WESTAR 2003 Fall Technical Conference on
PSD Increment Tracking & Cumulative Effects Modeling
Seattle, Washington
Conducting Class I Area Increment Analyses
Ken Rairigh, P.E.
State of Wyoming
Department of Environmental Quality - Air Quality Division
September 16, 2003
Requirements for Conducting a Class I Area
Increment Analysis in the PSD Rule
• No specific requirements provided in PSD Rule for conducting
increment analyses for New Source Review
• PSD Rule states:
“An analysis of the predicted impact of emissions from the facility is required
for all pollutants … which are emitted in significant amounts.
Such analysis shall identify and quantify the impact on the air quality in the area
of all emissions not included in the baseline concentrations including,
but not limited to, those emissions resulting from the instant application
and all other permits issued in the area.
The purpose of this analysis is to determine the total deterioration of air quality
from the baseline concentrations.”
EPA Guidance on Conducting a Class I Area
Analyses
• Guideline on Air Quality Models (Revised 2003)
• New Source Review Workbook (EPA, 1990)
If proposed major source or major modification located
< 100 kilometers from a Class I area:
- Increment Analysis
- Analysis of Air Quality Related Values (AQRVs)
Notifying the FLM of the Proposed
Modification or Proposed New Source
• If proposed major source or major modification
located < 100 kilometers from a Class I area
• March 19, 1979 memorandum from EPA Regional
offices:
“Provide notice to the Federal Land Manager of any proposed PSD
sources that would locate within 100 kilometers of a Class I area.”
Notifying the FLM of the Proposed
Modification or Proposed New Source
• Not clearly defined when proposed PSD source
located > 100 kilometers from Class I area
PSD Rule states, “the Administrator shall provide
written notification to all Federal Class I Area Federal
Land Managers of such proposed new major emitting
facility or major modification whose emissions may
affect the Federal Class I Area or affect visibility in such
Area.”
How to Determine If Proposed PSD Source
May Affect a Class I Area ?
• Use Class I Significant Impact Levels (SILs)
– Brought into Proposed Rules in 1996
– No prescribed distance criteria for using SILs
• < 100 km from Class I area – use Class I SILs for any PSD source
• > 100 km – Rely on Class I SILs for large PSD sources
- Modeled impact > Class I SILs => Cumulative analysis
• No prescribed distance for constructing the emissions inventory
for cumulative Class I increment analysis
Proposed Class I SILs
• Two Sets of Proposed Class I SILs (EPA & FLM)
Pollutant
• SO2
• PM10
• NOx
Ave Period
3-hour
24-hour
Annual
24-hour
Annual
Annual
EPA
1.0
0.2
0.1
0.3
0.2
0.1
FLM
0.48
0.07
0.03
0.27
0.08
0.03
• EPA Class I SILs are calculated as 4% of the PSD Class I increments
• FLMs have typically deferred to EPA Class I SILs
• Apply to Increment Consumption, not AQRVs
Constructing the Cumulative Class I
Increment Emissions Inventory
• Based on the lack of guidance, State of Wyoming
DEQ developed some concepts:
• Start with Class II increment source inventory (50 km)
» Includes major and minor sources
• Add 50 kilometers onto Class II increment source EI (100 km)
» Does not include sources near Class I areas
if distance from source to Class I area > 100 km
What About Sources Located Near the
Class I Area ?
• Alternative approaches under consideration by
WDEQ to better define increment inventory:
• Calculate distance (radius) from proposed major
source or major modification to Class I Area(s) and
include additional major sources:
1. Circle centered on location of PSD source
2. Circle centered on Class I Area(s)
Issues Associated With Acquiring Emissions
Inventories for Cumulative Analyses
• Difficult to acquire baseline source/emissions data
• Model actual or allowable emission rates ?
