Environmental Protection Agency (EPA).
Proposed rule; Reopening of Comment Period.
On November 30, 2012, the EPA published in the Federal Register the proposed rule, “Reconsideration of Certain New Source and Startup/Shutdown Issues: National Emission Standards for Hazardous Air Pollutants from Coal- and Oil-fired Electric Utility Steam Generating Units and Standards of Performance for Fossil-Fuel-Fired Electric Utility, Industrial-Commercial-Institutional, and Small Industrial-Commercial-Institutional Steam Generating Units.” That proposal opened for reconsideration certain issues, including those related to startup and shutdown. On April 24, 2013, we finalized reconsideration of all the issues included in the proposed rule except those related to startup and shutdown. The EPA is reopening the public comment period for the proposed reconsideration to solicit additional input on specific issues raised during the initial public comment period related to the proposed revisions to the requirements and definitions related to periods of startup and shutdown. The EPA also requests comment on the additional technical analyses it conducted in response to public comments on this subject in Docket ID EPA-HQ-OAR-2009-0234. The National Emission Standards for Hazardous Air Pollutants (NESHAP) rule is referred to as the Mercury and Air Toxics Standards (MATS), and the New Source Performance Standards rule is referred to as the Utility NSPS.
Comments. Comments must be received on or before August 26, 2013.
Comments. Submit your comments, identified by Docket ID. EPA-HQ-OAR-2011-0044 (NSPS action) or Docket ID EPA-HQ-OAR-2009-0234 (NESHAP/MATS action), by one of the following methods:
www.regulations.gov: Follow the on-line instructions for submitting comments.
Fax: (202) 566-1741.
Mail: Air and Radiation Docket and Information Center, Environmental Protection Agency, Mailcode: 2822T, 1200 Pennsylvania Ave. NW., Washington, DC 20460. Please include a total of two copies. The EPA requests a separate copy also be sent to the contact person identified below (see FOR FURTHER INFORMATION CONTACT).
Hand Deliver y: Air and Radiation Docket and Information Center, U.S. EPA, Room B102, 1301 Constitution Avenue NW., Washington, DC. Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information.
Instructions. All submissions must include agency name and respective docket number or Regulatory Information Number (RIN) for this rulemaking. All comments will be posted without change and may be made available online at http://www.regulations.gov, including any personal information provided, unless the comment includes information claimed to be confidential business information (CBI) or other information Start Printed Page 38002whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through http://www.regulations.gov or email. The http://www.regulations.gov Web site is an “anonymous access” system, which means the EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to the EPA without going through http://www.regulations.gov, your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, the EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If the EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, the EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses.
Docket. All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some information is not publicly available (e.g., CBI or other information whose disclosure is restricted by statute). Certain other material, such as copyrighted material, will be publicly available only in hard copy form. Publicly available docket materials are available either electronically in http://www.regulations.gov or in hard copy at the EPA Docket Center, Room 3334, 1301 Constitution Avenue NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Air Docket is (202) 566-1742.
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FOR FURTHER INFORMATION CONTACT:
For the NESHAP action: Mr. William Maxwell, Energy Strategies Group, Sector Policies and Programs Division (D243-01), Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711; Telephone number: (919) 541-5430; Fax number (919) 541-5450; Email address: email@example.com. For the NSPS action: Mr. Christian Fellner, Energy Strategies Group, Sector Policies and Programs Division (D243-01), Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711; Telephone number: (919) 541-4003; Fax number (919) 541-5450; Email address: firstname.lastname@example.org.
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On February 16, 2012, the EPA issued the final MATS and Utility NSPS (77 FR 9304). In the final MATS rule, the EPA included a work practice standard applicable during periods of startup and shutdown rather than finalizing the proposed requirement that sources comply with numerical limits during such periods. In the Utility NSPS, the EPA included the same work practice for particulate matter (PM) emissions during periods of startup and shutdown. The work practice standard was designed to minimize emissions of hazardous air pollutants (HAP) and PM during periods of startup and shutdown by requiring sources to maximize the use of clean fuels during such periods when electric utility steam generating unit (EGU) temperatures and air flow may not be sufficient to effectively engage certain air pollution control devices (APCD). Because the agency did not propose a work practice standard for periods of startup and shutdown, the EPA determined that it was appropriate to reconsider the startup and shutdown provisions to allow the public an opportunity to comment on the requirements.
