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The irradiation variations caused by cloud changes can cause rapid power fluctuations in large photovoltaic (PV) plants. The increased PV power share of the grid adversely affects the quality of power and the reliability of the power supply. Energy storage systems (ESSs)are often used to mitigate power fluctuations in the grid through various control algorithms. These algorithms create an ESS power reference that opposes the variations of the PV and reduces them to an acceptable value. Despite their everyday use, there have been few performance comparisons among the various methods, especially battery status, and the battery can operate in several systems with various smoothing methods. The paper aims to analyze the ramp-rate and step-rate control methods for smoothing solar PV fluctuations based on the irradiation profiles in a DC microgrid (MG) environment. The battery in the system operates as a continuous energy application, and a supercapacitor (SC) is used to remove transients in the battery system. The combined battery-SC coordinated system improves the performance of the DC microgrid system. The battery cycle analysis and depth are conducted using the well-established Coulomb counting technique. MATLAB/Simulink validates the simulation results, and the OP-5700 HIL test bench conducts real-time results. 2022 The Author(s) This work is supported by the Department of Science and Technology (DST), Government of India (GOI), with the project grant SR/FST/ETI-420/2016(C) under the FIST scheme. Open Access funding provided by the Qatar National Library. Scopus

The enhanced penetration of the renewable energy sources (RES) is dependent on microgrid (MG) to a power system is impact stability of the system due to a variation in dynamic properties of the MG from a traditional generator. As a result, analyzing the new issues with dynamic stability and controlling the operation of the power system in the connection of rising MG penetration becomes critical. This paper contains a MG system with renewable energy assisted, superconducting magnetic energy storage (SMES) storage and an extreme learning machine (ELM) based proportional integral derivative (PID) controller. The effect of renewable-based MG penetration on a dynamic stability and control of the multi machine multi area system under varied operating situations is comprehensively investigated in this study. Non-linear time-domain simulations and several performance indicators are used to evaluate the controller's ability with the different MG penetration percentages under various disturbances and operational conditions.

As the topic of sustainable development continues to prominence in global affairs, the case for renewable energy has never been stronger. To be regarded as a perfect alternative to conventional (non-renewable) energy sources in many climes, renewable energy, such as solar and wind, shows promise when considering concepts like grid parity. A significant number of studies have been devoted to understanding the concept. However, only a few studies have committed themselves to analysing the research activity carried out on it. This paper will present a bibliometric and empirical review of worldwide grid parity, energy transition, and electricity cost research. To situate the progress in this research area, a detailed search of Scopus was used to identify and situate research development in the field from 1965 until 2021. Using the data extracted from Scopus and VOSviewer for analysis, we explore different aspects of the publications, such as the volume, growth rate, and coverage of published documents, the most influential research papers and journals in this research area, and the most studied research themes in recent years. We also discuss Governmental policies in developed and developing economies that have accelerated the attainment of Grid parity in certain countries. Also, an empirical review of top-down, bottom-up, and artificial neural network approaches to evaluating grid parity was conducted. The study revealed a steady increase in the research articles focused on grid parity, energy transition, and electricity cost research from 2006. The geographic distribution of the publications shows that most of the publications on the subject originated from the USA, Germany, China, United Kingdom, and Spain, raking in 42.2% of the publications. Also, the top 7 authors with the highest document count from Scopus are from Finland, which coincidentally is one of the countries making significant progress in Grid parity attainment. Of the total document count from Scopus, only 0.02% are papers published from African Countries. Could this reluctance to publish research findings on energy transition be one of the reasons for the slow progression of sustainable energy for all in Africa? Therefore, it is imperative now more than ever for more research focusing on the attainment of grid parity, energy transition, and electricity costs for developing countries to be brought to the fore. This article provides a review of state-of-the-art research on the attainment of grid parity and energy transition with a focus on the Levelized Cost of Electricity (LCOE) models of renewable energy sources.

Modern power systems are facing the tremendous challenge of integrating vast amounts of variable (non-dispatchable) renewable generation capacity, such as solar photovoltaic or wind power. In this context, the required power system flexibility needs to be allocated in other units that can include energy storage, demand management or providing reserve from renewables curtailing the output power. The present paper proposes the new concept of grid-forming load, which can be considered a totally flexible concept of demand. The concept is not only ensuring the load is supporting the grid stability by adapting the load to the overall system balancing, but also ensures that the load is actually contributing to form the grid and to provide synchronization power to the overall system. In this sense, the new concept allows running a system powered only by renewables operating at maximum power (or operator defined set-point) in grid-following mode, while the overall system control is ubicated in the demand side. This is an important change of paradigm as it considers that all the flexibility, synchronism and stability provision is on the demand side. This concept can applied either to isolated systems or also to future power systems, where millions of loads steer the power system while the renewables are operating at full power. The paper proposes the concept, suggests possible control implementations of the grid-forming load and analyses the concept in four simulation case studies., 13 pages, 13 figures, accepted for publication in IEEE Trans. on Smart Grid

The problem of voltage restoration and current balancing has been a hot topic in the study of DC microgrids (MGs), and how to engineer a secondary controller to solve the conflict between these two is the concern of this paper. With the above consideration, an optimal distributed data-driven secondary control strategy is proposed in this paper, which relies entirely on the input and output (current measurements) data of DC MGs. The proposed framework completes the design of a secondary control strategy for DC MGs based on a data model for the first time, which incorporates the physical coupling relationship between voltage and current into the controller design and is independent of the global circuit parameters and topology information. As a result of the proposed cost function with future current prediction, the designed secondary control strategy not only retains the advantages of consensus control, such as facilitating the plug-and-play of generation units, but also enables DC MGs to achieve better output current quality at steady state, fast dynamic response and improves robustness to external disturbances. Unlike the existing schemes based on average voltage observer, this paper resorts to a combination of limiting the voltage reference value generated by the secondary controller and a current cooperative strategy based on the learned data model to achieve an easy-to-use trade-off between the two objectives of voltage regulation and current sharing in DC MGs. From the design and implementation point of view, the solution proposed in this paper is going to be simpler. Then, an analytical model of a closed-loop DC MG system under the proposed control scheme is developed, and the analysis of stability and consensus of weighted output current is given accordingly. Finally, the proposed control strategy is tested on a hardware DC MG system with solar panels and an MPPT controller to verify its feasibility.

©2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The high penetration of distributed energy resources, based on power electronics, is giving rise to stability issues in the electrical network, as initially those plants were not required to provide either voltage or frequency support. Due to this, transmission system operators (TSOs) and distribution system operators (DSOs) have set new requirements for them to provide grid support functionalities. This article presents a grid forming control strategy for power converters which is based on a virtual admittance loop. By means of this strategy it is possible to use a conventional current control based inverter, just adding this outer loop. By doing so, the converter is not only able to perform current control, but also frequency and voltage support functionalities. In this article, the proposed control is described and analyzed, checking as well its stability boundaries. After this analysis, the results obtained in a hardware-in-the-loop platform, where faulty scenarios, islanding or black start conditions, will be shown. Finally, the results obtained in an experimental true scale workbench will show its effectiveness for providing such services. This work was supported in part by LC-SC3-ES5-2018-2020-INTERRFACE project under Grant GA 824330 and in part by FlexiGRID project under Grant RTI2018-100921-B-C21.

