In this letter, we evaluate the potential of linear e+e− colliders to measure the top quark mass in radiative events and in a suitable short-distance scheme. We present a calculation of the ...differential cross section for production of a top quark pair in association with an energetic photon from initial state radiation, as a function of the invariant mass of the tt¯ system. This matched calculation includes the QCD enhancement of the cross section around the tt¯ production threshold and remains valid in the continuum well above the threshold. The uncertainty in the top mass determination is evaluated in realistic operating scenarios for the Compact Linear Collider (CLIC) and the International Linear Collider (ILC), including the statistical uncertainty and the theoretical and experimental systematic uncertainties. With this method, the top quark mass can be determined with a precision of 110 MeV in the initial stage of CLIC, with 1 ab−1 at s=380 GeV, and with a precision of approximately 150 MeV at the ILC, with L=4 ab−1 at s=500 GeV. Radiative events allow measurements of the top quark mass at different renormalization scales, and we demonstrate that such a measurement can yield a statistically significant test of the evolution of the MSR mass mtMSR(R) for scales R<mt.
The Compact Linear Collider (CLIC) is a proposed future high-luminosity linear electron-positron collider operating at three energy stages, with nominal centre-of-mass energies: 380 GeV, 1.5 TeV, and ...3 TeV. Its aim is to explore the energy frontier, providing sensitivity to physics beyond the Standard Model (BSM) and precision measurements of Standard Model processes with an emphasis on Higgs boson and top-quark physics. The opportunities for top-quark physics at CLIC are discussed in this paper. The initial stage of operation focuses on top-quark pair production measurements, as well as the search for rare flavour-changing neutral current (FCNC) top-quark decays. It also includes a top-quark pair production threshold scan around 350 GeV which provides a precise measurement of the top-quark mass in a well-defined theoretical framework. At the higher-energy stages, studies are made of top-quark pairs produced in association with other particles. A study of ttH production including the extraction of the top Yukawa coupling is presented as well as a study of vector boson fusion (VBF) production, which gives direct access to high-energy electroweak interactions. Operation above 1 TeV leads to more highly collimated jet environments where dedicated methods are used to analyse the jet constituents. These techniques enable studies of the top-quark pair production, and hence the sensitivity to BSM physics, to be extended to higher energies. This paper also includes phenomenological interpretations that may be performed using the results from the extensive top-quark physics programme at CLIC.
The integration of variable renewable resources and decentralized energy technologies generates the need for a larger flexibility of the energy demand. In order to fully deploy a demand side ...management approach, synergies between interconnected energy systems have to be systematically implemented.
By taking this standpoint, this study proposes a new approach to explore the potential of multi-energy integrated energy systems. This approach is constituted by two main steps, which are (1) the performance simulation of selected energy infrastructures and (2) the estimation of related techno-economic performance indicators. Step (1) expands the work presented in previous literature, by including a novel co-simulation feature. In step (2), the levelized cost of energy and location-dependent emission factors are used as key performance indicators.
In this paper, the presented approach is demonstrated by implementing two demand side management options for heat peak demand shaving. A Swedish residential neighborhood is considered as a case study. The first option explores the potential of storing heat in the thermal mass of residential buildings. The proposed strategies lead to a decrease of up to 70% of primary energy consumption, depending on the indoor comfort requirements. The second option estimates the techno-economic feasibility of a new set of scenarios based on the integration of geothermal distributed heat pumps within a district heating network. The district heating scenario is found to be the most techno-economical convenient. Nevertheless, a moderate penetration of distributed heat pumps (around 20%) is shown to have a good trade-off with the reduction of CO2 emissions.
•A techno-economic and environmental approach for multi-energy integrated systems.•Thermal mass control as a solution for reducing the generation cost of heating.•District heating networks as techno-economic optimal urban infrastructures.
The transition of district heating and electrical distribution grids from traditionally independent to actively coupled and operated networks is seen as an important step on the way to smart energy ...networks. This work presents a method that enables a detailed technical assessment of the operation of such coupled heat and power networks. It is based on a sequential coupling approach of a dynamic thermal-hydraulic model for the district heating network and a quasi-static model for the electrical distribution network. Different use cases are highlighted where a local coupling of the networks with power-to-heat is supporting the transition to smart energy networks, i.e., lowering district heating supply temperatures, accommodating renewable energy sources in the power network and integrating low-temperature heat sources into the district heating network. All three use cases are implemented in example applications to showcase the versatility of the method. The results underline the presented method's ability to perform detailed technical assessments of coupled heat and power networks.
Intelligent control schemes are essential for the implementation of smart energy systems, where district heating and electric networks are tightly interconnected. The increasing complexity of such ...networked infrastructure has resulted in the need to test and assess control algorithms before field deployment. This work presents a method to assess advanced control schemes for thermal-electric appliances with explicit consideration of coupled heat and power networks. It is based on closed loop simulation of high-fidelity physical system models, using dynamic thermal-hydraulic district heating and electric distribution network models, and low-fidelity time-discrete advanced control models. Co-simulation is used to perform coupled simulations of the different involved domains and tools. A test case is presented where a model predictive control scheme for grid friendly operation of domestic hot water electric booster heaters is implemented in a low-temperature district heating and low-voltage electric distribution network. Test case results show that the control is able to reduce peaks in district heating and electric networks compared to a simple reference controller. A comparison between using perfect and naive forecasts shows that control performance highly depends on the availability of accurate predictions. The results underline the versatility of the method to assess different control schemes in integrated networks.
