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The article is devoted to the problem of increasing the efficiency of using energy resources of enterprises of the pulp and paper industry in Ukraine. It has been determined that the pulp and paper industry belongs to energy-intensive types of economic activity. Based on the results of the correlation and regression analysis, a connection was revealed and an economic and mathematical model was formed of the dependence of energy costs for the production of 1 ton of paper on the productivity of paper machines, equipment wear and the volume of investments in energy saving measures. Application of the proposed model will improve information support for the analysis of the effectiveness of energy saving measures, forecasting energy costs and strategic energy management in general. It was carried out at pulp and paper mills, the main obstacles to replacing fossil fuels with biomass in heat production were identified. This made it possible to develop a scientific and organizational model for the energy modernization of enterprises in the pulp and paper industry. It includes financial, organizational, environmental, regulatory, technological, scientific and educational tools. Their application at management will help improve the infrastructure of enterprises in terms of the use of renewable energy resources.

The paper makes a comparison between four types of briquettes: first was wheat and rapeseed briquettes, second was wheat briquettes (batch 2018), third was wheat briquettes (batch 2017), and fourth was lucernes briquettes, from the point of view of the physical and energetic characteristics, in order to choose the best ones and their corresponding market. The main properties studied are the density and moisture of the briquettes, physical properties, and also calorific power and ash content as energetic properties. Research results show that wheat and rape briquettes have had high calorific value but low density, compared to other types of briquettes. A general conclusion rise from whole paper, respectively the vegetable biomass is a renewable material and briquettes from it remains the best option of combustible materials.

In this paper authors present research results which are the optimum parameters of the torrefaction process using straw from oats and maize. The most important parameters for the torrefaction process are temperature and residence time. Both parameters are essential to designing and construction of industrial biomass torrefaction installations. Energy crops and waste coming from agricultural production have the most promising perspective from all kind of renewable energy sources in Poland. Currently, intensive studies on the process of biomass torrefaction are being carried out. In this experimental investigation, authors examined the torrefaction process of two types of agriculture biomass, such as: oats, maize. The main overarching objective of the experimental studies described below is the development of various biochar as an additive to agricultural fertilizers resulting from the conversion of biomass from agriculture residues – straw from oats and maize. The last of enumerated biomasses is treated through different conversion processes such as: drying, torrefaction to homogenize their physical and chemical properties. Among many of its areas, it is extremely important to optimize the production of biomass energy plants and its refinement (in the torrefaction process), which will improve the balance and profitability of energy production from RES, and reduce the logistics and storage costs of this fuel and improve the efficiency of biomass combustion process. When implementing new technologies indicated in this work and optimizing the harvesting of plant biomass, the negative impact on the environment caused by stored municipal waste can be reduced. This biomass torrefaction process temperature and residence time were necessary for the design and construction of semi-pilot scale biomass torrefaction installations with dryer and torrefaction reactor to perform a continuous biomass torrefaction process using superheated steam

The daily needs of energy in remote areas, Indonesia, is dominated by biomass waste. The abundant types of biomass waste for heat transfer is empty fruits shell (EFS) of oil palm as briquette. This research discussed a brief analysis of oil palm shell by using physical treatment at different crushing pressure. It was also to examine the adequate size of particle for improving the heating value of briquette. The crushing pressure had a height dimension of 20 cm, as well as the briquette mold with a diameter of 2 cm and a height of 1 cm. The oil palm shell which was applied physical treatment at different crushing pressure of 400 J, 550 J, and 700 J, that resulted in particle size is smaller than 800 µm, 800 µm to 1 700 µm, 1 700 µm to 2 000 µm, and bigger than 2 000 µm. The adequate size of particle for briquette was found to be < 800 µm, which reached the heating value of 20 042.32 J g–1 and ash residue of 20 %. This study showed the advantages of oil palm shell briquette by using physical treatment is suitable and sustainable alternative to daily life use in Indonesia.

