Scenario quantification

The scenario quantification is carried out with the most recent version of the SMM as described in Section 2.1.1 and in Weidmann [11]. The energy service demands in the residential sector are provided by electricity and heat. The heat demand for hot water and space heating may be sup-plied by biomass, oil, district heat, natural gas, electricity, and solar energy, while the heat for cooking may be supplied by electricity, natural gas and wood (Appendix, Table 27). The hot wa-ter demanded for washing machines and dish washers is included in the district heating de-mand. The SMM’s commercial sector is also defined by its heating and electricity dede-mand. The heating demand is supplied by the same fuels as in the residential sector (Appendix, Table 27).

The industrial sector of the SMM demands electricity, process heat and space heating. The pro-cess heat demands are supplied by coal, oil, natural gas, district heat and biomass and waste (Appendix, Table 28). The transport sector of the SMM encompasses passenger and freight transport on rail, on the road and in the air. It is fuelled by kerosene, natural gas, diesel, gaso-line, electricity and hydrogen (Appendix, Table 28).

The scenario quantification with the SMM provides end-use energy demands per end-use sector (Figure 17) and domestic power generation mixes (Figure 18).

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The total end-use energy demand for all scenario variants consists of similar contributions from the residential, commercial and industrial sectors, while the share of the transport sector is larger. In the Ref variant, the two major contributors to the residential end-use energy demand are electricity and natural gas, and energy savings are also substantial. In the two climate sce-nario variants, the amount of electricity consumed is still high but the large natural gas share of the Ref case is replaced by district heating, solar energy and more energy savings, more pro-nounced in the Clim than in the Clim+CCS variant. The commercial end-use energy demand is mainly supplied by electricity, natural gas and biomass. For the two climate scenario variants, there is a shift from electricity to biomass compared to the Ref variant. All other energy carriers play a minor role in the commercial sector.

Figure 17: Swiss end-use energy demands per end-use sector for the three scenario variants in 2035 as quantified with the SMM

The industrial end-use energy demand is mainly satisfied by oil, natural gas and electricity, while the minor coal contribution is the same in all three variants. The absolute contributions of all other energy carriers drop in the two climate scenario variants compared to Ref, except for

3.2. Method and data ______________________________________________________________________________________________________________

41 the contribution of district heating, which is slightly higher. The transport sector heavily relies on fossil fuels, namely jet kerosene, diesel, gasoline and natural gas. Compared to the Clim vari-ant, the availability of CCS (and the resulting lower CO2 emissions in the electricity sector) al-lows for higher fossil fuel use in the transport sector while still meeting the CO2 target. Battery electric transport plays a minor role and is most important in the Clim variant. Hydrogen fuel cell-based transport is only present in the two climate scenario variants, when the climate tar-get leads to a fuel shift from diesel and gasoline cars to battery electric, hydrogen fuel cell and natural gas cars (the latter only in the Clim+CCS variant).

The phased-out nuclear power is mainly replaced with natural gas-fired power generation (Ref), renewable power generation (Clim) and renewable energies and natural gas-fired generation with CCS (Clim+CCS), while the contribution of hydro power is similar in all three scenario vari-ants (Figure 18). The Clim scenario variant has lower overall electricity production compared to Ref due to the constraints on renewable energy production and high-carbon power generation.

To meet the stringent CO2 target with the required (comparatively small) natural gas power, fossil fuels in other sectors must be replaced, e.g. fossil-fuelled passenger cars are replaced with hydrogen fuel cell and battery electric cars. Overall, the CO2 emissions of the Clim scenario vari-ant are shifted from the residential and transport to the power sector.

Figure 18: Swiss domestic power generation⁷ in 2035 per scenario variant as quantified with the SMM. PV = photovoltaics, CHP = combined heat and power, CC = combined cycle, CCS = carbon cap-ture and storage

7 In spite of the nuclear phase-out that is considered in all three scenario variants, nuclear energy is present in the quantification results for 2035. The SMM considers five-year time periods, i.e. reference year is the temporal centre of

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The availability of the CCS technology in the Swiss power sector (Clim+CCS) allows avoiding (more expensive) power generation from renewable energy sources and a higher overall elec-tricity production compared to Clim, while still reaching the GHG emission target. Given the lower CO2 emissions in the power sector in this case, expensive CO2 mitigation such as efficiency measures in the transport (hydrogen fuel cell and battery electric cars) and residential (district heating, heat pumps and energy savings) can be partially or mostly avoided. The lower deploy-ment of efficiency measures in the Clim+CCS scenario variant results in higher end-use energy demand compared to the Clim variant.