EPA finalizes boiler NESHAP

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Courtesy of Trinity Consultants

EPA published the final National Emission Standards for Hazardous Air Pollutants (NESHAP) for industrial, commercial, and institutional boilers and process heaters at both major and area sources of hazardous air pollutants (HAP) emissions. EPA developed separate rules for units at major sources of HAP emissions (greater than 10 tons per year [tpy] of any single HAP and/or greater than 25 tpy of total HAP) and area sources of HAP emissions (less than 10 tpy/25 tpy). The Maximum Achievable Control Technology (MACT) standards for units at major sources are codified in 40 CFR 63 Subpart DDDDD, while the Generally Available Control Technology (GACT)/MACT standards for units at area sources are codified in 40 CFR 63 Subpart JJJJJJ. The rules were proposed June 4, 2010.

On December 7, 2010, EPA asked the court for a 15-month extension to the deadline to issue final Boiler MACT rules to address stakeholder concerns. On January 20, 2011, EPA’s request was denied. Because the issuance of the final rules was rushed, EPA initiated the reconsideration process for both rules simultaneous with their publication.

Major Source Boiler MACT
The major source rule, known as the Boiler MACT, affects boilers and process heaters that burn coal, biomass, other solid fuels, fuel oil, natural gas, refinery gas, and other gaseous fuels. EPA estimates that 13,840 existing boilersand process heaters and 47 new units to be constructed during the next three years will be affected by the NESHAP. The estimated compliance costs for existing sources are $5.1 billion in capital expenditures and $1.8 billion in annual costs (down from $9.5 billion and $3.2 billion in the proposed rule, respectively).

Applicability
The affected sources for the rule are the collection of existing and new or reconstructed industrial, commercial, and institutional boilers and process heaters that do not burn solid waste at major sources of HAP emissions. The definition of solid waste is found in the Resource Conservation and Recovery Act (RCRA) regulations and EPA has issued simultaneous separate rule-making for these units. A unit is classified as a new source if construction commenced after June 4, 2010. Similarly, sources that are reconstructed (as defined in Section 63.2) after June 4, 2010 are classified as reconstructed sources. A boiler or process heater is classified as existing if it is not new or reconstructed. The compliance date for new sources is May 20, 2011, or upon startup, whichever is later. The compliance date for existing sources is March 21, 2014.

The units exempt from the requirements of the proposed rule were retained in the final rule, with additional clarification provided in the final rule. These include:

  • A boiler or process heater used as a control device for other MACT subparts if at least 50 percent of the heat input to the unit is provided by the gas stream regulated under another subpart
  • Any boiler specifically listed as an affected source in any other standard established under Section 129 of the Clean Air Act (CAA)
  • A boiler required to have a permit under Section 3005 of the Solid Waste Disposal Act or covered by 40 CFR 63 Subpart EEE

Emission Limits
The HAP categories targeted by the final rule remain unchanged from the proposed rule and include mercury (Hg), non-mercury metal HAP, non-dioxin organic HAP, non-metal inorganic HAP, and dioxin/furans. EPA selected hydrogen chloride (HCl) as a surrogate for non-metal inorganic HAP, particulate matter (PM) as a surrogate for metal HAP, and carbon monoxide (CO) as a surrogate for non-dioxin organic HAP. Emission limits were developed based on fuel type for HCl, PM, and Hg. Fuel and boiler design requirements apply for CO and dioxin. In the proposed rule, EPA requested comments on the Health Based Compliance Alternative (HBCA), however the final rule does not include HBCA for any affected sources.

In the proposed rule, units were divided into 11 subcategories depending on the fuel fired and the boiler design. In the final rule, EPA combined biomass- and coal-fired units into one subcategory (units designed to fire solid fuels) for the purpose of the fuel-dependent HAP emission limits. EPA also added subcategories for biomass suspension/grate units, limited use units (units greater than 10 MMBtu/hr limited to 876 hours per year), and non-continental liquid units.  The definition of each subcategory includes a 10 percent cutoff (on an annual average heat input basis) for determining the subcategory in which a boiler or process heater falls. EPA revised the definition of the Gas 1 subcategory to include other gaseous fuels that qualify based on mercury and hydrogen sulfide concentrations in the gas.

