Fuel |
Coal Type |
CO 2
kgCO 2
/ TJ
|
CH 4
kg CH 4 / TJ
|
N 2
O
kg N 2 O / TJ
|
Bituminous 93,089 0.10 0.70
Coal
Sub Bituminous 96,260 0.09 0.95 Lignite 105,116 0.04 0.56
Natural Gas 50,911 0.09 0.43
Table 1 : The annual weighted average of the emission factor for the electricity sector in Malaysia
specific emission factor which could be used to better estimate and assess the amount of GHG emissions for the country . The CO 2 emission factors developed and assessed in this project were based on fuel carbon contents , which are directly related to the composition of fuels .
All coal power plants in Malaysia except those located in Sarawak utilise imported coal from countries such as Indonesia , Australia and other coal-producing countries . Bituminous , subbituminous and lignites are used in Malaysia . Coal combustion emits a significantly higher amount of CO 2 per unit of heat energy compared with liquid and gaseous fuels . Furthermore , the project reinforced that even within the same classification of coal , the different origin and quality of coal exhibit different compositions of carbon content . The diversity of fuel sources is the main reason to further improve national GHG inventories and adopt Tier 2 and Tier 3 methods by reducing uncertainties and increasing the representativeness of data . Additionally , the use of default GHG emission factor values as in Tier 1 becomes more questionable because some coal power plants in Malaysia operate by mixing coal from different origins and different classes to meet the calorific values needed to produce the required electricity .
Gaseous fuels such as natural gas are mostly mixtures of hydrocarbons , carbon dioxide and monoxide , hydrogen and oxygen . The carbon content in the fuel depends on its composition , which is usually expressed in terms of the volume or mass percentage of individual components . The CO 2 emission factor depends on the composition of the gaseous fuel , which is primarily methane and small quantities of other hydrocarbons .
Table 1 summarises the CO 2 , CH 4 and N 2
O emission factors from the TNB Research study . The CO 2 emission factor of bituminous coal was lower , while the sub-bituminous and lignite coal factors were higher than the IPCC default values . The overall difference of the CO 2 emission factor with the IPCC default value was about 1-4 %. The natural gas CO 2 emission factor was lower than the IPCC default value . This is primarily because the net calorific value in the natural gas consumed by the power plants was higher than IPCC default values by 9-12 %. The coal and natural gas CH 4 emission factors are lower from the Tier-1 fuel-based method suggested by the IPCC . In contrast , the N 2
O emission factor is lower for all coal types except for natural gas .
To benchmark our emission factor with other countries , we find that Germany reported a lower CO 2 emission factor value with similar trends as Malaysia for bituminous coal while other countries reported higher values . The subbituminous coal and lignite emission factors for Malaysia are slightly higher than IPCC and show the same trend as other countries .
The power generation sector is the key source of GHG emissions because it is a major contributor . The development of a country-specific emission factor is crucial in taking the first step towards the Tier 2 method in estimating the GHG inventory . High quality , credible and representative reporting is essential to move forward in GHG emissions mitigation strategies . The sector players
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