Naomi Pena

Is woody bioenergy carbon neutral? A comparative assessment of emissions from consumption of woody bioenergy and fossil fuel

Under the current accounting systems, emissions produced when biomass is burnt for energy are accounted as zero, resulting in what is referred to as the ‘carbon neutrality’ assumption. However, if current harvest levels are increased to produce more bioenergy, carbon that would have been stored in the biosphere might be instead released in the atmosphere. This study utilizes a comparative approach that considers emissions under alternative energy supply options. This approach shows that the emission benefits of bioenergy compared to use of fossil fuel are time‐dependent. It emerges that the assumption that bioenergy always results in zero greenhouse gas (GHG) emissions compared to use of fossil fuels can be misleading, particularly in the context of short‐to‐medium term goals. While it is clear that all sources of woody bioenergy from sustainably managed forests will produce emission reductions in the long term, different woody biomass sources have various impacts in the short‐medium term. The study shows that the use of forest residues that are easily decomposable can produce GHG benefits compared to use of fossil fuels from the beginning of their use and that biomass from dedicated plantations established on marginal land can be carbon neutral from the beginning of its use. However, the risk of short‐to‐medium term negative impacts is high when additional fellings are extracted to produce bioenergy and the proportion of felled biomass used for bioenergy is low, or when land with high C stocks is converted to low productivity bioenergy plantations. The method used in the study provides an instrument to identify the time‐dependent pattern of emission reductions for alternative bioenergy sources. In this way, decision makers can evaluate which bioenergy options are most beneficial for meeting short‐term GHG emission reduction goals and which ones are more appropriate for medium to longer term objectives.

Zero, one, or in between : evaluation of alternative national and entity-level accounting for bioenergy

Accounting for bioenergys carbon dioxide (CO2) emissions, as done under the Kyoto Protocol (KP) and European Union (EU) Emissions Trading Scheme, fails to capture the full extent of these emissions. As a consequence, other approaches have been suggested. Both the EU and United States already use value‐chain approaches to determine emissions due to biofuels – an approach quite different from that of the KP. Further, both the EU and United States are engaged in consultation processes to determine how emissions connected with use of biomass for heat and power will be handled under regulatory systems. The United States is considering whether CO2 emissions from biomass should be handled like fossil fuels. In this context, this article reviews and evaluates the three basic bioenergy accounting options. CO2 emissions from bioenergy are not counted at the point of combustion. Instead emissions due to use of biomass are accounted for in the land‐use sector as carbon stock losses – a combustion factor (CoF) = 0 approach; CO2 emissions from bioenergy are accounted for in the energy sector – a CoF = 1 approach; and End users account for all or a specified subset of CO2 emissions, regardless of where geographically these emissions occur – 0 < CoF < 1.

Incentives for the use of forest biomass: a comparative analysis of Kyoto Protocol accounting pre- and post-2012

This article focuses on differences between incentives of current and post-2012 Kyoto Protocol land use, land-use change and forestry (LULUCF) accounting rules. Three changes to the LULUCF accounting rules were agreed to in Durban. These changes alter national-level incentives for retaining wood in forests, using wood for products or using it for energy. Post-2012, accounting for emissions from managed forests will be mandatory rather than voluntary, as is currently the case. Reference levels, rather than historical carbon stock levels, will be used to measure these emissions. Finally, increases and decreases in harvested wood products (HWP) pools will be reported. These changes provide national-level incentives to increase forest carbon stocks and to use nationally harvested wood for products. However, the rule that no emissions are counted at the point of combustion of biomass remains unaltered. This gives entities with greenhouse gas (GHG) obligations under the EU Emissions Trading Scheme (EU ETS) an incentive to use wood for energy, counteracting the national-level incentives. Use of additionally harvested wood for energy may increase national emissions within commitment period time-frames because combustion of biomass, in most cases, results in higher carbon dioxide emissions per unit of energy supplied than combustion of the fossil fuels it replaces. In contrast, retention of wood in forests or use of domestic wood for products, will, particularly under the post-2012 rules, tend to result in lower national-level emissions being accounted. However, neither retention of wood in forests nor increases in the HWP pool results in benefits to individual entities, as currently there is no EU scheme under which the entities involved face GHG obligations.

Accounting for Algae

Interest and research in the use of algae for energy is growing but an analysis of the different methods for the accounting for the carbon dioxide (CO 2) emissions that result, is lacking. In this article, four accounting systems are evaluated for their completeness, simplicity, sectoral accuracy, and scale‐independence. Two options under the Kyoto Protocol (KP), a value‐chain (end‐user responsibility) approach, and Point of Uptake and Release (POUR) are evaluated.