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

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 für 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 Elektrizität ist für 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 für das Energiemanagement auf der Verteilungsseite erreicht werden. Darüber 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 für den Energieeinsatz unter Verwendung einer modellprädiktiven Steuerung (MPC) entwickelt. Es wird zudem ein hybrides AC/DC-Microgrid-Konzept vorgeschlagen, um die Steuerungsentscheidungen, die von den Ansätzen der Geräteplanung und der hybriden Umschaltung getroffen werden, auf der Grundlage eines linearen Programmierungsoptimierungsrahmens zu berücksichtigen. Die vorgeschlagenen Optimierungskriterien verbessern die Zufriedenheit der Verbraucher, minimieren Netzabschaltungen und senken die Gesamtenergiekosten durch den Einsatz von kostengünstiger und sauberer Energieerzeugung. Verschiedene Beispiele aus einer Fallstudie demonstrieren den Einsatz des entwickelten EMS und der Entwurfsmethodik

Rooftop PV with battery storage for constant output power production

In this thesis, the application and control of battery storage (BS) system is introduced and developed to compensate for output power changes of rooftop PVs due to variations in the environmental conditions and household loads. A practical battery storage energy management strategy (BS-EMS) for operating small scale grid-connected rooftop PVs is implemented such that the net delivered output power to the grid is constant under various operating conditions

Decentralization in energy systems - Low-carbon technologies and sector coupling on the household, community and city scales

The number of installations of distributed energy technologies, such as solar photovoltaic (PV) and battery systems, has increased dramatically in recent decades. The required transition towards a decarbonized energy system entails electrification of the different sectors. Both these developments provide new opportunities for energy autonomy and sector coupling in decentralized systems, and allow local actors to contribute to reducing their climate impact.The aim of this thesis is to study the utilization of local energy technologies and the potential for system flexibility in three decentralized energy systems: prosumer households, prosumer communities, and city energy systems. In addition, the thesis investigates the interactions of decentralized systems with the surrounding regional energy system. In this work, four techno-economic energy system optimization models are used. In the first model, PV-battery systems in prosumer households are analyzed within the North European electricity system dispatch. In the second model, they are examined as part of prosumer communities. In the third, city-scale model the investment and dispatch in the electricity and district heating sectors are optimized, while considering flexible and inflexible charging of electric cars and buses. The fourth model combines the city and regional scales, to study the operation, design and interaction of both systems, while considering different connection capacities for electricity exchange between the systems.The results show that the economic incentives for electricity self-consumption in prosumer households promote a way of utilizing household battery systems that is not in line with the least‑cost dispatch of the electricity system. Consequently, prosumer households are, within the current tariff structure, unlikely to provide flexibility that would assist the balancing of intermittency in the regional electricity system. In prosumer communities, where prosumer households have the possibility to share electricity, a financial benefit accrues to the participating households primarily when there is a reduced connection capacity for electricity exchange to the energy provider. For city energy systems, it is shown that power-to-heat technologies in combination with thermal storage systems and flexibility with regards to the charging of battery electric vehicles facilitate the uptake of local solar PV. The city electric car fleet provides the potential to postpone up to 85% of the demand for charging, which leads to more than twice the share of solar PV in the electricity mix for charging, as compared with inflexible charging. A 50% connection capacity between the city-scale and regional-scale energy systems implies only 3% higher costs for the installation and operation of energy technologies on both scales, as compared with a system that has 100% connection capacity.This thesis outlines the potential for increased decentralization of the energy supply and highlights the need for strategies to integrate decentralized and centralized energy systems

Assessment of the Use of Renewable Energy Sources for the Charging Infrastructure of Electric Vehicles

Application of renewable energy sources is a relevant area of energy supply for urban infrastructure. In 2019, the share of energy produced by such sources reached 11% (for solar energy) and 22% (for wind energy) of the total energy produced during the year. However, these systems require an improvement in their efficiency that can be achieved by introducing electric vehicles. They can accumulate, store and transfer surplus energy to the city’s power grid. A solution to this problem is a smart charging infrastructure. The existing studies in the field of charging infrastructure organization for electric vehicles consider only models locating charging stations in the city or the calculation of their required number. These calculations are based on socio-economic factors and images of a potential owner of an electric vehicle. Therefore, the aim of this study is to develop a methodology for determining the location of charging stations and their required number. The calculation will include the operating features of the existing charging infrastructure, which has not been done before. Thus, the purpose of this article is to research the operation of the existing charging infrastructure. This will provide an opportunity to develop approaches to the energy supply of charging infrastructure and city’s power grid from renewable energy sources. The article presents an analysis of data on the number of charging sessions during the year, month and day. This data enable us to construct curves of the charging session number and suggest ways to conduct the next stages of this study. Doi: 10.28991/esj-2020-01251 Full Text: PD

