• Energy Research
• DE close
• UA close

Attempts to model any present or future power grid face a huge challenge because a power grid is a complex system, with feedback and multi-agent behaviors, integrated by generation, distribution, storage and consumption systems, using various control and automation computing systems to manage electricity flows. Our approach to modeling is to build upon an established model of the low voltage electricity network which is tested and proven, by extending it to a generalized energy model. But, in order to address the crucial issues of energy efficiency, additional processes like energy conversion and storage, and further energy carriers, such as gas, heat, etc., besides the traditional electrical one, must be considered. Therefore a more powerful model, provided with enhanced nodes or conversion points, able to deal with multidimensional flows, is being required. This article addresses the issue of modeling a local multi-carrier energy network. This problem can be considered as an extension of modeling a low voltage distribution network located at some urban or rural geographic area. But instead of using an external power flow analysis package to do the power flow calculations, as used in electric networks, in this work we integrate a multiagent algorithm to perform the task, in a concurrent way to the other simulation tasks, and not only for the electric fluid but also for a number of additional energy carriers. As the model is mainly focused in system operation, generation and load models are not developed. The financial support from EPSRC for Liz Varga on project entitled "Transforming Utilities’ Conversion Points" (no. EP/J005649/1) is gratefully acknowledged.

The thermo-hydro-mechanical behaviour of a water-saturated cement-based heat store for domestic applications has been investigated. Numerical simulations have been employed to locate the critical regions during thermal loading, for which analytical solutions have been derived and validated by numerical simulations. The analytical solutions allow a fast screening of materials and design parameters in relation to the stresses induced by thermomechanical loading. Maximum stresses in the system have been quantified based on the thermomechanical properties of three heat exchanger materials selected by design engineers and of the filling material. Sensitivity analyses indicate that the stress distribution is very sensitive to the thermal expansion coefficients of the involved materials. The results of this study can serve as a guide line for the design of the present and similar heat storage systems. The analytical solution developed is a fast and robust method for the evaluation of stresses around heat exchangers embedded in a solid material and can serve as a tool for design optimisation.

The transition towards sustainable energy systems necessitates effective management of renewable energy sources alongside conventional grid infrastructure. This paper presents a comprehensive approach to optimizing grid management by integrating Photovoltaic (PV), wind, and grid energies to minimize costs and enhance sustainability. A key focus lies in developing an accurate scheduling algorithm utilizing Mixed Integer Programming (MIP), enabling dynamic allocation of energy resources to meet demand while minimizing reliance on cost-intensive grid energy. An ensemble learning technique, specifically a stacking algorithm, is employed to construct a robust forecasting pipeline for PV and wind energy generation. The forecasting model achieves remarkable accuracy with a Root Mean Squared Error (RMSE) of less than 0.1 for short-term (15 min and one day ahead) and long-term (one week and one month ahead) predictions. By combining optimization and forecasting methodologies, this research contributes to advancing grid management systems capable of harnessing renewable energy sources efficiently, thus facilitating cost savings and fostering sustainability in the energy sector.

