Life cycle assessment of a biofuel production system from algal biomass cultivated in photobioreactors

Algae have been widely studied as a source of organic matter used by industrial technologies for the production of third generation biofuels, as well as for numerous other possible applications (e.g. human and animal food, environmental engineering solutions). In the energy field, the aim of using algae is to seek alternatives and sustainable energy solutions to fuels deriving from fossil fuels, but also from first- and second-generation biofuels. This paper describes results of a four-year experimental project for the development of a low-scale demonstration plant of an advanced energy system based on the massive cultivation of microalgae and their treatment. In particular, the article focuses on the results of the Life Cycle Assessment developed on the entire plant. The study compares the environmental impacts and the energy demand of different scenarios, analyzing their overall effects and evaluating alternative technological solutions, as well as further possible design alternatives. The system boundaries include algae cultivation, algae collection, lipids extraction, transesterification to produce bio-oil from lipids and anaerobic digestion of residual biomass. Results are be compared to those of conventional biodiesel from rape.