Harmonized and systematic assessment of microalgae energy potential for biodiesel production

Abstract

With their fast growth rate and ability to accumulate a high percentage of their weight as lipid and carbohydrate, microalgae potentially represent an ideal feedstock for the production of biodiesel and bioethanol. In addition, microalgae offer several environmental benefits, and do not compete with food production for land, fresh water, and nutrients. Therefore, the main goal of this work is to provide a quantitative, systematic and harmonized assessment of current bio-energy potential. The analysis is conducted by considering all the main steps in detail, from cultivation to biodiesel production, and by deriving an overall estimation of energy consumption for biodiesel production. Energy consumption uncertainty is also quantified and discussed. A systematic review of all the main technologies available for all the main processing steps towards the production of biodiesel from microalgae is presented, focusing on the derivation of the Net Energy Ratio (NER) of each combination of technologies, complemented by an uncertainty analysis of the data used and those obtained in the present work. A wide scatter in the data available in the literature has been identified, highlighting the need for an uncertainty analysis. If the average overall energy consumption per unit of biodiesel mass is considered, all the routes adopting a raceway pond have a lower energy consumption, but if the uncertainty on the overall energy consumption is also considered, the minimum value of the range of NER values for some of the routes adopting a photobioreactor is comparable to the NER value obtainable by using raceway ponds. Thus, the present framework proposes a harmonized and comprehensive methodology to compare and contrast technologies for the production of biodiesel from microalgae, and is applied in this paper to identify, with an appreciation of the uncertainty, the most promising combinations of technologies.

Advances in Biodiesel Production from Microalgae

“…Until now, four biofuel generations have been identified [6,7]. Biofuels of the first generation are produced from food crops, oil seeds (soybeans, sunflower seeds, rapeseeds), and animal fats using fermentation and esterification techniques [8][9][10][11]. One of the main issues concerning this biofuel is the competition with food and fiber production for land and water usage [5,9].…”

Development Prospect and Preparation Technology of Edible Oil From Microalgae

“…Biodiesel is a mixture of fatty acid alkyl esters (FAAE), most commonly methacrylate (FAME) or ethyl ester (FAEE), obtaining by alcoholysis of triacylglycerol (TAG) from microalgae oil (Halim et al, 2012). Studies are concentrated on the selection of oil-producing algae species (Nwokoagbara et al, 2015;Yu et al, 2015;Arroussi et al, 2017;Sadvakasova et al, 2019), fatty acid composition and fuel characteristics (Islam et al, 2017;Piloto-Rodríguez et al, 2017), upstream cultivation of microalgae for biodiesel production and downstream processing (Wang et al, 2016;Zhu et al, 2017Zhu et al, , 2019Kadir et al, 2018;Mathimani and Mallick, 2018;Tan et al, 2018;Goh et al, 2019;Yew et al, 2019;Yin et al, 2020), and analysis of economic feasibility and energy potential (Shin et al, 2018;Arcigni et al, 2019;Sun J. et al, 2019). Though there are few researches and evaluations on the production of microalgae edible oil.…”

Ru nanoparticles supported on hydrophilic mesoporous carbon catalyzed low-temperature hydrodeoxygenation of microalgae oil to alkanes at aqueous-phase

“…Bio-oil from liquefaction of biomass such as algae oil, triglycerides, fatty acids, lignin, and carbohydrates holds great potential to partially replace traditional non-renewable fossil fuels [1][2][3][4][5][6][7][8][9][10]. When the bio-oil was directly used in diesel en-gines, for example, algae-derived bio-oil cause engine issues such as carbon deposits, injector coking, and further oil ring sticking due to the high viscosity and high oxygen contents of these compounds [11,12].…”