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Carbon emissions from biomass

According to international standards, CO2 emissions are not attributed to biomass as biomass is assumed to absorb as much CO2 as is emitted during combustion (over the complete life cycle). However, climate change is not induced by annual CO2 emissions, but by the total amount of CO2 present in the air. Virtually any form of combustion contributes to the amount of CO2 in the air. The life cycle of biomass varies from a couple of months to over a century. If we continue to emit a similar amount of CO2, we are estimated to reach 2 degrees within 20 years. This means that the CO2 emitted by combustion of biomass is not always absorbed within a timescale that is relevant to delay climate change.

Which exact part of CO2 emissions from biomass is relevant to the environment is uncertain and speculative. The ETM makes it possible to explore the potential CO2 emissions of biomass combustion in the Supply>Biomass>'CO2 emissions from Biomass' section.

This page provides background information on the carbon debt, land-use change due to biomass and biomass policies.

Checkout: the 'Biomass' infopage for more information on the use of biomass in the ETM.

Carbon debt

Carbon debt is created when biomass is used for energy production. In short, CO2 is emitted instantaneously whilst the regrowth of biomass takes time. Furthermore, direct emission levels of biomass are sometimes higher than the emissions of fossil fuels. Diminishing carbon stock by land-use change can also contribute to carbon debt. (based on: PBL/Alterra, 2013)

Land-use change

Changes of land-use can either be direct or indirect. An example of direct land-use Change (LUC) is the cutting down of a forest to grow biomass on the created farmland. When, for example, farmland for food is converted into farmland for biomass and the food production is moved to forest-converted farmland there is Indirect Land-Use Change. (Based on: EC, 2010). The United Nations Framework Convention on Climate Change (UNFCCC) refers to LUC and ILUC as "land-use, land-use change and forestry" (LULUCF).

Source: Typical carbon increment curves for an even-aged stand of trees (PBL/Alterra, 2013) Source: Typical specifications of various wood species (PBL/Alterra, 2013)

Use of pruning and waste wood accelerates the natural decomposition process. Typical half-lives for natural decay in forests ranges from 2-5 years for bark to 10-35 years for dead trees.

Typical half-time values (in years) for the decay of wood residue in forests (PBL/Alterra, 2013)

There are also tree-species with a short rotation. Willow has an rotation cycle of several years. Using this type of biomass however involves risk of land change (LUC and ILUC).

Policy

Both European and Dutch policies contain rules regarding the combustion of biomass.

Policy in Europe

The Renewable Energy Directive (RED, European parliament, 2009) establishes an overall policy for the production and promotion of energy from renewable sources in the EU. The RED sets out biofuels sustainability criteria for all biofuels produced or consumed in the EU to ensure that they are produced in a sustainable and environmentally friendly manner. These criteria account for direct land-use change, but do not account for indirect land-use change. In 2015 an amendment was added to RED to reduce the risk of indirect land-use change. Sustainability criteria must be met by all biofuels, whether produced within the EU or imported, and must meet a 35% GHG emission savings requirement compared to fossil fuels. As of 2017, the threshold is set to rise to 50% and to 60% by 2018, for new installations. In this comparison the complete life cycle is taken into account. The reduction in carbon stock (cause by LUC) is calculated and spread over 20 years. CO2 emissions caused by combustion of biomass are set to 0 in the calculations.

RED does not set out criteria for solid or gaseous biomass. However, as part of the new Renewable Energy Directive (RED II) for the post 2020 period, the EC is developing a new bioenergy policy expected to be made public in the last quarter of 2016. The legislative proposal on a renewable energy target for 2030 will include sustainability criteria for both biofuels and biomass (USDA, 2016).

Policy in The Netherlands

The Netherlands generally follows EU policy when it comes to sustainability. So, for the use of liquid biofuels binding requirements are in place. There are currently no obligatory sustainability criteria for solid and gaseous biomass. A voluntary standard, NTA 8080, is available for organisations that can demonstrate that the biomass they use is sustainable. In the National Energy Accord (Nationaal Energieakkoord), the parties agreed that sustainability criteria will be formulated to encourage the use of biomass in coal-fired plants. It was agreed that this is done taking into account aspects such as carbon debt, ILUC and conditions for responsible forestry. In April 2016 concept regulation was submitted that restricts SDE+ subsidies to woody biomass that has been produced sustainably (EZ, 2016).