Reduction of water and energy requirement of algae cultivation using an algae biofilm photobioreactor

► This study reports the performance of an algal biofilm photobioreactor for biofuel production. ► The system cultivates algae as a biofilm with reduced energy and water requirement. ► The system produced a highly dense algal harvest of concentration 96.4 kg/m3. ► The system achieved a net energy ratio of 6.00 including dewatering. ► The photobioreactor achieved a light to biomass energy conversion efficiency of 2.02%.