1 

### Chang, Andy

From: Mathias, Scott Sent: Wednesday, January 20, 2016 9:27 AM To: Chang, Andy Subject: FW: SO2 air dispersion modeling: H.A. Wagner (Maryla nd) Attachments: Sierra Club comments and Sears Analysis, EPA-HQ-OAR -2015-0310.pdf; 2014 01 16 Draft COMAR 26.11.39 - SO2.pdf



### Scott Mathias | Associate Director, Air Quality Pol **icy Division | U.S. EPA, RTP, NC 27711 | 919.541.53 10** 

**From:** Joshua Berman [mailto:josh.berman@sierraclub.org] **Sent:** Wednesday, January 20, 2016 8:42 AM **To:** Mathias, Scott <Mathias.Scott@epa.gov> **Cc:** Jones, Rhea <Jones.Rhea@epa.gov>; Zachary Fabish <z achary.fabish@sierraclub.org> **Subject:** Re: SO2 air dispersion modeling: H.A. Wagner (Mary land)


### Thanks for your note, Scott. It appears that the AECOM SO2 Characterization Modeling Analysis fo r the H.A. Wagner and Brandon Shores Power Plants in Baltimore, Maryland was posted yesterday afternoon on your website (and , as you noted, lacks any explanatory documentation). I presume that this re port was submitted by the State of Maryland in furt herance of its requested attainment designation. However, for at least two major reaso ns and a number of subsidiary reasons, this report does not support an attainment designation for the area surrounding the H.A. Wagne r and Brandon Shores facilities.

First, contrary to EPA’s modeling protocols, the AE COM modeling utilizes neither actual historical emi ssion data nor enforceable maximum SO2 emissions. Rather, AECOM’s modeling is based on adjustments to historical emission data that lack any identified legal or regulatory basis. Specifically, for Wagner Unit 2 AECOM adjust s downward historical SO2 emissions greater than 1, 500 lb/hr because, AECOM states, Wagner Unit 2 is currently burning lower sulfur Col orado coal and actual emissions using this coal bas ed on the five mont hs of data AECOM provided are at or below 1,500 lb/hr. AECOM assume s, without any identified support, that the plant w ill “continue burning this or similar coal in Wagner Unit 2 in order to meet MATS” and th at, as a result, Wagner Unit 2’s emissions will rem ain below 1,500 lb/hr indefinitely (AECOM Rpt. at 3-2). This approach is deeply flawe d. AECOM cites no permit or SIP condition that enfo rceably limits Wagner Unit 2’s emissions to 1,500 lb/hr. Moreover, MATS cannot su pply this missing limit because it does not impose 1-hour emission limits on facilities that elect to rely on SO2 emissions as a proxy for acid gas emissions. Absent an enforceable 1-hour li mit on Wagner Unit 2’s SO2 emissions, there is no basis for adjusting the unit’s historic al operations. This adjustment is especially concer ning because AECOM's modeling projects near-violations of the NAAQS at the controlling rec eptor (186.0 vs. 196.2 ug/m3), driven overwhelmingl y by emissions from the Wagner facility. Even if Wagner 2 burned "similar coal" to the current Colorado coal in the future, even a sl ight increase in the sulfur content of the coal (which will dictate the SO2 emissions from Wag ner 2 given the lack of installed emission controls for SO2 on that unit) would push AECOM's modeled results above the NAAQS. Moreover, as previously provided by the Sierra Club, time ser ies modeling using actual historical emission data identifies significant vio lations of the 2010 1-hour SO2 NAAQS. Absent enfor ceable 1-hour SO2 emission limits that eliminate those violations, AECOM's modeling s imply provides no basis to avoid a nonattainment de signation.

