Comparative energy life-cycle analyses of microalgal biomass production in open ponds and photobioreactors.
An analysis of the energy life-cycle for production of biomass using the oil-rich microalgae Nannochloropsis sp. was performed, which included both raceway ponds, tubular and flat-plate photobioreactors for algal cultivation. The net energy ratio (NER) for each process was calculated. The results showed that the use of horizontal tubular photobioreactors (PBRs) is not economically feasible ([NER]<1) and that the estimated NERs for flat-plate PBRs and raceway ponds is >1. The NER for ponds and flat-plate PBRs could be raised to significantly higher values if the lipid content of the biomass were increased to 60% dw/cwd. Although neither system is currently competitive with petroleum, the threshold oil cost at which this would occur was also estimated.
Department of Environmental Engineering, Bahia Center for Clean Technologies, Federal University of Bahia, Rua Aristides Novis No. 2, 4 degrees andar, Polytechnique Institute, Salvador 40.210-630, BA, Brazil.
Orlando
O
Jorquera
Asher
A
Kiperstok
Emerson A
EA
Sales
Marcelo
M
Embiruçu
Maria L
ML
Ghirardi
D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D056890:Eukaryota / Q000254:growth & development* / Q000528:radiation effects*; D008027:Light; D013816:Thermodynamics