Growing concentrations of greenhouse gases in the atmosphere primarily from CO2 emissions from the combustion of fossil fuels are impacting the climate on earth. Replacing fossil fuels with forest fuels is becoming more and more urgent. That would reduce the net emissions of CO2 and the effects on the climate. This is shown in a dissertation from Mid Sweden University.
Large-scale, long-distance transports of biofuels from central Sweden to central Europe may be a cost-effective and attractive way to reduce CO2 emissions. This is confirmed by comparative analyses of costs, primary energy use, and CO2 emissions performed for various forest fuel systems. The findings show that a system of lashed branches and tops from harvested forests evinces good cost-effectiveness. It also has a high potential to reduce the net emissions of CO2 per hectare of forest.
“A large number of systems were compared in terms of terrain, concentration of forest fuel, and transport distance. If the preconditions are changed, then the potential for the various forest fuel systems changes as well,” says Lisa Eriksson at Mid Sweden University. These systems were compared on a local, national, and international scale.
A lashed system means that more biomass per hectare can be delivered to end users than with a pellet system. This is due to the consumption of biomass in the production of pellets. The amount of material gathered per hectare is a central factor. Extracting brush from thinning together with stumps, branches, and tops from harvesting yields a high potential to avoid fossil CO2 emissions per hectare of forest. The total amount of available forest fuel in Sweden has been estimated at roughly 66 TWh per year.
Lisa Eriksson will publicly defend her thesis at the Department of Engineering, Physics, and Mathematics at Mid Sweden University, Östersund Campus. The subject is Eco-technology and Environmental Science and the title of the dissertation is Forest Fuel Systems-Comparative Analyses in a Life Cycle Perspective.
For more information, see www.miun.se under Research.