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.
Jorquera
Orlando
O
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.
Kiperstok
Asher
A
Sales
Emerson A
EA
Embiruçu
Marcelo
M
Ghirardi
Maria L
ML
D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D056890:Eukaryota / Q000254:growth & development* / Q000528:radiation effects*; D008027:Light; D013816:Thermodynamics