Q805. What factors could have influenced trends in GHGs associated with natural gas and natural gas liquids supply?
A805. Among suppliers of natural gas liquids (Subpart NN) the default emission factors used for 2013 for propane, butane and isobutene increased by a few percent over those used in 2012 due to technical corrections. The default emission factor for ethane meanwhile decreased by over 30 percent. The impact these changes had on an NGL fractionators total CO2 value depends on the mixture of products supplied and whether the fractionator used the default value or a measured value. Generally, across the industry, NGL fractionators reported a lower CO2 value in 2013 than would have been reported if the factors had not been updated. The default emission factor for natural gas supplied also decreased by about 1%, and a local distribution company’s total CO2 value would have decreased similarly if the default emission factor was used in 2012 and 2013.
Source: Brian Cook, (Data Pub FAQ Edits to SAIC 9 26 14.doc), updated per K. Chiu 10/10/18
Approval / Publishing History: Version 1, Version 2 10/16/18
Relevant Subpart/Component: GHG Data and Publication
History Panel For Internal Use - Not Visible to the Public