Life cycle assessment of biofuel production from brown seaweed in Nordic conditions

► LCA showed that seaweed biogas was more sustainable compared to ethanol scenario. ► 961 kg of CO2 per functional unit are removed during seaweed production. ► 555 kW h of electricity per functional unit are recovered. ► Energy analysis showed that seaweed production was the most energy intensive step. ► Grow-out phase accounted for 95% of the total energy during seaweed production.