Absolute environmental sustainability of solid biofuels: An investigation by different environmental-ecological performance indicators

Research on the absolute environmental sustainability of biofuels is limited, and no studies to date have focused on the biomass pellet sector. Net environmental-ecological performance models can be used to quantify absolute sustainability in a life cycle approach, and this investigation provided an analysis of them in the context of biomass pellets as a case study. Four models were compared, where two models are based on results expressed in biophysical units, and two are given in monetary units. All the models were applied in a cradle-to-gate perspective for the two types of biomass pellets: pine pellets and peanut shell pellets. Ten environmental categories were investigated, and the results showed that the pine pellets were the best option and closer to an absolute sustainable profile. The problem with monetary-based models is the loss of accuracy in results. However, the communication of the results for non-experts could be based on monetary terms as they express the main findings more simply. To assist different stakeholders we provided recommendations on which model to apply in bioenergy systems.