On November 30, 2012, the EPA published in the Federal Register the proposed rule, “Reconsideration of Certain New Source and Startup/Shutdown Issues: National Emission Standards for Hazardous Air Pollutants from Coal- and Oil-fired Electric Utility Steam Generating Units and Standards of Performance for Fossil-Fuel-Fired Electric Utility, Industrial-Commercial-Institutional, and Small Industrial-Commercial-Institutional Steam Generating Units” (77 FR 71323). The November 30, 2012, action announced, among other things, reconsideration of certain new source standards for MATS and the requirements applicable during periods of startup and shutdown for MATS and the startup and shutdown provisions related to the PM standard in the Utility NSPS and proposed revisions to these identified provisions. The EPA also proposed certain technical corrections. On April 24, 2013, the EPA finalized reconsideration on all issues except those related to startup and shutdown (including related technical corrections) (78 FR 24073).
During the comment period, the EPA received data and other information from industry about EGU startup, and the industry commenters recommended that the startup and shutdown provisions as proposed be further amended. The comments raised several significant issues regarding the definition of startup, the types of “clean fuels” that must be used during startup, the means by which non-mercury (Hg) emissions are calculated during periods of startup and shutdown (e.g., requests for the use of a default diluent cap and for the use of a default electrical production rate),
and the manner in which EGUs that share a common stack demonstrate compliance during periods of startup and shutdown. Given the significance of these comments, the EPA believes it is appropriate to request additional comment on these issues. Therefore, we are reopening the public comment period so that the public can review the industry-provided information and data and comment on the suggested revisions to the startup and shutdown provisions. We are only reopening for comment the startup and shutdown provisions in the MATS rule and the startup and shutdown provisions related to PM in the Utility NSPS. We are not seeking comment on any other issues and will not respond to comments outside the scope of this notice.
In the November 2012 reconsideration proposal, the EPA proposed to revise the definitions of startup and shutdown to clarify the definitions and include a reference to making useful thermal energy. Specifically, in § 63.10042 we proposed to define the end of “startup” as being “. . .when the EGU generates electricity that is sold or used for any other purpose (including on site use), or the EGU makes useful thermal energy (such as heat or steam) for industrial, commercial, heating, or cooling purposes. . .whichever is earlier.” 77 FR 71339. We also proposed several revisions to the finalized work practice standards. These revisions included the addition of certain synthetic natural gas, syngas, propane and ultra low-sulfur diesel (ULSD) to the list of clean fuels. Start Printed Page 38003Further, we proposed to require EGU source owners and operators, when firing coal, solid oil-derived fuel, or residual oil in the EGU during startup and shutdown, to vent emissions to the main stack(s) and operate all control devices necessary to meet the operating standards that apply at all other times under the final rule (with the exception of limestone injection in fluidized bed combustors (FBC) EGUs, dry scrubbers, selective non-catalytic reduction systems (SNCRs) and selective catalytic reduction systems (SCRs)).
Moreover, we proposed that owners and operators of EGUs would be responsible for starting limestone injection in FBC EGUs, dry scrubbers, SNCRs and SCRs as expeditiously as possible, but, in any case, when necessary to comply with other CAA standards applicable to the source that require operation of those control devices. Additionally, we proposed to revise the final rule's work practice standards to recognize constraints of certain EGUs and APCDs. The proposed revised standards would allow limestone injection to start after appropriate temperatures have been attained in FBC EGUs that inject limestone for acid gas control and allow SNCR, SCR and dry scrubber systems to start as soon as technically feasible after the appropriate temperature has been reached. With regard to integrated gasification combined cycle (IGCC) EGUs, we proposed two options for IGCC EGUs for the handling of syngas that is not fired in the combustion turbine: (1) Syngas must be flared, not vented; or (2) syngas must be routed to duct burners, which may need to be installed, and the flue gas from the duct burners must be routed to the heat recovery steam generator. 77 FR 71330-71331.
The commenters' primary issue with the proposed standards for startup and shutdown concerned the definition of “startup” in the reconsideration notice (particularly with regard to the end of “startup”). Specifically, the commenters objected to the EPA's proposed definition which defined the end of startup to be “. . . when the EGU generates electricity that is sold or used for any other purpose (including on site use),” or “the EGU makes useful thermal energy (such as heat or steam) for industrial, commercial, heating, or cooling purposes,” whichever is earlier.” 77 FR 71339. As discussed below, the commenters advocated a different end point for startup. The EPA also received comments on the types of fuels considered “clean,” the required use of clean fuels throughout startup, the specifics of startup as related to IGCC EGUs, the use of diluent caps and sorbent trap monitoring during startup, and the application of the work practice standards to EGUs with a common stack. Below is a summary of some issues raised in the industry comments on which we are now requesting comment. The complete comments are contained in the MATS and Utility NSPS rulemaking dockets (see EPA-HQ-OAR-2009-0234 and EPA-HQ-OAR-2011-0044, respectively).