• Short-term emissions data not available
» Defer to allowable emissions on a short-term basis
• Acquiring emissions data from multiple states
» Need a regional database that states can access
» AIRS is gone, NEI is successor
» NEI format is widely used in regional scale analyses
Model Selection for Class I Area Analyses
• Distances < 50 km:
– ISC, AERMOD*, CTDMPLUS, CALPUFF
• Approved models under Appendix A of the
Guideline on Air Quality Models
• (* AERMOD expected to be added to Appendix A)
– September 8, 2003 Notice in Federal Register
Model Selection for Class I Area Analyses
• Distances > 50 km:
– CALPUFF, CMAQ, UAM-V, CAM-X
– CALPUFF is the least resource intensive
– Established guidance from EPA and FLMs
already being implemented for CALPUFF by some states
» (IWAQM Phase II Report)
– CALPUFF has been recommended by EPA for assessing
PSD increment consumption - April 15, 2003 Revisions to
Guideline on Air Quality Models
CMAQ, UAM-V, CAM-X
• Photochemical grid models are very resource intensive
• Model run times may preclude the use of more than
one year of meteorological data
• Much better treatment of chemistry than CALPUFF
• Could use at larger distances than CALPUFF
IWAQM Phase II
Prescribed Methodologies for CALPUFF
• CALPUFF “Lite” methodology
– Simplistic, single station met data
– Intended as a screening-level option for CALPUFF
– Typically limited to single source analyses
• CALPUFF refined methodology
– More complex, 3-D wind field, prognostic data)
– Required for cumulative source increment analyses
– Requires a lot more resources and time to QA/QC
meteorological inputs than CALPUFF “Lite analysis
Case Study: Conducting Class I Analyses
“The WYGEN 2 Experience”
• WYGEN 2 - Proposed Coal-Fired 500 MW Power Plant
• Located in Campbell County, WY
• Nearest Class I Areas to proposed WYGEN 2 location:
–
Wind Cave NP (SD) = 168 km
– Badlands NP (SD) = 213 km
– N. Cheyenne Indian Res. (MT) = 172 km
• Permit Review Period => April 2001 – September 2002
Class I Modeling Protocol
• April 25, 2001 – May 24, 2001
• WDEQ required applicant to submit a Class I modeling
protocol to WDEQ and FLM
• Follow-up meeting to be held after the FLM (NPS)
reviews Class I modeling protocol
• Class I area modeling protocol submitted to WDEQ
and the National Park Service (NPS)
• Conference call with NSR applicant, DEQ, and FLM (NPS)
Class I Modeling Protocol Cont’d.
• Proposed CALPUFF “Lite” for screening level analysis and
also CALPUFF refined analyses, if required
• Compare impacts from new source to proposed Class I SILs
• Class I protocol did not specifically commit to or identify
additional analyses if source's impact was greater than Class I SILs
(OUR BAD !!)
• The NPS did not comment on the Class I modeling protocol
Initial Proposed Emission Rates Used in
Class I Area Significance Analysis
• SO2
• Annual emission rate = 3,381 TPY
• Short-term rates for boiler = 0.15 lb/MMBtu (30-day average)
•
0.17 lb/MMBtu (2-hour average)
• NOx
• Annual emission rate = 2,028 TPY (0.09 lb/MMBtu)
• PM10
• Annual emission rate = 421 TPY (0.018 lb/MMBtu)
CALPUFF Screening Level Analysis
• Predicted PM10 and NOx impacts from the proposed
new source were at least 1-2 orders of magnitude
below the proposed Class I SILs for these two
pollutants
• WDEQ did not require applicant to conduct
cumulative Class I NOx and PM10 increment
consumption analyses
CALPUFF Screening Level Analysis
• July 2001 – November 2001
• Permit application received
• Modeled SO2 impact from the proposed new source greater
than 3-hour & 24-hour Class I SILs
• WDEQ required the applicant to conduct a cumulative
SO2 Class I increment consumption analysis for three (3)
designated Class I areas
• Cumulative analyses required going to refined CALPUFF
analysis (IWAQM Phase II)
CALPUFF Refined Increment Analysis
• November 2001 – March 2002
• CALMET wind field and SO2 emissions inventory
provided to applicant by WDEQ
• Cumulative source emissions inventory based on SO2 sources
located within 100 km of the proposed WYGEN 2 site
• Applicant submits cumulative PSD Class I increment
consumption analysis for SO2
» SO2 emission rates based on WDEQ’s BACT determination
BACT Emission Rates Used in CALPUFF
Refined Increment Analyses
• SO2
• Annual emission rate = 2,254 TPY
• Short-term rates for boiler = 0.10 lb/MMBtu (30-day average)
•
0.15 lb/MMBtu (3-hour average)
• NOx
• Annual emission rate = 1,578 TPY (0.07 lb/MMBtu)
• PM10
• Annual emission rate = 270 TPY (0.012 lb/MMBtu)
Permit Out to Public Notice
• May 2, 2002 - Permit analysis out on public notice
• May 9, 2002 - FLM requested CALMET & CALPUFF files
» First time we have heard from FLM in a year
» FLM had concerns that no upper air stations were
used in CALMET simulation
• May 31, 2002 - Comments received from EPA, FLM, and
Environmental Defense organization
Now, All He## Breaks Loose !!