Biomass from palm empty fruit bunch (EFB) is considered as potential renewable energy sources to be developed in Indonesia. Palm EFB can be efficiently converted into valuable and useful methanol products through gasification. Research about methanol synthesis from various biomass has been done. However, Little research about methanol production based on palm empty fruit bunch gasification has been found, and no research yet on technoeconomic analysis of methanol plant construction based on palm empty fruit bunch gasification. The purpose of this research is to find early-stage feasibility of small-scale methanol plant model based on gasification of palm EFB. Method methanol plant design, investment cost estimation, operating cost estimation, and calculation to estimate profitability in terms of economic feasibility parameters. Economic analysis calculated that the total investment to build a methanol plant in this study was USD 87 508 479 with manufacturing cost per annum USD 6 127 014. Net Present Value (NPV) calculated was USD -51 721 064 and IRR at 1.1 %. Based on NPV and Internal Rate of Return (IRR) value, the construction of methanol plant is not feasible. Feasibility predicted to be obtained when the capacity of the plant increased fivefold.

POME or palm oil mill effluent is currently still a waste problem that has not been utilized optimally. POME waste has the potential for renewable energy in the form of biogas, but some research results have shown that production is not optimal, so the addition of cow dung needs to be done to increase biogas production because methanogen bacteria found in cow dung help to maximize the anaerobic fermentation process and methane production. This research was conducted to determine the potential for biogas production from a mixture of POME and cow dung for 25 days by conducting a study of the biogas production process. The results of this study indicate that the biogas pressure increases with the addition of the loading rate, which is 101.102 N/m2/day to 101.107 N/m2/day with a daily biogas production of 0, 24247 liters/day with a total accumulation of biogas production for 25 days of 6.1 liters.

Increased rice production in Indonesia not only brings good news socially and economically, but also brings bad news for environmental ecology. In each rice crop produces 50% rice straw and 50% grain. The grain is divided into two again, namely 80% rice and 20% rice husk. In 2018, counted the rice husk up to 10,379,625 tons, a fantastic number if cannot be managed properly so that it can pollute the environment. One alternative to deal with the high rice husk is through conversion to biogas. Biogas is an energy that is formed under anaerobic conditions with organic material so that it is also called renewable energy. The development of research on biogas production from rice husks based SS-AD has experienced a positive increase in hardness. Studies have been conducted on the pre-treatment to other influencing factors. But after the authors describe the latest development of biogas research from rice husk, there are still some variables that have not been tested such as physical treatment, the influence of temperature, pH and alkalinity. Based on this review, further research is needed to complete a number of variables that have not been carried out so that it is expected that the development of biogas production from rice husk based SS-AD can move toward larger scales such as pilot scale and industrial scale.

Hydrogen is one of the clean energy carriers and it is obtained from fossil and renewable energy sources and waste of the food industry. In this study, whey, which is the waste of the cheese factory, was gasified using a high-pressure batch reactor at different temperatures (300, 350, 400 ºC) and an updraft tubular reactor at (650, 700°C). In order to find out suitable gasification conditions, the effect of reaction parameters such as catalyst type (K2CO3 and NaOH), temperature (300-700 °C) and time (30-120 min) were investigated. The highest hydrogen yield (14.47 mol H2/kg Whey Powder-2) was obtained with 2.51 M NaOH at 120 min. reaction time at 400 °C.

Avocado (Persea americana Mill) is a popular fruit in Indonesia. Its popularity leads to high consumption of this fruit and wastes from its seed. In order to develop renewable energy and reducing wastes in the environment, P. americana seed may be extracted for its oil to create biodiesel fuel. In this study, P. americana seed is obtained through the soxhlet apparatus and transesterification process. After obtaining P. americana seed oil, the oil was mixed with pure petro-diesel with a ratio of 10:90 (B10 fuel) and 20:80 (B20 fuel), respectively. These fuels were tested for their fuel characteristics and engine performances, together with pure petro-diesel and palm oil biodiesel. The fuel characteristics results suggest positive characteristics of B10 and B20 compared to other fuels. For engine performance tests, B10 and B20 fuels have less engine performance than other fuels. However, the differences between these fuels results are small. Overall, the positive aspect of B10 and B20 fuels supersede small disadvantages they have and thus suitable to substitute pure petro-diesel and palm oil biodiesel.