Second, AECOM conducted its modeling exclusively us ing the ADJ_U* and LOWWIND3 options in AERMET and A ERMOD even though EPA has not formally approved the use of these opti ons as the regulatory default under Appendix W and no demonstration has been provided regarding their appropriateness in this instance. Although AECOM devotes three appendices to an attem pt to establish the validity of ADJ_U* and LOWWIND3 (Appendices B-D), these appendi ces fail to support the preferability of the ADJ_U* and LOWWIND3 nondefault options for modeling the Baltimore-area coa l plants, especially for determining whether the ar ea is attaining the 1-hour SO2 NAAQS. AECOM’s own paper (Appendix C) indicates th at “[t]he AERMOD low wind speed options have a mino r effect for flat terrain locations,” such as those present around the coasta l Wagner and Brandon Shores facilities. (AECOM Appe ndix C, Paine et al., J. Air & Waste Mgmt. Ass’n 65 (2015) 1341-53, 1352). Consequ ently, it is unclear why AECOM even thinks it would be necessary to use these modules here. Moreover, AECOM’s Appendix C paper a nd accompanying reanalysis in Appendix D rely on da ta from only 4 or 5 SO2 monitors. But as set forth in the attached comments of Camille Sears, AERMOD’s demonstrated predictive accuracy is in determining the2 robust highest concentration (RHC) associated with an emission source or set of sources, not in identi fying the exact location of these impacts. With the extremely limited monitor datase t available to AECOM in North Dakota and Indiana, i t is simply not possible to evaluate whether the ADJ_U* and LOWWIND3 options more accura tely predict RHC than the current AERMET and AERMOD defaults. As the attached comments from Camille Sears demonstrate, “ [i]n many modeling applications, version 15181 AERM ET ADJ_U* and AERMOD LOWWIND3 non-default options will likely degrade pe rformance compared to current regulatory default ve rsions.” (Sears Comments at 10.) Given that it is the RHC, not the model’s pre dictive ability at a specific monitor location, tha t is critical to evaluating a ttainment with the NAAQS, AECOM has not provided a sufficient justific ation for deviating from the Appendix W defaults. As Appendix W, Section 3.2.2 requires, in order to use a non-default, AECOM must show that the alternate model “can be demonstrate to be applicable to the problem on a theoretical basis.” However, AECOM has not identifi ed a problem specific to the Maryland plants that u se of ADJ_U* and LOWWIND3 would purportedly solve. And, as noted above, given that the value of interest is the RHC, not AERMOD’ s predictive capability at a specific monitor location, AECOM has failed to establish eve n a theoretical basis for use of ADJ_U* and LOWWIND 3 in this instance. As Ms. Sears’ analysis of these non-default options shows, they tend to underpredict RHC. Given that AECOM’s modeled impacts closely approach the 1-hour SO2 NAAQS, failure to use the default mo dules in AERMET and AERMOD alone could readily acco unt for the modeled attainment rather than nonattainment (even setting aside the deeply flawed modeled emission rates disc ussed above). AECOM’s exclusive reliance on ADJ_U* and LOWWIND3 fails to support an attainment or unclassifiable designation.

Ultimately, AECOM appears to have elected inputs an d modeling options in order to decrease modeled imp acts--replacing actual historical emissions data with synthesized, hypothetical low-s ulfur coal emissions, removing entirely startup and shutdown emissions, adopting a low background emissions concentration, using non-regul atory default modeling options without any clear ju stification, using a small, sparse receptor grid, among others--yet nonetheless AECOM' s modeling yields peak concentrations just a few pe rcentage points below the NAAQS. Far from disputing the modeling submitted b y Sierra Club and the state of Maryland indicating that NAAQS exceedences can only be avoided through adoption of enforceable 1-hour e mission limits iden tified in the attached draft regulation, AECOM's mo deling goes a long ways towards confirming the presence of those problems and the need for ad ditional 1-hour enforceable limitations on SO2 emis sions from the Wagner facility.

Sincerely,

Josh



### On Wed, Jan 20, 2016 at 8:14 AM, Mathias, Scott < Mathias.Scott@epa.gov > wrote:
Josh,

I received your inquiry regarding posting material to EPA’s SO2 designations website. Our convention has been to post to the website the official state corr espondence of modified recommendations, but not necessarily all correspondence related to a designa tion action. When we receive new material our Regi onal office will take the time necessary to review any c orrespondence to determine its relevance, and if it conforms to our convention we will post it to the w ebsite. Otherwise, all relevant documentation supp orting EPA’s actions will be deposited in the official pub lic docket at the time we notify states of our inte nded designations (i.e., the 120-day letters). We are s cheduled to complete that milestone very soon, so a ny relevant material not posted to the website will be available in the public docket shortly.

**Scott Mathias | Associate Director, Air Quality Pol icy Division | U.S. EPA, RTP, NC 27711 |**  **919.541.5310**3 

### From: Joshua Berman [mailto: josh.berman@sierraclub.org ] **Sent:** Friday, January 15, 2016 4:26 PM **To:** Mathias, Scott < Mathias.Scott@epa.gov > **Cc:** Jones, Rhea < Jones.Rhea@epa.gov >; Zachary Fabish < zachary.fabish@sierraclub.org > **Subject:** Re: SO2 air dispersion modeling: H.A. Wagner (Mary land)



### Ms. Jones and Mr. Mathias:

It appears that the State Designations website, as of now, has not been updated with any additional su bmissions from Maryland. If Maryland did provide EPA with an identification of federally enforceable emissions limits or permit conditions that it believes may be needed to support its requested attainment demonstration (which it indicated it would provide by today), I would appre ciate if you could post these on the website and/or send me a copy.

Thank you, and I hope you have a good weekend,

Josh

On Tue, Jan 12, 2016 at 8:36 PM, Joshua Berman < josh.berman@sierraclub.org > wrote:

Dear Ms. Jones and Mr. Mathias:

As a follow-up to the time series modeling that I p rovided last week, I wanted to briefly address a co uple of points in Maryland’s November 20, 2015 SO2 designation submission.