The study pioneers in proposing a hybrid cloud-based framework for designing a totally stand-alone, green residential house, stable over load variations and fluctuations of renewable energy sources (RES). The framework uses wind turbine (WT) and photovoltaic panels (PV) as the main power supplies, while employing a fuel cell (FC), fed with an electrolyzer, as the secondary source of energy. A battery is also used, which together with the FC and electrolyzer, constitute the compensation system in the proposed framework. Taking into account the various types of residential electrical loads, including an electrical vehicle (EV), and applying a deep learning method, the proposed framework makes the day-ahead scheduling of all components in the house based on the forecasted profile of load demand and the energy generated by the RES. The compensation system comes into use to balance the real-time scheduling error caused by the uncertainties of the main sources of power. To ascertain the practicality of the proposed framework for real-life implementation, it is examined on a residential house considering components with authentic technical features. The real-time operation of the suggested residential system is also tested on the SpeadGoat real-time simulator, whose results corroborate the practicability of both the real-time and day-ahead operation of the proposed framework.

Europska unija svoj gospodarski rast i razvoj temelji na principima održivog razvoja, a on je nezamisliv bez obnovljivih izvora energije, koje Europa izdašno podupire financiranjem, promidžbom i dijeljenjem dobre prakse. U ovome se radu analiziraju efekti međunarodnog projekta FIRESPOL kroz koji se promicanjem dobre prakse i razmjenom iskustava između različitih zemalja i regija osnažuju ulaganja u obnovljive izvore energije (OIE), a time daje doprinos zapošljavanju i rastu niskougljičnog gospodarstva članica Europske unije., The European Union bases its economic growth and development on the principles of sustainable development – inconceivable without renewable energy sources – which Europe supports generously by financing, promoting and sharing best practice. This paper analyses the effects of the FIRESPOL international project which, by promoting best practice and exchanging experiences between different countries and regions, strengthens investments in renewable energy sources (RES), contributing to the employment and growth of EU’s low-carbon economy.

This paper addresses the attainment of a methodology aimed at obtaining simplified models embedding the regulatory constraints imposed by the country-specific remuneration mechanisms in the energy management system of long operating life renewable assets under a high degree of uncertainty. This methodology, composed of different steps in which sensitivity analysis as well as Monte Carlo simulation play a key role, is focused on a significant case study that has implemented two of the most widely used worldwide remuneration mechanisms in the promotion of renewable energies, i.e., feed-in tariffs and auctions. The earnings before interest, tax, depreciation and amortization have been used as the output variable of the energy management model, as it is essential to take into account both revenues and operating costs of these renewable assets to manage them optimally. Some valid simplified models have been achieved by applying the proposed methodology to the case study with generalized errors below 5%. Specifically, one simplified energy management system model has been obtained under the feed-in tariff scheme, which involves acting on almost 40% of the equations of the original model and reducing the initial input parameters by 22%. Meanwhile, two simplified energy management system models have been obtained under the auction scheme. The most conservative simplified model involves acting on almost 50% of the equations of the original model and reducing the initial input parameters by 35%, while in the less conservative case it involves acting on more than 50% of the equations of the original model and reducing the initial input parameters by 42%. In short, although the uncertainty on the energy assets cannot be completely eliminated, it can be considerably reduced by facilitating the assessment of its prospective financial results. The validity of the achieved simplified models demonstrates the suitability and usefulness of the proposed simplifying methodology, providing a touch of quality in the long-term judgement and decision-making of the stakeholders when optimally managing renewable energy facilities under any type of remuneration scheme.

Decarbonizing the energy sector in order to reduce the consequences of climate change is possible through a comprehensive set of new measures in this sector: integration of a higher share of electricity from renewables and reduction in the share of fossil fuels in the energy mix, improvements in energy efficiency across the board, but also the development of a new, functioning model of the electricity market. As the electricity market is a complex and dynamic environment, this paper highlights that the new vision for the sector outlined here requires a holistic approach with multiple perspectives. The paper focuses on possible challenges in achieving these goals. Having in mind a common vision, it has been up to each country to reshape its domestic energy sector, as well as to use the opportunity to benefit from such a transition to the suggested framework. The contribution of this paper are detailed suggestions for that transition process in the case of the Republic of Serbia. To the best of our knowledge, this is the first paper to systematically explore the evolution of the electricity market design in the Republic of Serbia to ensure a feasible decarbonization process.

The article presents the results of research on the issues of Poland’s energy transformation from a sociological perspective. The exploratory analysis covered the attitude of the Polish society to the energy transformation, i.e. a change in the methods of generating energy in Poland, which results from the climate policy adopted by the Polish government.1 The aim of the article is to present social awareness – the social expectations and perceptions of Poles regarding the energy transformation understood in this way – to determine whether the opinions and views of the Polish society are in line with the planned and implemented energy transformation processes. The article provides an answer to the question about the Polish society’s attitudes towards the energy transformation and energy sources – to what extent the attitudes towards the proposed solutions to the problems are positive, and to what extent negative. For this purpose, the method of analysing the existing statistical data was used The basis of the secondary data analysis are the results of public opinion polls, carried out by the Public Opinion Research Centre (CBOS) in the period from 19872 to 2021. The sociological perspective adopted here assumes that the energy transformation is not only an economic but also a social process. For this reason, public support, in particular the positive attitude of respondents to new energy sources, is considered an important element of its success. Artykuł prezentuje wyniki badań dotyczące problematyki transformacji energetycznej Polski w perspektywie socjologicznej. Analizie eksploracyjnej poddany został stosunek społeczeństwa polskiego do transformacji energetycznej, czyli zmiany dotyczącej sposobów wytwarzania energii w Polsce, która wynika z przyjętej przez rząd Polski polityki klimatycznej. Celem artykułu jest prezentacja świadomości społecznej – społecznych oczekiwań i wyobrażeń Polaków dotyczących tak właśnie rozumianej transformacji energetycznej – określenie czy istnieje zgodność opinii i poglądów społeczeństwa polskiego z planowanymi i wdrażanymi procesami transformacji energetycznej kraju. Artykuł udziela odpowiedzi na pytanie, jakie są postawy społeczeństwa polskiego wobec transformacji energetycznej i źródeł energii – w jakim zakresie postawy społeczeństwa wobec proponowanych rozwiązań problemów są pozytywne, a w jakim negatywne. W tym celu wykorzystana została metoda analizy zastanych danych statystycznych. Wykorzystano reprezentatywne dla społeczeństwa polskiego sondażowe badania opinii publicznej realizowane przez Centrum Badania Opinii Społecznej (CBOS) w okresie od 1987 do 2021 roku. Przyjęta tu perspektywa socjologiczna zakłada, że transformacja energetyczna jest procesem nie tylko gospodarczym, ale także społecznym. Z tego powodu za istotny element jej powodzenia przyjmuje się społeczne poparcie, w szczególności pozytywny stosunek badanych do nowych źródeł energii.

With the urgent requirement of the utilization of renewable energy (RE) for the decarbonization of energy systems, power transmission via high-voltage direct current (HVDC) lines shows limits in the face of fluctuations of RE generation. This paper addresses the coordinated planning of HVDCs and power-to-hydrogen supply chains (P2HSCs) for RE utilization. First, the lumped cluster model of the large-scale power-to-hydrogen is established based on the derivation of the maximum production points. On this basis, P2HSC is modeled as a constrained power load. Then, a multi-objective multi-stage stochastic planning model of HVDCs and P2HSCs is proposed to fully consider RE fluctuation and uncertainty characteristics. Furthermore, a decomposition algorithm based on the dynamic programming method is designed to solve this problem. Finally, the proposed model and algorithm are applied in real Inner Mongolia-Shandong case studies. The effectiveness and robustness of the proposed model are quantitatively verified. Furthermore, the investment interplay of HVDCs and P2HSCs on the planning timeline and the operational interplay of the two sectors as complementary power loads are verified to create the maximum social benefit in renewable energy systems.

