U.S. EPA Revises Framework for Assessing Biogenic CO2 Emissions

In November 2014, U.S. EPA issued a memorandum and a second draft of its “Framework for Assessing Biogenic Carbon Dioxide Emissions from Stationary Sources” that describes how biogenic carbon dioxide (CO₂) emissions will be addressed for the purposes of the Clean Power Plan (CPP) and Prevention of Significant Deterioration (PSD) permitting.  The take-home message of this action is that the use of waste-derived feedstocks, as well as certain forest-derived industrial products are likely to have minimal or no net atmospheric contribution of biogenic CO₂ emissions, and likely reduces the impact when compared with disposal practices.

The original framework, which was published in September 2011, explored the scientific and technical issues associated with biogenic CO₂ emitted from stationary sources and presented a way to estimate biogenic CO₂ emissions.  The second draft lays out a series of formulas to determine if CO₂ emissions from biomass combustion are completely carbon neutral, must be counted in full, or are somewhere in between.  Both the original and revised framework, as well as various resources, can be found here. 

As for the impacts on CPP, U.S. EPA anticipates that states will incorporate the use of biogenic feedstocks obtained from sustainable practices in their compliance plans.  U.S. EPA plans to evaluate the biogenic feedstock components of proposed state plans, provide feedback, and consult experts when needed.

Revisions to the PSD rules that include an exemption from the Best Available Control Technology (BACT) requirement for greenhouse gases (GHGs) from waste-derived or sustainable non-waste biogenic feedstocks are also planned by U.S. EPA.  U.S. EPA will propose that for waste-derived feedstocks, biogenic CO₂ emissions would be exempt from GHG BACT analyses based on the findings in the framework.  U.S. EPA will also propose that for sustainable non-waste biogenic feedstocks, biogenic CO₂ emissions would be exempt from GHG BACT analyses if the applicant can show that the feedstocks came from sustainably managed lands. Potential changes to PSD permitting regulations related to GHGs may be necessary to align the recent Supreme Court decision with this proposed accounting framework.