum outlined recommendation for setting in-stack NOX/NO2 ratios for local sources greater than 4 km from permitted source at 0.2



Development of air quality modeling protocol – 2 Months from project start

Agency review of air quality modeling protocol – 3 Months

Development of NSR Air Permit Application – 6 Months

Agency Review of NSR Air Permit Application – 1 Year

Time from development of air quality modeling protocol to receipt of final air permit – 18 Months

Air Permitting Process Timeline


Plan ahead

Develop air quality modeling protocol and gain acceptance on meteorological dataset as early as possible

• Meteorological representativeness analysis required for all off-site data and if representativeness cannot be demonstrated the collection of 1-year of onsite data could be required

Identify ERCs early in the process

Have a competent consultant that knows the ins and outs of air permitting and air quality modeling and how they overlap

Lessons Learned Throughout Air Permitting Process


Plan ahead (even more)

Utilize variable emissions rate option in AERMOD to present realistic start-up scenario for 1-Hour NO2 NAAQS

Be prepared for potential appeals from NIMBYs and EnviroGroups

Support state reviewing authority for developing responses to comments from third parties (general public, Federal Land Managers, and regional U.S. EPA) for complex air permitting projects

Additional Lessons Learned on Other Similar Air Permitting Projects

the complexities of nsr permitting ddix

Environment