The commenters asked the EPA to define “startup” as the setting in operation of an affected source.
According to the commenters, this involves igniting fuel in the boiler, producing steam to begin generating electricity either before or after the primary fuel is added to the boiler and getting all of the APCDs operational to meet the applicable requirements. The commenters maintained that “startup” does not end “when any steam from the boiler is used to generate electricity for sale over the grid or for any other purpose” as the EPA proposed. The commenters asserted that an EGU remains in “startup” mode beyond the first generation of electricity because, according to the commenters, at that point in time many of the APCDs needed to comply with the requirements of this subpart may not be technically or safely capable of operation and those that are may be operating far from design conditions because the requisite temperature(s) and/or flow conditions have not been achieved. For example, the commenters expressed concern that operating electrostatic precipitators (ESPs) at temperatures less than the temperatures recommended by the manufacturer/supplier could create a safety risk.
The commenters also stated that electricity generation may begin when the boiler's steam load is as low as 10 percent of nameplate capacity.
At this point, the commenters stated that startup fuel is still being burned, either alone or in combination with primary fuel, but many major components of the EGU (e.g., APCDs) may neither be online nor fully functioning. The commenters further noted that at many EGUs the boiler igniters have low capacity (e.g., 5 percent of the EGU capacity).
So, according to these commenters, the igniters as currently constructed may not be able to bring an EGU to flue gas temperatures at which APCD can be made operational. The commenters stated that this inability to use igniters alone to bring the EGU and APCD to the proper temperatures stems from a number of reasons, among which is the fact that some igniters offer only a low heating value and, thus, cannot serve a heating function well over long periods of time.
As noted above, the commenters asserted that some igniters may not have sufficient capacity (i.e., size) and were generally not designed to preheat the APCD without the co-firing of the primary fuel and, for this reason, the commenters maintained that some igniters may not be able to generate adequate heat to preheat the APCD even if they were operated for an “extended period of time.” 
Commenters also stated that certain EGU facilities do not have sufficient natural gas capacity to bring their EGUs up to the temperatures necessary to engage certain APCDs (e.g., because the natural gas burners or pipeline are currently too small).
The commenters maintained that, generally, the igniters (and warm-up guns in some cases) are used to begin to raise boiler pressure, supply steam to heat plant equipment (e.g., piping, steam turbine, pulverizers) and raise the furnace temperature to a point where the primary fuel can be burned. Therefore, the commenters asserted that the startup period involves (and in some cases must involve) co-firing of startup and primary fuels.
The commenters also stated that, in its proposal, the EPA did not adequately account for the operational differences among different types of EGUs. The Start Printed Page 38004commenters stated, for example, that the startup process for supercritical pulverized coal (PC) EGUs is different from that for subcritical EGUs.
The commenters stated that supercritical EGUs are designed to commence startup producing subcritical steam to the steam turbine, and then transition to supercritical operation at a certain point as steam production and electricity generation are increased. The commenters asserted that a supercritical EGU does not complete its startup until its transition from subcritical to supercritical operation is complete. The commenters recommended that the end of startup for supercritical EGUs should correspond with the point in time corresponding to 6 hours past the time when the EGU achieves supercritical mode of operation.
For subcritical EGUs, the commenters provided information reflecting the sequence of events during startup for two subcritical EGUs, stating that the baghouse, the activated carbon injection (ACI) and the SCR are not operational when the EGU goes online (i.e., connected to the grid). However, the comments indicate that the baghouse and the ACI controls are operational approximately 4 hours after the EGU reaches the 25-percent load point. The commenters stated that the SCR system is operational about 12 hours after the EGU goes online. The commenters requested that the end of startup be changed to be 4 hours after 25-percent load is first reached or 12 hours after first electricity generation, whichever occurs first.
The commenters explained that the 4-hour timeframe would provide for a transition period during which a facility phases out the supplemental fuel, shuts down a dedicated startup system (like a startup boiler feed pump, if applicable) and transitions to bring emission controls online safely and within the manufacturer's intended design capabilities. The commenters maintained that the 12-hour alternative definition would allow for situations where the startup sequence is delayed for unexpected reasons, but provided assurance that an EGU will not idle at low load.
Relative to FBC EGUs, the commenters stated that if limestone is added too early in the startup sequence, the flame could be extinguished. According to the commenters, FBC EGUs that inject limestone must reach a minimum bed temperature of approximately 1,500°F for the limestone to calcine, and, thus, become effective at reducing acid gases. The commenters stated that these EGUs often burn coal for about 45 minutes before limestone is added, and additional time is then required for the bed chemistry to stabilize. They stated that normally the bed is stable and up to temperature when approximately 40-percent load is reached. The commenters requested that the EPA apply the same definition of “startup” to FBC EGUs as was suggested for the other types of EGUs (i.e., 4 hours after 25-percent load is first achieved, or 12 hours after first electricity generation, whichever occurs first).
