Biodiesel, produced from various vegetable and/or animal oils, is one of the mo st promising alternative
fuels for transportation in Thailand. Currently, the waste oils after us e in cooking are not disposed
adequately. Such oil s could serve as a feed stock for biodiesel which would also address the waste
disposal issue. This stud y comp ares the life cycle greenhouse gas (GHG) emissions from used coo king oil
methyl ester (UCOME) and co nventional diesel used in transport. The functional unit (FU ) is 100 km
transportation by light duty diesel vehicle (LDDV) under identical driving conditions. Life cycle GHG emissions from conventional diesel are about 32.57 kg CO2-eq/FU whereas those from UCOME are 2.35 kg
CO2-eq/FU. The GHG emissions from the life cycle of UCOME are 93% less than those of conventional
diesel production and use. Hence, a fuel switch from conventional diesel to UCOME will contribute
greatly to a reduction in global warming potential. This will also support the Thai Government’s policy to
promote the use of indigenous and renewable sources for transportation fuels.