CO2 emissions from fuel combustion were calculated by the International Energy Agency. See Part I for details on the estimation methodology.
The data sources for fugitive CO2 emissions and CH4 and N2O from energy are listed below. Data for fossil fuel production and use for 138 countries were taken from the IEA energy statistics for OECD and non-OECD countries 1970-2005 (extended energy balances, in energy units) (IEA, 2007). This dataset comprises 94 sectors and 64 fuel types. For the countries of the Former Soviet Union and Former Yugoslavia a modified dataset was used to achieve a complete time series for the new countries for 19702005 of which the sum converges to the older dataset for the total Former Soviet Union and Yugoslavia. For another 62 countries, the aggregated IEA data for the regions 'Other America', 'Other Africa' and 'Other Asia' have been split using the sectoral IEA data per region and total production and consumption figures per country of coal, gas and oil from energy statistics reported by the US Energy Information Administration (EIA, 2007).
Please note that the figures of CO2 from fuel combustion and non-energy use of fuels in this report differ somewhat from the EDGAR 4.0 dataset. This is due to the following reasons:
• IEA energy statistics used may differ slightly due to updates included in more recent IEA releases. For EDGAR 4.0 the release of 2007 was used (IEA, 2007);
• the IEA uses the default CO2 emission factors from the Revised 1996 IPCC Guidelines, which differ slightly due to different default oxidation factors (coal updated value +2%, oil products +1%, natural gas +0.5%) and due to updated defaults for carbon content for some fuels of which the quality may vary considerably (mainly refinery gas, updated value -7%, coke oven gas -7%, blast furnace gas +7%, coke -1%);
• the IEA estimates CO2 emissions from carbon released in fossil fuel use labelled in the sectoral energy balance as 'non-energy use' or 'chemical feedstock' using default fractions stored. For EDGAR 4.0, default emission factors and methods from the 2006 IPCC Guidelines were applied, which may give rise to considerable differences compared to the 1996 guidelines.
In addition, the subtraction of the non-energy/feedstock fuel use part of the EDGAR dataset for combining with the IEA CO2 dataset also introduces some uncertainty.
For estimating CH4 emissions from fossil fuel production and transmission, hard coal and brown coal production data have been split into surface and underground mining based on various national reports. For gas transport and distribution, pipeline length was used as activity data. Pipeline length and material statistics are taken from reports on Europe by Eurogas and Marcogaz, national reports (e.g. the United States and Canada), UNFCCC (2008) and supplemental data from CIA (2008). Total amounts of natural gas flared (including venting) are based on CO2 trends from CDIAC (Marland et al, 2006), supplemented with EIA (2008) and UNFCCC (2008) for missing years and missing countries and GGFR (2008) for 2004 and 2005.
Biofuel data were also taken from IEA (2007). However, to avoid incomplete time series for large sectors, solid biomass production and consumption in the residential and commercial sectors in nonOECD countries were replaced by fuelwood and charcoal consumption from FAO (2007a). Vegetal waste used as fuel is based on the amounts of crop residues per country and fractions used as fuel based on Yevich and Logan (2003) and IPCC (2006). The amount of dung used a fuel is based on the total amount of manure produced per country and the fraction of total manure burned as fuel with fractions from IPCC (2006) and UNFCCC (2008). The results are rather close to the work of Fernandes et al.
(2007) who did an extensive analysis of global and regional biofuel use in 2000.
Emission factors for fossil fuel production and use are based on the default values in the 2006 IPCC Guidelines (IPCC, 2006). Methane emission factors for coal mining are based on average depths of coal production based on CIAB (1994), EURACOAL (2008), Kirchgessner et al. (1993) and include post mining emissions. Methane recovery from coal mining was included for twelve countries amounting to about 1.3 Tg in 1990 (of which about one-third was allocated to the United States and Germany). Recovery in
2005 was estimated at 2.2 Tg (of which 40% in the United States and 20% in China) (UNFCCC, 2008; Thakur et al., 1994, 1996; EPA, 2008).
Emission factors for oil and gas production, transport and distribution are from IPCC (2006), supplemented with data from UNFCCC (2008), except for the emission factor for CH4 from oil tanker transport which is from Rudd and Hill (2001). The CH4 emission factor for venting and flaring has been derived from country-specific data reported to UNFCCC (2008); the CO2 emission factor for venting and flaring includes the indirect emissions through gas venting.
For N2O from gasoline cars in road transport, the fraction of cars equipped with a different types of catalytic converters was taken into account (based on various references). The factors for biofuel combustion and charcoal production were also taken from the
2006 IPCC Guidelines.
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