283 research outputs found

    Load Shifting Versus Manual Frequency Reserve: Which One is More Appealing to Flexible Loads?

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    This paper investigates how a thermostatically controlled load can deliver flexibility either in form of manual frequency restoration reserves (mFRR) or load shifting, and which one is financially more appealing to such a load. A supermarket freezer is considered as a representative flexible load, and a grey-box model describing its temperature dynamics is developed using real data from a supermarket in Denmark. Taking into account price and activation uncertainties, a two-stage stochastic mixed-integer linear program is formulated to maximize the flexibility value from the freezer. For practical reasons, we propose a linear policy to determine regulating power bids, and then linearize the mFRR activation conditions through the McCormick relaxation approach. For computational ease, we develop a decomposition technique, splitting the problem to a set of smaller subproblems, one per scenario. Examined on an out-of-sample simulation based on real Danish spot and balancing market prices in 2022, load shifting shows to be more profitable than mFRR provision, but is also more consequential for temperature deviations in the freezer

    Optimierungsrahmen fĂŒr die Verbesserung der EnergieflexibilitĂ€t in WohngebĂ€uden

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    Energy flexibility is balancing the supply and demand of a building according to climate conditions, user preferences, and grid constraints. Energy flexibility in households is a practical approach to achieving sustainability in the building sector. However, the diversity in flexibility potential of energy systems and climatic variability complicate the selection of envelope parameters and building energy systems (BESs). This study aimed to design a framework to improve the energy flexibility of the building. For this purpose, a single-family house and diversified BESs were simulated in a TRNSYS-Python co-simulation platform. Initially, the bi-objective optimization identified flexible building envelopes in twenty-four locations. Then, the multi-criteria assessment of BESs was conducted using life-cycle energy flexibility indicators. Lastly, the energy flexibility potential of the BES was evaluated by employing steady-state optimization and model predictive control (MPC). The findings of this work set a benchmark for flexible household envelopes. The systematic approach for selecting BES could guide the energy system design, providing insight into energy flexibility. Further, this investigation has established that the dataset of building thermal load, boundary conditions, and control disturbances can be used to develop an MPC-based dynamic control. That controller could be employed on different BESs to achieve energy flexibility.EnergieflexibilitĂ€t ist der Ausgleich von Versorgung und Bedarf eines GebĂ€udes je nach Klima, NutzerprĂ€ferenzen und NetzbeschrĂ€nkungen. EnergieflexibilitĂ€t ist damit ein praktischer Ansatz fĂŒr Nachhaltigkeit in GebĂ€uden. Die Vielfalt des FlexibilitĂ€tspotenzials von Energiesystemen und die klimatischen Unterschiede erschweren jedoch die Auswahl von HĂŒllparametern und GebĂ€udeenergiesystemen (BESs). Diese Studie zielte darauf ab, einen Rahmen zur Verbesserung der energetischen FlexibilitĂ€t von GebĂ€uden zu entwickeln. Hierzu wurden ein Einfamilienhaus und verschiedene BES in einer TRNSYS-Python Co-Simulationsplattform simuliert. ZunĂ€chst wurden ĂŒber eine bi-objektive Optimierung flexible GebĂ€udehĂŒllen an vierundzwanzig Standorten ermittelt. Danach erfolgte eine multikriterielle Bewertung der BES anhand von EnergieflexibilitĂ€tsindikatoren ĂŒber den gesamten Lebenszyklus. Schließlich wurde das EnergieflexibilitĂ€tspotenzial der BES durch den Einsatz statischer Optimierung und modellprĂ€diktiver Regelung (MPC) bewertet. Die Ergebnisse dieser Arbeit setzen einen Maßstab fĂŒr flexible GebĂ€udehĂŒllen. Der systematische Ansatz zur Auswahl von BES könnte als Leitfaden fĂŒr die Auslegung zukĂŒnftiger Systeme dienen. DarĂŒber hinaus hat die Untersuchung ergeben, dass Daten zu thermischer Belastung des GebĂ€udes, Randbedingungen und Regelungsstörungen zur Entwicklung eines MPC verwendet werden können. Dieser Regler könnte bei verschiedenen BES eingesetzt werden, um EnergieflexibilitĂ€t zu erreichen

