Framework for Assessing Biogenic CO2 Emissions from Stationary Sources

This report presents a methodological framework for assessing the extent to which the production, processing, and use of biogenic material at stationary sources results in a net atmospheric contribution of biogenic carbon dioxide (CO2) emissions. Biogenic CO2 emissions are defined as CO2 emissions related to the natural carbon cycle, 1 as well as those resulting from the production, The framework examines direct emissions of biogenic CO2 from stationary sources that combust or process biogenic material, taking into account factors related to the biological carbon cycle. These factors include changes in biogenic carbon-based stocks and emissions—known as " carbon fluxes " 3 —that occur (or are avoided) as a result of (1) feedstock growth and harvest; (2) processing, transport, storage, and use of a biogenic feedstock at the stationary source; and/or (3) the possible alternative fate of biogenic feedstock materials if not used for bioenergy. 4 The framework is a revision of the U.S. Environmental Protection Agency's (EPA's) original September 2011 Draft Accounting Framework for Biogenic CO2 Emissions from Stationary Sources and was developed in response to a peer review by the Biogenic Carbon Emissions Panel of EPA's Science Advisory Board (SAB Panel). In the review, 5 the SAB Panel stated that: Carbon neutrality cannot be assumed for all biomass energy a priori. There are circumstances in which biomass is grown, harvested and combusted in a carbon neutral fashion but carbon neutrality is not an appropriate a priori assumption; it is a conclusion that should be reached only after considering a particular feedstock's 1 The term " carbon cycle " is used to describe the flow of carbon (in various forms, for example, as CO2) through the atmosphere, ocean, terrestrial biosphere, and lithosphere (IPCC, 2007a). 2 Biologically based feedstocks, also referred to in this report as " biogenic materials, " are non-fossilized and biodegradable organic materials originating from modern or contemporarily grown plants, animals, or microorganisms (including products, by-products, residues, and wastes from agriculture, forestry, and related industries, as well as the non-fossilized and biodegradable organic fractions of industrial and municipal wastes, including gases and liquids recovered from the decomposition of non-fossilized and biodegradable organic material). These feedstocks do not include materials such as peat, coal, petroleum, natural gas, and other products that are derived from biologic materials but are considered non-renewable during the time frame relevant to policymaking. 3 The IPCC defines " carbon flux " as the transfer of …