LIFE CYCLE ASSESSMENT OF HEAT PRODUCTION FROM WILLOW CHIPS OF SALIX VIMINALIS L. IN UKRAINE

The results of the life cycle assessment of heat production from willow chips of Salix Viminalis L. are presented. Energy efficiency and greenhouse gas emissions reduction are estimated. The influence of the most significant parameters is analyzed and optimal relationships are determined to ensure maximum energy efficiency and environmental sustainability. The purpose of the paper is to define the energy efficiency and environmental sustainability of bioenergy value chain for heat production from willow chips of Salix Viminalis in Ukraine. The methodology of Life Cycle Assessment (LCA) was used, according to which, the scope of the product system includes the feedstock cycle of willow Salix Viminalis L. cultivation and harvest, and the subsystem of willow chips conversion to heat in a 500 kW biomass boiler. Cumulative energy demand and energy yield coefficient were chosen as energy efficiency indicators. The product system was compared with the similar one using natural gas. Non- renewable energy yield coefficient was used to define how many times the energy output was bigger than input of non- renewable energy. An acceptable value for renewable energy installations and systems is to receive twice as much energy output as was spent of non-renewable energy, however the recommended value assumed in the work is to receive a 5 times more energy output compared to non-renewable energy input. As an environmental sustainability indicator, a reduction of GHG emissions was used. The acceptable level of GHG emissions reduction was chosen at a level of 60% for the whole life cycle from cultivation-to-heat, compared to traditional heat production in gas boilers. Results of the assessment identified that the most significant parameter affecting energy efficiency and environmental sustainability is transportation distance. The growing of willow Salix Viminalis L. in Ukraine for the subsequent production of biofuel in the form of chips and its combustion in biofuel boilers is environmentally sustainable with a maximum transportation distance of 390 km and energy efficient with a maximum transportation distance of 180 km.