A Review of Energy Consumption in the Acquisition of Bio-Feedstock for Microalgae Biofuel Production

Abstract

Microalgae biofuel is expected to be an ideal alternative to fossil fuels to mitigate the effects of climate change and the energy crisis. However, the production process of microalgae biofuel is sometimes considered to be energy intensive and uneconomical, which limits its large-scale production. Several cultivation systems are used to acquire feedstock for microalgal biofuels production. The energy consumption of different cultivation systems is different, and the concentration of culture medium (microalgae cells contained in the unit volume of medium) and other properties of microalgae vary with the culture methods, which affects the energy consumption of subsequent processes. This review compared the energy consumption of different cultivation systems, including the open pond system, four types of closed photobioreactor (PBR) systems, and the hybrid cultivation system, and the energy consumption of the subsequent harvesting process. The biomass concentration and areal biomass production of every cultivation system were also analyzed. The results show that the flat-panel PBRs and the column PBRs are both preferred for large-scale biofuel production for high biomass productivity.

Current Advancements in Biofuel Production from Microalgae: Harvesting and Conversion Technologies

“…The benefits and drawbacks of cultivation systems are mentioned in Tab. S1 of the Supporting Information [9][10][11][12][13].…”

“…Column systems are manufactured using transparent substances that have moderate strength whereas the airlift column setup is considered as the most suitable PBR system for extensive biomass production due to less power utilization, decreased shear stress, better agitation capability, and higher mass transfer rates. Moreover, higher investments and cleaning process is a challenging aspect of column airlift systems that limits their utilization capabilities [13].…”

Recent Advances in Algae-Derived Biofuels and Bioactive Compounds

“…Direct transesterification without pretreatment is undoubtedly more economically viable and environmentally friendly compared to traditional methods. For example, predrying accounts for approximately 59.3–85% of total energy consumption for producing biofuels from algae . Recent studies on the direct transesterification using microwave heating, supercritical fluids, ionic liquids, and newly developed catalysts for producing biodiesel from algae without lipid extraction pretreatment are discussed in this section.…”

Recent applications of biological technologies for decontaminating hormones in livestock waste and wastewater

“…MBRs have high energy consumption (0.6e2.3 kWh/m 3 ) owing to the membrane component used in this technology [66]. MBSs are also energy-consuming technologies, and the energy consumption of algae cultivation and harvesting is 0.004e1.321 kWh/m 3 and 0.0003e 2.15 kWh/m 3 , respectively [67].…”