Currently, the production of thermal energy by biomass has shown a clear trend toward densified biofuels (pellets). This is due to their consistent size and shape that can be more easily delivered to homes, businesses, and power plants and can be automatically fed into advanced pellet boilers in a controlled and calibrated way. The use of densified biofuels also reduces the costs associated with handling and transportation, due to the increase in density involved by densification process. Demand for wood pellets is currently growing at a faster rate than supply in Europe. It is estimated that pellet market is growing to 50 Mt year−1 by 2025; however, most wood waste is already committed for pressed wood products and pellets, therefore more supply of raw materials are needed. With the possible shortage of woody raw materials for pellet production and considering the low forestry residues potential in several countries, agricultural residues could be largely used in the future for fuel pellets manufacturing. Agricultural pellets, as well known as “agripellets”, are emerging and promising. However, they have certain differences compared to conventional wood pellets.
Part of the book: Frontiers in Bioenergy and Biofuels
In recent years, the establishment of perennial grasses as energy crops has emerged as a very viable option mainly due to their comparative ecological advantages over annual energy crops. Nonwoody biomass fuels have a great potential to replace fossil fuels and reduce greenhouse gas emissions. At the same time, their application in small-scale combustion appliances for heat production is often associated with increased operational problems such as slagging in the bottom ash or deposit formation, as well as elevated gaseous and particulate matter emission levels. To mitigate these problems, scope and limitation of blending raw materials owing to critical fuel composition with less problematic biomasses have been systematically studied during combustion experiments in a commercially available small-scale combustion appliance. Apart from traditional use, perennial rhizomatous grasses display several positive attributes as energy crops because of their high productivity and low demand for nutrient inputs, consequent to the recycling of nutrients by their rhizomes and resistance to biotic as well as abiotic stresses. Therefore, they are used to generate heat and electricity. In addition, grasses appear to be an economically and environmentally appropriate fuel for generating some local energy in rural areas. This chapter gives an overview on species characteristics, their soil-climate requirements, cultivation technology, yielding, and energy characteristics of lignocellulosic biomass of giant miscanthus (Miscanthus × giganteus), reed canary grass (Phalaris arundinacea L.), switchgrass (Panicum virgatum L.), and giant reed (Arundo donax L.).
Part of the book: Advances in Biofuels and Bioenergy