Based on additional emission information received during the comment period, EPA revised emission limits in the final rule. The emission limits in the proposed and final rules are summarized in Table 1 for new sources and Table 2 for existing sources. In addition to heat input based emission limits, EPA added the option for complying with heat output (MMBtu of steam output) based emission limits.

Consistent with the vacatur of provisions regarding HAP emissions during periods of startup, shutdown, and malfunction1, the standards apply at all times (i.e., including periods of malfunction). The final rule requires sources subject to numeric emission limits to meet work practice standards for periods of startup and shutdown. The work practice standards include minimizing the startup and shutdown time in accordance with manufacturer’s recommended procedures. This was changed from the proposed rule which stipulated specific emission limits for periods of startup and shutdown. For periods of noncompliance during a malfunction, EPA added language in the final rule regarding affirmative defense. To assert the claim of affirmative defense, facilities must meet the notification and evaluation criteria in the final rule.

EPA retained the work practice standards in the proposed rule for units not subject to numeric emission limits. In the final rule, new and existing units in the Gas 1 or metal furnace subcategories, with a heat input capacity equal to or greater than 10 MMBtu/hr, are subject to a work practice standard consisting of annual tune-ups. Furthermore, the work practice standard consisting of tune-ups every two years was expanded to both new and existing units of all fuel types with a heat input capacity less than 10 MMBtu/hr (the proposed rule had emission limits for new units) and limited use units.

Energy Assessment
The final rule provided additional information regarding the scope of the one-time energy assessment for cost-effective energy conservation measures that is required for affected units. The rule provides a detailed definition of the qualified energy assessor required to perform the assessment. Although the energy management program is consistent with the ENERGY STAR Guidelines for Energy Management, the requirement to use the ENERGY STAR Facility Energy Assessment Matrix was removed.

The final rule clarifies the duration and scope for the energy assessment based on the annual heat input of the affected boilers and process heater, as follows:

  • The energy assessment for facilities with affected boilers and process heaters using less than 0.3 trillion Btu per year of heat input will be one day in length maximum. The boiler system and energy use system accounting for at least 50 percent of the energy output must be evaluated to identify energy savings opportunities, within the limit of performing a one-day energy assessment.
  • The energy assessment for facilities with affected boilers and process heaters using 0.3 to 1.0 trillion Btu per year will be 3-days in length maximum. The boiler system and any energy use system accounting for at least 33 percent of the energy output must be evaluated to identify energy savings opportunities, within the limit of performing a 3-day energy assessment.
  • In the energy assessment for facilities with affected boilers and process heater using greater than 1.0 trillion Btu per year, the boiler system and any energy use system accounting for at least 20 percent of the energy output must be evaluated to identify energy savings opportunities.

In lieu of submitting the energy assessment as part of the compliance demonstration, as originally proposed, the final rule requires submitting a certification that the assessment was completed and is an accurate depiction of the facility.

Source Testing
In a change from the proposed rule, dioxin/furan stack testing is only required for initial compliance (i.e., no periodic tests are required). Annual stack testing is required to demonstrate compliance with the emission limits for all other regulated pollutants, except for hydrogen chloride and/or mercury if the fuel analysis option is utilized, or for particulate matter if continuous emissions monitoring is required. Facilities must maintain the operating load of each unit below 110 percent of the average operating load during the most recent performance test.

Rather than the proposed four-hour test runs, the final rule outlines a minimum test duration and/or sampling volume per run for each pollutant. Stack testing can be reduced to once every three years if test results for at least two consecutive years show emissions at or below 75% of the limit. The results of the annual stack test shall be submitted using an EPA web-based electronic reporting tool (ERT).

Compliance Monitoring
If a facility uses performance tests to demonstrate compliance with emission limits, it must develop a site-specific monitoring plan. The plan must be submitted to the permitting authority upon request, at least 60 days before the initial performance evaluation. The plan must address ongoing operation and maintenance, quality assurance, and recordkeeping and reporting. For operating limits that require the use of parametric monitoring, the facility will be required to install, operate, and maintain a continuous parameter monitoring system (CPMS).

Continuous Emissions Monitoring
In a departure from the proposed rule, units with capacities equal to or greater than 100 MMBtu/hr are not required to install and operate a continuous emissions monitoring system (CEMS) for CO. However, an oxygen CEMS is still required. Compliance with the CO (and dioxin/furan) limit will be demonstrated by maintaining the 12-hour block average oxygen concentration above the minimum value established during the performance test.