Biogas technology solves the problem of energy crisis. Biogas is a renewable and environment friendly fuel (Franthena, 2015). This study aims to determine the optimum value of grinding size variations in biogas production with the solid state anaerobic digestion (SS-AD) method of biogas production from rice husk waste. We divide the method used into four stages, namely, the testing phase of total rice content, solids, preparation phase, operation phase, and results analysis. The rice husk waste used for this study came from the Rowosari area. We accept rice for preliminary treatment with chemical pretreatment (NaOH). We soaked rice husk with a concentration of 6% NaOH for 24 hours as a control variable. Milling variations used as physical pretreatment are 10 mesh, 18 mesh, 35 mesh, 60 mesh. We used bioreactors with a volume of 200 ml. We observed all biogas reactors produced every two days for ± 60 days of research. The results showed that the reactors with 10 mesh, 18 mesh, 35 mesh, 60 mesh milling variations obtained a total biogas yield of 11.688484; 9,479955; 12.50772; 19,03718 ml / grTS until the 60th day. The control reactor (without grinding variations) produced 9,084606 ml / grTS. The highest biogas production level is 60 mesh with a value, (A) 19.03718 (ml / grTS); the rate of biogas production (U) 0.2416979 (ml / gr TS.day); and the minimum time for biogas formation (λ) is 3.83908 days.

Biogas is a renewable energy source that can be used as an alternative fuel to replace fossil fuel such as oil and natural gas. This research aims to analyze the impact of NaOH (Sodium hydroxide) and enzyme usage on the production of rice husk biogas using Solid State Anaerobic Digestion (SS-AD). Generally, SS-AD occurs at solid concentrations higher than 15%. The waste of rice husk are used as substrate with a C/N ratio of 25% and the total of solid that are used is 21%. Rice husk contains high lignin, therefore it is handled with chemical and biological treatment. The chemical preliminary treatment was using NaOH with various concentrations from 3%, 6% and 9% while the biological preliminary treatment was using enzyme with various concentration from 5%, 8%, and 11%. The biogas that is produced then measured every two days during 60 days of research with the biogas volume as a parameter observed. The result of the research shows that preliminary treatment with NaOH and enzyme can increase the production of biogas. The highest biogas production was obtained by the NaOH pretreatment using 6% NaOH which was 497 ml and by enzyme pretreatment using 11% enzyme which was 667,5 ml.

Microbial fuel cell (MFC) is an alternative approach in generating renewable energy by utilising bacteria that will oxidize organic or inorganic substrates, producing electrons yielded as electrical energy. Different species of exoelectrogenic bacteria capable of generating significant amount of electricity in MFC has been identified, using various organic compounds for fuel. Soil sample taken from rice paddy field is proven to contain exoelectrogenic bacteria, thus electricity generation using mixed culture originally found in the soil, and pure culture isolated from the soil is studied. This research will isolate the exoelectrogenic bacterial species in the rice paddy field soil responsible for energy generation. Growth of bacteria isolated from the MFC is observed by measuring the optical density (OD), cell density weight (CDW) and viable cell count. Mixed bacterial species found in paddy field soil generates maximum power of 77.62 μW and 0.70 mA of current. In addition, the research also shows that the pure bacterium in rice paddy field soil can produce maximum power and current at 51.32 μW and 0.28 mA respectively.

Methane fermentation has been a waste management technique for years. The main advantages of fermentation include the production of electricity and heat from biogas or biomethane, which are a source of renewable energy. In order for the fermentation process to have good economic indicators, the continuous monitoring of process parameters is necessary. To control the fermentation process, an anaerobic test determining the biochemical methane potential (BMP) is particularly recommended. The disadvantage of this test is the long duration of measurements. Nowadays, AT4 respiration tests are increasingly used to assess the methane potential of waste. The main advantages of AT4 include: the 4-day duration of the test, the simple method for implementation and the possibility of applying the test to all types of waste. In practice, in most cases physical (VS) and chemical indicators (TOC and COD) are used to assess the suitability of substrates for fermentation and its effectiveness. However, these indicators specify only the total content of organic matter, yet do not give information on the fraction of biodegradable matter. The article presents an assessment of the efficiency of fermentation substrates selected from the agri-food sector on a physical, chemical and biological basis and presents the correlation between these indicators.

