Christian Schaffner

Last Name

Schaffner

First Name

Christian

ORCID

0000-0001-8888-6122

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02228 - Energy Science Center (ESC) / Energy Science Center (ESC)

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Publications 1 - 10 of 28

Complete Insecurity of Quantum Protocols for Classical Two-Party Computation
Buhrman, Harry; Christandl, Matthias; Schaffner, Christian (2012)
Physical Review Letters
A fundamental task in modern cryptography is the joint computation of a function which has two inputs, one from Alice and one from Bob, such that neither of the two can learn more about the other’s input than what is implied by the value of the function. In this Letter, we show that any quantum protocol for the computation of a classical deterministic function that outputs the result to both parties (two-sided computation) and that is secure against a cheating Bob can be completely broken by a cheating Alice. Whereas it is known that quantum protocols for this task cannot be completely secure, our result implies that security for one party implies complete insecurity for the other. Our findings stand in stark contrast to recent protocols for weak coin tossing and highlight the limits of cryptography within quantum mechanics. We remark that our conclusions remain valid, even if security is only required to be approximate and if the function that is computed for Bob is different from that of Alice.
Valuation of Controllable Devices in Liberalized Electricity Markets
Schaffner, Christian (2004)
Combining Investment, Dispatch, and Security Models - An Assessment of Future Electricity Market Options for Switzerland
Garrison, Jared B.; Abrell, Jan; Savelsberg, Jonas; et al. (2018)
2018 15th International Conference on the European Energy Market (EEM)
Generation Expansion Planning in Switzerland Considering Climate Change Scenarios
Raycheva, Elena; Schaffner, Christian; Hug, Gabriela (2022)
2022 IEEE Power & Energy Society General Meeting (PESGM)
In this work a formulation of the generation expansion planning problem is applied to the detailed Swiss power system to study the impacts of possible climate-driven changes in hydro inflows on the country's generation portfolio in 2050. To capture the influence of electricity trade on the investment decisions, we include an aggregated representation of the production capacities of the surrounding countries under a net-zero GHG emission scenario and market-based tie line constraints. Our results show that investing in new generators in Switzerland is more economically viable than relying only on imports regardless of the simulated hydrological conditions. Despite the projected annual decrease in hydro inflows during a typical hydrological year impacted by climate change, the total system costs are lower compared to a typical year under current climate conditions. This is due to the fact that in the future we expect wetter winters and thus more water during months when the system load is higher.
Nexus-e: Input Data and System Setup
Garrison, Jared; Gjorgiev, Blazhe; Han, Xuejiao; et al. (2020)
Policy changes in the energy sector result in wide-ranging implications throughout the entire energy system and influence all sectors of the economy. Due partly to the high complexity of combining separate models, few attempts have been undertaken to model the interactions between the components of the energy-economic system. The Nexus-e Integrated Energy Systems Modeling Platform aims to fill this gap by providing an interdisciplinary framework of modules that are linked through well-defined interfaces to holistically analyze and understand the impacts of future developments in the energy system. This platform combines bottom-up and top-down energy modeling approaches to represent a much broader scope of the energy-economic system than traditional stand-alone modeling approaches. In Phase 1 of this project, the objective is to develop a novel tool for the analysis of the Swiss electricity system. This study illustrates the capabilities of Nexus-e in answering the crucial questions of how centralized and distributed flexibility technologies could be deployed in the Swiss electricity system and how they would impact the traditional operation of the system. The aim of the analysis is not policy advice, as some critical developments like the European net-zero emissions goal are not yet included in the scenarios, but rather to illustrate the unique capabilities of the Nexus-e modeling framework. To answer these questions, consistent technical representations of a wide spectrum of current and novel energy supply, demand, and storage technologies are needed as well as a thorough economic evaluation of different investment incentives and the impact investments have on the wider economy. Moreover, these aspects need to be combined with the modeling of the long- and short-term electricity market structures and electricity networks. This report illustrates the capabilities of the Nexus-e platform. The Nexus-e platform consists of five interlinked modules: 1. General Equilibrium Module for Electricity (GemEl): a computable general equilibrium (CGE) module of the Swiss economy, 2. Centralized Investments Module (CentIv): a grid-constrained generation expansion planning (GEP) module considering system flexibility requirements, 3. Distributed Investments Module (DistIv): a GEP module of distributed energy resources, 4. Electricity Market Module (eMark): a market-based dispatch module for determining generator production schedules and electricity market prices, 5. Network Security and Expansion Module (Cascades): a power system security assessment and transmission system expansion planning module. This report provides the description and documentation for the input data used by all modules.