Increasing implementation of energy storage systems (ESS) is an available way to mitigate the fluctuation of renewable energy sources (RES) in smart grid. This paper proposes distributed control strategies without/with event-triggered information delivery for a group of heterogeneous energy storage systems (HESS) with different parameters such that the power fluctuation of renewable generation and load variation can be smoothed, meanwhile ensuring power and energy sharing among various ESS. To mitigate the impacts of parameter differences in HESS, a weighted control matrix is designed, and the method of deriving optimal feedback control gain is designed with the help of Riccati control theory. Aiming at reducing communication burdens meanwhile guaranteeing system performance, an event-triggered information delivery strategy without Zeno behavior is introduced to the distributed control method. Convergence and stability of the proposed methods are verified by rigorous mathematical analysis. Simulation studies are conducted to verify the effectiveness of the proposed method. The results show that the proposed method can achieve the state-of-charge (SoC), the state-of-temperature (SoT) and the state of-energy (SoE) balance of HESS, proportional power sharing and power tracking objectives, even if the states of HESS are interfered by random disturbances.

Refereed/Peer-reviewed With the proliferation of electric vehicles (EVs), EV charging cost will become an integral part of household energy cost. This research proposes a novel household energy cost optimisation method for grid-connected homes with EV under power export constraints. It addresses the limitations of previous studies by incorporating more realistic variable EV charging characteristics, power export limits, degradation of battery energy storage (BES) and battery salvage revenue into a comprehensive techno-economic energy system model. Cost optimisation results are presented for four system configurations using relatively new time-of-use (ToU) tariff and real load and photovoltaic (PV) generation data for South Australian households. Sensitivity analysis for annual energy cost (AEC) is conducted by varying daily household load demand, PV/BES capacity, power export limits and PV/BES cost. Power flow and peak demand analyses are presented to the impacts of PV, BES and EV on household demand. Results show that PV with BES and EV is the most economical configuration for individual households, where the AEC can be reduced by up to 39.6% compared to a normal household without EV, PV and BES. The BES can effectively reduce household power and energy demands during peak periods by up to 80.4% and 89.1%, respectively.

Renewable generation has grown rapidly these years due to its advantages in low environmental impacts. Stand-alone microgrid with renewable generation and energy storage is a promising option in remote areas beyond the reach of an existing power grid. This paper proposes a multiobjective optimization model to co-optimize the sizes of renewable generation and energy storage in stand-alone microgrids, which minimizes the load shedding risk and the total investment cost. The load shedding degree is obtained by an optimal operation problem and measured by shortfall risk, considering the uncertainties of demand and renewable resources. To deal with the inaccurate empirical distribution, distributionally robust shortfall risk is further established under a Wasserstein-metric based ambiguity set, and an equivalent distributionally robust formulation is obtained. Then a conservative approximation is developed, and the resulting problem appears to be a bi-objective linear program. The Pareto frontier is proven to be piecewise linear, and the analytical expression of the Pareto frontier is derived. Case studies demonstrate the effectiveness and performance of the proposed method.

Due to its inherent geographical potential for wind/solar power and other renewable energy sources (RES) generation, Tamil Nadu is one of the pioneering Indian states in the early development and utilisation of RES. Tamil Nadu accounts for roughly 25% of India's total wind energy capacity. Increased penetration of RES in a power system indicates that RESs have replaced traditional power plants that have historically managed and stabilised the power system, resulting in novel power flow situations. Grid stability must be enhanced in light of the integration of large-scale RES into the grid. The purpose of this research is to analyse and evaluate the impact of large-scale integration of RES by examining mitigating methods from the most recent academic articles and technical reports in this field. This will aid in identifying the key risks affecting the network's stability margin as a result of the widespread integration of RES generation, allowing for a reasonable increase in the network's stability margin. The study's findings will also help to guide the selection of appropriate mitigation strategies. As the stability margin improves, the future fraction of RES additions to the Tamil Nadu extra high voltage (EHV) grid will be increased significantly.

Unutar ovog rada obrađena je tema implementacije “pametnih” uređaja nužnih za automatizaciju distribucijske mreže. Dat je tehnički opis I princip rada “pametnih” uređaja koji se ugrađuju u elektroenergetske objekte u dubinu distribucijske mreže. Automatizacija distribucijske mreže smanjuje vrijeme trajanja kvarova koje uzrokuju prekidi opskrbe električne energije te umanjuje troškove nastale pojavom kvarova. Zbog sve veće implementacije, izgradnje I puštanja u pogon obnovljivih izvora energije(sunčane I vjetro elektrane) potrebno je poboljšavati, odnosno provoditi veći stupanj automatizacije uvođenjem daljinskog upravljanja u distribucijsku mrežu. U radu je opisan način rada “pametnih” uređaja koje se ugrađuju po dubini distribucijske mreže. Daljinski upravljane rastavne naprave osim osnovne funkcije daljinskog upravljanja omogućuju i mjerenje električnih veličina koje su zanimljive za detaljniju analizu pojava koje su praćene nastankom kvarova na distribucijskoj mreži., Within this paper, the topic of implementation of "smart" devices necessary for the automation of the distribution network is discussed. It is a technical description and principle of operation of "smart" devices that are installed in power facilities in the depth of the distribution network. The automation of the distribution network reduces the duration of failures caused by interruptions in the supply of electricity and reduces the costs caused by the occurrence of failures. Due to the increasing implementation, construction and commissioning of renewable energy sources (solar and wind power plants), it is necessary to improve or implement a greater degree of automation by introducing remote control into the distribution network. The paper describes the operation of "smart“ devices that are installed along the depth of the distribution network. In addition to the basic function of remote control, remotely controlled disconnecting devices also enable the measurement of electrical quantities, which are interesting for a more detailed analysis of phenomena that are accompanied by the occurrence of faults in the distribution network.

International audience; In this paper we propose an integrated power and transportation system control framework, combining the power grid model with a macroscopic electromobility model including charging stations under V2G operation. In this framework, the electrical vehicles (EVs) act as energy storage, but also as an additional virtual power grid link, transporting energy from one point to another. This new holistic model is used as a basis for optimal control design seeking to minimize renewable energy curtailment, while accounting for the structural limitation of the grid and other SoC constraints necessary for the optimal operation of the EVs. The proposed control scheme is shown to eliminate approximately 50% of curtailment compared to uncoordinated EV charging.