The commenters also provided input on the types of fuels considered “clean,” the specifics of startup as related to IGCC EGUs, the use of diluent caps and sorbent trap monitoring during startup and the application of the work practice standards to EGUs with a common stack. The commenters suggested that the EPA should expand the proposed list of “clean fuels” to include biodiesel and other renewable fuels that meet the 40 CFR Part 80, subpart M, requirements and that biodiesel and other biofuels be among the clean fuels allowed.
The commenters stated that it is important that either flaring syngas or routing it to duct burners remain as options for IGCC EGUs and indicated that flaring should remain an option for routine startups and shutdowns of IGCC EGUs and as a viable option for non-routine events such as unit “trips” when the combustion turbine cannot combust syngas.
The commenters suggested that the EPA should reinstate the use of the diluent cap and/or provide for a diluent cap for non-mercury pollutants, as is allowed for Hg in Appendix A of subpart UUUUU. 77 FR 9606. Commenters believed the use of a diluent cap is appropriate when complying with a heat input-based emission standard because emissions must be reported during periods of startup and shutdown, and using the actual carbon dioxide or oxygen concentrations in the stack during startup and shutdown will, according to the commenters, grossly overstate emissions, as the initial (or final) concentrations during those periods are close to ambient levels.
Moreover, because EGU owners or operators who use CEMS, continuous parameter monitoring systems (CPMS) or sorbent traps will be required to report emission rates during periods of startup and shutdown, some commenters recommended that a default electrical output rate (in terms of megawatt-hours (MWh) or gigawatt-hours (GWh)) be established for use during startup and shutdown periods.
According to the commenters, use of such a default electrical output rate would prevent EGU owners or operators from reporting infinite emissions, which is what the commenters state would occur when no (or zero) electrical output for these periods was placed in the denominator when performing these calculations. One commenter recommended that an EGU should not have to sample for Hg with sorbent traps until startup has ended because, unlike a CEMS, a sorbent trap system collects an integrated sample over an extended time period and does not provide real-time data.
Therefore, according to the commenter, it is not possible to separate the Hg compliance data from data collected during startup and shutdown periods. The commenter noted that although startup and shutdown events are generally short, if startup and shutdown emissions are included in the compliance calculations, this could potentially skew the results.
The final rule contains specific requirements for EGUs that use a common stack (see § 63.10010(a)(2) and (3)). Even with these requirements, some commenters asserted that the rule does not adequately account for startup and shutdown periods for individual EGUs. Some commenters stated that the proposed rule does not resolve how the startup and shutdown definitions and work practice provisions apply to EGUs that share a common stack. Several commenters acknowledged that the work practice standards would be applied separately on each EGU that shares a common stack, but they argued that the rule should provide that the numerical emission limits do not apply Start Printed Page 38005if even one EGU sharing the common stack is starting up or shutting down.
The EPA requests comment on the information and data provided in the public comments regarding the startup and shutdown provisions and, in particular, the commenters' recommendations concerning the definition of “startup.” The EPA requests additional input on the following startup/shutdown-related issues that were raised by commenters on the proposed rule:
- The use of default diluent gas cap values during periods of startup and shutdown;
- How to calculate startup/shutdown emissions when multiple affected EGUs share a common stack; and
- The use of a default electrical production rate value to calculate output-based emission limits during startup and shutdown hours where the electrical load is zero.
In addition, the EPA requests comment on the additional technical analyses it conducted in response to the above comments concerning the end of startup. See “Assessment of startup period at coal-fired electric generating units” in Docket ID EPA-HQ-OAR-2009-0234. In this analysis of EGUs, the EPA examined several indicators that can aid in assessing the time required to achieve operating benchmarks.
Using these indicators, we found no significant difference in performance related to startup between the different groups assessed in this analysis. We believe these results could support defining the end of startup at coal-fired EGUs as occurring at 25 percent of nameplate capacity plus 3 hours or the start of electricity generation plus 6 hours, whichever comes first, and we are soliciting comment on the analysis.
We are only reopening for comment the startup and shutdown issues described above. We are not seeking comment on any other issues and will not respond to comments submitted that are outside the scope of this notice.
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- Environmental protection
- Administrative practice and procedure
- Air pollution control
- Hazardous substances
- Intergovernmental relations
- Reporting and recordkeeping requirements
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Dated: June 18, 2013.
[FR Doc. 2013-15146 Filed 6-24-13; 8:45 am]
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