title: Comparison between solar utilization of a closed microalgae-based bio-loop and that of a stand-alone photovoltaic system.
abstract: This study compared the solar energy utilization of a closed microalgae-based bio-loop for energy efficient production of biogas with fertilizer recovery against that of a stand-alone photovoltaic (PV) system. The comparison was made from the perspective of broad life cycle assessment, simultaneously taking exergy to be the functional unit. The results indicated that the bio-loop was more environmentally competitive than an equivalent stand-alone PV system, but had higher economic cost due to high energy consumption during the operational phase. To fix the problem, a patented, interior pressurization scheduling method was used to operate the bio-loop, with microalgae and aerobic bacterial placed together in the same reactor. As a result, the overall environmental impact and total investment were respectively reduced by more than 75% and 84%, a vast improvement on the bio-loop.
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Road, Minhang District, Shanghai 200240, PR China. Electronic address: qiang.jin@outlook.com.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Jin
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Road, Minhang District, Shanghai 200240, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China.
authors.forename: Aimin
authors.initials: A
authors.lastname: Li
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China.
authors.forename: Fuqiang
authors.initials: F
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Long
authors.affiliation: School of Environmental Science and Engineering, Shanghai Jiao Tong University, No. 800, Dongchuan Road, Minhang District, Shanghai 200240, PR China.
authors.forename: Aidang
authors.initials: A
authors.lastname: Shan
authors.affiliation: Institute of Energy Systems, School of Engineering, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3JL, UK.
authors.forename: Alistair G L
authors.initials: AGL
authors.lastname: Borthwick
mesh_terms: D001709:Biotechnology / Q000191:economics / Q000379:methods*; D003365:Costs and Cost Analysis; D058086:Microalgae / Q000378:metabolism*; D010777:Photochemistry; D012993:Solar Energy; D013816:Thermodynamics
keywords: Biogas; Biomass; Exergy; Life cycle assessment; Microalgae