Obnovljivi izvori energije, poput Sunca i vjetra, imaju kontinuirani porast utjecaja na elektroenergetski sustav. Razvojem svijesti o klimatskim promjenama te željom za smanjenjem emisija stakleničkih plinova, bilježi se porast potreba za obnovljivim izvorima u proizvodnji električne energije. Međutim, električna energija proizvedena npr. iz solarnih panela ovisi o insolaciji Sunca, proizvodnja energije u vjetroelektranama ovisi o jakosti vjetra, što znači da proizvodnja iz obnovljivih izvora nije uvijek konstantna i predstavlja izazov u stabilizaciji elektroenergetskog sustava. S druge strane, sunčane i vjetroelektrane, ovisno o instaliranoj snazi, priključuju se na postojeću prijenosnu i distributivnu mrežu. Ali, to stvara zagušenje i opterećenje postojeće mreže elektroenergetskog sustava te istovremeno zahtijeva znatna ulaganja u postojeću infrastrukturu elektroenergetske mreže. Cilj je analizirati kako se „ponaša“ energetski sustav nakon implementacije elektrane na obnovljive izvore. Istraživanjima u posljednje vrijeme donose se zaključci o utjecaju proizvodnje električne energije iz obnovljivih izvora na okoliš te implementaciji iste u elektroenergetski sustav s aspekta praćenja vršnog opterećenja i stvaranja viškova energije iz postojećih elektrana. Naime, obnovljivi izvori (Sunce, vjetar i dr.) nepredvidivi su te stvaraju probleme u planiranju proizvodnje i potrošnje električne energije., Renewable energy sources, such as the Sun and wind, have a continuously increasing influence on the power system. With the development of awareness about climate change and the desire to reduce greenhouse gas emissions, there is an increase in the need for renewable sources in the production of electricity. However, electricity produced, for example, from solar panels depends on the insolation of the Sun, energy production in wind farms depends on the strength of the wind, which means that production from renewable sources is not always constant and represents a challenge in stabilizing the power system. On the other hand, solar and wind farms, depending on the installed power, are connected to the existing transmission and distribution network. However, this creates congestion and load on the existing power system network and at the same time requires significant investments in the existing power network infrastructure. The goal is to analyze how the energy system "behaves" after the implementation of a power plant based on renewable sources. Recent research has led to conclusions about the impact of electricity production from renewable sources on the environment and its implementation in the power system from the aspect of peak load monitoring and the generation of excess energy from existing power plants. Namely, renewable sources (sun, wind, etc.) are unpredictable and create problems in planning the production and consumption of electricity.

The solar power industry is a rapidly growing sector of renewable energy, and it is crucial that the available energy is accurately forecast. Using numerical weather prediction models, we can forecast the global horizontal irradiance on which the amount of energy produced by photovoltaic systems depends. This study presents the forecast effects for one of the most challenging weather conditions in modelling, occurring in central and eastern Europe. The dates of the synoptic situations were selected from 2021 and 2022. Simulations were carried out for 18 days with a cold front and, in order to verify the model configuration, for 2 days with a warm front, 2 days with an occlusion front and 2 days with a high pressure situation. Overall, 24 forecasts were made for each of the three parameterizations of the Weather Research and Forecasting model. The data were compared with the values measured in situ at the station performing the actinometric measurements belonging to Germany’s National Meteorological Service. This paper presents the spatial distribution of the global horizontal irradiance parameters for several terms to explain the differences between the results of the different simulations.

Sector coupling has a remarkable role in the optimal fulfilment of the energy transition. In order to reduce emissions of the energy sector, but also to increase the flexibility of the electricity system, clean energy production solutions offering multi-sector flexibility are needed, such as power-to-heat technologies and various thermal energy storages. In this paper, the participation of power-to-heat technologies and thermal energy storages in the electricity market are examined. In particular, the paper aims to review the key enablers, barriers, and drivers for power-to-heat and thermal energy storages in the context of electricity markets. Additionally, the technical potential of power-to-heat technologies combined with thermal energy storages are examined. The study is based on a literature review and examines especially the context of Finnish energy system and market. Post-print / Final draft

The energy crisis in Europe in 2022 and its consequences have brought changes to approaches towards the issue of energy security, energy policy, and the ability to react to crisis phenomena in the energy market in a short period of time. European countries that are dependent on Russian fossil fuels have faced numerous dilemmas and challenges in 2022. This paper aims to analyse the instruments and energy policies introduced as the reactions of European countries, specifically with the examples of Poland and Germany, to the ongoing fossil fuel crisis in the context of a short period. Due to the specificity of the energy market, the countries’ energy policies mainly concern long- and medium-term goals. In 2022, there was an unprecedented situation in which many European countries had to make significant changes to their fossil fuel imports quickly. We analyse and evaluate how two European countries that are heavily reliant on imported energy resources responded in a short time to the necessity of modifying their patterns of fossil fuel supply and demand. The results of our research are models that illustrate both countries’ reactions to the disturbances in the energy market during the initial months of the energy crisis. As part of the research, we conducted an analysis of the energy mix of Poland and Germany, their import energy dependency, and self-sufficiency. We then compared them with the short-term energy policies of both countries. As a result, we elaborate on a comparative analysis of the models of Poland’s and Germany’s responses to the crisis. The research also assesses the similarities and differences in the response models in Poland’s and Germany’s short-term energy security policies. The results of our research may help, in the future, to choose the available short-term instruments in the energy policy of countries in the face of a sudden need resulting from disruptions in supply chains. The article contributes to the future discussion on renewed national and regional energy security, as well as efficiency concepts. Our research findings could be valuable in selecting appropriate short-term energy policy tools for countries during supply chain disruptions. This article provides significant input for future deliberations on enhancing national and regional energy security, and also efficiency strategies.

ispartof: IET RENEWABLE POWER GENERATION vol:17 issue:9 pages:2411-2432 status: published

European institutions have decided to ban the sale of Internal Combustion Vehicles (ICEVs) in the EU from 2035. This opens a possible scenario in which, in the not-too-distant future, all vehicles circulating in Europe are likely to be Battery Electric Vehicles (BEVs). The Spanish vehicle fleet is one of the oldest and has the lowest percentage of BEVs in Europe. The aim of this study is to evaluate the hypothetical scenario in which the current mobility of ICEVs is transformed into BEVs, in the geographical area of the province of Barcelona and in Spain in general. The daily electricity consumption, the required installation capacity of wind and solar photovoltaic energies, and the potential reduction of NOx and particulate matter (PM) emissions are estimated. The daily emission reduction would be about 314 tons of NOx and 17 tons of PM in Spain. However, the estimated investment required in Spain to generate the additional electricity from renewable sources would be enormous (over EUR 25.4 billion), representing, for example, 5.5% of the total national budget in 2022. Award-winning Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructura Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant

European institutions have decided to ban the sale of Internal Combustion Vehicles (ICEVs) in the EU from 2035. This opens a possible scenario in which, in the not-too-distant future, all vehicles circulating in Europe are likely to be Battery Electric Vehicles (BEVs). The Spanish vehicle fleet is one of the oldest and has the lowest percentage of BEVs in Europe. The aim of this study is to evaluate the hypothetical scenario in which the current mobility of ICEVs is transformed into BEVs, in the geographical area of the province of Barcelona and in Spain in general. The daily electricity consumption, the required installation capacity of wind and solar photovoltaic energies, and the potential reduction of NOx and particulate matter (PM) emissions are estimated. The daily emission reduction would be about 314 tons of NOx and 17 tons of PM in Spain. However, the estimated investment required in Spain to generate the additional electricity from renewable sources would be enormous (over EUR 25.4 billion), representing, for example, 5.5% of the total national budget in 2022.

The shift towards RES introduces challenges related to power system stability due to the characteristics of inverter-based resources (IBRs) and the intermittent nature of renewable resources. This paper addresses these challenges by conducting comprehensive time and frequency simulations on the IEEE two-area benchmark power system with detailed type 4 wind turbine generators (WTGs), including turbines, generators, converters, filters, and controllers. The simulations analyse small-signal and transient stability, considering variations in active and reactive power, short-circuit events, and wind variations. Metrics such as rate of change of frequency (RoCoF), frequency nadir, percentage of frequency variation, and probability density function (PDF) are used to evaluate the system performance. The findings emphasise the importance of including detailed models of RES in stability analyses and demonstrate the impact of RES penetration on power system dynamics. This study contributes to a deeper understanding of RES integration challenges and provides insights for ensuring the reliable and secure operation of power systems in the presence of high levels of RES penetration.

