Swiss TIMES Energy systems Model (STEM)

The Swiss TIMES Energy System Model (STEM) is a multi-sector, multi–energy carrier model representing Switzerland’s entire energy system. STEM is designed to identify least-cost technological pathways for assessing the country’s energy transition. It provides a long-term perspective combined with high intra-annual resolution, enabling detailed analysis of seasonal and temporal variations in both energy demand and supply.
In addition to the extensive representation of current and emerging energy technologies, STEM includes a suite of advanced features such as electric dispatch characterization, energy storage modeling, grid ancillary services (reserves), electric grid and pipeline infrastructure, and detailed charging-station deployment. It is a powerful tool for evaluating energy and climate mitigation policies across a wide range of stakeholders

STEM represents a broad suite of energy and emission commodities, technologies and infrastructure as illustrated in the reference energy system below. The model also combines a long time horizon (2010-2100) with an hourly representation of weekdays and weekends in three seasons. The model is used to identify the least-cost combination of technologies and fuels to meet future ESDs (which are given exogenously based on a set of scenario drivers), while fulfilling other technical, environmental and policy constraints (e.g. CO2 mitigation policy). 

The model's outputs include a detailed breakdown of primary energy supply, final energy consumption, and electricity demand and supply patterns by season, day, and hour for each technology type. It also provide CO₂ emissions, technology investments, energy supply costs, and the marginal costs of energy and emission commodities, among other key indicators.

STEM
  • Hahn Menacho AJ, Sacchi R, Bauer C, Moretti C, Panos E, McKenna R, et al.
    The global environmental footprint of Switzerland’s net-zero energy system uncovers impacts abroad
    Communications Earth & Environment. 2025; 6(1): 266 (14 pp.). https://doi.org/10.1038/s43247-025-02220-5
    DORA PSI
  • Kelk R, Podofillini L, Dang VN, Panos E
    Explorative application of discrete Bayesian networks as surrogate models for energy systems analysis
    Applied Energy. 2025; 394: 126146 (20 pp.). https://doi.org/10.1016/j.apenergy.2025.126146
    DORA PSI
  • McDermott J, Morrow I, Glynn J, Panos E
    Symbolic regression for modelling decarbonisation pathways in the global energy-economy-climate system
    In: Ochoa G, ed. GECCO '25: proceedings of the genetic and evolutionary computation conference. New York, NY: Association for Computing Machinery (ACM); 2025:871-874. https://doi.org/10.1145/3712255.3726704
    DORA PSI
  • Panos E, Hassan A
    Accelerating the performance of large-scale TIMES models in the modelling of sustainable development goals
    In: Labriet M, Espegren K, Giannakidis G, Gallachóir BÓ, eds. Aligning the energy transition with the sustainable development goals. Key insights from energy system modelling. Lecture notes in energy. Cham: Springer Nature; 2024:67-95. https://doi.org/10.1007/978-3-031-58897-6_4
    DORA PSI
  • Stermieri L, Kober T, McKenna R, Schmidt TJ, Panos E
    The role of digital social practices and technologies in the Swiss energy transition towards net-zero carbon dioxide emissions in 2050
    Energy Policy. 2024; 193: 114203 (17 pp.). https://doi.org/10.1016/j.enpol.2024.114203
    DORA PSI
  • Vandepaer L, Panos E, Bauer C, Amor B
    Energy system pathways with low environmental impacts and limited costs: minimizing climate change impacts produces environmental cobenefits and challenges in toxicity and metal depletion categories
    Environmental Science and Technology. 2020; 54(8): 5081-5092. https://doi.org/10.1021/acs.est.9b06484
    DORA PSI
  • Panos E, Kober T, Wokaun A
    Long term evaluation of electric storage technologies vs alternative flexibility options for the Swiss energy system
    Applied Energy. 2019; 252: 113470 (14 pp.). https://doi.org/10.1016/j.apenergy.2019.113470
    DORA PSI
  • Luh S, Kannan R, McKenna R, Schmidt TJ, Kober T