First, contrary to the State’s suggestion, the ambi ent monitor data collected during a two-month perio d in 2013 if anything supports a nonattainment designation—not an attainment designa tion—for the area around the Wagner and Brandon Sho res facilities. Notably, this is the only reported ambient monitor data that was col lected in any proximity to the Wagner and Brandon S hores facilities. Given its limited two-month duration, the occurrence of a maximum 1-h our SO2 concentration of 101.7 ppb at the monitor c losest to those plants during that time, and the fact that the monitoring was con ducted during the summer months even though Wagner Unit 2 has been operating at far higher capacity factors in winter than summer month s in recent years (and Unit 3’s operations show no seasonal bias), even a basic extrapolation the monitored results produces a 99 th percentile 1-hour maximum far in excess of the 75 ppb standard.

Second, in Attachment 6, the State indicates that o n January 15, 2016 it will “identif[y] federally en forceable emissions limits or permit conditions that may be needed to support the attain ment designation.” Unless those limitations have been fully reviewed and vetted by EPA to ensure they adequately maintain the SO2 NAAQ S and are already embodied in federally enforceable permits or regulations, EPA cannot rely on the State’s unenforceable promise of potential future action as a basis for declining t o propose a nonattainment designation at this time. I also wanted to draw your attention to SO2 modeling that MDE previously completed for these plants and modelinginformed SO2 emission limits that MDE previously sh ared with stakeholders in early 2014. I have attac hed MDE's presentation to4

stakeholders from February 2014 in which MDE summar izes the results of its modeling (as well as Sierra Club's prior modeling) and explains the unit-specific emission rates necessary to ensure compliance with the 1-hour SO2 NAAQS. S hortly before that stakeholder meeting, MDE released to stakeholders a draft SO2 r egulation (attached) that includes modeling-informe d unit- or plant-specific emission rates. EPA should review with special care any new ly proposed emission limitations that differ meanin gfully from those identified by Maryland as requisite to maintain the NAAQS in 2014

.

Finally, the State indicates that it will be submit ting “further emissions and modeling analyses and i nformation” in “early 2016.” To date, EPA has not posted any additional submissions on it s State Designations webpage. If EPA has or receiv es any additional submissions from Maryland, I would appreciate if you could post those on the website and/or provide a copy to me.

Thank you,

Josh



### On Tue, Jan 5, 2016 at 10:47 AM, Mathias, Scott < Mathias.Scott@epa.gov > wrote:

Mr. Berman,

On behalf of Ms. Jones, I’m acknowledging that we h ave received your email and its attachments pertain ing to the power plants located in the Baltimore area.

**Scott Mathias | Associate Director, Air Quality Pol icy Division | U.S. EPA, RTP, NC 27711 |**  **919.541.5310**

**From:** Joshua Berman [mailto: josh.berman@sierraclub.org ] **Sent:** Monday, January 04, 2016 4:19 PM **To:** Mathias, Scott < Mathias.Scott@epa.gov >; Jones, Rhea < Jones.Rhea@epa.gov > **Cc:** Fernandez, Cristina < Fernandez.Cristina@epa.gov >; Esher, Diana < Esher.Diana@epa.gov >; George Aburn -MDE-

< george.aburn@maryland.gov >; Zachary Fabish < zachary.fabish@sierraclub.org > **Subject:** SO2 air dispersion modeling: H.A. Wagner (Maryland )



### Ms. Jones and Mr. Mathias:

Per the attached cover letter, please find enclosed time series and steady-state sulfur dioxide air di spersion modeling for the H.A. Wagner, C.P. Crane, and Brand on Shores power plants located in the Baltimore are a in Maryland. This modeling was previously provided as an attachment to a June 18, 2015 letter to the Maryland Department of the Environment, and is prov ided here again as an attachment along with the5



### original June 18th letter. CDs with the input and output files are being sent via FedEx and copied to the other recipients on this email.

If you have any questions, please let me know.

Thank you,

Josh

--
Joshua Berman Staff Attorney
Sierra Club Environmental Law Program
50 F St. NW, 8th Floor
Washington, DC 20001

Tel: (202) 650-6062

Fax: (202) 547-6009

--
Joshua Berman Staff Attorney
Sierra Club Environmental Law Program
50 F St. NW, 8th Floor
Washington, DC 20001

Tel: (202) 650-6062

Fax: (202) 547-60096 

### --
Joshua Berman Staff Attorney
Sierra Club Environmental Law Program
50 F St. NW, 8th Floor
Washington, DC 20001

Tel: (202) 650-6062

Fax: (202) 547-6009

-- Joshua Berman Staff Attorney Sierra Club Environmental Law Program 50 F St. NW, 8th Floor Washington, DC 20001 Tel: (202) 650-6062 Fax: (202) 547-6009