The mass-based allocation between biodiesel and glycerin
(allocation factor of 0.9) showed that the total GHG emissions
after allocation were 109.20 g CO2-eq/L-biodiesel (412.77 g CO2
-eq/gal), while that of petroleum diesel is 3,082.20 CO2-eq/L
(11,650.70 CO2-eq/gal) (Sheehan et al., 1998). The reduction of
GHG emissions was hence 96.46%. If compared based on work
delivered (brake horsepower-hour, bhp-h), the total GHG emission
of biodiesel was 25.19 g CO2-eq/bhp-h, while that of petroleum
diesel is 638.72 g CO2-eq/bhp-h. Due to the difference in energy
content, the corresponding reduction of GHG was 96.06%. The
overall GHG reduction by displacing 3153 L (834 gallons) of petroleum
at UC was estimated to be 9.37 tonnes of CO2-eq per year.