Climate - DNE21+
|Institution||Research Institute of Innovative Technology for the Earth (RITE), Japan, .|
The non-CO2 GHG assessment model, one of the DNE21+ model group, disaggregates the world into the 54 regions, consistent with the regional definition in the DNE21+ model (Akimoto et al.(2009), Akimoto et al.(2009)). The model converts bottom-up assessments of mitigation technologies performed by the USEPA (2002) to a proxy model using elasticity (Dowaki et al., 2006). The historical emission of non-CO2 GHGs was adjusted using the UNFCCC inventory (UNFCCC, 2009) and the IEA statistics (IEA, 2007) for Annex I countries and non-Annex I countries, respectively. The emission mitigation costs and potentials were modified using new technology assessments performed by the USEPA (2006b).
Equation (1) indicates the relationship between the individual non-CO2 GHG mitigation ratio and marginal abatement costs evaluated by using the elasticities. In the model, the non-CO2 GHG mitigation in 54 regions is estimated when the non-CO2 GHG abatement costs are equalized to the CO2 marginal abatement costs. The elasticities are determined such that the marginal abatement cost curves correspond to the USEPA estimates obtained separately for each sector and type of gas. The estimates are calculated using a technology database for non-CO2 GHG measures. Thus, the model used here is not a direct bottom-up model; however, marginal costs and potentials of non-CO2 GHG mitigation are essentially based on the bottom-up analysis of the USEPA.
Basically the elasticities in the model developed by Hyman et al. (2003) are applied to the model, but the elasticities are adjusted to be consistent with the result of analysis for a 20%/year discount rate which are close to the rate usually observed in decision makings of socio-economic activities, taking into consideration the results of sensitivity analysis for the discount rate (payback period) carried out by the USEPA (2002). The elasticities are also partially adjusted on the basis of the mitigation effect report of the USEPA (2006b). The elasticities of gases and the mitigation potentials in the model are estimated to be less than those reported by Hyman et al (2003).
where g represents the gas; h, the sector; n, the region; and t, the year. Red is the reduction rate for the total emission, P is the marginal abatement cost, and ? is the elasticity derived on the basis of studies by the USEPA (2002, 2006b) and Hyman et al. (2003).
The baseline emissions were estimated using the above assumptions for population and GDP adopted in the model. The model considers five types of emissions: CH4 in seven sectors, N2O in six sectors, hydrofluorocarbons (HFCs) in one sector, perfluorocarbons (PFCs) in one sector, and SF6 in one sector for 54 regions.
CH4 emissions were considered in seven sectors: agriculture, oil, coal, natural gas, residential, transportation, and energy intensive industries. N2O emissions were considered in six sectors: agriculture, oil, natural gas, residential, transportation, and energy-intensive industries. HFCs, PFCs, and SF6 emissions were considered for one macro-sector each. The baseline HFCs, PFCs, and SF6 emissions were basically estimated using the SRES B2 scenario for each of the four regions the world was divided into.