Energy from Biomass: A Review of Combustion and Gasification Technologies (World Bank Technical Papers)

While energy is essential for development, standard fossil fuels are often in short supply in countries where it is needed most. However, alternative fuel resources abound in the form of agricultural and municipal waste or 'biomass'. This report reviews the state of the art of biomass combustion and gassification systems, their advantages and disadvantages. It also encourages investment in use of these technologies to enable developing countries to better exploit their biomass resources and help close the gap between their energy needs and their energy supply. Biomass materials have properties that differ from those of conventional solid fuels such as coal. A major difference is the high content of volatile matter in biomass materials, whereas coal has less than 20 percent. The design of a combustion or gasification system depends heavily on the specific biomass material - its morphology, moisture content, and mix of contaminants. The last determines which flue-gas cleaning systems will be applied. Combustion systems based on steam cycles are technically mature and commercially available. Gasification systems are commercially available. However, small-scale applications need much supervision and suffer from frequent interruptions. Advanced integrated gasification and combined heat and power concepts are promising but still not demonstrated. A demonstration plant has been built but is not yet in full operation. Comparisons have been made between gasifier/engine and steam-cycle concepts with capacities of 1 MWe (Megawatt electric). Production costs for the gasifier/engine capacities for the considered base are lower than that of the steam cycle. However, some uncertainty is involved in assumptions of the base case, and sensitivity analyses show that change in those assumptions is larger than the difference in costs between the two concepts. Therefore, one cannot conclude that one concept is more attractive than the other. Rather, feasibility studies must be performed to determine which system is most suitable. Peter Quaak, Harrie Knoef, Hubert Stassen. Includes Bibliographical References (p. 54-55).