    Quantifying the impact of travel time duration and valuation on modal shift in Swiss passenger transportation
    Applied Energy. 2024; 356: 122412 (26 pp.). https://doi.org/10.1016/j.apenergy.2023.122412
    DORA PSI
  • Luh S, Kannan R, McKenna R, Schmidt TJ, Kober T
    How, where, and when to charge electric vehicles - net-zero energy system implications and policy recommendations
    Environmental Research Communications. 2023; 5(9): 095004 (30 pp.). https://doi.org/10.1088/2515-7620/acf363
    DORA PSI
  • Obrist MD, Kannan R, McKenna R, Schmidt TJ, Kober T
    High-temperature heat pumps in climate pathways for selected industry sectors in Switzerland
    Energy Policy. 2023; 173: 113383 (20 pp.). https://doi.org/10.1016/j.enpol.2022.113383
    DORA PSI
  • Panos E, Kannan R, Hirschberg S, Kober T
    An assessment of energy system transformation pathways to achieve net-zero carbon dioxide emissions in Switzerland
    Communications Earth & Environment. 2023; 4(1): 157 (18 pp.). https://doi.org/10.1038/s43247-023-00813-6
    DORA PSI
  • Kannan R, Panos E, Hirschberg S, Kober T
    A net‐zero Swiss energy system by 2050: technological and policy options for the transition of the transportation sector
    Futures & Foresight Science. 2022; 4(3-4): e126 (22 pp.). https://doi.org/10.1002/ffo2.126
    DORA PSI
  • Luh S, Kannan R, Schmidt TJ, Kober T
    Behavior matters: a systematic review of representing consumer mobility choices in energy models
    Energy Research and Social Science. 2022; 90: 102596 (23 pp.). https://doi.org/10.1016/j.erss.2022.102596
    DORA PSI
  • Obrist MD, Kannan R, Schmidt TJ, Kober T
    Long-term energy efficiency and decarbonization trajectories for the Swiss pulp and paper industry
    Sustainable Energy Technologies and Assessments. 2022; 52: 101937 (14 pp.). https://doi.org/10.1016/j.seta.2021.101937
    DORA PSI
  • Rüdisüli M, Bach C, Bauer C, Beloin-Saint-Pierre D, Elber U, Georges G, et al.
    Prospective life-cycle assessment of greenhouse gas emissions of electricity-based mobility options
    Applied Energy. 2022; 306(Part B): 118065 (20 pp.). https://doi.org/10.1016/j.apenergy.2021.118065
    DORA PSI
  • Obrist MD, Kannan R, Schmidt TJ, Kober T
    Decarbonization pathways of the Swiss cement industry towards net zero emissions
    Journal of Cleaner Production. 2021; 288: 125413 (13 pp.). https://doi.org/10.1016/j.jclepro.2020.125413
    DORA PSI
  • Panos E, Kober T, Ramachandran K, Hirschberg S, Bauer C, Schildhauer T, et al.
    Transformation of the Swiss energy system for a net-zero greenhouse gas emission society. Results from the joint activity scenarios & modelling
    Zurich: ETH Zurich; 2021.
    DORA PSI
  • Kober T, Kannan R, Pietzcker R, Deane P, Fuso-Nerini F
    Research and innovation needs for clean energy supply
    sine loco: Dialogue on European Decarbonisation Strategies (DEEDS); 2020.
    DORA PSI
  • Kober T, Kannan R, Obrist M, Panos E, Heald S, Clements L, et al.
    Swiss industry: price elasticities and demand developments for electricity and gas (SWIDEM)
    Bern: Swiss Federal Office of Energy SFOE; 2020.
    DORA PSI
  • Velazquez A, Pietzcker R, Siskos P, Luh S, Kannan R
    Research and innovation needs to decarbonise the transport sector
    sine loco: Dialogue on European Decarbonisation Strategies (DEEDS); 2020.
    DORA PSI
  • Landis F, Marcucci A, Rausch S, Kannan R, Bretschger L
    Multi-model comparison of Swiss decarbonization scenarios
    Swiss Journal of Economics and Statistics. 2019; 155: 12 (18 pp.). https://doi.org/10.1186/s41937-019-0040-8
    DORA PSI
  • Densing M, Kannan R, Panos E, Kober T
    Long term role of Swiss hydropower from an energy systems and market perspective. Zukunftspotenzial der Schweizer Wasserkraft durch Synergien im Energiesystem und Markt Perspektiven
    Villigen PSI, Switzerland: Paul Scherrer Institute; 2018.
    DORA PSI
  • Friedl M, Kober T, Ramachandran K, Mühlethaler J
    Fokusstudie "Saisonale Flexibilisierung einer nachhaltigen Energieversorgung der Schweiz"
    Rapperswil; Villigen PSI: Hochschule für Technik Rapperswil (HSR); Paul Scherrer Institut (PSI); 2018.