Comments From EPA
• Inclusion of additional major sources in Class I increment
consumption analyses:
– Colstrip power plant (MT)
– Ben French power plant (SD)
– South Dakota cement plant (SD)
• Include baseline facilities near the proposed WYGEN 2 site
if there have been emission increases since the minor source
baseline date was triggered
Comments From FLM
• FLM did not receive a technical report describing Class I
increment analysis and assumptions used
• FLM claims application is incomplete
» Based on lack of cumulative AQRV analyses
• Concerns regarding the impacts of emissions to visibility
and other AQRVs at Wind Cave and Badlands National Parks
• No formal adverse impact determination to AQRVs
Comments From Environmental Defense
• WDEQ unlawfully relied upon significant impact
levels (SILs) for Class I areas to exempt WYGEN 2
from a cumulative modeling analysis for the NO2
and PM10 increments at the nearby Class I areas
• WDEQ did not require the applicant to conduct
cumulative visibility and AQRV analyses
Remember what the PSD Rule requires:
» An analysis of the impairment to visibility, …
that would occur as a result of the facility or modification …
WDEQ Ran Additional Analyses To
Evaluate Impact From Colstrip
• Colstrip power plant (Unit #3 & Unit #4) included in Class I
increment analysis
» Unit #1 & Unit #2 are pre-baseline sources
» Not included in Class I increment analysis
• Ben French power plant and South Dakota cement plant were
also pre-baseline sources and were not included in our analyses
Cumulative Class I Increment Analysis
Results
• Badlands National Park
HSH 3-hr = 1.8 mg/m3
– HSH 24-hr = 0.5 mg/m3
–
Class I Increments
3-hr = 25 mg/m3
24-hr = 5 mg/m3
• Wind Cave National Park
HSH 3-hr = 2.1 mg/m3
– HSH 24-hr = 0.7 mg/m3
–
• Northern Cheyenne Indian Reservation
–
–
HSH 3-hr = 27.3 mg/m3 => Single modeled exceedance
HSH 24-hr = 3.5 mg/m3
» Colstrip power plant (MT) contribution = 99.9%
Use Class I SILs To Demonstrate
Insignificant Impact From WYGEN 2
• Modeled exceedance was due to Colstrip power plant
located 24 km south of Northern Cheyenne Indian Reservation
» Near-field impact – CALPUFF may not be the right tool
• WDEQ compared new source’s contribution to Class I SIL:
» Contribution from WYGEN2 at NCIR was 0.07 mg/m3
(7% of Class I SO2 3-hr SIL)
• Proposed new source does not significantly impact the location
of the modeled exceedance
Final Decision
• September 26, 2002
• WDEQ demonstrated that the proposed source does not
exceed the Class I increments, or contribute significantly to
any existing Class I increment exceedances
• WDEQ issued final decision to approve NSR permit for
WYGEN 2 after having reviewed all comments received
• NPS has appealed WDEQ's final issuance of permit
• NPS appeal based on visibility impacts, not increment issues
FLM Involvement in the Permit Review
Process
• WDEQ involved FLM in the application review process as
required by the PSD Rule:
– Early involvement with FLM
– Consultant sent Class I modeling protocol to FLM
and requested approval
– Submitted permit application to FLM within 30 days of receipt
– Submitted permit analysis review, permit conditions, and
proposed decision on public notice
FLM Responsibility in the Permit Review
Process
• FLMs are part of the PSD review process
• WDEQ expects the FLM to review permit application
in a timely fashion
• WDEQ expects some kind of response from FLM
if a protocol has been submitted to FLM
• FLM needs to understand and work within our
review process and required time lines as well
Changes in FLM Notification Based on this
Experience
• Improve on communications with FLM
• Upon determining completeness of application:
- Notify FLM that application is complete
- Submit all information to FLM that has been
received since initial permit application
Questions ??