Inter-comparison of spatial models for high shares of renewable electricity in Switzerland
Heinisch, Verena; Dujardin, Jérôme; Gabrielli, Paolo; et al. (2023)
Applied Energy
This study presents an inter-comparison of three structurally different electricity system models (EXPANSE, Nexus-e, and OREES) with sub-national spatial resolution in Switzerland in 2035. We analyze technology and regional implications of three targets for electricity generation from new renewable sources (17 to 25 TWh/year from solar PV, wind, biomass, and waste incineration) and compare results at a national level as well as at a higher spatial resolution of Swiss cantons and municipalities. All three models align on high capacities of solar PV in 2035 as the key technology for reaching the three targets, but there is flexibility where PV can be placed to achieve the targets: either on roofs and facades or also on land. Electricity interconnection with Europe remains of key importance in Switzerland because any increases in electricity demand or lower deployment of new renewable generation are compensated by import. For the rest, the three models provide internally-consistent storylines of future strategies for Switzerland: a future with a diversified range of technologies (EXPANSE), a future with the focus on decentralized rooftop solar PV with batteries (Nexus-e), and a future with the prioritization of most productive areas for wind and solar PV, including open-field PV (OREES).
Nexus-e: A platform of interfaced high-resolution models for energy-economic assessments of future electricity systems
Gjorgiev, Blazhe; Garrison, Jared B.; Han, Xuejiao; et al. (2022)
Applied Energy
Energy systems are transitioning toward sustainable power generation largely due to new policies that are motivated by climate and renewable generation targets. This transition is felt throughout the entire economy and is affecting the long and short term operations of the energy system. In the last decade, the research community has made significant efforts to model the energy transition and its impacts. Typically, these models focus on a limited subset of the different components of the energy-economic system, including investments in centralized and distributed generation, electricity markets, electric power grids, security of supply, and macro-economic effects. However, there are research questions that require the analysis of how these different aspects are connected to each other and how they may interact. Therefore, the research community has stressed the need to leverage models across domains to enhance the capabilities and robustness of their results. Due partly to the high complexity of combining models developed in tangential domains, few attempts have been made to model in full the interactions among the interdependent components of the energy-economic system. The Nexus-e: interconnected energy systems modeling platform aims to show how this gap can be filled by demonstrating that an interdisciplinary set of models can be integrated in a model framework by linking them through structured interfaces. This platform combines four bottom-up models that capture different aspects of the electricity system and one top-down macro-economic model to represent a much broader scope of the energy-economic system as compared to traditional stand-alone modeling approaches. In this paper, we study the benefits and limitations of the interfaces established among the modules in Nexus-e with reference to the Swiss electricity system in a European context. We demonstrate that prominent changes in operational behavior could drive investments and should therefore be assessed in a framework that considers both transmission and distribution systems in a coordinated manner. We show that the bottom-up investments and operations (transmission and distribution) can have an impact on the overall economy, which in response can affect the demand for electricity. Moreover, we demonstrate that the changes in generation mix and operation behaviors may have a significant impact on system security. For policymakers, the approach can provide spatially detailed power system transformation options that enable decisions that are socially, politically, and technically acceptable.
Optimal Design of Time-of-Use Tariffs using Bilevel Optimization
Venkatraman, Ashwin; Hug, Gabriela; Schaffner, Christian; et al. (2022)
2022 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe)
In this paper, the optimal design of Time-of-Use tariffs is presented. The tariff design is formulated as a bilevel optimization problem. The upper level problem models the utility/network operator (leader) and sets the tariff, whereas the lower level problem models the consumer’s (follower) response to the set tariff. In the model, both the tariff rates and the tariff windows are controllable parameters, and the resultant problem is solved using a Genetic Algorithm. The tariff algorithm is simulated on a local Zürich network and the effect of Electric Vehicle charging on the tariffs is investigated.
Technology Outlook 2021
Anken, Thomas; Bach, Christian; Ballif, Christophe; et al. (2021)
Nexus-e: CentIv Module Documentation
Raycheva, Elena; Schaffner, Christian; Hug, Gabriela (2020)
