EPA releases updated biogenic emissions framework

On Nov. 19, the U.S. EPA released a revised framework for assessing biogenic carbon dioxide (CO2) emissions from stationary sources. According to a notice published by the EPA, the second draft of the framework will undergo further review. The agency has also issued a memo providing regulatory guidance on how the updated framework will impact the Clean Power Plan and Prevention of Significant Deterioration Program.

A notice published by EPA explains that in order to continue advancing technical understanding of the role biomass can play in reducing overall greenhouse gas (GHG) emissions, the EPA has developed a second draft of its “Framework for Assessing Biogenic Carbon Dioxide for Stationary Sources” report, which will subject to additional review. “The revised report takes into account the latest information from the scientific community and other stakeholders. As a next step forward, EPA will continue to refine its technical assessment by initiating a second round of targeted peer review with the Science Advisory Board,” said the agency in a notice posted to its Climate Change website. The notice also indicates Acting Administrator Janet McCabe has issued a memorandum to the EPA’s Regional Air Division Directors describing the EPA’s current thinking pertaining to biogenic CO2 emissions in the context of the CPP and PSD program.

The revised 69-page framework describes the factors that are to be considered when assessing biogenic CO2 emissions. It also presents an equation that could be used to calculate the extent to which use of biogenic materials at stationary sources results in a net atmospheric contribution of biogenic CO2 emissions.

The EPA released the first draft of its biogenic emissions framework in September 2011. That report was reviewed by member of a Biogenic Carbon Emissions Panel appointed by the EPA’s Scientific Advisory Board. In its review, the SAB Panel said “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 production and consumption cycle. There is considerable heterogeneity in feedstock types, sources and production methods and thus net biogenic carbon emissions will vary considerably. Carbon neutrality cannot be assumed for all biomass energy a priori.” According to the EPA, the majority of the panel also said it is not appropriate to use Intergovernmental Panel on Climate Change national accounting methodologies to evaluate biogenic CO2 emissions from individual stationary sources. The EPA also indicated that although the SAB Panel did agree with some basic tenets of the first draft of the framework, they also indicated it lacked some technical elements. The panel recommended more consideration of different spatial and temporal scales, different baselines, broader discussions on leakage and soil carbon implications, and the concept of regional feedstock-specific calculations and default assessment factor values.

The updated framework addresses the SAB Panel recommendations and those made by stakeholders. According to the EPA, the updated draft includes more comprehensive discussion and analysis of baseline approaches, spatial and temporal scale decisions and implications, inclusion of alternative fate analysis for certain feedstocks and methane, leakage, and illustrative regional feedstock-specific calculations using existing data sources and models and resulting example regional biogenic assessment factor values.

The memo issued by McCabe notes that the EPA expects many states and stakeholders to look to the updated framework draft for indications of how biogenic CO2 emissions will be treated under the CPP and PSD program going forward. As such, the memo describes the EPA’s current thinking with respect to those programs and their treatment of biogenic emissions.

Within the memo, McCabe said that information considered by the EPA in preparing the second draft of the framework supports the finding that the use of waste-derived feedstocks and certain forest-derived industrial byproducts are likely to have minimal or no net atmospheric contributions of biogenic CO2 emissions. Rather, the use of those materials may even reduce such impacts when compared to the alternate fate of disposal. “The EPA intends to apply this preliminary finding further with the policy contexts and regulatory actions described below,” wrote McCabe.

 “While we continue the development of the Framework to reflect ongoing technical and scientific work, we believe that our approach to the treatment of biomass in the CPP and PSD program should be determined by policy and programmatic objectives, goals and considerations, based on and supported by technical information - an outlook that the SAB peer reviewers acknowledged in their review of the initial draft Framework,” McCabe wrote. “In light of those considerations, we believe that it is appropriate for the EPA to take additional actions to implement the policies described below in the CPP and the PSD program in parallel with our intended further work on the Framework.”

“In the implementation of the CPP, the EPA anticipates that some states will wish to include the use of biogenic feedstocks in their compliance plans. When considering state compliance plans, the Agency expects to recognize the biogenic C02 emissions and climate policy benefits of waste-derived and certain forest-derived industrial byproduct feedstocks, based on the conclusions supported by a variety of technical studies, including the revised Framework,” McCabe continued. “In addition, given the importance of sustainable land management in achieving the carbon reduction goals of the President's Climate Action Plan, the EPA expects that states' reliance specifically on sustainably-derived agricultural- and forest-derived feedstocks may also be an approvable element of their compliance plans. This approach is consistent with the EPA's recognition in the proposal that every state has different energy systems and available fuel mixes. Many states already recognize the importance of forests and other lands for climate resilience and mitigation, and have developed a variety of sustainable forestry and land use management policies and programs to address these concerns. Some states also encourage participation in sustainable forest management programs developed by third-party forestry and/or environmental entities.”

According to McCabe, the EPA will evaluate the biogenic components of proposed state plans as part of the compliance plan review and approval process, and will provide clarification as needed on the basis on which it will make such biomass-related evaluations.

McCabe also indicated the EPA plans to propose revisions to the PSD rules to include an exemption from the best available control technology (BACT) requirement for GHGs from waste-derived feedstocks and from non-waste biogenic feedstocks derived from sustainable forest or agricultural practices. For waste-derived feedstocks, McCabe said the EPA intends to propose exempting biogenic CO2 emissions from GHG BACT analyses based on the rationale that those emissions are likely to have minimal or no net atmospheric contributions of biogenic CO2 emissions when compared with an alternate fate of disposal. For sustainable non-waste feedstocks, McCabe said the EPA intends to propose exempting biogenic emissions from GHG BACT analyses if the applicant can demonstrate that these feedstocks come from sustainably managed lands. For all other biogenic feedstsocks, the memo indicates the EPA intends to propose biogenic CO2 emissions would remain subject to the GHG BACT requirement at this time. According to McCabe, the EPA also anticipates providing additional guidance to sources undergoing BACT analyses involving biogenic feedstocks.

Within the memo, McCabe also noted the EPA is working through the legal process to respond to the Supreme Court’s decision in Utility Air Regulatory Group v. EPA and the current proceedings in appeals court. “When developing the PSD regulations described above, the EPA intends to consider the outcome of this process and coordinate its PSD regulations specific to biogenic C02 emissions with other rule revisions that may be necessary to address application of PSD permitting requirements to GHGs. Our goal would also be to enable permitting authorities and sources to implement the permitting requirements in a practical manner that is consistent with the policy objectives articulated above for the CPP,” McCabe wrote.

The memo also specifies that a second round of targeted peer review through the SAB will begin this month. That review will include public comment.

Full copies of the revised framework and McCabe memo can be downloaded from the EPA’s Climate Change website.