May 2009

Summary of Greenhouse Gas Reporting Requirements for Soda Ash Manufacturing

ALERT: Your facility may be one of the 13,000 facilities in the US potentially impacted by EPA’s proposed greenhouse gas emissions regulations.

On March 10, 2009, the Environmental Protection Agency (EPA) proposed rule 40 CFR 98, which would require mandatory reporting of greenhouse gas (GHG) emissions from large sources in the United States. The proposed rule was published in the Federal Register on April 10, 2009, and the public comment period is open until June 9, 2009. The rule would require collecting and reporting comprehensive emissions data from certain facilities, suppliers of fossil fuels and industrial GHGs, manufacturers of vehicles and engines, and some facilities that emit 25,000 metric tons per year or more of GHGs. The purpose of this memorandum is to provide a brief overview of the proposed rule relative to this industrial sector.

General Provisions - 40 CFR Part 98
If enacted, the rule would require reporting of annual emissions of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), perfluorochemicals (PFCs), and other fluorinated gases (e.g., nitrogen trifluoride, hydrofluorinated ethers [HFEs]). The rule would apply to certain facilities that emit GHGs, including petroleum refineries, and to suppliers of fossil fuels. The proposed rule (40 CFR 98) would apply to certain facilities that emit GHGs, including soda ash manufacturers, and to suppliers of fossil fuels and industrial GHGs.

Background - Soda Ash Manufacturing
Soda ash (sodium carbonate, Na2CO3) is a raw material utilized in numerous industries including glass production, pulp and paper production, and soap production. Approximately 11 million metric tons (tonnes) of soda ash is produced in the United States annually, the majority coming from the raw material trona (Na3HCO3CO3•2H2O). Trona is a naturally-occurring carbonate material mined exclusively in Wyoming. The processes by which soda ash is made from trona are commonly referred to as “natural production” methods. These methods produce CO2 as a by-product through the calcination (heating) of trona in kilns.

GHG emissions from natural soda ash manufacturing were estimated to be 3.1 million tonnes CO2 equivalents (CO2e) in 2006 (less than 0.04 percent of U.S. total GHG emissions). The GHG emissions are the result of the calcination process and on-site stationary combustion sources. EPA has proposed that all “natural” soda ash manufacturers report regardless of their total GHG emissions and estimates that each facility would report GHG emissions in excess of 100,000 tonnes CO2e per year.

Subpart P – Soda Ash Manufacturing Source Category
The proposed rule defines a soda ash manufacturing facility as:

“…any facility with a manufacturing line that calcines trona to produce soda ash.”

Soda ash manufacturers would be required to report CO2 emissions from each soda ash manufacturing line associated with the calcination of the trona feedstock (process emissions). In addition to process emissions, soda ash manufacturers would be required to report CO2, CH4, and N2O emissions resulting from fuel combustion at each kiln and stationary combustion source.

GHGs to Report / Inventory
The following sources would be included in a soda ash manufacturer’s GHG inventory:

• CO2 emissions from the evolution of CO2 during calcination of trona (process emissions)
  
• CO2, CH4, and N2O emissions from stationary combustion sources
  
• Other emissions and sources for which a soda ash manufacturing facility would have to account as specified in Section 98.2 (a)
  

Monitoring of Emissions
The proposed rule lists three monitoring methods to estimate process emissions. These methods include the following:

1. Use of default emission factors in conjunction with the amount of either trona consumed or soda ash produced
   
2. Development of a site-specific emission factor (determined by an annual stack test)
   
3. Direct measurement of emissions using Continuous Emission Monitoring Systems (CEMS)
   

Under the proposed rule, if a soda ash manufacturing facility is required to use an existing CEMS to meet the requirements outlined in Part 98, Subpart C, a CEMS would be required to estimate CO2 emissions. Where the CEMS would not adequately account for process emissions or does not meet the conditions outlined in Subpart C of the rule, process-related CO2 emissions would be estimated using a modified form of Method 1 described above.

Emissions Estimations
Process Emissions - In the proposed rule, EPA elected that a soda ash manufacturing line meeting certain criteria would estimate CO2 emissions using a CEMS. If a CEMS is not required, facilities would estimate process emissions using measured (monthly average) inorganic carbon content of the trona or soda ash and a simplified emission factor. The measured inorganic carbon content of the trona or soda ash would be required to be determined on a daily basis for each soda ash manufacturing line.

Combustion Sources - GHG emissions from combustion sources would be estimated using one of four approaches (denoted as tiers by the proposed rule). Tier 1 estimates have the lowest certainty, while Tier 4 has the greatest certainty. The data requirements for the four Tiers range from simple flow rate data to CEMS data for Tier 1 and Tier 4 approaches, respectively. Combustion sources operating under certain conditions (outlined in Subpart C of the proposed rule) would be required to use the Tier 4 approach to estimate CO2 emissions.

Recordkeeping / Reporting
If enacted, all affected soda ash manufacturing facilities would begin monitoring GHG sources on January 1, 2010. The proposed schedule calls for facilities to report all GHG emissions on March 31, 2011, for the 2010 reporting year. Each annual GHG report would be certified by the facility to be true, accurate, and complete. EPA would have the jurisdiction to perform selective random audits of all facilities in respective EPA regions. Furthermore, the proposed rule would require a QA/QC document and demonstrate emission source calculation procedures. Facility record maintenance would be required for 5 years.

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