The U.S. Environmental Protection Agency is amending certain provisions of its Mandatory Reporting of Greenhouse Gases Rule (MRR) to address issues raised after the MRR was first published in October 2009. Revisions will affect, among others, facilities combusting municipal solid waste or tires as fuels. These facilities no longer need to have continuous emission monitoring systems to use ASTM D6866 analysis.
In the first MRR, ASTM D6866 is used to quantify biogenic CO2 emissions from general stationary combustion units using MSW and heterogeneous fuels (a mix of biomass and fossil inputs).
The EPA has also provided a comprehensive list of materials that qualifies as municipal solid waste (MSW) as part of its proposed amendments. Other recommended changes include the option not to report biogenic carbon dioxide emissions from biomass combustion and recognition of tires as part biomass.
The proposed amendments were signed July 20, 2010. The 45-day public comment period begins after publication of the revised MRR in the Federal Register. The EPA expects to publish the final amended MRR before 2010 ends. Deadline for reporting of 2010 GHG emissions is on March 31, 2011.
The EPA is proposing to lift restrictions limiting the use of ASTM D6866 analysis to facilities with continuous emission monitoring systems. The EPA would allow combustion units using a mix of biomass and fossil fuels, regardless of proportion, to measure their biogenic CO2 emissions on a quarterly basis via ASTM D6866 analysis. Even without a CEMS in place, gas sample collection is still to be done according to ASTM D7459. [Page 79111] of the MRR Proposed Changes]
Gas sampling via ASTM D7459 is still required by the EPA in a quarterly basis. Under the MRR, sample collection is done for a minimum of 24 consecutive operating hours every calendar quarter.
In the proposed amendments, the EPA would allow collection of an integrated sample by taking 1-5 cubic centimeters of flue gas during every operating hour over the course of a calendar quarter to obtain a more representative sample for ASTM D6866 analysis. This will solve issues with alternative fuels like tires whose composition varies over time. According to the EPA, if the type of fuel combusted and their relative proportions are not consistent throughout the quarter, more frequent, periodic sampling of the flue gas should be considered. [Page 79111] of the MRR Proposed Changes]
The EPA has also clarified the meaning of municipal solid waste to include the solid phase of household, commercial/retail, and institutional waste. Materials not considered as MSW are used oil, wood pellets, clean wood, industrial process or manufacturing wastes, medical waste, motor vehicles, and construction/renovation/demolition waste. Yard waste, refuse-derived fuel, and motor vehicle maintenance materials like batteries and tires, are considered MSW. [Page 79138] of the MRR Proposed Changes]
In the first MRR, tires were classified as fossil fuel-derived fuels; thus, tire combustion emissions would have been reported as 100% fossil CO2. In the proposed changes, the EPA now recognizes used tires as “partly biogenic.”
For facilities that combust tires, separate reporting of biogenic CO2 emissions is optional. Measurement of biogenic CO2 is to be done via ASTM D6866. [Page 79109] of the MRR Proposed Changes]