NDP-030/R6 (Table 4)

Table 4. Factors and units for calculating CO₂ emissions from fuel production and trade data

CO_2i = (P_i) (FO_i) (C_i)

From primary and secondary gas fuel production and trade¹
	CO_2g = CO₂ emissions in 10⁶ metric tons of carbon
	P_g = annual production or consumption in thousands of 10¹² joules
	FO_g = 0.98 + 1%
	C_g = carbon content in 10⁶ tons per thousand 10¹² joules = 0.0137 + 2%

From crude oil and natural gas liquids production in the global-total accounts²
	CO_2l = CO₂ emissions in 10⁶ metric tons of carbon
	P_l = annual production or consumption in 10⁶ tons
	FO_l = 0.918 + 3%
	C_l = carbon content in tons C per ton fuel = 0.85 + 1%

From primary and secondary liquid fuel production and trade in the national accounts when non-energy liquid products are specifically subtracted³
	CO_2l = CO₂ emissions in 10⁶ metric tons of carbon
	P_l = annual production or consumption in 10⁶ tons
	FO_l = 0.985 + 3%
	C_l = carbon content in tons C per ton fuel = 0.85 + 1%

From liquid bunker fuel consumption⁴
	CO_2l = CO₂ emissions in 10⁶ metric tons of carbon
	P_l = annual production or consumption in 10⁶ tons
	FO_l = 1.00 + 3%
	C_l = carbon content in tons C per ton fuel = 0.855 + 1%

From primary and secondary solid fuel production and trade⁵
	CO_2s = CO₂ emissions in 10⁶ metric tons of carbon
	P_s = annual production or consumption in 10⁶ tons coal equivalent⁶
	FO_s = 0.982 + 2%
	C_s = carbon content in tons C per ton coal equivalent = 0.746 + 2%

From natural gas flaring⁷
	CO_2f = CO₂ emissions in 10⁶ metric tons of carbon
	P_f = annual production or consumption in 10¹² joules
	FO_f = 1.00 + 1%
	C_f = carbon content in 10⁶ tons C per 10¹² joules = 13.454 + 2%

¹With respect to the above gas-related calculations, the following procedures and assumptions should be noted:

(1) If a solid was produced and then converted to a gas that was subsequently consumed, the assumption was made that the solid was produced and consumed. In this situation, none of the gas records were influenced. (2) If a solid was produced and then converted to a gas that was exported, it was assumed that in the producing country a solid was produced and the gas was exported. As a result, gas consumption for this country could show a negative value (consumption = production + imports exports: C = (0 + 0) exports). In the consuming country, gas was imported and consumed. (3) Natural gas contains 13.7 metric tons of carbon per terajoule. (4) Some of the units seem contrived but are chosen to accommodate data reported in the primary data sources.

² With respect to the above global liquid-related calculations, the following procedures and assumptions should be noted:

(1) Crude petroleum, natural gas liquids, and all secondary energy liquids were summed on an equal basis in mass units. That is, a ton of any liquid contains the same fraction of carbon. (2) When calculating global total CO₂ emissions from liquids, we have estimated that a quantity of liquids equivalent to 6.7% of liquids produced are not oxidized each year and another 1.5% passes through burners unoxidized or is otherwise spilled. Hence, 91.8% of annual liquid production is oxidized each year. (3) Liquid fuels contain 85.0% carbon by weight.

³With respect to the above national liquid-related calculations, the following procedures and assumptions should be noted:

(1) Crude petroleum, natural gas liquids, and all secondary energy liquids were summed on an equal basis in mass units. That is, a ton of any liquid contains the same fraction of carbon. (2) When calculating CO₂ emissions by country, non-energy secondary liquids were subtracted at the time of production and additional transactions (i.e., imports, exports, changes in stock) were not accounted further. Therefore, CO₂ production is only for energy products and CO₂ production from the oxidation of non-energy products is not included. (3) When calculating national total CO₂ emissions from liquids, we have estimated that a quantity of liquids equivalent to 1.5% passes through burners unoxidized or is otherwise spilled. (4) Liquid fuels contain 85.0% carbon by weight.

⁴With respect to the above bunker liquid-related calculations, the following procedures and assumptions should be noted:

(1) Crude petroleum, natural gas liquids, and all secondary energy liquids were summed on an equal basis in mass units. That is, a ton of any liquid contains the same fraction of carbon. (2) Liquid bunker fuels contain 85.5% carbon by weight. (3) Emissions from bunker fuels are calculated at the point where final fuel loading occurs but are not included in any national totals.

⁵The UNSTAT Database provides specific values of the energy content (in kcal/kg) for solid fuels for many country-commodity-year combinations. Where no conversion factor exists in the UN data set for a country/commodity, the following standard factors (kcal/kg) are used:

Coal 7000 Lignite brown coal 2695 Peat 2275 Coke-oven coke 6300 Gas coke 6300 Brown coal coke 4690 Hard coal briquettes 7000 Brown coal briquettes 4690

⁶The data for annual fuel production must recognize that all coal is not of the same composition, and thus may have varying energy content and CO₂ potential. There is a strong correlation between energy content and C content so the C content is quite constant when production is in units of tons coal equivalent where 1 ton coal equivalent is defined as 29.31 10⁹ joules.

⁷With respect to the above gas flaring-related calculations, the following derivation and assumption should be noted:

(1) The carbon conversion factor of 13.454 metric tons of C TJ^-1 is the result of dividing the average carbon content of a cubic meter of flared natural gas (525 g C/m³) by the average heating value of a cubic meter of flared natural gas (39.021 TJ/10⁶ m³). (2) These calculations assume that flared gas is released to the atmosphere immediately as CO₂, even though it is known that a small fraction is initially discharged as methane or carbon monoxide.