Energy efficiency, greenhouse gas emissions and durability when using additives in the wood fuel pellet chain

Abstract

The use of renewable resources for bioenergy should be performed to support sustainable development. Since the use of bioenergy has increased significantly worldwide in recent years and biomass is made of limited resources it must be used efficiently and with a low environmental impact. The wood fuel pellet industry has the possibility to meet these criteria; however, it also has the potential for improvements. This work investigates how the additives, cornstarch and molasses, affect: the electricity consumption of the pellet press, the emission of Carbon dioxide equivalents (CO2 eq.) from the production of wood fuel pellets in three different countries with different emissions from electricity, the durability of the pellets and its effects on energy efficiency. The results show that pellet production is more energy efficient when additives are used, and that the amount of CO2 eq. increases with an increased use of additives. In countries with a low usage of fossil fuels for electricity production, the global warming impact gets higher due to the additives; while in countries that use a lot of fossil fuels to produce electricity, the global warming impact will be reduced because of the additives by up to 1%. The increased global warming impact from the additives can be balanced by the decrease in the reduced amount of rejected material within the production. That is because the durability of the pellets increases with an increasing amount of additive.