В даній роботі проведено аналіз відхилення напруги в мережі 0,4 кВ, та здійснено розробку рекомендацій щодо нормалізації параметрів відхилення напруги. Отримані наступні результати: – Здійснено аналіз показників якості електричної енергії та їх нормування. Доведено, що будь-яке відхилення напруги від встановленого номінального значення електричної мережі є негативним. – Представлено причини низької якості електричної енергії та вплив параметрів електроенергії на роботу електрообладнання. – Проведено аналіз засобів та способів, а також обґрунтувано необхідність регулювання напруги в мережах 10 кВ. Подано можливі способи зміни та регулювання режиму напруги та їх використання при експлуатації. – Дано опис трансформаторної підстанції ТП-10/0,4 кВ. – Здійснено аналіз характеристик та розглянуто принцип роботи приладу для вимірювання ПЯЕ «Metrel MI 2892». – Проведено зняття показів ПЯЕ на ТП-10/0,4 кВ, за допомогою приладу «Metrel MI 2892». Представлено результати даних ПЯЕ на ТП-10/0,4 кВ. ; У цій кваліфікаційній роботі проведено аналіз відхилення напруги в мережі 0,4 кВ, та розробка рекомендацій щодо нормалізації параметрів відхилення напруги. Розглянуто питання, пов'язані з показниками якості електричної енергії, визначено вплив низької якості напруги на експлуатаційну надійність та енергоефективність, а також обґрунтовано необхідність регулювання напруги. Місцем оцінки було обрано ТП –10/0,4 кВ. Робота зі зняття ПКЕ проводилася на двох фідерах ТП – 5172. Дана робота присвячена оцінці якості напруги тільки на фідері ТП –10/0,4 кВ. Виконано реєстрацію показників якості електричної енергії на шинах ТП –10/0,4 кВ за допомогою приладу «Metrel MI 2892». На підставі отриманих даних проведено обробку та аналіз результатів, виявлено джерела, що викликають відхилення напруги, надано рекомендації щодо нормалізації параметрів відхилення напруги. ; This qualified robot carried out an analysis of voltage reduction at a level of 0.4 kV, and developed recommendations for normalizing voltage reduction parameters. The power supply ...

SummaryEnvironmentally extended multiregional input‐output (EE MRIO) tables have emerged as a key framework to provide a comprehensive description of the global economy and analyze its effects on the environment. Of the available EE MRIO databases, EXIOBASE stands out as a database compatible with the System of Environmental‐Economic Accounting (SEEA) with a high sectorial detail matched with multiple social and environmental satellite accounts. In this paper, we present the latest developments realized with EXIOBASE 3—a time series of EE MRIO tables ranging from 1995 to 2011 for 44 countries (28 EU member plus 16 major economies) and five rest of the world regions. EXIOBASE 3 builds upon the previous versions of EXIOBASE by using rectangular supply‐use tables (SUTs) in a 163 industry by 200 products classification as the main building blocks. In order to capture structural changes, economic developments, as reported by national statistical agencies, were imposed on the available, disaggregated SUTs from EXIOBASE 2. These initial estimates were further refined by incorporating detailed data on energy, agricultural production, resource extraction, and bilateral trade. EXIOBASE 3 inherits the high level of environmental stressor detail from its precursor, with further improvement in the level of detail for resource extraction. To account for the expansion of the European Union (EU), EXIOBASE 3 was developed with the full EU28 country set (including the new member state Croatia). EXIOBASE 3 provides a unique tool for analyzing the dynamics of environmental pressures of economic activities over time.

Abstract The paper presents an equivalent circuit based simulation model for the static and dynamic behavior of lithium-ion battery systems and explains the different steps of the theoretical and experimental modeling process. The equivalent circuit based model describes the voltage-current characteristic, the state of charge behavior and the occurring losses of the battery system. A parameter identification method based on three characteristic experiments, a cycle test, an open circuit voltage test and pulse tests, is introduced. The model parameters are estimated employing a nonlinear optimization method. Furthermore, the experimental test bed for investigation of lithium-ion battery systems is described. The battery model approach is demonstrated and validated for a commercial 5 kWh lithium-ion battery system, including the model validation for test profiles and emulated battery charging and discharging profiles of a real photovoltaic home storage application. The comparison of measured and simulated voltage profiles indicates an excellent performance of the battery model.

Abstract Radiation damage in biological systems is initiated by free radicals and progresses with time through a variety of mechanisms. The time-scale and details of these mechanisms are briefly reviewed. Because of the variety of mechanisms of radio-biological damage, any single radio-protective or therapeutic agent can be only partially effective. The potential of and need for simultaneously using several radio-protective and therapeutic agents, including sulfhydryl compounds, superoxide dismutase, antioxidant proteins, and DNA repair enzymes, are examined, based on a priori considerations of the consequences of radiation exposure.