    Scaling energy management in buildings with artificial intelligence

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    L'abstract Ăš presente nell'allegato / the abstract is in the attachmen

    Design and analysis of smart home energy management system for energy-efficient and demand response operations

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    In the movie “Iron Man”, Tony Stark, with his highly connected and smart home system, shows the audience an appealing vision of future work and domestic life. Many audiences desire such a living environment where they can not only interact with their homes but also let the homes manage their operation automatically. As technology progressively steps into such a future, realizing a responsive and autonomous smart home is not just a fantasy. To establish grid-interactive homes that help save costs for users and improve grid reliability, this study introduces an energy management framework for smart home environments. This framework provides optimal operation of multiple appliances, taking into account dynamic responses to external factors such as outside weather conditions, homeowner’s preferences, and particularly, gird conditions like time-varying pricing in demand response programs. As one of the largest energy consumers in the home, the operation of the HVAC system holds great potential for cost savings and energy flexibility—the latter being the ability to adjust its consumption based on grid signals such as time-of-use (TOU) pricing. Achieving cost savings and energy flexibility requires intelligent strategies, one of which is precooling—a control strategy where an air conditioner (AC) cools space when the electricity price is low to avoid expensive operation when the electricity price is high. In previous studies, Model Predictive Control (MPC)-based precooling strategies are typically analyzed through simulations, and field studies in residential buildings are quite limited. In this study, we developed an MPC agent and carried out extensive field tests on nine homes over a period of four months in Oklahoma and Miami. Filed test results show that the MPC agent can reduce energy cost by 28.72%–51.31% on hot summer days and by up to 60.32% on mild summer days, in addition to achieving significant energy flexibility. Moreover, the agent's performance is found to be most impacted by weather conditions, AC performance, user comfort preferences, and floor areas of the homes. In addition, to further comprehend diverse factors that may impact the results of MPC-based precooling, an EnegyPlus virtual testbed and a corresponding control framework for co-simulation are developed. The purpose of developing such a virtual testbed is to create a simulation environment that enables experiments without the limitation and variability of field tests. The virtual testbed is modified by using the Python script to mimic the on/off cycle in the majority of U.S. residential building HVAC systems. By conducting the sensitivity analysis and ablation study, the MPC-based precooling co-simulation results are evaluated. It was observed in our case study that cost savings achieved through MPC-based precooling were primarily influenced by the use of forecast weather. The accuracy of the models and the prediction horizon of the MPC models also plays a substantial but lesser extent role. With the optimal operation framework shifting from the HVAC system to multiple appliances, the proposed energy management framework has a broader scope, encompassing not only the HVAC system but also water heaters, non-thermal appliances, and the power flow between photovoltaics panel (PV), batteries, and the grid. Apart from the cost-savings and energy flexibility that can be achieved, the proposed framework also provides a more realistic simulation scenario by considering the user’s appliance time usage preference, water usage, and thermal comfort preferences. Finally, the framework also embedded multi-objective optimization to support the homeowner’s decision-making between cost saving and thermal comfort. Overall, this study aims to realize the optimal operation of various load-flexible resources under demand response programs in residential buildings. This study investigates the fundamental research for the investigation of methodologies to enhance and understand the interactions between buildings, homeowners, and the grid. Due to the flexibility of the model, this study can be adapted to other residential buildings and even in larger communities

    Komponentenbasierte dynamische Modellierung von Energiesystemen und Energiemanagement-Strategien fĂŒr ein intelligentes Stromnetz im Heimbereich

