On March 14, the US Environmental Protection Agency (USEPA) made good on a promise to consider excluding emissions of carbon dioxide (CO2) from bioenergy and other biogenic sources (biomass) for the purposes of the Best Available Control Technology (BACT) analysis and applicability to the Prevention of Significant Deterioration (PSD) program. It published a proposed rule that would defer, for a period of three years, greenhouse gas (GHG) permitting requirements for CO2 emissions from biomass-fired and other biogenic sources. USEPA is also making available a guidance document, Guidance for Determining Best Available Control Technology for Reducing Carbon Dioxide Emissions from Bioenergy Production, to assist facilities and permitting authorities with permitting decisions until the proposed rule is finalized. USEPA will accept public comments on the Proposed Deferral (but not, of course, on the Guidance) for 45 days following publication in the Federal Register. Also, look for a hearing in Washington, D.C. on the matter, tentatively scheduled for 15 days after publication in the Federal Register.

After a background discussion of the issue, this post addresses the significant actions the Proposed Deferral and Guidance take with regard to: (1) timing, (2) applicability, and (3) the co-firing question.

First, why does biomass get special treatment? In short, two words: carbon cycle. The combustion (direct or indirect) of biomass as a fuel indisputably places CO2 in the atmosphere. But this carbon is part of the current carbon cycle: it was absorbed during the growth of the biomass over the previous few months or years and, provided the land continues to support growing plant material, a sustainable balance is maintained between carbon emitted into the atmosphere and absorbed into the biomass. In sum, the carbon used to construct biomass is absorbed from the atmosphere as carbon dioxide (CO2) by plant life, using energy from the sun.

Second, what is biomass? While it can mean different things to different people, this post cares about how USEPA defines it. USEPA defines biomass as “biogenic CO2 emissions,” in turn defined as emissions of CO2 from a stationary source directly resulting from the combustion or decomposition of biologically based materials other than fossil fuels. Examples include, but are not limited to:

  • CO2 generated from the biological decomposition of waste in landfills, wastewater treatment or manure management processes
  • CO2 from the combustion of biogas collected from biological decomposition of waste in landfills, wastewater treatment or manure management processes
  • CO2 from fermentation during ethanol production
  • CO2 from combustion of the biological fraction of municipal solid waste or biosolids
  • CO2 from combustion of the biological fraction of tire-derived fuel
  • CO2 derived from combustion of biological material, including all types of wood and wood waste, forest residue, and agricultural material

It is important to note that non-CO2 emission from combustion of biomass (methane, nitrous oxide) are not part of USEPA’s definition and thus are not subject to the Proposed Deferral and Guidance.

The applicability to both PSD and the Title V programs is dependent on whether the stationary source meets certain emissions thresholds. On June 3, 2010, USEPA issued the Tailoring Rule and established two steps to implement PSD and Title V. Tailoring Rule Step 1 began January 2, 2011. Step 1 applies to sources subject to PSD or Title V anyway because of their emissions of other pollutants (“anyway” sources) and that have the potential to emit 75,000 tpy CO2e (or to increase emissions by that amount for modifications). Tailoring Rule Step 2 begins July 1, 2011. In addition to anyway sources, Step 2 applies to new facilities emitting GHGs in excess of 100,000 tpy CO2e, and facilities making changes that would increase GHG emissions by at least 75,000 tpy CO2e, and that also exceed 100/250 tpy of GHGs on a mass basis. The question raised by these threshold determinations is: does biomass “count” for purposes of meeting these thresholds?

To answer this question, USEPA published a Call for Information in July 2010 to obtain scientific and technical information concerning GHG resulting from the use of biomass and PSD. Some data supported the conclusion that certain biomass materials, such as waste whose inevitable decomposition will result in greenhouse gas emissions anyway, have only very limited climate impacts when combusted as fuel. However, other data indicated that the use of certain other biomass as fuel could have more significant climate impacts.

This contradiction led USEPA to announce January 12, 2011 that it will undertake an expedited rulemaking to be completed by July 1, 2011 to defer application of pre-construction permitting requirements to biomass for a period of three years. During that time, USEPA proposed to initiate a scientific examination with partners from other federal agencies and scientists outside the government with relevant expertise to assist the agency in determining how CO2 emissions from biomass should be handled under PSD. Further, in the interim, USEPA indicated it will issue guidance that states and local agencies can use to conclude that BACT for GHG at biomass sources is combustion of biomass fuels alone.

Summary of Three Significant Issues in Proposed Deferral and Guidance

As noted above, the Proposed Deferral and Guidance take significant actions with regard to (1) timing, (2) applicability, and (3) the co-firing question.

Timing and the Proposed Deferral

First, note that no biomass source is deferred until the Proposed Deferral is finalized as a final rule. USEPA indicated final action on the Proposed Deferral by July 2011. This is a very ambitious timeline, particularly in light of the admissions by USEPA in the Proposed Deferral that the deferral of biomass will require State Implementation Plan revisions for certain states under the Clean Air Act. These facts call into question whether USEPA can meet the deadline of July 2011. And keep in mind that as the deadline is extended, it increases the likelihood that PSD and Title V permitting provisions will apply to biomass sources.

Applicability and the Proposed Deferral and Guidance

The scope of the Proposed Deferral is wider than the scope of the Guidance. Whereas the Proposed Deferral applies to “all sources of biogenic CO2 emissions,” the Guidance applies merely to “bioenergy facilities.” This means that to the extent a biomass facility does not fit into the definition of “bioenergy facility,” the source is left without guidance (except as biomass is addressed in the GHG BACT guidance) with regard to the applicability of the PSD and Title V programs until the Proposed Deferral is finalized (again, potentially a longer period of time than optimistically estimated by USEPA).

The good news is that the Guidance definition of “bioenergy facility” is quite broad and defined as “a facility that generates energy via the combustion of biologically-derived material other than fossil fuels, for example, wood, biosolids, or agricultural products. This could be undertaken either alone or in addition to traditional fossil fuels.” See Guidance, footnote 1. The last sentence of the definition includes co-firing or mixed fuel facilities – and greatly extends the reach of the Guidance. However, even if the facility qualifies as a “bioenergy” facility, USEPA has left the door open to walk away from a strict application of the Guidance by stating that USEPA believes the analysis described in Guidance will be sufficient in most cases to support the conclusion that utilization of biomass fuel alone is BACT for a bioenergy facility.  

The Co-Firing Question

The Proposed Deferral states that for stationary sources, co-firing fossil fuel and biologically based fuels and/or combusting mixed fuels (e.g., tire-derived fuels, municipal solid waste), the biogenic CO2 emissions from that combustion are included in the deferral. However, the fossil CO2 emissions are not.

USEPA acknowledged that various methods are available to calculate that fraction of biogenic CO2 emissions from co-firing facilities. USEPA is specifically requesting comments regarding: (1) whether the deferral should specify whether co-firing biomass faculties should use a specific method for determining biogenic CO2 emission; and (2) other ways to ensure there is an accurate estimate of how much biogenic CO2 is subject to deferral at co-firing facilities, particularly when combusting mixed fuels. This is an important opportunity for co-firing facilities’ voices to be heard on this important issue.