The contribution of ash recycling to the sustainability of bioenergy from forest biomass: An analysis of Götaland, Sweden

In Sweden, bioenergy use is promoted under the light of climate change mitigation and energy security. In 2009 31% of Sweden’s total energy supply was provided by bioenergy. Almost have of this energy is generated from forest biomass. Forestry has a long tradition in Sweden and sustainable resource management is advanced. However, the increased extraction of forest biomass results in export of nutrients and alkalinity which are important for forest growth and vitality. Recycling the ash, which is produced during bioenergy generation, is a well-known compensation method. In Sweden it is only applied to 5% of suitable ash in 2006. The Swedish Forest Agency’s goal to spread ash on all areas where forest residues are extracted in 2010 is far from reached. This study assesses the barriers to ash recycling and opportunities to increase this process. A systems perspective using causal loop diagramming and the Driver Pressure State Impact Response (DPSIR) scheme is employed. A quantitative approach, namely material flow analysis, and a qualitative approach, stakeholder analysis are carried out. The research is embedded in theoretical considerations evolving around concepts of industrial ecology, precisely the precautionary approach and ecological modernisation. The study shows that incentives for bioenergy plants, other than environmental consciousness, to ash recycling are missing. However, bioenergy plants own the ash and should recycle suitable ash to ensure long term sustainability of forestry and thus bioenergy. Recommendations how to establish incentives are discussed, including the potential connection of ash recycling to the electricity certificate. Other results like technological, organisational and social barriers were identified and incorporated in these considerations.