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    The motivation of this work is to present an energy cost reduction concept in a home area power network (HAPN) with intelligent generation and flexible load demands. This study endeavors to address the energy management system (EMS) and layout-design challenges faced by HAPN through a systematic design approach. The growing demand for electricity has become a significant burden on traditional power networks, prompting power engineers to seek ways to improve their efficiency. One such solution is to integrate dispersed generation sources, such as photovoltaic (PV) and storage systems, with an appropriate control mechanism at the distribution level. In recent years, there has been a significant increase in interest in the installation of PV-Battery systems, due to their potential to reduce carbon emissions and lower energy costs. This research proposes an optimal economic power dispatch strategy using Model Predictive Control (MPC) to enhance the overall performance of HAPN. A hybrid AC/DC microgrid concept is proposed to address the control choices made by the appliance scheduling and hybrid switching approaches based on a linear programming optimization framework. The suggested optimization criteria improve consumer satisfaction, minimize grid disconnections, and lower overall energy costs by deploying inexpensive clean energy generation and control. Various examples from actual case study demonstrate the use of the established EMS and design methodology.Die Motivation dieser Arbeit besteht darin, ein Konzept zur Senkung der Energiekosten in einem Heimnetzwerk (HAPN) mit intelligenter Erzeugung und exiblen Lastanforderungen vorzustellen. Im Rahmen dieser Forschungsarbeit wird ein Entwurf fĂŒr ein HAPN entwickelt, indem das Energiemanagementsystem (EMS) und der Entwurf des Layouts auf der Grundlage des Systemmodells und der betrieblichen Anforderungen gelöst werden. Die steigende Nachfrage nach ElektrizitĂ€t ist fĂŒr traditionelle Stromnetze kostspielig und infrastrukturintensiv. Daher konzentrieren sich Energietechniker darauf, die Effizienz der derzeitigen Netze zu erhöhen. Dies kann durch die Integration verteilter Erzeugungsanlagen (z. B. Photovoltaik (PV), Speicher) mit einem geeigneten Kontrollmechanismus fĂŒr das Energiemanagement auf der Verteilungsseite erreicht werden. DarĂŒber hinaus hat das Interesse an der Installation von PV-Batterie-basierten Systemen aufgrund der Reduzierung der CO2-Emissionen und der Senkung der Energiekosten erheblich zugenommen. Es wird eine optimale wirtschaftliche Strategie fĂŒr den Energieeinsatz unter Verwendung einer modellprĂ€diktiven Steuerung (MPC) entwickelt. Es wird zudem ein hybrides AC/DC-Microgrid-Konzept vorgeschlagen, um die Steuerungsentscheidungen, die von den AnsĂ€tzen der GerĂ€teplanung und der hybriden Umschaltung getroffen werden, auf der Grundlage eines linearen Programmierungsoptimierungsrahmens zu berĂŒcksichtigen. Die vorgeschlagenen Optimierungskriterien verbessern die Zufriedenheit der Verbraucher, minimieren Netzabschaltungen und senken die Gesamtenergiekosten durch den Einsatz von kostengĂŒnstiger und sauberer Energieerzeugung. Verschiedene Beispiele aus einer Fallstudie demonstrieren den Einsatz des entwickelten EMS und der Entwurfsmethodik

    Opening of Ancillary Service Markets to Distributed Energy Resources: A Review

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    Electric power systems are moving toward more decentralized models, where energy generation is performed by small and distributed power plants, often from renewables. With the gradual phase out from fossil fuels, however, Distribution Energy Resources (DERs) are expected to take over in the provision of all regulation services required to operate the grid. To this purpose, the opening of national Ancillary Service Markets (ASMs) to DERs is considered an essential passage. In order to allow this transition to happen, current opportunities and barriers to market participation of DERs must be clearly identified. In this work, a comprehensive review is provided of the state-of-the-art of research on DER integration into ASMs. The topic at hand is analyzed from different perspectives. First, the current situation and main trends regarding the reformation processes of national ASMs are analyzed to get a clear picture of the evolutions expected and adjustment required in the future, according to the scientific community. Then, the focus is moved to the strategies to be adopted by aggregators for the effective control and coordination of DERs, exploring the challenges posed by the uncertainties affecting the problem. Coordination schemes between transmission and distribution system operators, and the implications on the grid infrastructure operation and planning, are also investigated. Finally, the review deepens the control capabilities required for DER technologies to perform the needed control actions