Introduction. The renewable energy sources such as solar and wind power have increased significantly in recent years. However, as the generation of renewable energy has become more integrated, its intermission and instability have a major impact on the power system’s stability, such as voltage instability and frequency flicker. Purpose. In order to address the different power quality issues brought on by intermittent and unreliable renewable energy sources, electric spring offers a novel solution. It was proposed as a technique for regulating load and adjusting output power. For the integration of electric springs with noncritical loads, a contemporary control mechanism is described in this paper. Novelty. The suggested work is innovative in that it presents an improved control technique that efficiently maintains voltage stability as voltage changes. Method. The proposed technique is based on an analysis of the initial conditions and input data for developing fuzzy rules for calculating compensating voltages in relation to the difficulties. Results. This suggested fuzzy controller will be able to maintain the regular operation of the electric spring of power output control stability as well as continuing to provide power factor improvement and voltage control for significant loads, including the home’s protection system. Practical value. A detailed study of typical voltage regulation is undertaken, supported by simulation results, to demonstrate the effectiveness of the applied control scheme in cancelling the corresponding issues with power quality., Вступ. Відновлювані джерела енергії, такі як сонячна та вітрова енергія, значно збільшилися останніми роками. Однак у міру того, як виробництво відновлюваної енергії стало більш інтегрованим, його перебої та нестабільність впливають на стабільність енергосистеми, наприклад, нестабільність напруги та коливання частоти. Мета. Щоб вирішити різні проблеми з якістю електроенергії, викликані уривчастими та ненадійними відновлюваними джерелами енергії, електрична пружина пропонує нове рішення. Вона була запропонована як метод регулювання навантаження та регулювання вихідної потужності. Для інтеграції електричних пружин із некритичними навантаженнями у цій статті описано сучасний механізм керування. Новизна. Пропонована робота є новаторською, оскільки представляє вдосконалений метод управління, який ефективно підтримує стабільність напруги за зміни напруги. Метод. Запропонована методика заснована на аналізі початкових умов і вихідних даних для розробки нечітких правил розрахунку компенсуючих напруг стосовно труднощів. Результати. Пропонований нечіткий регулятор зможе підтримувати стабільну роботу електричної пружини контролю вихідної потужності, а також продовжувати забезпечувати покращення коефіцієнта потужності та контроль напруги для значних навантажень, включаючи систему захисту будинку. Практична цінність. Зроблено докладне дослідження типового регулювання напруги, підтверджене результатами моделювання, щоб продемонструвати ефективність схеми управління, що застосовується в усуненні відповідних проблем з якістю електроенергії.

Due to the high consumption of resources and energy in the construction sector, the development of resource-efficient and sustainable construction solutions is gaining increasing attention. The awareness of sustainability and resource conservation results in the interest of using natural and renewable materials in contemporary architecture. Timber construction methods offer both constructive and ecological potential for sustainable solutions. From a building physics perspective, the acoustic performance of lightweight buildings, such as those made of timber, presents a challenge. Even if standard requirements are met, the increased low-frequency sound transmission typical for light-weight construction can cause discomfort and is already the subject of questions in building physics, which are currently increasingly extending to timber construction. Within the framework of a holistic approach, this paper compares the problem of acoustic properties, design optimizations and the ecological properties of timber-frame and solid timber construction components. The comparison with heavy materials, such as concrete, shows the relation of acoustic optimization with the change of the environmental profile. In order to establish the interaction between acoustic quality of wooden ceiling constructions and their ecological characteristics, this article aims to demonstrate the potential of materials used in the building sector under ecological aspects considering a life cycle analysis., Deutsche Forschungsgemeinschaft

The article presents a study on the impact of the domain nesting method on the results of simulated solar conditions using the mesoscale Weather Research and Forecasting model. The analysis included 8 consecutive days (July 2022), which were characterized by cloudless conditions, as well as complex situations related to the passing of a cold front. The study covered a region located in Central and Eastern Europe—the southern area of eastern Germany. The results of the model simulations using the adopted domain configurations (with spatial resolutions of 9, 3, and 1 km; 3 and 1 km; and 5 and 1 km) were compared to data from ground measurements from Deutscher Wetterdienst (DWD) stations. The effect of the duration of the triggered prediction on the quality of the output data was also investigated, and for this purpose, short-term predictions covering 24 and 48 h, respectively, were selected. Research revealed the advantages of one combination of domains—3 and 1 km—over the others and showed that the results of simulations with different duration lengths were characterized by consistent results. Research supports the demand for high-quality forecasts of solar conditions, which are extremely important in the process of managing energy systems.

These days, with the significant increase in the use of renewable energy sources as additional energy sources connected to the distribution network, many challenges and difficulties arise in ensuring sustainability and reliability. The generation, transmission and distribution, in the current state of the electricity system, are facing quite dynamic changes. They are the result of the liberalization of the energy market, the increased use of renewable energy sources such as photovoltaic systems, wind turbines and the charging stations for hybrid and electric vehicles. The most important factors are related to the balancing of the energy system, the analysis of voltage stability, overcoming the consequences of the increase in short-circuit currents, increasing the transmission capacities of the system forming and distribution networks, as well as the accurate forecasting of the development of loads and consumption over the coming years. This article presents an analysis of the voltage stability in a smart microgrid for two different scenarios. The studied cases describe a linear low-voltage p-type microgrid with loads connected to it at different nodes. Data on the type and cross-section of the conductors of the studied power line are presented. Simulation studies were carried out to determine the limits of grid voltage stability when connecting photovoltaic plants with a set power. The simulation results are commented on and an analysis of the optimal operating mode of the system is realized. The model studies were implemented in the NEPLAN program environment. The research carried out allows an evaluation of the permissible limits for network stability when connecting photovoltaic plants. Through this evaluation, it can be determined how many and at which node the loads should be connected without causing an imbalance in the network. This is useful from the point of view of ensuring the sustainability and reliability of electrical energy in a microgrid.

The FCC study commissioned a feasibility analysis for the supply with electricity from renewable sources to two companies who regularly carry out such investigations, McKinseyand Accenture. This report summarises the results of this analysis and provides details about the assumptions, the supply scenarios, and the options to supply an FCC with renewable energy one a long time scale.

In order to utilize the energy from the renewable energy sources, power conversion system is necessary, in which the voltage source inverter (VSI) is usually the last stage for injecting power to the grid. It is an economical solution to add the function of power quality conditioning to the grid-connected VSI in the low-voltage distribution system. Two multifunctional VSIs are studied in this paper, that is, inductive-coupling VSI and capacitive-coupling VSI, which are named after the fundamental frequency impedance of their coupling branch. The operation voltages of the two VSIs are compared when they are used for renewable energy integration and power quality conditioning simultaneously. The operation voltage of the capacitive-coupling VSI can be set much lower than that of the inductive-coupling ИИН when reactive power is for compensating inductive loads. Since a large portion of the loads in the distribution system are inductive, the capacitive-coupling VSI is further studied. The design and control method of the multifunctional capacitive-coupling VSI are proposed in this paper. Simulation and experimental results are provided to show its validity.

