Decarbonization strategies for Switzerland considering embedded greenhouse gas emissions in electricity imports

Decarbonizing the energy system by electrification of heat and transport is only effective when using low-carbon electricity sources. As many countries such as Switzerland rely on imported electricity to meet their demand, the greenhouse gas (GHG) content of electricity imports must be correctly accounted for. By assuming an average GHG content for each amount imported, impacts of electricity required in peak periods are underestimated because this additional (marginal) demand is primarily met with fossil power plants. This study employs a model to capture marginal GHG contents of imported electricity from a direct and indirect (life-cycle) perspective at an hourly resolution. Implications on GHG are explored for various electricity demand and supply scenarios including electrification of heat and transport, large-scale expansion of renewables, and nuclear phase-out. We find that depending on the scenario, the average GHG intensity of consumed electricity may double, while diurnal and seasonal variations are even larger. Nonetheless, results show substantial GHG mitigation up to 45% with electrification in case of deploying a diversified electricity generation portfolio including photovoltaics and wind. For optimal GHG mitigation, short-term flexibility as provided by hydropower is necessary to manage electricity surpluses. The main challenge, however, surrounds seasonal energy storage including sector coupling

Impacts of an Increased Substitution of Fossil Energy Carriers with Electricity-Based Technologies on the Swiss Electricity System

Electrifying the energy system with heat pumps and battery electric vehicles (BEV) is a strategy of Switzerland and many other countries to reduce CO2 emissions. A large electrification, however, poses several new challenges for the electricity system, particularly in combination with a simultaneous substitution of nuclear power plants (NPP) by volatile renewables such as photovoltaics (PV). In this study, these challenges in terms of additional electricity demands, deficits and surpluses as well as effective CO2 mitigation are assessed in a dynamic and data-driven approach. To this end, electricity demand and production profiles are synthesized based on measured data and specifications and assumptions of the key technologies at a high temporal resolution. The additional electricity demand of heat pumps is estimated from hourly measured heat demand profiles of a Swiss district heating provider, while for BEV different recharging patterns are combined. For electricity production, NPP are deducted from the current electricity production profile, while PV is added at an hourly resolution. In order to estimate CO2 emissions, life-cycle analysis (LCA) CO2 intensities of the different technologies are used. It is shown that with a BEV and heat pump penetration of 20% and 75%, respectively, there is an almost 25% (13.7 TWh/year) increase of the electricity demand and—just as challenging—an additional maximum power requirement of 5.9 GWh/h (hourly-averaged power). Without additional storage options, large amounts of electricity must be imported in winter and at night, while in summer at noon there is a large surplus from PV. Due to their high CO2 intensities—at least for the next decades—electricity imports and PV may—depending on the reference scenario (with or without NPP) and assumptions on other key parameters—even offset the overall CO2 savings of a highly electrified Swiss energy system

Concurrent deficit and surplus situations in the future renewable Swiss and European electricity system

European countries aim to achieve net zero CO2 emissions by mid-century. Consequently, the European energy system and particularly the electricity system must undergo major changes. An increasing electrification of the mobility and heating sector is required for decarbonisation, which reserves electricity a central role on the path towards net zero CO2 emissions. However, to meet emission targets, the electricity supply must originate from low emission generation sources. According to the TYNDP 2018 scenarios, the electricity supply in Europe is expected to predominantly originate from renewable energy converters, introducing new challenges to energy systems. Due to the seasonality of renewable energy sources, most European countries, including Switzerland, are expected to face seasonal imbalances of supply and demand in the electricity system. According to national energy strategies of countries with deficits in electricity, the resulting shortages in supply should be covered with imports from their neighbouring countries. This study assesses concurrent deficit and surplus situations among different balancing zones and highly renewable energy systems. Thereby, possible infeasible energy balances are identified by analysing the case of Switzerland and its neighbouring countries Austria, Germany, France and Italy based on published scenarios. The results show, that there are concurrent deficit situations in Switzerland and its neighbouring countries in particular during winter. Hence, the results of this analysis challenge the current energy strategies and the aim to reach net zero CO2 emissions in Switzerland and Europe

The Potential of Vehicle-to-Grid to Support the Energy Transition: A Case Study on Switzerland

Energy systems are undergoing a profound transition worldwide, substituting nuclear and thermal power with intermittent renewable energy sources (RES), creating discrepancies between the production and consumption of electricity and increasing their dependence on greenhouse gas (GHG) intensive imports from neighboring energy systems. In this study, we analyze the concurrent electrification of the mobility sector and investigate the impact of electric vehicles (EVs) on energy systems with a large share of renewable energy sources. In particular, we build an optimization framework to assess how Evs could compete and interplay with other energy storage technologies to minimize GHG-intensive electricity imports, leveraging the installed Swiss reservoir and pumped hydropower plants (PHS) as examples. Controlling bidirectional EVs or reservoirs shows potential to decrease imported emissions by 33–40%, and 60% can be reached if they are controlled simultaneously and with the support of PHS facilities when solar PV panels produce a large share of electricity. However, even if vehicle-to-grid (V2G) can support the energy transition, we find that its benefits will reach their full potential well before EVs penetrate the mobility sector to a large extent and that EVs only contribute marginally to long-term energy storage. Hence, even with a widespread adoption of EVs, we cannot expect V2G to single-handedly solve the growing mismatch problem between the production and consumption of electricity

The potential of vehicle-to-grid to support the energy transition: A case study on Switzerland

Energy systems are undergoing a profound transition worldwide, substituting nuclear and thermal power with intermittent renewable energy sources (RES), creating discrepancies between the production and consumption of electricity and increasing their dependence on greenhouse gas (GHG) intensive imports from neighboring energy systems. In this study, we analyze the concurrent electrification of the mobility sector and investigate the impact of electric vehicles (EVs) on energy systems with a large share of renewable energy sources. In particular, we build an optimization framework to assess how Evs could compete and interplay with other energy storage technologies to minimize GHG-intensive electricity imports, leveraging the installed Swiss reservoir and pumped hydropower plants (PHS) as examples. Controlling bidirectional EVs or reservoirs shows potential to decrease imported emissions by 33–40%, and 60% can be reached if they are controlled simultaneously and with the support of PHS facilities when solar PV panels produce a large share of electricity. However, even if vehicle-to-grid (V2G) can support the energy transition, we find that its benefits will reach their full potential well before EVs penetrate the mobility sector to a large extent and that EVs only contribute marginally to long-term energy storage. Hence, even with a widespread adoption of EVs, we cannot expect V2G to single-handedly solve the growing mismatch problem between the production and consumption of electricity.ISSN:1996-107

Potential of renewable surplus electricity for power-to-gas and geo-methanation in Switzerland

Energy systems are increasingly exposed to variable surplus electricity from renewable sources, particularly photovoltaics. This study estimates the potential to use surplus electricity for power-to-gas with geo-methanation for Switzerland by integrated energy system and power-to-gas modelling. Various CO2 point sources are assessed concerning exploitable emissions for power-to-gas, which were found to be abundantly available such that 60 TWh surplus electricity could be converted to methane, which is the equivalent of the current annual Swiss natural gas demand. However, the maximum available surplus electricity is only 19 TWh even in a scenario with high photovoltaic expansion. Moreover, making this surplus electricity available for power-to-gas requires an ideal load shifting capacity of up to 10 times the currently installed pumped-hydro capacity. Considering also geological and economic boundary conditions for geo-methanation at run-of-river and municipal waste incinerator sites with nearby CO2 sources reduces the exploitable surplus electricity from 19 to 2 TWh