ENERGY EFFICIENCY, ENVIRONMENTAL ASPECTS AND COST-EFFICIENCY OF SMALL-SCALE BIOCARBON CONVERSION APPLICATIONS – VALUE CHAIN ANALYSIS

摘要

Biocarbon can be potentially utilized as a high quality fuel in small-scale heating applications, asrncharcoal, powder, briquettes or pellets. However, there are only few studies on the use of biocarbon in residentialrnstoves. Charcoal based modern residential stoves can achieve high thermal efficiency and low emissions.In thisrnstudy, objective is to assess the energy efficiency of the whole value chain of spruce wood residue conversion torncarbonized biocarbon and co-district heat potential, as well, conversion of biocarbon to pellets and applyingrnconverted biocarbon pellets in stoves of nominal capacity of 8 kW. Study evaluated the overall specific pellet andrnheat production cost for the value chain using techno-economic method specific to Norwegian conditions. Studyrnconcluded that carbonization temperature generally resulted in increased total energy efficiency of pellet productionrnboth with and without district heat production. However, carbonization temperature did not affected the stovernthermal efficiency significantly. However, at higher carbonization temperatures higher biocarbon pellet productionrncost and higher overall heat production cost were obtained when standalone pellet production was consideredrnwithout district factor. In the case of pellet and district heat coproduction, the pellet production cost was alwaysrnlower than the corresponding one without district heat production.