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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.

This study provides an LCA of coal derived DME vehicle fuel cycle. Two DME production systems were evaluated, one is single DME production system, and the other is DME/IGCC cogeneration (polygeneration) system. The effects of CCS technology on energy use and GHG emissions were analyzed. For single DME production design, WTW total energy use and fossil energy is about 80% larger than that for petroleum diesel production, and increases life-cycle GHG emissions by more 200% relative to petroleum diesel. Results for DME/IGCC production design pathway from displacement method are almost the same with the petroleum diesel pathway. CCS incurs an energy penalty of 7-16%.