By Andrew Childers
WASHINGTON, D.C.--The Environmental Protection Agency will propose revising the global warming potentials industries use to calculate their annual greenhouse gas emissions to conform with international reporting standards.
A proposed rule to be published in the Federal Register April 2 would revise the global warming potential values listed in Table A-1 of EPA's mandatory greenhouse gas reporting rule (40 C.F.R. Part 98) to align with the values in the Intergovernmental Panel on Climate Change's Fourth Assessment Report.
As part of the proposal, the global warming potential for methane would increase from 21 times more potent than carbon dioxide over a 100-year timeline currently to 25 times more potent. Other greenhouse gases, such as nitrous oxide and sulfur hexafluoride, would have their global warming potentials decreased as part of the proposed rule.
The proposal also will include global warming potentials for 26 fluorinated greenhouse gases that were not previously included in EPA's reporting rule.
EPA's greenhouse gas reporting program currently requires reporting industries to use the global warming potential values from IPCC's Second Assessment Report. The Fourth Assessment Report was issued in 2007.
Revising the global warming potentials used for the reporting rule will make that data consistent with the data collected for EPA's annual Inventory of U.S. Greenhouse Gas Emissions and Sinks, which will also begin to use the fourth assessment potentials in 2015.
EPA is not proposing to include global warming potentials for ozone-depleting substances controlled by the Montreal Protocol or by Title VI of the Clean Air Act such as chlorofluorocarbons, hydrochlorofluorocarbons, and halons because they are exempted from the reporting rule requirements.
EPA used the Fourth Assessment Report values when it developed its greenhouse gas emissions standards for light-duty vehicles. Revising the table also will affect industries that use the global warming potentials to calculate their greenhouse gas emissions for the purposes of prevention of significant deterioration and Title V permitting, EPA said.
“To the extent that a Table A-1 amendment raises permitting implementation questions or concerns, EPA's regional offices and the Office of Air Quality Planning and Standards, which manage the PSD and title V programs, will work with permitting authorities and other stakeholders as necessary to provide guidance on their issues and concerns,” EPA said.
EPA also is seeking comment on options for revising the greenhouse gas emissions data reported for the years 2010, 2011, and 2012 to make them compliant with the revised global warming potentials.
The proposed rule also includes several other technical amendments to EPA's greenhouse gas reporting program.
EPA will accept comments on the proposed rule until May 17. Comment can be made at http://www.regulations.gov and should reference docket No. EPA-HQ-OAR-2012-0934.
In a separate Federal Registernotice, EPA will withdraw a direct final rule that would have required oil and natural gas companies to inform EPA by June 30 of each year if they intend to use alternative calculation methods to report their greenhouse gas emissions the next year. These could include using supplier data, engineering calculations, or other company records.
EPA set the June 30 deadline in a Feb. 19 direct final rule (78 Fed. Reg. 11,585; 28 DEN A-13, 2/11/13).
EPA is withdrawing the direct final rule because it received adverse comments. Instead, EPA will proceed through the proposed rule process. The agency also issued the revisions as a proposed rule Feb. 19 (78 Fed. Reg. 11,619).
EPA's proposed rule is available at https://s3.amazonaws.com/public-inspection.federalregister.gov/2013-06093.pdf.
For more information on EPA's proposed revisions to the greenhouse gas reporting rule, contact Carole Cook in EPA's Office of Atmospheric Programs at (202) 343-9263 or GHGReporting@epa.gov.