    DORA PSI
  • Kannan R
    Dynamics of long-term electricity demand profile: insights from the analysis of Swiss energy systems
    Energy Strategy Reviews. 2018; 22: 410-425. https://doi.org/10.1016/j.esr.2018.10.010
    DORA PSI
  • Panos E, Kannan R
    Challenges and opportunities for the Swiss energy system in meeting stringent climate mitigation targets
    In: Giannakidis G, Karlsson K, Labriet M, Ó Gallachóir B, eds. Limiting global warming to well below 2 °C: energy system modelling and policy development. Lecture notes in energy. Cham: Springer; 2018:155-172. https://doi.org/10.1007/978-3-319-74424-7_10
    DORA PSI
  • Panos E, Kober T, Kannan R
    Die Bedeutung von Flexibilitätsoptionen und Netzen für die langfristige Entwicklung des schweizer Elektrizitätssystems
    In: 12. VDI-Fachtagung Optimierung in der Energiewirtschaft. Vol. 2303. VDI-Berichte. Düsseldorf: VDI Verlag; 2017:47-60.
    DORA PSI
  • Kannan R, Hirschberg S
    Interplay between electricity and transport sectors – integrating the Swiss car fleet and electricity systemi
    Transportation Research Part A: Policy and Practice. 2016; 94: 514-531. https://doi.org/10.1016/j.tra.2016.10.007
    DORA PSI
  • Kannan R, Turton H
    Long term climate change mitigation goals under the nuclear phase out policy: the Swiss energy system transition
    Energy Economics. 2016; 55: 211-222. https://doi.org/10.1016/j.eneco.2016.02.003
    DORA PSI
  • Panos E, Kannan R
    The role of domestic biomass in electricity, heat and grid balancing markets in Switzerland
    Energy. 2016; 112: 1120-1138. https://doi.org/10.1016/j.energy.2016.06.107
    DORA PSI
  • Kannan R
    Can the decentralized CHP generation provide the flexibility required to integrate intermittent RES in the electricity system?
    Presented at: 67th Semi-annual ETSAP meeting; June 1-2, 2015; Abu Dhab.
    DORA PSI
  • Kannan R
    Development and Application of Energy-Economic Models for Switzerland's Climate Change Mitigation Scenarios
    Presented at: 2nd Asian Energy Modelling Workshop on Climate Change and Sustainable Development; July 23, 2015; Singapore.
    DORA PSI
  • Kannan R, Turton H, Panos E
    Methodological significance of temporal granularity in energy-economic models - insights from the MARKAL/TIMES framework
    In: Giannakidis G, Labriet M, Gallachóir BÓ, Tosato GC, eds. Informing energy and climate policies using energy systems models. Insights from scenario analysis increasing the evidence base. Lecture notes in energy. Cham: Springer; 2015:185-200. https://doi.org/10.1007/978-3-319-16540-0_11
    DORA PSI
  • Kannan R, Turton H
    Interplay between electricity and transport sectors - Integrating the Swiss car fleet and electricity system
    Presented at: IAEE European Energy Conference; October 29-31, 2014; Rome, Italy.
    DORA PSI
  • Pattupara R, Kannan R
    Exploring uncertainties in CCS - De-carbonization of the power sector and country-wise opportunities
    Presented at: IAEE European Energy Conference; October 29-31, 2014; Rome, Italy.
    DORA PSI
  • Ramachandran K, Turton H
    Switzerland energy transition scenarios - development and application of the Swiss TIMES energy system model (STEM)
    Villigen PSI, Switzerland: Paul Scherrer Institut; 2014. PSI Bericht: 14-06.
    DORA PSI
  • Kannan R, Turton H
    A long-term electricity dispatch model with the TIMES framework
    Environmental Modeling and Assessment. 2013; 18(3): 325-343. https://doi.org/10.1007/s10666-012-9346-y
    DORA PSI
  • Kannan R, Turton H
    Cost of ad-hoc nuclear policy uncertainties in the evolution of the Swiss electricity system
    Energy Policy. 2012; 50: 391-406. https://doi.org/10.1016/j.enpol.2012.07.035
    DORA PSI
  • Weidmann N, Kannan R, Turton H
    Swiss climate change and nuclear policy: a comparative analysis using an energy system approach and a sectoral electricity model
    Swiss Journal of Economics and Statistics. 2012; 148(2): 275-316. https://doi.org/10.1007/BF03399368
    DORA PSI
  • Kannan R, Turton H
    Documentation on the development of the Swiss TIMES electricity model (STEM-E)
    Villigen PSI, Switzerland: Paul Scherrer Institut; 2011. PSI Bericht: 11-03.
    DORA PSI
  • Kannan R
    The development and application of a temporal MARKAL energy system model using flexible time slicing
    Applied Energy. 2011; 88(6): 2261-2272. https://doi.org/10.1016/j.apenergy.2010.12.066
    DORA PSI
  • Skea J, Chaudry M, Ekins P, Ramachandran K, Shakoor A, Wang X
    A resilient energy system
    In: Skea J, Ekins P, Winskel M, eds. Energy 2050. Making the transition to a secure low-carbon energy system. London: Routledge; 2011:145-186. https://doi.org/10.4324/9781849775311
    DORA PSI