The purpose of this study is to investigate the factors influencing the co-adoption of EMS installed in residential single- or multi-family buildings linked to PV and EV charging stations in Switzerland by means of a statistical analysis of an already done survey, and compare them to the factors influencing the adoption of both PV and EV, i.e. compared to the situation where only one of these technologies was implemented. Several are the main contributions of this study: (i) analyzing the influencing factors of EMS co-adopted with other technologies; (ii) comparing the factors influencing the adoption process of different energy technologies; (iii) the influence of the existing energy technology stock in buildings (i.g. heat pump, hot water boiler) on the technology adoption of EMS, PV and EV; (iv) the integration of the co-adoption decision within a conceptual model integrating several theories which model individuals’ behavior and technology adoption decision processes. The results indicate that PV is key for the diffusion of both EMS and EV, and that EMS co-adopters share characteristics in a higher measure with PV adopters, but also with EV adopters. Overall, information is found to be a crucial lever to promote energy technologies, jointly with creating a favorable legal framework and regulations, and making certain infrastructural changes

Poland, which has been a European Union member since 2004, has undertaken compliance with its commitments to increase its share in the generation of energy from renewable sources. The target set for 2020, which is to attain a share of 15 percent of the gross final consumption of energy coming from renewable sources, has been met by Poland. The new targets for 2030, incorporated in the draft the Energy Policy of Poland 2040, assume an increase to at least 23 percent of the proportion of energy obtained from renewable sources in the gross final energy consumption. On the basis of data from the Central Statistical Office, the authors of this work analysed the changes in electricity generation based on renewable energy sources. In the period of 2004–2021, it was stated that the percentages of individual renewable sources constitute 43.7% for wind energy, 35.3% for solid biofuels, 14% for hydropower, 4.2% for biogas, 2.5% for solar energy, and 0.3% for other sources (municipal waste and liquid biofuels). In addition, this work indicates the maximal relative changes in production and the maximal changes in the portion of production, in addition to the annual and periodic rate of changes in the production of these energy sources in Poland.

This paper presents an analysis of the instability of the electricity generation of renewable energy sources (RESs), specifically Digital Twins of RESs. The first part deals with the analysis of RES electricity generation around the world and Ukraine. The following chapter describes features of functioning power grids in modern conditions in Ukraine and ways to ensure the balance reliability in the power system for conditions of high-grade RES integration. The rapid increase in electricity generation RESs causes control problems of distributed power supply in the power grid. A mathematical model of the parameter controls in normal mode electric power systems for conditions with high integration of RESs is proposed in the second part. The study investigates components of the optimality criterion at the control of normal mode parameters of the electric power system with RESs. In general, digital transformation helps decarbonize the energy supply, decrease dependency on fossil fuels, and integrate renewables into power systems. A model Digital Twin (DT) of a photovoltaic system, or an exact 3D visualization, analyzing the accumulator system depending on load and generation, are presented. The problems of Digital Twin are very widely discussed, but many papers and studies are general without any practical implementations. The main part of this paper focuses on research and deals with daily electricity generation from different kinds of RESs, namely mini-hydropower stations, photovoltaic power stations, and wind power stations. Measured data of electricity generation from photovoltaic power plants, wind power plants, and mini-hydropower plants and obtained meteorological factors were used for the calculation of Spearman’s, Kendall’s, and Pearson’s correlation rank coefficients. The main contribution of this research is to determine the main metrological factors for each kind of studied RES. In the future, it will help to decide the task of forecasting power generation more presciently. Additionally, the presented model of DT RESs allows the installation and operation of grids with higher efficiency, because it can help to predict all influences, from shading up to the optimization of the battery storage system.

A dynamic reconfiguration method based on the improved multi-objective dung beetle optimizer (IMODBO) is proposed to reduce the operating cost of the distribution network with distributed generation (DG) and ensure the quality of the power supply, while also minimizing the number of switch operations during dynamic reconfiguration. First, a multi-objective model of distribution network dynamic reconfiguration with the optimization goal of minimizing active power loss and voltage deviation is established. Secondly, the K-means++ clustering algorithm is used to divide the daily load of the distribution network into periods. Finally, using the IMODBO algorithm, the distribution network is reconstructed into a single period. The IMODBO algorithm uses the chaotic tent map to initialize the population, which increases the ergodicity of the initial population and solves the problem of insufficient search space. The algorithm introduces an adaptive weight factor to solve the problem of the algorithm easily falling into a locally optimal solution in the early stage with weak searchability in the later stage. Levy flight is introduced in the perturbation strategy, and a variable spiral search strategy improves the search range and convergence accuracy of the dung beetle optimizer. Reconfiguration experiments on the proposed method were conducted using a standard distribution network system with distributed power generation. Multiple sets of comparative experiments were carried out on the IEEE 33-nodes and PG&E 69-nodes. The results demonstrated the effectiveness of the proposed method in addressing the multi-objective distribution network dynamic reconfiguration problem.

Worldwide, smart/co-working spaces are growing significantly, and prefabricated movable buildings for such an application could (i) save energy, CO2 emissions, and costs; (ii) enhance the worker’s perceived sense of surroundings; and (iii) support the rebirth of small villages with high regenerative potential. Innovative prefabricated movable building configurations to be used as an office for smart/co-working by a maximum of 6 persons have been designed and analyzed based on simulation data. In particular, 10 case studies corresponding to building configurations differing in terms of innovative energy-efficient measures related to the building envelope (smart windows operated under various control logics) and the energy systems serving the building (photovoltaic panels, small wind turbines, and electric storages) have been modeled and simulated by applying detailed dynamic simulation models via the simulation software TRNSYS. The performance of the 10 case studies has been compared from energy, environmental, and economic points of view with respect to a baseline system characterized by conventional building envelope and energy systems, with the aim of assessing the proposed measures and identifying the most efficient configuration. The simulation results highlighted that: (i) all the proposed alternative configurations allow to save primary energy (from 10.3% up to 100%), equivalent CO2 emissions(from 10.3% up to 100%), and operating costs (from 8.5% up to 100%) with respect to the baseline building; (ii) the building configurations including the smart windows only are not economically feasible in terms of simple pay-back (SPB) period, while the building configurations equipped with photovoltaic panels and/or electric storages and/or wind turbine represent a suitable investment thanks to an SPB lower than 15.2 years; (iii) a stand-alone building configuration for smart/co-working with energy demands totally covered by means of renewable sources can be obtained by combining smart windows, photovoltaic panels, electric storages and wind turbine.

This article focuses on the role of local government in energy transition. The aim of this article is to answer the question of whether local government authorities undertake actions aimed at the energy transformation of the region. This article is based on both literature studies and independent research. The empirical research was carried out in the Lower Silesian Voivodeship, located in Southwestern Poland. This region was chosen because it experienced the negative effects of economic transformation (liquidation of the Lower Silesian Coal Basin). Two hypotheses (H1 and H2) were adopted in the article. H1 assumes that in Polish conditions, bottom-up energy transformation requires the involvement of local authorities, and they should act as both initiators and shareholders of energy cooperatives. According to H2, local authorities participate in the energy transition to a limited extent. According to the conducted surveys, there has been no investment in wind farms, hydroelectric power plants or biogas plants. Communes are not interested in large, capital-intensive investments, limiting themselves to local actions with a small spatial range and small economic significance, although they are aware of the advantages of RES.