The pure PV-EV energy system – A conceptual study of a nationwide energy system based solely on photovoltaics and electric vehicles

The objective of this conceptual study is to reveal the substantial potential and synergy of solar energy and electric vehicles (EVs) working together. This potential is demonstrated by studying the feasibility of a nationwide energy system solely reliant on solar energy and EVs. Photovoltaic (PV) solar energy is already an important energy source globally, but due to its intermittency it requires energy storage to balance between times of high and low production. At the same time, a global drive is underway in the transport sector: the change from internal combustion engines to EVs. Cars are in fact stationary 95% of the time, and when the vehicle is connected to the grid, the EV battery can regulate the intermittent PV source using vehicle-to-grid (V2G) technology. This paper presents a conceptual study of a pure PV-EV based energy system, with Spain as a case study. Provided that Spain’s entire fleet of 29.4 million road going vehicles is switched to EVs, the study shows that 3.45 billion m2 of PV (73 m2 per capita) could give Spain a completely self-reliant energy system. The theoretical study is based on a combination of measured values, simulations, and assumptions. The conclusion of the analysis is undoubtedly extraordinary, namely that an entire country like Spain can power its complete energy system solely on PV, using EVs as the only energy storage resource

Financial Analysis of Household Photovoltaic Self-Consumption in the Context of the Vehicle-to-Home (V2H) in Portugal

Publisher Copyright: © 2023 by the authors.This paper focuses on the purpose to see if it is possible to increase the earnings associated to the installation of PV systems in people’s homes. In accordance with this, a different way of thinking was adopted, namely the investment in batteries to maximize the energy earnings. The main problem of this classical approach is that the investment in those batteries is important. In this way, a different perspective was taken into account, namely the use of the electrical vehicles. This kind of vehicles is starting to become a real reality. In fact, the selling of these vehicles start to become a solution for the ordinary people, and it is expected in a very near future to be a reality for most of them. Thus, this study presents the use of a storage system based on the vehicle-to-home (V2H) technology for the people’s homes. The V2H availability varies among prosumers profile regarding the daily routines, weather conditions, and business aspects, besides other aspects. These profiles were combined with different power panels with and without injection into the grid. The costs of each configuration considering a residential consumer located in Portugal, as well as, their peak solar hours in a year were estimated. From this study, it will be possible to verify that the obtained economical results show that the usage of V2H as storage system based on batteries for modern homes is very attractive.publishersversionpublishe

Decentralization in the electricity system: At the household, community and city levels

Recent years have seen a rise in the number of implementations of small-scale generation and storage technologies for electricity and heat at different levels in the energy system. This trend towards decentralization of the system is driven by rapid decrease in technology costs, as well as the intentions expressed by various stakeholders to contribute to a carbon-neutral energy system. This thesis investigates the investments and operation of generation and storage technologies at three levels within the energy system: i) residential Prosumer households, which use photovoltaic (PV)-battery systems to supply and shift their electricity demand; ii) Prosumer communities, in which prosumer households share electricity; and iii) Smart integrated cities, which make use of interconnections between the electricity, heating, and transport sectors.Three techno-economic optimization modeling methods are utilized to study technology investment and dispatch, self-consumption of electricity and heat at different levels of decentralization, and the interactions that occur between decentralized systems and the centralized electricity system. Prosumer households are modeled by combining a household electricity cost optimization model and a northern European electricity system dispatch model. The optimization model developed to study prosumer communities directly compares the PV-battery system investments and operations in individual prosumer households and in prosumer households within a community. The city energy system optimization model is designed to analyze interconnections between the urban electricity and heat (and in future work, also transport) sectors.It is shown that prosumer households under the current Swedish tariff system experience a strong incentive to self-consume PV-generated electricity within their households and experience a weak incentive to operate their battery systems such as to reduce operational costs within the electricity system. Being part of a prosumer community can provide the highest monetary benefit to prosumer households for the purpose of reducing the connection capacity to the centralized system. Prosumer communities exhibit different patterns of electricity trade to the centralized system than individual prosumer households, due to local balancing of electricity within the community. On the city level, the installation of local generation and storage technologies for electricity and heat can reduce the stress on the connection to the centralized electricity system. Thus, local electricity generation can help to meet increases in electricity demand and demand peaks at the city level, stemming from city growth or electrification of energy use within the city. An interaction between the electricity and heating sectors in the city energy system can in the modeling results be seen in, for example, the utilization of power-to-heat technologies, which often use electricity during low-cost hours. Storage systems for electricity and heat are utilized within the city to shift electricity and heat between different periods