As in the proposed rule, coal, biomass, and residual oil fired units equal to or greater than 250 MMBtu/hr, must install a PM CEMS. Unlike the proposed rule, the final rule requires that compliance with the PM emissions limit be determined based on the 30-day rolling average (not the 24-hour daily average as in the proposed rule) of the hourly arithmetic average emissions concentrations using the CEMS data.

For units with an applicable opacity operating limit, continuous monitoring is required using a continuous opacity monitoring system (COMS). There are three specified exceptions to COMS monitoring:

  • Units equipped with wet scrubbers
  • Units with a heat input capacity250 MMBtu/hr or greater (PM is being monitored)
  • Bag leak detection systems for fabric filters

The opacity limit is for dry control systems and is 10% opacity on a daily block average basis. As an alternative to installing COMS, facilities can install a bag leak detection system (BLDS) for units controlled by fabric filters subject to opacity limits. To demonstrate continuous compliance using a BLDS, a facility must initiate corrective action within one hour of a bag leak detection system alarm, complete corrective actions as soon as practical, and operate and maintain the fabric filter system such that the alarm does not sound more than five percent of the operating time during a six-month period.

Fuel Monitoring
As an alternative to operating add-on controls for HCl and mercury, facilities may elect to demonstrate the concentration of HAP in the fuel fired by the unit is below the emission limit. To demonstrate compliance with the mercury or HCl limits based on fuel analysis, monthly fuel analyses for each type of fuel burned are required. Facilities must develop and submit a site-specific fuel analysis plan to the EPA Administrator for review and approval. When burning a new type of fuel, a fuel analysis must be conducted prior to burning the new type of fuel. Fuel usage (type and amount) must be recorded on a monthly basis for each unit to demonstrate that no new fuels or solid waste has been burned in the unit. The proposed rule had required daily fuel monitoring.

Emissions Averaging
The emissions averaging provisions in the final rule are similar to the proposed rule. The option to comply with the emission limits using emission averaging is allowed only for existing affected units within the same subcategory. Emissions averaging is limited to PM, HCl, and mercury. A 10% discount factor is applied to the combined emissions average (i.e., combined emissions cannot exceed 90% of the limit). If selecting emissions averaging for compliance, facilities must develop and implement an emissions averaging plan. The plan must be submitted for approval at least 180 days before averaging will begin. Annual testing is required for facilities utilizing emissions averaging.

Reporting
The timeline for notifications and reports required by the proposed rule are:

  • Initial Notification – Due September 17, 2011 for existing sources or within 15 days of startup for new sources
  • Notification of Performance Test – No later than 30 days prior to conducting performance test
  • Notification of Compliance Status – No later than 60 days after the completion of the performance test/compliance evaluation
  • Notification of Natural Gas Curtailment – Within 48 hours of the declaration of a period of natural gas curtailment or supply interruption and intention to fire different fuels
  • Semiannual Compliance Report – Within 31 days from the end of each reporting period (January 1 - June 30 and July 1 - December 31)

These reports are in addition to any reports required by the general provisions in Subpart A.

Area Source Boiler NESHAP
The area source Boiler NESHAP (also called area source Boiler MACT/GACT) will affect boilers that burn coal, oil, biomass, or non-waste materials, but not solid waste. EPA estimates that approximately 183,000 existing area source boilers at 92,000 U.S. facilities and 6,800 new area source boilers over the next three years will be affected.

Applicability
The general applicability in the final rule for affected sources remains the same as the proposed rule. The affected source is the collection of existing and each new or reconstructed industrial, commercial, and institutional boilers at area sources of HAP emissions. Note that process heaters and natural gas boilers are excluded from the area source rule. A unit is classified as a new source if construction or fuel switching from natural gas to coal, biomass, or oil commenced after June 4, 2010. It is important to note that the fuel switching applicability is unique to the area source Boiler MACT. Similarly, sources that are reconstructed (as defined in 40 CFR 63.2) after June 4, 2010 are classified as reconstructed sources. A boiler is classified as existing if it is not new or reconstructed.

