Environmental assessment of bioethanol from onshore grown green seaweed

Algae are an attractive, alternative renewable source for biofuel production compared to biomass from food crops or cellulosic materials. Marine algae do not need fresh water or arable land and, thus, production of marine algae does not compete with food production. In contrast to biofuel production from microalgae, the use of macroalgal biomass as feedstock for biofuel production is still in its infancy. This study presents an environmental assessment of bioethanol from onshore grown green seaweed using the life cycle assessment (LCA) methodology. The environmental assessment is based on data from literature and initial laboratory scale experiments, as industrial scale facilities for bioethanol production from macroalgae do not exist. Alternative systems are compared to the reference system and the limits of the LCA are discussed with respect to the co-product management (allocation vs. substitution) in the LCA model. Impact assessment results showed that nutrients for seaweed growth and electricity consumption by the culture system were the main contributors to the environmental burdens of the reference system. Bioethanol from onshore cultivated green seaweed turned out to be an environmentally efficient biofuel compared to fossil fuel and bioethanol from sugarcane. The type of co-product management selected in LCA largely affected the impact assessment results. © 2015 Society of Chemical Industry and John Wiley & Sons, Ltd