An Overview on Functional Integration of Hybrid Renewable Energy Systems in Multi-Energy Buildings

Buildings are responsible for over 30% of global final energy consumption and nearly 40% of total CO2 emissions. Thus, rapid penetration of renewable energy technologies (RETs) in this sector is required. Integration of renewable energy sources (RESs) into residential buildings should not only guarantee an overall neutral energy balance over long term horizon (nZEB concept), but also provide a higher flexibility, a real-time monitoring and a real time interaction with end-users (smart-building concept). Thus, increasing interest is being given to the concepts of Hybrid Renewable Energy Systems (HRES) and Multi-Energy Buildings, in which several renewable and nonrenewable energy systems, the energy networks and the energy demand optimally interact with each other at various levels, exploring all possible interactions between systems and vectors (electricity, heat, cooling, fuels, transport) without them being treated separately. In this context, the present paper gives an overview of functional integration of HRES in Multi-Energy Buildings evidencing the numerous problems and potentialities related to the application of HRESs in the residential building sector. Buildingintegrated HRESs with at least two RESs (i.e., wind–solar, solar–geothermal and solar–biomass) are considered. The most applied HRES solutions in the residential sector are presented, and integration of HRES with thermal and electrical loads in residential buildings connected to external multiple energy grids is investigated. Attention is focused on the potentialities that functional integration can offer in terms of flexibility services to the energy grids. New holistic approaches to the management problems and more complex architectures for the optimal control are described

Historical data based energy management in a microgrid with a hybrid energy storage system

In a micro-grid, due to potential reverse output profiles of the Renewable Energy Source (RES) and the load, energy storage devices are employed to achieve high self-consumption of RES and to minimize power surplus flowing back into the main grid. This paper proposes a variable charging/discharging threshold method to manage energy storage system. And an Adaptive Intelligence Technique (AIT) is put forward to raise the power management efficiency. A battery-ultra-capacitor hybrid energy storage system (HESS) with merits of high energy and power density is used to evaluate the proposed method with onsite measured RES output data. Compared with the PSO algorithm based on the precise predicted data of the load and the RES, the results show that the proposed method can achieve better load smoothing and maximum self-consumption of the RES without the requirement of precise load and RES forecasting

Current Status and Future Prospects of Electric Power as Automotive Fuel

The deployment of electric vehicles and plug-in hybrid vehicles on the premise of using low-carbon power sources (renewable energy and nuclear power) is expected to not only contribute to a stable energy supply by lowering dependence on oil (dependence on foreign supply sources) as fuel but also help to reduce CO2 emissions. Moreover, the use of night-time electricity is likely to help spread the use of electric vehicles for commuter use by reducing energy cost. However, it is important to remember that if conventional electricity, mainly generated by coal-fired power plants, is to be used as a power source, the deployment of electric vehicles and plug-in hybrid vehicles may not necessarily be effective in reducing CO2 emissions. It is also true that compared with vehicles powered by an internal-combustion engine, electric vehicles still have some shortcomings, such as their short driving range, some 100 km on a single charge of the battery, and the long battery-recharging time. To significantly increase the use of electric vehicles in the future, the key will be to develop a low-cost, high-performance battery. It will also be necessary to further reduce the cost of wind and photovoltaic power generation. As the use of electric vehicles spreads, it will become necessary to conduct a quantitative study on the optimization (cost minimization) of the power source mix (cost minimization), including additional power sources for automobiles.electric vehicles, optimization, power source