The TIMER Emissions Model (TEM) of IMAGE 2.2 is closely linked to the TIMER model. TEM replaces the original energy-industry emission model of the energy industry system (EIS) of IMAGE 2.1 (Alcamo et al., 1998), and is extensively described in de Vries et al. (2001). The main objective of TEM is to calculate the regional emissions from energy use and industrial processes of:
For an explanation of compounds and groups of compounds, see definitions - chemical compounds.
The model consists of two submodels:
The scenarios of emissions of halocarbons are derived from literature.
The major input and output variables of TEM are described below:
| Model input (energy) | Income per capita |
| Energy production and energy end-use consumption (TIMER) | |
| Fraction surface and deep coal mining (CH4) (fossil trade flows) | |
| Submodel assumptions | Emission factors for energy sectors and carriers (technological and efficiency improvements, structural changes) |
| Fraction of catalyst-equipped cars | |
| Technological improvements and end-of-pipe control techniques for CO, NMVOC, NOx and SO2 (FGD in power plants, fuel specification standards for transport, clean-coal technologies industry, etc.) | |
| Model input (industry) | Regional population |
| Energy end-use consumption by industry (TIMER) | |
| Submodel assumptions | Emission factors for industrial sectors and carriers |
| End-of-pipe control techniques for CO, VOC, NOx and SO2 | |
| Marine bunkers and feedstocks | |
| Model output | Emissions of CO2, CH4, N2O, NOx and SO2, CO, NMVOC and halocarbons. |
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The energy emissions submodel calculates the regional energy-related emissions by applying emission factors to energy consumption and production for the nine energy sectors and five energy carriers:
Energy sectors:
Energy carriers:
The energy emissions submodel distinguishes between surface and underground coal mining (related to the CH4 emissions). The use of energy carriers as chemical feedstock is treated as a non-fuel source of CO2 in the industry emissions submodel.
The general methodology to estimate the combustion emissions for a compound, c, is by applying emission factors (EF) to the regional activity levels (EN), energy consumption and production, as calculated by TIMER for each energy sector and carrier:
with:
EMc = emission of compound c
EN = energy consumption and production
EFc = emission factor for compound c
abtc = abatement factor representing mitigation and abatement technologies for compound c
The emission factors for 1990 and 1995 are based on aggregated data from EDGAR 2.0 (Olivier et al., 1996), except for SO2 in industrialized regions, where they were calibrated against other published emission estimates as described by de Vries et al. (2001). The EDGAR 3.0 data (Olivier et al., 2001) is used for the historical trend in the emission factors for the 1970-1990 period. The EDGAR emission factors agree with the values used by IPCC (2001) and CDIAC (2000). Tthe emission factors for years after 1995 are based on scenarios as outlined below .
For the calculation of SO2 emissions from power generation the volume of regional fuel consumption is combined with data on fuel properties, in particular the S content of coal and oil , ash retention characteristics of each fuel and combustion process, and the level of emission control in each sector. For each region, EMSO2 is summed over fuel types according to:
with:
SUC = S content of coal and oil
fash = the fraction of the sulphur retained in ash
fcontrol = the fraction that is removed by emissions controls
SUC for coal and oil is calculated by the TIMER model on the basis of regional production and trade flows between regions. Included in fcontrol are several end-of-pipe desulphurization techniques, such as Flue Gas Desulphurization (FGD) in the electricity sector. It is calculated as follows as the willingness-to-pay multiplier (WTP):
with:
PPPmult = Purchase Power Parity multiplier
ENV = environmental multiplier
PPP is an alternative for GDP per capita based on relative regional purchase power. PPPmult increases along with PPP, reflecting increasing emphasis on environmental pollution measures with increasing incomes. The environmental multiplier (ENV) increases along with the acidification hazard, which is represented by the acidification impact index. This index is calculated on the basis of the total regional SO2 emissions divided by the size of the affected area within that region, and the sensitivity of that area to acidification. The environmental multiplier is indexed on the basis of the acidification impact index calculated for Western Europe for the 1980s when the acidification abatement policies were first implemented.
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The Industry Emissions submodel computes emissions of greenhouse gases or their precursors associated with industrial production, feedstock use of energy carriers and solvent use. The various sources with associated emitted compounds are listed below:
| Source | Compound(s) |
| cement production | CO2, NOx |
| feedstock use of energy carriers | CO2 |
| chemical manufacturing | NMVOC |
| adipic acid production | N2O |
| nitric acid production | N2O, NOx |
| ammonia production | NOx |
| solvent use | NMVOC |
| steel and iron industry | CO, NMVOC |
| sulphuric acid production | SO2 |
| copper melting | SO2 |
| miscellaneous | NMVOC, SO2 |
The historical (1970-1995) activity level of these industrial processes is based on data from the literature. For the 1995-2100 period, the cement production is related to population growth, and the level of other industrial activities are related to energy end-use consumption in industry, as simulated by the TIMER model. The final emissions are calculated with the same methods as in the energy emissions submodel, except for chemical feedstock emissions and emissions from adipic acid production. The atmospheric release fraction is taken into account for the chemical feedstock emissions. The estimates of N2O emissions from adipic acid production were taken from the IPCC-SRES emission scenarios (Fenhann, 1999).
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The emissions of halocarbons are exogenous input based on the IPCC SRES emission scenarios developed by Fenhann (1999). The halocarbon emissions regulated in the Montreal Protocol, i.e. CFCs, HCFCs, halons, carbon tetrachloride and methyl chloroform, follow the WMO (1999) Montreal protocol scenario (A3) of. The emissions of hydrofluorocarbon (HFCs), perfluorocarbon (PFCs) and sulphur hexafluoride (SF6) emissions, which were included with the CO2, CH4 and N2O gases in the Kyoto Protocol, are also based on Fenhann (1999).
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