	Introduction

Biomass energy, or bioenergy, may receive more attention from stakeholders as an alternative to fossil fuels because of its potential to minimize the environmental impacts of energy production, provide energy security, and promote economic development. The carbon-neutral designation typically is assigned to an energy-production activity that essentially produces no net increase in greenhouse gas (GHG) emissions on a life-cycle basis (or one that absorbs the amount of carbon dioxide emitted during the power-production cycle). Some biomass feedstock producers and biopower generators, among other stakeholders, contend that biopower is carbon neutral because the carbon released during bioenergy production comes from a feedstock that removed the carbon from the atmosphere as it was growing—biomass. Additionally, biopower production may receive increased attention due to executive branch actions, such as the U.S. Environmental Protection Agency's (EPA's) Clean Power Plan and EPA's proposed framework to account for emissions of biogenic carbon dioxide (CO 2 ) from stationary sources. No commonly accepted definition for a carbon-neutral activity exists in the biopower arena. A life-cycle assessment (LCA) is one method to calculate the environmental footprint. The first three phases of the biopower pathway (cultivation and harvest, transport, and electricity generation) are where the bulk of GHG emissions occur. GHG flux during the first three phases is site and operation specific and depends on many factors, including the biomass type, management strategies, and biopower generation technology. The LCA time frame can be long (e.g., "cradle to grave") or relatively short (e.g., "cradle to gate"). In August 2015, the EPA released the final rule for CO 2 emission reductions from existing fossil fuel-fired electric power plants. This rule, commonly referred to as the Clean Power Plan (CPP), requires states to reach a state-specific CO 2 emission-reduction goal (measured in pounds of CO 2 emissions per megawatt-hour of electricity generation) by 2030. EPA reports that "qualified biomass"—biomass feedstock that has been demonstrated to be a method to control increases of CO 2 levels in the atmosphere—may be included in a state's plan. Framework for Assessing Biogenic CO2 Emissions from Stationary Sources

EPA released two draft frameworks—the first in 2011 and the second in 2014—that establish a process to evaluate and account for GHGs associated with the use of biomass to produce energy at stationary sources (e.g., biopower). EPA acknowledges that the 2014 framework is an analytical methodology and that some stakeholders may consider the framework a precursor to how EPA treats biogenic emissions for both the standards for GHG emissions from existing fossil-fueled power plants and the Prevention of Significant Deterioration program (see " Prevention of Significant Deterioration/New Source Review Program and Title V Greenhouse Gas Permitting Requirements ," below). However, EPA reports that it "has not yet determined how the framework might be applied in any particular regulatory or policy contexts or taken the steps needed for such implementation." These findings included that "carbon neutrality cannot be assumed for all biomass energy a priori." Biopower's carbon neutrality is a contentious aspect of the bioenergy debate. Congress could decide to use existing legislative authorities to address carbon accounting for biopower. To the extent carbon neutrality continues to be a legislative concern, Congress could examine whether the current carbon-neutral assumption for biopower is adequate. Congress may consider if additional carbon accounting for biopower is warranted and what impact this accounting might have on renewable energy, agricultural, and environmental legislative goals. If biopower is a part of an RES or CES, the carbon-neutrality designation of biopower may need to be considered in response to environmental and sustainability concerns.
To promote energy diversity and improve energy security, Congress has expressed interest in biopower—electricity generated from biomass. Biopower, a baseload power source, can be produced from a large range of biomass feedstocks nationwide (e.g., urban, agricultural, and forestry wastes and residues). The two most common biopower processes are combustion (e.g., direct-fired or co-fired) and gasification, with the former being the most widely used. Proponents have stated that biopower has the potential to strengthen rural economies, enhance energy security, and minimize the environmental impacts of energy production. Challenges to biopower production include the need for a sufficient feedstock supply, concerns about potential health impacts to nearby communities from the combustion of biomass, and its higher generation costs relative to fossil fuel-based electricity. At present, biopower generally requires tax incentives to be competitive with conventional fossil fuel-fired electric generation.
An energy production activity typically is classified as carbon neutral if it produces no net increase in greenhouse gas (GHG) emissions on a life-cycle basis. The legislative record shows minimal debate about the carbon status of biopower. The argument that biopower is carbon neutral has come under scrutiny in debate on its potential to help meet U.S. energy demands and reduce U.S. GHG emissions. Whether biopower is considered carbon neutral depends on many factors, including the definition of carbon neutrality, feedstock type, technology used, and time frame examined. Carbon flux (emission and sequestration) varies at each phase of the biopower pathway, given site- and operation-specific factors. A life-cycle assessment (LCA) is a common technique to calculate the environmental footprint, including the carbon flux, of a particular biopower pathway. However, past legislation would not have required a standardized LCA for biopower.
The carbon-neutral status of biopower may be of concern to stakeholders, especially if Congress expands support for biopower. Questions such as where the feedstock supply for biopower originates, if it is managed in a sustainable manner, and whether the associated air-quality impacts from biopower generation are tolerable are part of the biopower carbon-neutrality debate. Congress may decide whether the current approach regarding the carbon status of biopower is acceptable or whether additional carbon accounting for biopower is warranted and what impact this accounting might have on renewable energy, agricultural, and environmental legislative goals.
Two recent actions by the executive branch—the U.S. Environmental Protection Agency's (EPA's) Clean Power Plan (CPP), which addresses carbon dioxide (CO2) emission reductions from existing fossil fuel-fired electric power plants, and EPA's proposed framework to account for biogenic CO2 emissions from stationary sources—could focus attention on biopower's carbon neutrality. The CPP—which was granted a stay by the Supreme Court on February 9, 2016—requires states to devise a plan that allows them to reach a state-specific CO2 emission reduction goal by 2030, using various options, including renewable energy (e.g., biopower). In the CPP final rule, EPA specifies that "qualified biomass" may be included in a state plan given certain conditions. In November 2014, EPA released its second biogenic accounting framework. The framework addresses some of the EPA Science Advisory Board's recommendations from the first framework, released in 2011, including the finding that "carbon neutrality cannot be assumed for all biomass energy a priori." EPA acknowledges that the framework is an analytical methodology and that some stakeholders may consider it an example of how EPA may treat biogenic emissions in both the CPP and the Prevention of Significant Deterioration program. However, EPA reports that it "has not yet determined how the framework might be applied in any particular regulatory or policy contexts or taken the steps needed for such implementation."