Bioenergy Research, cilt.16, sa.2, ss.1065-1072, 2023 (SCI-Expanded)
© 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.In this study, a life cycle energy assessment is applied to estimate the efficiency of different products from microalgae biomass as a source of bioenergy. The combination of different processes were studied to search for the most energy efficient approach. Processes included cultivation (bubble column vs raceway) photobioreactors (PBRs), dewatering and drying (centrifuge, rotary press, solar, and thermal drying), oil extraction (wet and dry) and conversion to biodiesel. Laboratory data along with previous studies reported data and, for well-established technologies, producer’s datasheets were used to estimate energy demands. It was estimated that the type of PBR has the major effect on the efficiency where raceway and bubble column type requires 19.15 and 5.8 GJ/t dried biomass. At the best scenario, net energy efficiency of 3.5 was estimated for 98% dried microalgae biomass as a source of energy product when produced in raceway PBR followed by centrifuge/rotary-press/solar/thermal drying approach. It was concluded that the technology at current status cannot be efficient enough without solar drying, where at the best value of 0.4 happens for 98% dried biomass in raceway PBR.