This paper addresses the problem of economic/environmental optimal power flow with a multiobjective formulation using a second-order conic programming (SOCP) optimization model. This problem formulation considers renewable energy sources (RES), fossil-fuel-based power generation units, and voltage control. The proposed SOCP model is a stochastic scenario-based approach to deal with RES and load behavior uncertainties. An ε-constrained algorithm is used to handle the following three objective functions: (1) the costs of power generation, (2) active power losses in the branches, and (3) the emission of pollutant gases produced by fossil-fuel-based power generation units. For comparative purposes, the SOCP model is also presented using a linearized formulation, and numerical results are presented using a 118-bus system. The results confirm that changing the energy matrices directly affects the cost of objective functions. Additionally, using a linearized SOCP model significantly reduces reactive power violation in the generation units when compared to the nonlinearized SOCP model, but also increases the computational time consumed.

This thesis addresses the question: Can we characterize requirements for flexibility over different timescales in electricity systems dominated by solar and wind power? Storage and flexibility play an increasingly important role, but there is great uncertainty about amounts of flexibility needed and how they depend on generation mix and demand, including electrification of heating and transportation. Furthermore, to inform investment and planning, it is valuable to characterize the timescales over which flexibility will be needed, as different resources can be used to shift energy over different time horizons. To address this problem, the analysis uses the novel application of three methods to disaggregate overall flexibility requirements into short-, medium-, and long-term requirements, without relying on assumptions about technology parameters or costs. These methods are illustrated using the case of Great Britain and results are used to draw insights into GB flexibility needs under future scenarios. Flexibility is required over multiple timescales, from less than hourly to interseasonal or longer. Overcapacity of renewables provides value in terms of avoided storage costs, particularly displacing requirements for the longest duration storage, though generation capacity beyond 120% of demand yields diminishing marginal returns. Heating electrification has a larger impact than EVs, though flexible heating can partially offset additional power capacity needs. In all cases, the capacity required to shift energy by up to a day was on the order of 1 TWh; this could account for over half of all energy shifted depending on flexible resource operation. Electricity systems with at least 80% of energy from solar and wind require 3-150 TWh to shift energy by weeks or longer. The required capacity to shift energy by more than one year could potentially be avoided using renewables overcapacity, dispatchable generation, or interconnectors.

The building sector accounts for over 40% of global energy consumption, and many buildings are old and inefficient. However, the current pace of building renovation is not sufficient to make a tangible impact. A new strategy is needed to accelerate the renovation process. Renovation at the district level and the use of digital tools, such as a digital twin (DT) of a city district, can provide a solution. This paper proposes a novel approach to city block renovation using renewable energy sources (RES), including photovoltaic (PV) solar panels, heat pumps (HP), and electric heaters (EH), while utilizing a DT of a city district to provide a user-friendly representation of the results and data needed for holistic solutions. The proposed method combines an optimization model of the optimal heating system with a solar PV simulation technique to analyse hybrid RES solutions and potential on-site energy generation and supply. Several scenarios are simulated to evaluate RES solutions in the renovation process of the city block using the DT concept. The simulation results demonstrate that a hybrid RES solution, which includes a PV system and a heating system, is optimal when the on-site generated energy is used not only for domestic electricity consumption, but also for the operation of HPs and EHs for heat generation. This study highlights the importance and significance of a DT approach to city block renovation and provides a new solution to accelerate the renovation process and reduce energy consumption in the building sector.

Many proponents of organic farming claim that it is a sustainable alternative to conventional agriculture due to its reliance on natural agro-inputs, such as manure based fertilizers and organic pesticides. However, in this analysis we argue that although particular organic farming practices clearly benefit ecosystems and human consumers, the social context in which some organic farms develop, limit the potential environmental benefits of organic agriculture. Specifically, we argue that certified organic farming’s increased reliance on agro-inputs, such as organic fertilizers and pesticides, reduces its ability to decrease global water pollution. We review recent research that demonstrates the environmental consequences of specific organic practices, as well as literature showing that global organic farming is increasing its reliance on agro-inputs, and contend that organic farming has its own metabolic rift with natural water systems similar to conventional agriculture. We use a fixed-effects panel regression model to explore how recent rises in certified organic farmland correlate to water pollution (measured as biochemical oxygen demand). Our findings indicate that increases in the proportion of organic farmland over time increases water pollution. We conclude that this may be a result of organic farms increasing their reliance on non-farm agro-inputs, such as fertilizers.

In this new era of energy transition, access to reliable and correctly functioning electricity markets is a huge concern for all economies. The restructuring path taken by most electricity markets involves the movement towards green generation structures and the increasing integration of wind and solar photovoltaic energy sources. Furthermore, it involves the electrification of energy systems, which implies a substantial increase in electricity demand levels. It is also important to add that electricity use has been pivotal in achieving efficient productivity levels in many sectors and is thus crucial to boosting economic activity. Nevertheless, this shift in generation structures has raised several challenges in electricity markets, mainly because the electricity produced from wind and solar photovoltaics is intermittent. In turn, adopting green power sources has been claimed to increase electricity price volatility and thus increase pricing risks. Therefore, to ensure that the right market signals are being sent to investors, the behaviour of electricity prices should be carefully assessed. There are three main types of pricing mechanisms commonly used in electricity markets: zonal, uniform and nodal. This study provides a short literature survey on these three pricing mechanisms. Our analysis has revealed that the assessment of the behaviour of nodal electricity price volatility is rarely studied in the literature. This fact has motivated the exploration of this topic and the consideration of the New Zealand electricity market case. The New Zealand electricity market is an energy-only system with no interconnections with other electricity markets. Furthermore, it has plenty of electricity produced from hydropower, which has a high potential to reduce price volatility through its backup role. The nodal pricing mechanism is complex, and data on it are hard to process. This paper elucidates the main challenges in processing electricity big data. Three different procedures to make this data more useable are described in detail. The main conclusions of this paper highlight the need to access easy-to-manage data and identify certain variables that significantly affect nodal prices for data which are unavailable.

Дипломний проект бакалаврського рівня освіти на тему «Система теплопостачання і кондиціювання повітря в будинку з використанням відновлюваних джерел енергії», враховує: 96 сторінок, 20 рисунків, 8 таблиць, 27 бібліографічних найменувань. Додатково: 3 кресленики формату А1 та 2 кресленики формату А2. Об’єкт роботи – будинок в місті Суми. Мета роботи – створити комфортні умови для прожиття в будинку як влітку, так взимку за допомогою сонячних колекторів та ґрунтового теплообмінника в поєднанні з традиційними джерелами енергії. Наведені розрахунки теплових втрат будинку, що проектується, розрахунок поверхні та кількості нагрівальних приладів для певних приміщень. Результатом розрахунків стало рішення встановити 4 повітряних колекторів розміром 1x1,6 м на південному фасаді будинку, що забезпечить додатковий тепловий потік в систему опалення. Наведено прямоточну схему кондиціювання повітря в будинку в теплий період, що буде здійснюватися за рахунок вертикального коаксіального ґрунтового теплообмінника, який буде встановлюватись на глибині більше 10 метрів, аби на нього не впливали зовнішні фактори (погодні фактори). За результатами аеродинамічних обрахунків було обрано вентилятор СВМ 270/270-1/3. Передбачені заходи з охорони праці працівників будівлі. Додано креслення, що включають східний фасад будинку з розміщенням ґрунтового теплообмінника, бака-акумулятора разом із сонячним колектором, схему системи опалення та ГВП, фасад будинку з повітряним сонячним колектором та його розміщення, план будинку. The diploma project of the bachelor's level of education on the topic «Heating and air conditioning system in the house using renewable energy sources» includes: 96 pages, 20 figures, 8 tables, 27 bibliographic titles. Additionally: 3 drawings of A1 format and 2 drawings of A2 format. The object of the work is a house in the city of Sumy. The goal of the work is to create comfortable conditions for living in the house both in summer and in winter with the help of solar collectors and a soil heat exchanger in combination with traditional sources. Calculations of heat losses of the house being designed, the calculation of the surface area and the number of heating devices for certain premises are given. Because some rooms will be heated due to mass transfer. The result of the calculations was the decision to install 4 air collectors measuring 1x1.6 m on the southern facade of the building, which will provide additional heat flow to the heating system. A direct-flow scheme of air conditioning in the house in the warm period is presented, which will be carried out at the expense of a vertical coaxial soil heat exchanger, which will be installed at a depth of more than 10 meters, so that it is not affected by external factors (weather factors). According to the results of aerodynamic calculations, the СВМ 270/270-1/3 fan was chosen. Anticipated measures for labor protection of building workers. Have been added drawings that include the eastern facade of the house with the placement of the soil heat exchanger, the storage tank together with the placement of the solar collector, the diagram of the heating and hot water system, the facade of the house with the air solar collector and its placement, the plan of the house.