•Closed-loop simulation of dynamic heat and power network models with advanced control.•Introduction of grid-friendly model predictive control for electric booster heaters.•Example heat and power networks with multiple distributed electric booster heaters.•Performance comparison of perfect and naive forecasting.•Results show reduced peaks in heat and power network and high self-consumption of PV.
The energy system of the future is expected to be composed of a large variety of technologies and applications. However, the diverse nature of these components, their interlinked topology, and the ...sheer size of the system lead to an unprecedented level of complexity. Industry is confronted with severe problems in designing interoperable grid components, analyzing system stability, and improving efficiency. This paper describes the main challenges of continuous time-based and discrete event-based models of such cyber-physical energy systems. Using a characteristic test model, the scalability of the two approaches is analyzed. The results show the strengths and weaknesses of these two fundamentally different modeling principles that need to be considered when working with large scale cyber-physical energy systems.
Worldwide, cities are nowadays formulating their own sustainability goals, including ambitious targets related to the generation and consumption of energy. In order to support decision makers in ...reaching these goals, energy experts typically rely on simulation models of urban energy systems, which provide a cheap and efficient way to analyze potential solutions. The availability of high-quality, well-formatted and semantically structured data is a crucial prerequisite for such simulation-based assessments. Unfortunately, best practices for data modelling are rarely utilized in the context of energy-related simulations, so data management and data access often become tedious and cumbersome tasks. However, with the steady progress of digitalization, more and more spatial and semantic city data also become available and accessible. This paper addresses the challenge to represent these data in a way that ensures simulation tools can make use of them in an efficient and user-friendly way. Requirements for an effective linking of semantic 3D city models with domain-specific simulation tools are presented and discussed. Based on these requirements, a software prototype implementing the required functionality has been developed on top of the CityGML standard. This prototype has been applied to a simple yet realistic use case, which combines data from various sources to analyze the operating conditions of a gas network in a city district. The aim of the presented approach is to foster a stronger collaboration between experts for urban data modelling and energy simulations, based on a concrete proof-of-concept implementation that may serve as an inspiration for future developments.
Innovations in today’s energy grids are mainly driven by the need to reduce carbon emissions and the necessary integration of decentralized renewable energy sources. In this context, a transition ...towards hybrid distribution systems, which effectively couple thermal and electrical networks, promises to exploit hitherto unused synergies for increasing efficiency and flexibility. However, this transition poses practical challenges, starting already in the design phase where established design optimization approaches struggle to capture the technical details of control and operation of such systems. This work addresses these obstacles by introducing a design approach that enables the analysis and optimization of hybrid thermal-electrical distribution systems with explicit consideration of control. Based on a set of key prerequisites and modeling requirements, co-simulation is identified as the most appropriate method to facilitate the detailed analysis of such systems. Furthermore, a methodology is presented that links the design process with the implementation of different operational strategies. The approach is then successfully applied to two real-world applications, proving its suitability for design optimization under realistic conditions. This provides a significant extension of established tools for the design optimization of multi-energy systems.
Integrated operation of distribution grids for multiple energy carriers promises hitherto unused synergies in terms of efficient generation, storage, and consumption. A major obstacle to the ...investment in such systems is their increased complexity, as conventional tools and methods were not designed to capture all relevant technical and economic aspects of hybrid grids. To address this obstacle, this work proposes a methodology to systematically assess multi-carrier energy grids under a holistic scope. By adopting a simulation-based approach that relies on detailed technical and economic models, an efficient and precise evaluation of both short-term (operational) and long-term (strategic) aspects is supported. The methodology enables the assessment of system configurations, control strategies, business models, and regulatory conditions in one coherent approach. As a proof-of-concept, the new methodology is applied to a real-world use case of a hybrid thermal-electrical distribution grid in a central European city. The results are comprehensively discussed to showcase how the various aspects of hybrid energy systems are addressed. The outcomes also demonstrate how this methodology aids the involved stakeholders in understanding the associated risks and potentials, paving the way for early adopters to realize multi-carrier energy distribution grids.
•A holistic methodology to study multi-carrier energy systems is presented.•Operational technical and strategic economic perspectives are considered.•Established tools for different domains are coupled in a co-simulation framework.•Multiple market participants and opposing objectives are taken into account.•The methodology is demonstrated by a comprehensive study in a central European city.
Energy systems experience a rise in complexity: new technologies, topologies and components, tighter links to other systems like markets and the increased usage of information technology. This leads ...to challenging questions that can not be answered via traditional methods. The goal of including renewable energy and clean technologies in the grid, however, requires solutions for the resulting complex problems. This paper investigates dynamic demand response for intelligent electric vehicle charging as a use-case for detailed hybrid models that cannot be properly handled by traditional tools alone. Universal modeling languages and specialized domain-specific modeling solutions are brought together via standardized co-simulation interfaces to achieve maximal flexibility and minimal implementation efforts. This combination of previously numerically incompatible modeling paradigms enables a detailed look into the dynamics of hybrid component models while keeping the comfort and the strength of established tools. This coupling of a Modelica-based physical simulation engine, a commercial power system simulation tool and an agent-based discrete event simulator for energy grids results in a novel co-simulation platform. This visionary concept provides the high level of detail, scope, flexibility, scalability and accuracy in simulations needed to analyze and optimize energy systems of the future.
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