Potential environmental impacts and water consumption of Populus spp. bioenergy systems in Southern Europe

Objective of the study is to assess water consumption, energy and environmental performance of an experimental plantation of Populus spp. in short rotation forestry (SRF). The plantation is located in Girona, in northeastern Spain, and covers an area of 1 ha and has been managed with two different scenarios, with a low density and a high density model. The evapotranspitation for two years of Populus spp. cultivation is 8,875 m3 ha-1 and the water consumption has been 2,286 m3 ha-1yr-1 and 6,859 m3 ha-1yr-1 for low and high scenario, respectively. The energetic efficiency obtained is 11.18 and 6.84 and the environmental assessment shows a reduction of emissions of 10.16 g CO2 eq. MJ-1 (low density) and 6.36 g CO2 eq. MJ-1 (high density) in comparison with natural gas system. The anthropical pressure on the Ter basin is high and the introduction of irrigated crops would increase the pressure even more. However, water needed for growing SRF is lower than that one used for existing crops. Thus, cultivation of Populus spp. could be an alternative. In addition, the results of the analysis support that Populus spp. system is viable from an energy balance and environmental perspective for producing energy.