At a conference a few weeks ago, the question was asked: “what is BACT for GHG”? The answer is…”it depends”. As detailed in previous posts on this website, and highlighted several times throughout the EPA BACT GHG Guidance, it is important to remember that BACT for any pollutant is determined on a case-by-case basis via a BACT Analysis, including BACT for GHG. That being said, the EPA has provided white papers that outline GHG control measures for several industrial sectors. These include:

• Electric Generating Units
• Large Inustrial/Commercial/Institutional Boilers
• Pulp and Paper
• Cement
• Iron and Steel Industry
• Refineries
• Nitric Acid Plants

The control measures discussed in these documents include energy efficiency, alternative fuel considerations, and carbon capture and sequestration.

If you have any questions regarding BACT and GHG, or permitting of GHG under the CAA, feel free to send me an e-mail at BMogan@Geosyntec.com.

• Carbon Dioxide (CO2)
• Methane (CH4)
• Nitrous Oxide (N2O)
• Hydrofluorocarbons (HFC)
• Perfluorocarbons (PFC)
• Sulfur Hexafluoride (SF6)

The EPA is proposing that the GHG emissions from facilities be estimated using carbon dioxide equivalents (CO2e), which is the international standard. This metric uses the global warming potential of gases other than CO2 to translate them into CO2e.

Under the Title V program (40 CFR part 70), facilities would be considered a major source if they emit greater than 25,000-tons/year of CO2e and would be required to obtain a Title V operating permit. Under the New Source Review (NSR) Prevention of Significant Deterioration (PSD) program, a new source, or major modification at an existing source, would be considered major if it emits greater than 25,000-tons/year of CO2e and would be required to obtain a PSD permit. Modifications at existing major sources resulting in CO2e emissions increases of 10,000-tons/year to 25,000-tons/year (the exact number has not yet been decided) would be required to obtain a PSD permit.

The facilities with GHG emissions that trigger the PSD permitting requirements would be required to perform a BACT Analysis and incorporate BACT to control GHG emissions from their facility. Facilities that may be subject to this proposed rule include: power plants, refineries, and municipal solid waste landfills. Small facilities such as farms and restaurants will not be subject to the proposed rule.

The BACT for Carbon Monoxide (CO) from many of these large facilities is an oxidizer (or incinerator). These devices control CO emissions by converting them into CO2. Under this new rule, a facility could be required to obtain a Title V or PSD permit due to the secondary emissions from their CO control device (i.e., without the control device they would not have to be permitted for their CO2e emissions). Furthermore, the same facility may be required to install BACT for GHG emissions. This could pose a great financial burden on facilities subject to this rule. One possible solution to this issue is that the EPA could allow that only primary CO2 emissions (not those generated during CO control) be included when comparing CO2e emissions with the GHG permitting threshold.

Natural Gas Fired Boiler

The BACT Requirement applies to new sources, or modifications of existing sources, which emit the following NSR pollutants:

• Pollutants with a National Ambient Air Quality Standards (NAAQS), also known as criteria pollutants, which include:
  • Ozone
  • Carbon Monoxide
  • Particulate Matter
  • Sulfur Dioxide
  • Lead
  • Nitrogen Oxide
• Other pollutants including sulfuric acid mist, hydrogen sulfide, etc.
• Note that some states, such as Connecticut require BACT for ANY pollutant

The federal regulations require that “Major Sources” and “Major Modifications to existing sources” perform a BACT Analysis. However, some states have more stringent requirements. The following are a few examples:

• Connecticut
  • Potential emissions greater than the threshold for major sources and major modifications
  • Potential emissions greater than 15-tons per year from ANY new emission unit or modification to existing emission units (not just major sources)
• South Carolina
  • Any new construction when the net VOC emissions increase is greater than 100-tons per year

For your state’s specific BACT requirements, you should check with your local regulator (City, County, State).