Greenhouse gas performance of heat and electricity from wood pellet value chains – based on pellets for the Swedish market

Abstract

Increased bioenergy demand has triggered a discussion on the sustainability of solid biomass-based fuels and a system for sustainability criteria has been discussed within the EU. This paper assesses the greenhouse gas (GHG) emissions for heat and electricity from selected wood pellet value chains for the Swedish market and the associated potential emissions reduction in relation to fossil fuels using a life cycle assessment (LCA) perspective, and in relation to the approach described in recent EU policy developments. Nine different wood pellet value chains for heat and/ or power production in Sweden are assessed (including pellets from Sweden, Latvia, Russia, and Canada). Selected assumptions are varied in a sensitivity analysis. The total factory-gate GHG emissions at the conversion facility for the wood pellet value chains studied, range between 2 and 25 g CO 2 -eq/MJ pellets with Swedish pellets at the lower end, and Russian pellets using natural gas for drying the raw material at the higher end. Imported pellets from Latvia, Russia, and Canada that use biomass for drying may also reach relatively low levels of GHG emissions. The potential GHG reduction as compared to a certain fossil fuel default energy comparator is 64-98% for the electricity produced in the pellet value chains studied and 77-99% for the heat produced. Thus, many wood pellet value chains on the Swedish market will most likely be able to meet strict demands for sustainability from a GHG perspective.

Logistical, economic, environmental and regulatory conditions for future wood pellet transportation by sea to Europe: The case of Northwest Russian seaports

“…Sikkema et al [76] and Hansson et al [77] suggest that there is a potential for GHG reduction from wood pellet value chains. Magelli et al [21] recommend shorter ocean transportation distances for wood pellets to improve the energy balance (the ratio of energy gained from the use of wood pellets for energy production in comparison to energy consumption of the supply chain) of the wood pellet supply chain.…”

“…Pellets imported to Sweden from Latvia, Russia, and Canada that use biomass in the drying process, e.g. biomass-based electricity, may reach relatively low levels of total GHG emissions compared to other wood pellet chains [77]. Thus, depending on the specific production method of the wood pellets, and in view of the shorter shipping distances from Russia, Russian wood pellets have the possibility to remain attractive, from an environmental viewpoint, in comparison to those shipped from North America.…”

The potential influence of sustainability criteria on the European Union pellets market—the example of Sweden

“…The functional unit is 1 MJ of pellets (in fuel terms, heating value is specified in Table ). In general, only emissions of carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O) are included in the assessment (see Ref ). The global warming potential GWP100 factors presented in the IPCC AR4 report are used for the conversion to CO 2 ‐equivalent when needed.…”

“…The conversion efficiencies for pellets to heat and electricity used represent typical Swedish biomass‐fired CHP plants applying established allocation methods as presented in Ref . The pellets are assumed to be used in a large‐scale (20–50 MW th ) CHP plant.…”

“…In determining the exergy factor (Carnot efficiency) for heat an average temperature of 100°C was assumed implying that the total GHG emissions from the CHP plant are allocated approximately 40–50% for the produced heat and 50–60% for the produced electricity, depending on the performance of the CHP. For a description of exergy allocation versus other allocation methods, see Ref . The impact of allocation methodology is assessed in Ref .…”