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The aim of this study is to evaluate the land requirement, energy consumption and GHG (greenhouse gases) emissions of microalgal biodiesel (M-BD) and Jatropha curcas seeds (J-BD) based biodiesel from the perspective of life cycle assessment (LCA). Mass and energy balance was used through the whole LCA calculation for each process. Two types of biodiesel (100% biodiesel: BD100, and 20% blends of biodiesel: BD20) were assumed to be combusted in the suitable diesel engine. Displacement method was adopted to measure the co-products credits. The results showed that the land requirement of producing 1 kg biodiesel from microalgae was about 1/31 of that from Jatropha curcas seeds. The well to pump (WTP) stage for microalgal biodiesel had higher fossil energy requirement but lower petroleum energy consumption and GHG emissions compared to Jatropha curcas and conventional diesel (CD). The WTP energy efficiency for J-BD100 and M-BD 100 were 26% and 17.4%, respectively.

This study provides a life cycle assessment (LCA) of plug-in hybrid electric vehicle (PHEV) fuel cycle. PHEVs recharging from the average electricity generation mix of China provide 16%-29% fossil energy consumption reduction, 39%-52% petroleum energy consumption reduction and 5%-26% greenhouse gas (GHG) emissions reduction compared with conventional gasoline vehicle. The range of the results is primarily attributed to the different all electric range (AER) and PHEV types (power-split versus series designs). Impacts of electricity generation mix for battery recharging are studied by six different interprovincial power grids, one prediction electricity scenario, and the average electricity generation mix of China. Fossil energy consumption and GHG emissions of PHEVs recharging from six different interprovincial power grids show 9%-24% and 12%-29% differences respectively.