This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy. United States Office of Atmospheric Programs September 2011 Environmental Protection Agency _____________________________________________________________________________________________ ACCOUNTING FRAMEWORK FOR BIOGENIC CO2 EMISSIONS FROM STATIONARY SOURCES Accounting Framework for Biogenic CO2 Emissions from Stationary Sources Prepared by the U.S. Environmental Protection Agency Office of Atmospheric Programs Climate Change Division Washington, DC September 2011 This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy. How to Obtain Copies: You may electronically download this document from the U.S. EPA's webpage at: http://www.epa.gov/climatechange/emissions/biogenic_emissions.html. For Further Information: Contact Jennifer Jenkins ([email protected]) or Sara Ohrel ([email protected]), Climate Change Division, Office of Atmospheric Programs, U.S. Environmental Protection Agency. Acknowledgements: The Environmental Protection Agency would like to acknowledge these contributors to this report: Thomas Buchholz, Spatial Informatics Group and University of Vermont Charles Canham, Cary Institute of Ecosystem Studies Mark Flugge, ICF International Katie Hanks, RTI International Gregg Marland, Appalachian State University Bruce McCarl, Texas A&M University Stephen Ogle, Colorado State University Diana Pape, ICF International Stephen Prisley, Virginia Polytechnic Institute and State University Neil Sampson, The Sampson Group September 2011 Page i This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy. Acronyms ACRES Acres Needed AFOLU Agriculture, Forestry, and Other Land Use ASTM American Society for Testing and Materials AVOIDEMIT Avoided Emissions BAF Biogenic Accounting Factor BAU Business-As-Usual BTU British thermal unit(s) C Carbon C&D Construction and Demolition CCS Carbon Capture and Storage CH4 Methane CO Carbon monoxide CO2 Carbon dioxide CO2e Carbon dioxide equivalent DDG Distiller Dried Grains EPA U.S. Environmental Protection Agency FEEDN Feedstock Needed FIA Forest Inventory and Analysis GHG Greenhouse gas GPP Gross Primary Production GROW Growth GWP Global warming potential IPCC Intergovernmental Panel on Climate Change LAR Level of Atmospheric Reduction LEAK Leakage LUCF Land-Use Change and Forestry MMS Manure Management System MSW Municipal Solid Waste N2O Nitrous Oxide NASS National Agricultural Statistics Service NBE Net Biogenic Emissions PGE Potential Gross Emissions PNW Pacific Northwest PRODC Carbon in Products SEQP Sequestered Fraction SITE_TNC Total Net Change in Site Emissions SITE_TNCacre Total Net Change in Site Emissions per Acre SITEEMIT Changes in Net Site Emissions September 2011 Page ii This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy. SITESEQ Changes in Net Site Sequestration tCO2e Metric Tons of Carbon Dioxide Equivalent TDW Tire-Derived Waste TFP Tons of Feedstock Produced Tg Teragrams UNFCCC United Nations Framework Convention on Climate Change USDA United States Department of Agriculture USFS United States Forest Service YIELD_ACRE Yield per Acre September 2011 Page iii This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy. Executive Summary ACCOUNTING FRAMEWORK FOR BIOGENIC CO2 EMISSIONS FROM STATIONARY SOURCES The purpose of this report is to consider the scientific and technical issues associated with accounting for emissions of biogenic carbon dioxide (CO2) from stationary sources, and to develop a framework to account for those emissions. In this report, biogenic CO2 emissions are defined as CO2 emissions directly resulting from the combustion, decomposition, or processing of biologically based materials other than fossil fuels, peat, and mineral sources of carbon through combustion, digestion, fermentation, or decomposition processes. Biogenic CO2 is emitted from stationary sources through a variety of energy-related and industrial processes. This report and accounting framework were developed for the policy context where it has been determined that a stationary source emitting biogenic CO2 requires a means for “adjusting” its total onsite biogenic emissions estimate on the basis of information about growth of the feedstock and/or avoidance of biogenic emissions and more generally the carbon cycle. The decision on whether to adjust biogenic CO2 emissions from a stationary source in any particular program is a policy decision, and this study does not provide any recommendations or judgments about that issue. Rather, this report provides a general accounting framework that could be used as a means to adjust biogenic CO2 emissions at stationary sources. As discussed in Section 2, fossil and biogenic carbon interact with the overall carbon cycle on very different time scales, and this difference has implications for understanding estimates of biogenic CO2 emissions from stationary sources. CO2 emissions from the consumption of fossil fuels will inevitably increase the amount of carbon in the atmosphere on policy-relevant time scales, but such an outcome is not inevitable with the consumption of biologically based feedstocks. The amount of biologically based feedstocks consumed at stationary sources during a year may be partially or completely balanced by the amount of feedstock that grows during the year. On that basis, as discussed in Section 2, EPA concludes that in order to develop an accounting framework to adjust total onsite biogenic emissions at a stationary source, it is essential to assess the carbon stored by growth of biologically based feedstocks. Consistent with this conclusion, the Intergovernmental Panel on Climate Change (IPCC) notes the importance of looking at the status of carbon fluxes on land in order to understand the CO2 impacts of bioenergy: If energy use, or any other factor, is causing a long term decline in the total carbon embodied in standing biomass (e.g., forests), this net release of carbon should be evident in the calculation of CO2 emissions described in the Land-Use Change and Forestry chapter. 1 The balance of this report addresses the development of a framework that can be applied from the perspective of a stationary source that is adjusting its total onsite biogenic emissions, and reflects the connection between onsite biogenic CO2 emissions and the land base providing the biologically based feedstock. The report and the framework are narrower in scope and are not intended to address the different issues that arise when considering biogenic CO2 emissions outside of this specific context, such as issues that arise when comparing lifecycle emissions between biogenic and fossil fuels. In order to develop an approach that could be relatively easily adopted and understood, EPA designed the framework to meet certain criteria. Therefore, the framework: 1 Page 1.10. Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories: Reference Manual September 2011 Page iv This information is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy. • Accurately reflects the carbon outcome. • Is scientifically rigorous/defensible. • Is simple and easy to understand. • Is simple and easy to implement. • Is easily updated with new data. • Uses existing data sources. Section 3 identifies the important technical and methodological issues that should be considered when constructing any framework for developing an adjustment factor for biogenic CO2 emissions at stationary sources that reflects changes in carbon stocks occurring beyond the stationary source. Decisions on these factors are critical in development of the framework, and may differ in application depending on program and policy requirements and objectives. Section 3 presents an overarching discussion of these issues, along with the implications of specific decisions about the issues, which are summarized here. • The starting point for the framework is to identify which greenhouse gases (GHGs) to include: i.e., only biogenic CO2 or other GHGs as well. The next step is to consider the quantity of onsite biogenic emissions from the stationary source, also called “direct emissions” of biogenic CO2. Determining the boundary for offsite factors that are included in the framework is another critical step. Offsite factors include