The BACT Analysis Guide: EPA Proposes Permit and BACT Requirements for Greenhouse Gases
On September 30, 2009 the EPA announced a proposed rule that sets permitting and Best Available Control Technology (BACT) requirements for large facilities that emit over 25,000-tons of greenhouse gases (GHG) per year. The proposed rule has been titled “Prevention of Significant Deterioration and Title V Greenhouse Gas Tailoring Rule” and focuses on emissions of the following group of GHG:
- 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.