Water and energy consumption of Populus spp. bioenergy systems: A case study in Southern Europe

With the objectives of climate change mitigation and energy independence, energy crops have been proposed as an alternative to fossil fuels. In recent years short rotation energy crops have been promoted because they provide biomass in short periods of time. However, the impacts of water consumption, in both the impact on the energy balance due to the consumption of irrigation as the impacts on existing water resources, have not been analyzed in depth. This study evaluates the relationship between water, energy and CO2 emissions of a plot of Populus spp. in Spain with the aim of evaluating the feasibility of its implementation as large-scale cultivation. For the energy and environmental assessment it has been used the life cycle analysis methodology. The results show positive energy balance and environmental improvement respect other energies such as natural gas. Consumption of water required to avoid a kg of CO2 is 4.6 m3 and per unit of energy obtained is 45 m3 GJ−1 considering a life cycle approach and in relation to the water availability of the basin could increase the pressure. Hence, in order to establish energy crops for climate change mitigation water consumption associated must be taken into account for future energy planning.