It can be seen in Figure 2-4 (left), by type of fuel the major sources of CO2 emissions in energy sector is gas fuels combustions. Figure 1 (right) shows the sectoral sources of CO emissions in energy during 2005-2015 is dominated by the up-stream oil and gas production facility, in which the GHG emissions is generated from natural gas combustions for own use in the up-stream oil and gas production facility. After this up-stream facility, the main sectoral sources are dominated by road and water-born transportation, power generation, residential and fugitive. However, after 2012 the contribution of GHG emissions from fuel combustions for power generation increase exceeds the GHG emissions from fuel combustions for the road and water-born transportation. The calculation of CO emissions from fuel combustions using sectoral approach usually is slightly higher if compare those are calculated by reference approach. It indicates possible problems with the collection of activity data and parameters used in estimating GHG emission level that related to net calorific values, carbon content, excluded carbon calculation, etc. The reference approach still can be used in the estimation of GHG emissions in energy sector if there is no comprehensive energy balance table available in the national Statistics. However, for the case of Timor-Leste, the comparison of the calculation of CO emissions from fuel combustions under reference and sectoral approaches shows that there is no significant discrepancy (see Figure 2-4). It can be seen from the figure that the discrepancy is almost neglected, and it is only occurred in 2015, i.e. 0.02%.