Environmental Aspects of Bioenergy from Microalgae

In recent years, the oil shortage and fossil fuel environmental impact have driven the most Developed Countries to utilize renewable energy and, in particular, biomass. However the 1st generation of biofuels seems to be unsustainable because it competes with food production. On the other hand, microalgal-based biofuels (considered the 3rd generation) show great promise as a sustainable alternative to conventional transport fuel. Bioenergy from microalgae is an useful substitute for energy crops for high biomass yield, CO2 absorption and water pollutant removal. Nevertheless economic analyses have shown elevated costs in producing biodiesel from microalgae. For these reasons, efforts are currently being made to improve biomass yield or to facilitate lipid excretion from algae cells by genetic modifications. However to date a limited amount of research is being carried out to assess the environmental aspects of microalgae production. In this context, through the available scientific references, this paper aims to critically analyze these environmental problems considering some impacts: greenhouse gas emissions, energy balance, water demand and polluting effluents.