Policy changes in the energy sector result in wide-ranging implications throughout the entire energy system and influence all sectors of the economy. Due partly to the high complexity of combining separate models, few attempts have been undertaken to model the interactions between the components of the energy-economic system. The Nexus-e Integrated Energy Systems Modeling Platform aims to fill this gap by providing an interdisciplinary framework of modules that are linked through well-defined interfaces to holistically analyze and understand the impacts of future developments in the energy system. This platform combines bottom-up and top-down energy modeling approaches to represent a much broader scope of the energy-economic system than traditional stand-alone modeling approaches. In Phase 1 of this project, the objective is to develop a novel tool for the analysis of the Swiss electricity system. This study illustrates the capabilities of Nexus-e in answering the crucial questions of how centralized and distributed flexibility technologies could be deployed in the Swiss electricity system and how they would impact the traditional operation of the system. The aim of the analysis is not policy advice, as some critical developments like the European net-zero emissions goal are not yet included in the scenarios, but rather to illustrate the unique capabilities of the Nexus-e modeling framework. To answer these questions, consistent technical representations of a wide spectrum of current and novel energy supply, demand, and storage technologies are needed as well as a thorough economic evaluation of different investment incentives and the impact investments have on the wider economy. Moreover, these aspects need to be combined with modeling of the long- and short-term electricity market structures and electricity networks. This report illustrates the capabilities of the Nexus-e platform. The Nexus-e Platform consists of five interlinked modules: 1. General Equilibrium Module for Electricity (GemEl): a computable general equilibrium (CGE) module of the Swiss economy, 2. Centralized Investments Module (CentIv): a grid-constrained capacity expansion planning module considering system flexibility requirements, 3. Distributed Investments Module (DistIv): a generation expansion planning module of distributed energy resources, 4. Electricity Market Module (eMark): a market-based dispatch module for determining generator production schedules and electricity market prices, 5. Network Security and Expansion Module (Cascades): a power system security assessment and transmission system expansion planning module. This report provides the description and documentation for the GemEl module, which is utilized in the Nexus-e framework to provide feedback between the economy and the bottom-up models, as well as give insights in the economic effects of the implemented scenarios. GemEl is a recursive-dynamic CGE model with up to 75 sectors and 14 household types. It is based on the 2014 Swiss energy-specific differentiated input–output table for the energy sector (IOT-Energy). --> Policy changes in the energy sector result in wide-ranging implications throughout the entire energy system and influence all sectors of the economy. Due partly to the high complexity of combining separate models, few attempts have been undertaken to model the interactions between the components of the energy-economic system. The Nexus-e Integrated Energy Systems Modeling Platform aims to fill this gap by providing an interdisciplinary framework of modules that are linked through well-defined interfaces to holistically analyze and understand the impacts of future developments in the energy system. This platform combines bottom-up and top-down energy modeling approaches to represent a much broader scope of the energy-economic system than traditional stand-alone modeling approaches. In Phase 1 of this project, the objective is to develop a novel tool for the analysis of the Swiss electricity system. This study illustrates the capabilities of Nexus-e in answering the crucial questions of how centralized and distributed flexibility technologies could be deployed in the Swiss electricity system and how they would impact the traditional operation of the system. The aim of the analysis is not policy advice, as some critical developments like the European net-zero emissions goal are not yet included in the scenarios, but rather to illustrate the unique capabilities of the Nexus-e modeling framework. To answer these questions, consistent technical representations of a wide spectrum of current and novel energy supply, demand, and storage technologies are needed as well as a thorough economic evaluation of different investment incentives and the impact investments have on the wider economy. Moreover, these aspects need to be combined with modeling of the long- and short-term electricity market structures and electricity networks. This report illustrates the capabilities of the Nexus-e platform. The Nexus-e Platform consists of five interlinked modules: 1. General Equilibrium Module for Electricity (GemEl): a computable general equilibrium (CGE) module of the Swiss economy, 2. Centralized Investments Module (CentIv): a grid-constrained capacity expansion planning module considering system flexibility requirements, 3. Distributed Investments Module (DistIv): a generation expansion planning module of distributed energy resources, 4. Electricity Market Module (eMark): a market-based dispatch module for determining generator production schedules and electricity market prices, 5. Network Security and Expansion Module (Cascades): a power system security assessment and transmission system expansion planning module. This report provides the description and documentation for the CentIv module, which is utilized in the Nexus-e framework to provide information regarding optimal investments in new generation and storage technologies at the transmission system level.

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Christian Schaffner

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