A greenhouse gas balance of two existing international biomass import chains: The case of residue co-firing in a pulverised coal-fired power plant in the Netherlands

Various utility companies are considering or already initiated the import of biomass from abroad for electricity generation, especially via co-firing in coal-fired power plants. This results in international logistic biomass supply chains, which raise questions on the environmental performance of such chains. In this study, a life cycle inventory has been performed on two existing biomass import chains to evaluate the greenhouse gas balance of biomass import for co-firing. We considered production, transport and co-firing of wood pellets from Canada and palm kernel shells from Malaysia in a 600 MW e coal-fired power plant in the Netherlands. Those chains are compared with various reference systems for energy production and the alternative use of biomass. Primary energy savings of these import and co-firing chains are between 70% and 100% of the biomass energy content. Net avoided greenhouse gas emissions are in the range of 340-2100 g/kWh. In the most optimistic scenario, pellet co-firing avoids methane emissions that would have occurred if the pellets were decomposed at landfills when not applied for energy production. In the most pessimistic scenario, palm kernel shell co-firing competes with the application as resource for animal feed production, which requires production and transport of an alternative resource. As the energy reference systems of the importing and exporting country and the alternative application of biomass have a significant impact on the net avoided greenhouse gas emissions, these factors should be considered explicitly when studying biomass trade for energy purposes. © 2006 Springer Science+Business Media, Inc.