Life Cycle Analysis on Fossil Energy Ratio of Algal Biodiesel: Effects of Nitrogen Deficiency and Oil Extraction Technology

Table 5

The primary energy demands, energy outputs, and life cycle fossil energy ratios for algal biodiesel production in different researches.

Oil extraction technology	This study		Lardon et al., 2009 [8]		Yang et al., 2014 [14]	Batan et al., 2010 [12]
	Dry	Wet	Dry	Wet	Wet	Wet
Basic condition
Oil content/%	40		40		24	50
Productivity/g/m^2·d	19.85		19.25		16	24.9
Primary fossil energy consumption/MJ
Cultivation	0.65	0.71	0.41	0.59	2.246	0.73
Concentration	0.11	0.11	—	—	0.103	—
Dewatering	0.04	0.04	—	—	—	0.17
Drying	0.7	—	1.39	—	—	—
Oil extraction	0.17	0.19	0.14	0.52	1.895	0.21
Esterification	0.06	0.06	0.03	0.03	—	0.17
Fertilizer production	0.05	0.05	0.08	0.11	1.041	—
Chemicals production	0.08	0.08	0.27	0.43	0.443	—
Biogas generation	—	—	—	—	0.089	—
Sewage treatment	—	—	—	—	0.884	—
Energy production/MJ
Biodiesel	1	1	1	1	1	1
Oilcake	0.9474	1.1096	0.57	1.23	—	0.79
Glycerin	0.1474	0.1474	—	—	0.565	—
Credit for “fresh” water	—	—	—	—	0.162	—
Biogas	—	—	—	—	1.378	—
Credit for ammonium compounds	—	—	—	—	0.027	—
Life cycle fossil energy ratio	1.13	1.82	0.68	1.34	0.4	1.4