The compliance date for new sources is May 20, 2011 or upon startup, whichever is later. The compliance date for existing sources has changed from the proposed rule. The compliance dates for existing sources are as follows:

  • If an existing affected boiler is subject to a work practice or management practice standard of a tuneup, the facility must comply with the work practice or management standard no later than March 21, 2012
  • If an existing affected boiler is subject to emission limits, the facility must comply with the emission limits no later than March 21, 2014
  • If an existing affected boiler is subject to the energy assessment requirement, the facility must comply with the energy assessment requirement no later than March 21, 2014

The exemptions in the proposed rule were retained in the final rule, namely: units subject to another Part 63 standard or CAA Section 129 standard, gas-fired boilers, research and development boilers, and hazardous waste boilers. The final rule also exempts hot water heaters as defined in the rule and boilers used as control devices under another subpart. Unlike the proposed rule, no facilities are required to obtain a Title V operating permit as part of compliance with the final area source rule.

EPA revised the subcategory definitions from the proposed rule. The biomass subcategory in the final rule is defined as any boiler that burns more than 15 percent biomass on an annual heat input basis (the proposed subcategory excluded units that burned coal). The coal subcategory includes any boiler that combusts solid fossil fuel and no more than 15 percent biomass on an annual heat input basis. The oil subcategory includes boilers that burn any liquid fuel and is not in either the coal or biomass subcategory.

Emission Limits
The rule includes standards to limit emissions of mercury, particulate matter (as a surrogate for non-mercury metals) and carbon monoxide (as a surrogate for organic air toxics), depending on new or existing status, fuel type, and size.

Standards for area sources can be based on either generally available control technology (GACT) or maximum achievable control technology (MACT). The standards for existing and new coal-fired boilers are based on MACT for mercury and CO, and based on GACT for PM. In a change from the proposed rule, the standards for existing and new biomass and oil-fired boilers are based on GACT for CO, mercury and PM (the proposed rule had included MACT for CO). Existing and new small coal boilers (i.e., less than 10 MMBtu/hr) and existing oil and biomass boilers of all sizes are required to perform a boiler tune-up every two years. Emission limits in the final rule compared to the proposed rule are summarized in Table 3.

Similar to the major source Boiler MACT, the area source standards apply at all times, with work practice standards for startup and shutdown for new and existing coal, new biomass, and new oil units with a heat input greater than 10 MMBtu/hr. The final rule also includes provisions for affirmative defense for exceedances caused by malfunctions.

Energy Assessment
Similar to the major source rule, the area source rule includes a one-time energy assessment of cost-effective energy conservation measures that is required for existing units with heat input capacities greater than 10 MMBtu/hr. The same requirements and procedures for energy assessments required under the major source rule apply to area sources.

Source Testing
Stack testing in the final rule is limited to initial testing and every three years thereafter. The proposed rule had required annual stack testing. The results of the stack test must be submitted using EPA’s ERT. Facilities must maintain the operating load of each unit below 110 percent of the average operating load during the most recent performance test.

Compliance Monitoring
If facilities use performance tests to demonstrate compliance with emission limits and establish operating limits, they must develop a site-specific monitoring plan. The plan must be submitted to the permitting authority upon request, at least 60 days before the initial performance evaluation. The plan must address ongoing operation and maintenance, quality assurance, and recordkeeping and reporting. For operating limits that require the use of a continuous monitoring system (CMS), facilities must install, operate, and maintain a CPMS.

Continuous Emissions Monitoring
Similar to the major source Boiler MACT and unlike the proposed rule, units with capacities equal to or greater than 100 MMBtu/hr are not required to install and operate a CEMS for CO. However, an oxygen CEMS is still required for units subject to a CO emission limit. Compliance with the CO limit will be demonstrated by maintaining the 12-hour average oxygen concentration above the minimum value established during the performance test.

For units with an applicable opacity operating limit, continuous monitoring is required using a COMS. The opacity limit is for dry control systems and is 10% opacity on a daily block average basis. As an alternative to installing COMS, facilities can install a BLDS for units controlled by fabric filters or monitor secondary power input for electrostatic precipitators subject to opacity limits. To demonstrate continuous compliance using a BLDS, facilities must initiate corrective action within one hour of a bag leak detection system alarm, complete corrective actions as soon as practical, and operate and maintain the fabric filter system such that the alarm does not sound more than five percent of the operating time during a six-month period.

