Annual Basis Carbon (ABC) Accounting for Assessing Biofuel Environmental Impacts

Life Cycle Assessment (LCA) is a common approach for the assessment of biofuel sustainability. It is currently used by regulatory bodies, such as California's Low Carbon Fuel Standard and the US Renewable Fuel Standard, for evaluating environmental impacts of different biofuel types. However, drawbacks of this approach (such as "critical but difficult-to-verify assumptions, limits of available data and disputes about system boundaries) have prompted the development of other approaches in the assessment of sustainability.

Dr. John DeCicco from the School of Natural Resources and Environment, University of Michigan (United States) recently proposed an alternative approach in the evaluation of biofuel sustainability. In his paper, he recommended the use of annual basis carbon (ABC) accounting to track the stocks and flows of carbon and other relevant greenhouse gases (GHGs) throughout fuel supply chains. In ABC accounting, "the fuel and feedstock production facilities are the focus of accounting while treating the carbon dioxide emissions from fuel end-use at face value regardless of the origin of the fuel carbon".

The ABC approach is said to differ from the LCA approach in the following ways: (1) the ABC approach does not automatically credit biogenic carbon (biogenic carbon can be interpreted as the carbon released from biological activities or from the processing of biological material), (2) "the ABC policy does not fundamentally rely on a need for baselines because it is not attempting to treat the issue as an offsets problem", (3) the ABC approach has a "source focus", rather than a "product focus".

There are three elements to the ABC approach, as summarized by the Greencar Congress website: (1) full accounting of carbon dioxide emissions from fuel end-use regardless of the fuel's origin; (2) an attributional accounting protocol that relies on facilities-level GHG balances to report net carbon dioxide uptake and track otherwise unregulated GHG emissions throughout fuel and feedstock supply chains; and (3) a mechanism for mitigating consequential impacts, particularly, the leakage due to indirect land use change. The full paper is published in the journal, Biofuels and Carbon Management (URL above).