Prevention of Significant Deterioration (PSD) Permitting Process

Introduction

The Prevention of Significant Deterioration (PSD) program was established on 7 August 1977, after the US Congress substantially amended the federal CAA and outlined a detailed PSD program. The federal PSD program is set forth in Part C of the federal CAA (Sections 160 through 169B). The PSD program was developed to prevent significant environmental impacts on “attainment areas” from large industrial sources of air pollution. Attainment areas are regions of the US where air quality meets standards established by EPA (also called NAAQS). Before the PSD program was developed, construction projects in large industrial facilities were being permitted with the primary goal of not worsening air pollution in problematic areas, and improving it if possible. Congress realized that this needed to be extended to ensure that those areas with clean, healthy air would stay that way, and that industrial activity would not significantly impact protected (e.g. Class I, wilderness) areas.

The PSD Program Goals

• Economic growth in harmony with preserving clean air resources.
• To protect public health from adverse effects of air pollution.
• To preserve, protect, and enhance air quality in national parks and wilderness areas.

The PSD program does not completely stop sources from increasing emissions. In fact, for a project to become subject to PSD review, there must be a significant increase in emissions after the use of control equipment. Instead, the PSD program is designed to (USEPA 1990)

• prevent significant deterioration of ambient air quality
• ensure compliance with all NAAQS
• protect public health and welfare from any adverse effect which might occur even at air pollution levels lower than the NAAQS
• preserve, protect, and enhance the air quality in classified Class I areas (which include national parks, national wilderness areas, national monuments, national seashores, and other areas of special national or regional natural, recreational, scenic, or historic value)
• ensure that economic growth will occur in a manner consistent with the preservation of existing clean air resources and to prevent the development of any new non‐attainment areas
• assure that any decision to permit increased air pollution in any area to which PSD permitting requirements apply is made only after careful evaluation of all the consequences of such a decision, and after adequate procedural opportunities for informed public participation in the decision‐making process

The PSD program preserves local air quality and protecting areas of special value by reviewing PSD applications to ensure the requirement to apply BACT, and they comply with the NAAQS, the applicable PSD increment concentrations, as well as evaluating visibility impacts, energy and environmental impacts, soils and vegetation impacts, and growth impacts. The program includes an opportunity for public participation in the decision‐making process.

The PSD regulations apply to new “major stationary sources” and “major modifications.” A stationary source includes all pollutant‐emitting activities which belong to the same industrial grouping, are located on contiguous or adjacent properties, and are under common control. A “major modification” means a physical change or a change in the method of operation of a major stationary source which would result in a contemporaneous significant net increase in the emissions of any regulated pollutant. In determining if a proposed increase would cause a significant net increase to occur, several detailed calculations must be performed.

PSD review is only triggered if the prospective or existing location of the major source or modification has been formally designated by EPA as “attainment” or “unclassifiable” for any pollutant for which a NAAQS exists. Conversely, non‐attainment new source review (NNSR) applies to new major sources or major modifications at existing sources for pollutants where the source is located in an area not in attainment with the NAAQS. NNSR requirements are customized for the non‐attainment area. All non‐attainment NSR programs have to require

• the installation of the lowest achievable emission rate (LAER)
• emission offsets
• opportunity for public involvement

The entire preconstruction permitting program, including both the PSD and NNSR permitting programs, is referred to as the New Source Review (NSR) program. PSD review and NNSR are conducted on a pollutant‐by‐pollutant basis. For example, a facility may emit many air pollutants; however, depending on the magnitude of the emissions of each pollutant, only one or a few may be subject to the PSD permit requirements. Since EPA has not established a NAAQS for greenhouse gases (GHGs), the NNSR program does not apply to GHGs.

Table 4.8 Coal‐fired power plant title V/PSD permit emission limits and related monitoring and reporting requirements for boiler.

Source: Southwest Clean Air Agency, Vancouver, Washington.

Parameters	Limits and averaging period (shall not exceed)a	Monitoring and reporting
NOx	0.21 lb/MMBtu (30‐boiler operating day rolling average, both units combined)	Primary compliance is determined through use of continuous emissions monitoring systems (CEMS) operated in accordance with 40 CFR 75 (Acid Rain Program) for NOx and SO2, and 40 CFR 63 Subpart UUUUU for Hg. In case of Hg, it may also utilize sorbent trap monitoring system. Reference test methods: NOx: EPA Method 7E SO2: EPA Method 6 or 6C Hg: EPA Method 30B Hourly data must be reported to EPA and delegated air quality agencies quarterly.
SO2	10 000 T/Y
SO2	250 ppmvd at 7% O2 (1‐hour average)
SO2	1350 lb/h (both units combined, 1‐hour average)
Hg	1.2 lb/TBtu (30‐boiler operating day rolling average)
CO	200 ppm (both units averaged together, annual average)	Primary compliance is determined through use of continuous emissions monitoring systems (CEMS) operated in accordance with 40 CFR 60, Performance Specification 4. Reference test method: EPA Method 10 Summary results must be reported quarterly.
PM (filterable)	0.010 gr/dscf corrected to 7% O2 (1‐hour average)	EPA Method 5 is the primary reference test method. Testing, consisting of three 1‐hour test runs, is required each operating quarter. Additional compliance assurance monitoring consists of continuously monitoring the opacity in the ductwork upstream of the wet scrubber to assure the opacity of emissions remains below levels correlated with compliance.
	0.030 lb/MMBtu (or 0.30 lb/MWh) (30‐boiler operating day average)

Typical permit renewal in every five years. This table outlines only the quantitative limits. The entire permit is 128‐pages long.

dscf, dry standard cubic foot; gr, grain; ppm, parts per million; ppmvd, parts per million volume dry; TBtu, trillion British thermal unit.

^aAll deviations from permit requirements must be reported no later than 30 days after the end of the month during which the deviation is discovered. Deviations which represent a potential threat to human health or safety must be reported as soon as possible but no later than 12 hours after the deviation is discovered.

Table 4.8 presents a 1400 MW coal‐fired power plant Title V/PSD permit emission limits and related monitoring and reporting requirements for boiler. This is only a brief summary of relevant emission limits. There are many additional details and requirements. Also, there are many different aspects of coal‐fired power plants and many factors that result in different plants being subject to different emissions limits – the limits in the Table 4.8 are somewhat unique to this facility (Lamoreaux, personal communication).