Report IEA Task 33 -Lessons learnt about thermal biomass gasification English)

Abstract 

• This Report “Lessons learned about thermal biomass gasification” was elaborated by the IEA Bioenergy under Task 33 (Thermal Gasification).  
• The renewable resource of biomass (BM), the vision for a more CO2 neutral energy supply and the high numbers of different value chain, as well the idea to overcome energy shortage were and are the main argument for that long-lasting research activities over decades in the field of thermal gasification for energy and material conversion. This report shall show why there is a gap between implementation and the communicated success of this technology. What lessons shall we learn about the past activities and what can we do for future thermal gasification projects, that they will become successful.  
• At the beginning of this study, the authors assumed that problems with biomass gasification systems occur mainly at the technical level. It soon became apparent, however, that the plants built did not fail because of technical challenges, but often because of economic reasons. For the central European forestry, smaller (<10 MW) plants are suitable, since usually no gigantic forest areas are present.  
• Optimal initial situations are offered, for example, by carpentries, which can generate added value with a connected heat network for process heat or district heating. Waste, that is produced and must be disposed anyway, can be recycled, electricity and heat can be sold or used by themselves. 
• If large plants (50-100MW and more) are to be built, it must be expected that this plant will have direct effect on the price of raw materials in the surrounding forestry. If e.g. a 100 MW plant is built in the border area of Switzerland, Germany and Austria, the biomass price will increase within a radius of about 200km, because the biomass material flow will be significantly changed. 
• If a complex plant, including heat and power output, is considered over its entire life cycle, it becomes clear that, in addition to long-term heat and power purchase agreements, the feedstock must also be secured in the long term. Only in this way long-term economic indicators can be reasonably calculated. 
• From a business point of view, direct competition with fossil technologies also makes no sense. For example, a plant must always be supported with a "greenhouse gas subsidy" or a CO2 bonus. This subsidy must, of course, be guaranteed for the entire lifetime of the plant. This means that a large plant cannot be operated under free market conditions. 
• This can be different for large state (e.g. Scandinavian, Ukrainian or Canadian) forest owners. Large plants with various technologies are already being built there today. Nevertheless, large combined heat and power (CHP) plants, which are to be operated separately from an industrial company, are hardly ever realised.