Recent advances in biomass utilization. An overview of available technologies

Energy conversion, related environmental concerns and sustainability remain to be one of the most critical issues that will require tremendous attention by governments, industry and researchers. The role of biomass, fossil fuels, nuclear generation and renewable resources are frequently debated for future planning to meet the growing need of energy. Biomass can be utilized as a potential fuel source in advanced energy systems. Raw biomass is usually obtained from energy crops that are grown specifically for the purpose of biofuel production. Switchgrass, hybrid poplars and willows, are typical examples of such crops. Secondary biomass fuels are usually obtained form recycled materials such as paper and cardboard, leather, rubber, municipal solid wastes and, agricultural crop waste. Molten carbonate (MCFC) and solid oxide fuel cells (SOFC) are considered to be best suited for biomass applications due to their high operating temperature level, flexibility to different fuel, and greater tolerance to contaminants. According to the biomass conversion methodology used, some of the other fuel cell types may also be useful. For example, landfill gas and digester gas are mostly used with Phosphoric Acid Fuel Cell (PAFC) today and their usage with this kind of fuel cell has been successfully demonstrated. Additionally, the suitability of biogas as a fuel for PEMFC has been experimentally confirmed. In this paper, an overview of energy supply and demand, with a specific emphasis on biomass, is given. A critical comparison of biomass and fossil fuels and the current status of technology together with results from a number of case studies are presented. (author)