    Sustainability Matchmaking: Exploration into using excess renewable energy to deliver ‘free’ energy to fuel poor homes – a preliminary case study in Ireland

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    The aggregated fuel cost of domestic hot water (DHW) generation in Ireland, in 2022, was €529M with associated emissions/load of 1.3MtCO2/289GWh. The shadow price of carbon monetises the negative impact of emissions, rising with time; DHW generation has an associated shadow carbon cost of €13M in 2022, rising to €42M in 2030 and €335M in 2050. In 2020, c12%/€441M of wind was curtailed or wasted as inter alia, there was no demand at times of high wind. Meanwhile, a ‘silent crisis’ is occurring in Ireland wherein one-in-two dwellings were considered in fuel poverty in 2022. Households in fuel poverty are known to limit DHW generation, impacting hygiene and well-being. As most Irish households have an electrical immersion already installed in DHW tanks, this research develops a preliminary (first round) wind allocation model to assess the potentials and economics of redeploying excess wind to heat DHW and, in the interest of a just-transition, focuses on households at risk of fuel poverty. It is found that fuel-poor households in Ireland could be theoretically provided with a ‘free’ full tank of hot water, once in every 3 weeks, redeploying 89% of overnight curtailed wind energy in 2019, realising a potential carbon cost saving to the Irish state of c€4M in 2030, rising to c€11M in 2050 along with a better quality of life for fuel-poor citizens. This research concludes this massive, readily deployable, shared, citizen-owned dispatch-down resource should be utilised and further research into redeployment of dispatch-down as a service is merited

    Wind Farms and Flexible Loads Contribution in Automatic Generation Control: An Extensive Review and Simulation

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    With the increasing integration of wind energy sources into conventional power systems, the demand for reserve power has risen due to associated forecasting errors. Consequently, developing innovative operating strategies for automatic generation control (AGC) has become crucial. These strategies ensure a real-time balance between load and generation while minimizing the reliance on operating reserves from conventional power plant units. Wind farms exhibit a strong interest in participating in AGC operations, especially when AGC is organized into different regulation areas encompassing various generation units. Further, the integration of flexible loads, such as electric vehicles and thermostatically controlled loads, is considered indispensable in modern power systems, which can have the capability to offer ancillary services to the grid through the AGC systems. This study initially presents the fundamental concepts of wind power plants and flexible load units, highlighting their significant contribution to load frequency control (LFC) as an important aspect of AGC. Subsequently, a real-time dynamic dispatch strategy for the AGC model is proposed, integrating reserve power from wind farms and flexible load units. For simulations, a future Pakistan power system model is developed using Dig SILENT Power Factory software (2020 SP3), and the obtained results are presented. The results demonstrate that wind farms and flexible loads can effectively contribute to power-balancing operations. However, given its cost-effectiveness, wind power should be operated at maximum capacity and only be utilized when there is a need to reduce power generation. Additionally, integrating reserves from these sources ensures power system security, reduces dependence on conventional sources, and enhances economic efficiency

    Multi-agent system implementation in demand response: A literature review and bibliometric evaluation

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    This research provides a comprehensive literature overview and bibliometric evaluation of multi-agent system (MAS) implementation in energy demand response (DR) to identify gaps. The review encompasses 39 relevant papers from searches in three academic databases, focusing on studies published from 2012 to the middle of 2023. The review includes MAS frameworks, optimization algorithms, communication protocols, market structures and evaluation methodologies. Bibliometric analysis of 587 documents from the search on the Scopus database identified prolific authors, influential articles and collaborative networks within the field. The findings reveal growing research interest in implementing an MAS for DR, focusing on integrating intelligent agents into electricity grids to enable effective load management and enhance grid stability. Additionally, the review outlines potential research directions, including exploring advanced MAS techniques, interoperability challenges, policy implications and the integration of renewable energy sources
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