Fuel Monitoring
To demonstrate compliance with the mercury limits based on fuel analysis, monthly fuel analyses for each type of fuel burned are required. Before burning a new type of fuel, a fuel analysis must be conducted. Fuel usage (type and amount) must be recorded on a monthly basis for each unit.

Reporting
The deadlines for notifications and reports required by the rule are:

  • Initial Notification – Due September 17, 2011, for existing sources or within120 days after the source becomes subject to the standard
  • Notification of Compliance Status – No later than 120 days after the applicable compliance date unless a performance test is required; in that instance, no later than 60 days after the completion of the performance test/compliance evaluation
  • Annual Compliance Certification Report – Prepare by March 1 of each year for the previous calendar year and submit upon request

These reports are in addition to any reports required by the general provisions in Subpart A.

Reconsideration
On December 7, 2010, EPA asked the court for a 15-month extension on the deadline to issue the final rules. EPA intended to re-propose the rules so as to address stakeholder concerns. However, on January 20, 2011, the request was denied and the deadline for final rules was set as February 21, 2011. Due to technical concerns raised during the comment period, EPA initiated the reconsideration process for both rules.

EPA believes that reconsideration and additional opportunity for public review and comment should be obtained for the following provisions of the two rules:

  • Revisions to the proposed subcategories in the major source boilers rule
  • Establishment of a fuel specification in the major source boiler rule through which gas-fired boilers that use a fuel other than natural gas may be considered Gas 1 units
  • Development of work practice standards for limited use major source boilers
  • Establishment of standards for biomass and oil-fired area source boilers based on GACT
  • Revisions to the proposed monitoring requirements for carbon monoxide for major source boilers
  • Revisions to the proposed dioxin emission limit and testing requirement for major source boilers
  • Establishing a full-load stack test requirement for carbon monoxide coupled with continuous oxygen monitoring for major source boilers
  • Clarification on the applicability of Title V permitting requirements for area source boilers

Solid Waste Rules
Concurrent with the final boiler rules, EPA published a final rule entitled Identification of Non-Hazardous Secondary Materials That Are Solid Wastes. This RCRA final rule identifies which non-hazardous secondary materials are, or are not, solid wastes when burned in combustion units. For units that do not burn exclusively fossil fuels or their derivatives, this distinction is critical, as units that burn non-hazardous secondary materials that are solid waste under RCRA would be subject to section 129 CAA (i.e., Commercial/ Industrial Solid Waste Incinerators [CISWI]) requirements, but units that burn non-hazardous secondary materials that are not solid waste under RCRA would be subject to section 112 CAA (i.e., MACT) requirements.

The CAA specifically excludes the following types of units from the definition of ‘‘solid waste incineration unit’’:

  • Incinerators or other units required to have a permit under section 3005 of RCRA
  • Material recovery facilities (including primary and secondary smelters) which combust waste for the primary purpose of recovering metals
  • Qualifying small power production facilities, as defined in section 3(17)(C) of the Federal Power Act, or qualifying cogeneration facilities, as defined in section 3(18)(B) of the Federal Power Act, which burn homogeneous waste for the production of electric energy or in the case of qualifying cogeneration facilities which burn homogeneous waste for the production of electric energy or steam or forms of useful energy (such as heat) which are used for industrial, commercial, heating or cooling purposes, or
  • Air curtain incinerators, provided that such incinerators only burn wood wastes, yard wastes and clean lumber and that such air curtain incinerators comply with the opacity limitations to be established by the Administrator by through rulemaking

For additional discussion of the solid waste definition, please read Defining Solid Waste, also in this issue.

Compliance Considerations
Now that the Boiler NESHAP rules are final and compliance deadlines are set, facilities will begin evaluating the applicability of the rules and determining the necessary control devices, monitoring systems, and work practice upgrades required. In addition to reviewing applicability of the new rules, facilities will need to prepare project schedules to make sure that necessary modifications will be completed in time to meet the compliance deadlines. With control devices and monitoring systems required for thousands of units, it appears that resources will be stretched. Trinity can assist facilities with evaluating applicability and developing a path forward to meet the compliance deadlines in the final rules.

1Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008)

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