CSIRO Reports on GHG Emissions in Australia

The comparative analysis of life cycle greenhouse gas (GHG) emissions of biodiesel blends relative to regular diesel blends in Australia, has recently been reported by the Australian Commonwealth Scientific and Industrial Research Organization (CSIRO). “Life cycle GHG emissions” of a biodiesel product can be interpreted as an inventory of GHG emissions from its production phase to its utilization phase as fuel; it is commonly expressed as “grams CO2 equivalents per kilometer” (g CO2-e/km) (related information below). Overall results showed a “savings” in total life cycle greenhouse emissions for the following biodiesel feedstocks: canola (49% or 422 g CO2-e/km), palm oil from existing plantations (80% or 680 g CO2-e/km), tallow (76% or 646 g CO2-e/km), and used cooking oil (87% or 746 g CO2-e/km). The percentage values are relative to the life cycle GHG emissions of extra low sulphur diesel (XLSD) which is 855 g CO2-e/km. The use of cooking oil as biodiesel feedstock for the replacement of base biodiesel resulted in the highest “savings” in life cycle GHG emissions. Details of the comprehensive CSIRO report can be accessed from the URL above.

Carbon dioxide equivalents and emission standards
http://en.wikipedia.org/wiki/Grams_per_mile_average_CO2-equivalent_value 
http://en.wikipedia.org/wiki/Emission_standard