Browsing by Author "Ghazanfari, Darius"

During recent years the use of forest fuels such as felling residues has increased in Finland, mainly due to the emission trade system and the inflation in fossil fuel prices. The procurement area of forest fuels must be diversified and enlarged to get sufficient amount of fuel from the forest to the major customers (CHP, combined heat and power production). There may be a need for different type of logistical and longdistance transportation methods in future. The use of forest fuels is important in mitigating climate-change. The reductions in CO2-emissions can be achieved due to its greenhouse gas neutrality but also from better procurement. The procurement of forest chips has usually been based on truck transportation and comminution at the landing sites using mobile chippers (roadside chipping). Truck transportation from longer distances is however expensive because of the low energy density of forest chips. An alternative procurement system based on waterway transportation from satellite terminals and chipping at the terminal could be more costefficient, and produce less CO2 in large-scale procurement of forest fuels. The loading and unloading places at terminals could also be used as buffer storage. The alternative procurement could be suitable for power plants next to large inland water areas such as the Lake Saimaa region. The study was based on Stora Enso Varkaus' increasing use of forest fuels, which could reach 2 TWh (1 milj. m3 forest chips) in future for the CHP-plant and the new biorefinery. The maximum procurement distance around the city is 80 km due to the demand from neighbouring cities. The comparison of the CO2- emissions indicated that the alternative procurement produced 3-18 % less CO2, depending on the transportation distance in traditional method (60-120 km). If crushing (electricity) instead of chipping was deployed the difference grew to 28-39 %. The alternative method became favorable after 52 km distance in traditional procurement. The decrease in CO2 is a consequence of less diesel-fuel needed in the procurement chain and thus can be connected with the costs of procurement. However, for a complete cost-analysis much more information is needed, such as the variable and fixed costs and the indirect emissions.