The building sector accounts for over 40% of global energy consumption, and many buildings are old and inefficient. However, the current pace of building renovation is not sufficient to make a tangible impact. A new strategy is needed to accelerate the renovation process. Renovation at the district level and the use of digital tools, such as a digital twin (DT) of a city district, can provide a solution. This paper proposes a novel approach to city block renovation using renewable energy sources (RES), including photovoltaic (PV) solar panels, heat pumps (HP), and electric heaters (EH), while utilizing a DT of a city district to provide a user-friendly representation of the results and data needed for holistic solutions. The proposed method combines an optimization model of the optimal heating system with a solar PV simulation technique to analyse hybrid RES solutions and potential on-site energy generation and supply. Several scenarios are simulated to evaluate RES solutions in the renovation process of the city block using the DT concept. The simulation results demonstrate that a hybrid RES solution, which includes a PV system and a heating system, is optimal when the on-site generated energy is used not only for domestic electricity consumption, but also for the operation of HPs and EHs for heat generation. This study highlights the importance and significance of a DT approach to city block renovation and provides a new solution to accelerate the renovation process and reduce energy consumption in the building sector. Keywords: deep renovation; city block; photovoltaic; heat pumps; digital twin; renewable energy sources; photogrammetry.

At the current stage of the integration of renewable energy sources into the power systems of many countries, requirements for compliance with established technical characteristics are being applied to power generation. One such requirement is the installed capacity utilization factor, which is extremely important for optimally placing power facilities based on renewable energy sources and for the successful development of renewable energy. Efficient placement maximizes the installed capacity utilization factor of a power facility, increasing energy efficiency and the payback period. The installed capacity utilization factor depends on the assumed meteorological factors relating to geographical location and the technical characteristics of power generation. However, the installed capacity utilization factor cannot be accurately predicted, since it is necessary to know the volume of electricity produced by the power facility. A novel approach to the optimization of placement of renewable energy source power plants and their capacity factor forecasting was proposed in this article. This approach combines a machine learning forecasting algorithm (random forest regressor) with a metaheuristic optimization algorithm (grey wolf optimizer). Although the proposed approach assumes the use of only open-source data, the simulations show better results than commonly used algorithms, such as random search, particle swarm optimizer, and firefly algorithm.

To meet the goal of sustainability and transition to a green economy, renewable energy sources have to be used. Although many countries have declared their transition to a smart, green and sustainable economy, there is still modest evidence of achieving climate change goals, Sustainable Development Goals and other related societal and environmental goals. This paper aims to give an overview of the current global and regional trends, and the strategic frameworks on the use of wind energy with the purpose of clarifying its potential, especially offshore wind energy, using the example of the United Kingdom as one of the global leaders in this area. For several decades, the United Kingdom has implemented various regulations and mechanisms to improve climate action and the transition to a green economy. It offers specific Contract for Difference schemes to offshore wind producers, under which they are entitled to a specially defined purchase price of electricity produced for a period of 15 years. Thus, the United Kingdom is one of the global leaders in offshore wind energy generation. Initiatives, strategic frameworks and regulations in the United Kingdom can serve as guidelines for other countries in developing their own strategic framework.

PURPOSE: The aim of the research undertaken in the article is to present the concept of the functioning of the system of stabilization of the operation of power grids in terms of supply chain phases into activities based on the hydrogen energy buffer from the use of hydrogen., DESIGN/METHODOLOGY/APPROACH: There is a research gap in the world literature related to the project of the concept of stabilizing the operation of power grids. This article assumes that the main factor destabilizing the operation of power grids in the long term is the surplus of energy from RES (supply phase). There is no interdisciplinary approach to the presented issues, therefore the common area discussed in the article is of great scientific and application significance., FINDINGS: The current work on hydrogen technologies shows that the use of hydrogen in the economy adjusts the systems to its extraction, production and distribution. In this scope, there must be comprehensive design and management of processes in the phase of supply, production, storage and distribution of hydrogen, in terms of efficiency and maximum support for the achievement of socio-economic goals., PRACTICAL IMPLICATIONS: Solving the problem related to the instability of renewable energy sources due to the dependence of the volume of energy produced on uncontrolled factors. In the near future, this problem will only increase due to the increase in the number of producers of electricity from RES and the instability of the operation of power grids. Therefore, it is important to prepare a concept for the operation of the power grid stabilization system in terms of the supply chain phases., ORIGINALITY/VALUE: The priority direction of political actions in the field of sustainable development of the energy sector is the course of the energy transformation (decarbonisation) and the flourishing share of renewable energy sources (RES) in the primary energy supply. It is an innovative research area, integrating both theoretical achievements in the field of hydrogen supply chains and the operation and development of power grids., peer-reviewed

Following the urgency of climate change issues, investments in renewable energy sources and electrification of the transportation sector have enormously increased to facilitate the transition to a more sustainable future. However, as renewable resources like wind parks are replacing conventional power plants, new balancing solutions are required to strengthen grid stability. As responsive loads with quick dynamics, electrolysers operating in HRSs can present flexible balancing services to the power grid. To gain this benefit, this work examines the techno-economic features of providing different frequency grid services by an HRS, considering the possibility of hydrogen injection into the industrial and natural gas pipelines. The ratings of the subcomponents and dispatch plans are optimised to enhance the performance of the plant. A probabilistic mixed-integer linear programming problem is solved over one year with a time resolution of one hour and using real-world historical data based on the European electricity market. The simulation results indicate that the economic profits can be increased significantly as a result of participating in the ancillary service markets and meeting its operation specifications while the stable performance of the HRS is guaranteed.

Share of renewable energy sources increased rapidly over last two decades primary as wind and solar power plants. Their increase was driven by governmental subsidies and priority access and dispatch regarding conventional units. Wind and solar power plants are inflexible sources because their generation depends on exterior, weather conditions and they cannot be controlled as conventional units. This paper will define term power system flexibility and provide an insight into flexibility of conventional and modern power systems. Detailed mathematical model of power system and all its components has been created and explained. Modeling has been executed as mixed integer linear program using Fico Xpress optimization suite. Using those models, flexibility analyses of power systems with different renewable energy sources share has been conducted