Climate benefits of biomass energy

To implement these targets, the EU is currently in the process of updating its climate and energy policies. Since new policies are to be decided on in late 2016 or early 2017, it is essential that EU policymakers are well informed about the climate benefits of biomass energy. An issue that has been contentious is the carbon neutrality of biomass.

Last month, the European Forest Institute released the report, Forest biomass, carbon neutrality and climate change mitigation. This report – prepared by 11 scientists from Europe, the United States, and Canada: Goran Berndes, Bob Abt, Antti Asikainen, Annette Cowie, Virginia Dale, Gustaf Egnell, Marcus Lindner, Luisa Marelli, Davide Pare, Kim Pingoud and Sonia Yeh – reviews various international perspectives and provides recommendations for policymakers.

The report confirms that in industrialized countries, forest biomass feedstocks typically come from forests managed for the production of pulp and saw logs, and provision of other ecosystem services. Feedstocks consist mainly of sawdust, small diameter trees, and thinnings. In processing feedstocks into bioenergy, supply chain emissions from harvesting, processing and transportation are just a small fraction of the biogenic carbon flows. With efficient handling and shipping, forest biomass transported over long distances can deliver high GHG emissions reductions.

According to the authors, non-GHG factors can affect climate change. The impact of changes in land use can impact global and local climate by affecting how much radiation is either absorbed or reflected. For example, land covered in forest is effective at absorbing radiation, while land covered in snow will reflect radiation back into the atmosphere.

In evaluating carbon balances and climate impacts, the authors argue that the exact timing of CO2 emissions is less important than how much carbon is emitted in total in the long run. This means that we should focus on how biomass harvesting for energy influences carbon stocks over the long term, since this in turn influences cumulative net CO2 emissions. There are various methods that researchers use to assess the climate change mitigation effects of forest bioenergy including:

Definition of a counterfactual no-bioenergy scenario: How do forest markets, forest management, and forest carbon stocks evolve in the absence of bioenergy production?

Spatial system boundary: Are carbon balances assessed at the forest stand level or at the forest landscape (system) level?

Temporal system boundary: What is the time period of assessment and how does it compare with the forest rotation period? When is the accounting begun in relation to the first harvest for bioenergy?

Scope: Are economic and social aspects included?  Is the bioenergy system assessed in isolation or does the study examine how forest management as a whole responds to bioenergy incentives?

It is important to understand the appropriate context for the chosen method in order to draw the correct conclusions and policy implications.

The report discusses how biomass extraction can affect forest management. Reviews have concluded that there are no consistent, unequivocal and universal effects of more intense biomass harvest on forest soils. With respect to water, forest bioenergy systems are judged compatible with maintaining high-quality water supplies. As for biodiversity, biomass removal, the quality of dead wood left behind is more important for biodiversity than quantity, with larger logs and stumps being more valuable than slash. Stumps and an appropriate amount of residual wood should be left on site.

The authors argue that instead of debating about carbon neutrality of biomass, we should be concerned with the net climate change effect of bioenergy in the context in which it is produced. Studies should analyze bioenergy systems as components in value chains or production processes that also produce material products, such as sawnwood, pulp, paper and chemicals. They reported that the efficiency of biomass conversion and the GHG displacement associated with the use of bioenergy and other forest products are very influential on the assessed mitigation value of forest bioenergy, regardless of feedstock; and the mitigation value grows over time as the quantity of displaced GHG emissions accumulates.

Forest bioenergy should be considered as just one of several products in a value chain that also includes material products, such as sawnwood, pulp, paper and chemicals. The forest product portfolio could potentially include bioenergy products that, according to some studies, do not provide near/medium-term GHG savings. But it is not certain that excluding these feedstocks from bioenergy markets will result in a new product portfolio with a higher contribution to climate change mitigation in the short and longer-term. Regarding the need to balance short-term GHG targets with strategies that pursue long-term temperature stabilization goals, the authors caution that focusing exclusively on short-term GHG targets may result in decisions that make the longer-term objectives more difficult to meet. For example, a decision to prioritize carbon sequestration and storage in forests managed for wood production may help in meeting near-term GHG targets. However, this could mean an end-point where forests store more carbon but have a lower capacity for producing bioenergy and other forest products.

The authors advocate that policies to drive climate change mitigation should recognize the roles that forests and forest industries play in the EU GHG balance: they sequester and store carbon and displace fossil fuels and other products that would otherwise cause GHG emissions. Their recommendations include

• Researchers who plan to assess GHG balances and the climate effects of forest bioenergy should involve policymakers and stakeholders in defining their research questions to increase the likelihood that results are relevant and useful.
• It is critical for policies and regulations to create a situation where the promotion of bioenergy and other non-fossil energy options leads to fossil fuel displacement rather than competition among non-fossil options.
• Policymakers need to consider policies that incorporate regional forest and energy sector conditions and avoid one-size-fits-all policies.
• A generic categorization system, which specifies only some forest biomass types as eligible bioenergy feedstocks, may prevent the effective management of forest resources to economically meet multiple objectives, including climate change mitigation. There is a risk that bureaucracy and costly administration may discourage investment in bioenergy.
• Policies regarding the cascading use of forests should be applied with flexibility and consideration of what is optimal for specific regional circumstances.
• Policymakers should utilize knowledge and experience from European regions where biomass utilization has been a long-lasting practice.
• The use of forest biomass for energy is likely to make economic and environmental sense if accompanied by a package of measures to promote best practices in forest management for climate change mitigation.

The debate about the benefits of bioenergy in mitigating the effects of climate has often been contentious. Special interest groups have presented conflicting opinions, often without proper scientific support.

This report was written by independent scientists not representing any special point of view.  Its balanced findings should be useful to regulators as they develop bioenergy policy in support of Europe’s new targets under its Climate and Energy Framework.