This paper aims at explaining the universality and broadness of the research in energy studies. Specifically, it wants to show that the energy research is not a solely engineering or natural sciences field and how it can be done in social sciences. The paper draws some relevant examples including energy research in literature and poetry, history, religion, art, as well in other social sciences and humanities. In general, it becomes apparent that energy research can boast vast depths and angles that are worth exploring for any social scientist. Given the key importance of energy research in the third decade of the 21st century and the worldwide focus on the renewable energy sources, electrification of transport and heating in the face of the threatening global warming and climate change, it seems relevant to focus on researching the perspectives and paradigms for the traditional and renewable energy sources in the 21st century using the toolbox of the social sciences.

The exploitation of fossil fuels is undoubtedly responsible of environmental problems such as global warming and sea level rise. Unlike energy plants based on fossil fuels, energy plants based on renewable energy sources may be sustainable and reduce greenhouse gas emissions. However, they are unpredictable because of the intermittent nature of environmental conditions. For this reason, energy storage technologies are needed to meet peak energy demands thanks to the stored energy. Moreover, the renewable energy systems composing the plant must be optimally designed and operated. Therefore, this paper investigates the challenge of the optimal design and energy management of a grid connected renewable energy plant composed of a solar thermal collector, photovoltaic system, ground source heat pump, battery, one short-term thermal energy storage and one seasonal thermal energy storage. To this aim, this paper develops a methodology based on a genetic algorithm that optimally designs a 100% renewable energy plant with the aim of minimizing the electrical energy taken from the grid. The load profiles of thermal, cooling and electrical energy during a whole year are taken into account for the case study of the Campus of the University of Parma (Italy).

The use of renewable energy sources in buildings is more and more common (both for heating and cooling purposes, as well as electricity generation). The paper focuses on the thermal comfort tests in two buildings: the traditional one (that uses non-renewable sources of energy) and the modern intelligent building “Energis” of Kielce University of Technology. The thermal sensations of students in these two buildings have been compared based on the questionnaire survey and conclusions have been drawn regarding the differences between the feelings of thermal comfort in those two buildings. Apart from subjective feelings of the volunteers, the measurements of indoor air parameters were conducted in both buildings and have been presented in the paper.

In the face of climate change, it is urgent to transform the energy system. Germany has played an important role in the development of renewable energy. Hence, it is necessary to figure out why Germany makes structural change in its energy sector in order to have a better understand on the current situation and the future development of renewable energy. Adopting the theory of interdependence, this paper analyzes the motivation of Germany’s energy transition. It demonstrates that Germany on the one hand endeavors to reduce its energy dependence on other countries and increase other countries’ dependence on it in the field of renewable energy, on the other hand. Thereby Germany would get more advantage in international negotiation and competition. This paper reveals the principle of interdependence in energy transition, which provides a new perspective to discuss the politics of climate change.

Renewable energy technologies (RET) that emerged as a result of the shift towards the renewable energy sources (RES) which aims at setting the path towards decentralized low-carbon energy systems intended for tackling global warming are becoming key elements of the smart grids of the future. Our paper applies the economic, social and technological model of the renewable energy platforms to the energy markets of the 21st century. The paper analyses the growing importance of the individual players (prosumers) on the energy market, especially when it comes to the renewable energy generation and trading. It shows that modern advanced information and communication technologies enabled the energy prosumers to trade their energy and information in two-way flows. All of these might be important for the transition towards sustainable economy and green technology.

As a bridge between the economy and society, air transportation plays an important role, and the aircraft engine, which is the “heart” of the aircraft, is the key to achieve all this. However, in recent years, the particulate matter emission and carbon dioxide greenhouse effect of aircraft have brought serious pollution to the world and are of great concern. Therefore, this paper will be based on the concepts of low carbon, green, energy saving, environmental protection and safety, as well as the social development requirements of carbon balance. By studying the pollution sources and elimination methods of aviation engines, further analyzing the development process of green aviation in China and the experience and inspiration of developing green aviation in Europe, the paper aims to propose innovative development ideas in the field of aviation power in order to better serve economic development and social progress.

This paper focuses in the natural and economic effects of renewable energy sources in the developing countries using a case of Azerbaijan. Traditional fuel supplies dependent on gas, oil, and coal are highly useful for the development of a country’s economy. However, certain detrimental effects of these commodities on the environment have limited us to use these resources under clear cut-off points. As a result, we were able to turn our intuition into renewable energy sources. By using renewable energy sources, social, natural, and financial challenges can be ignored because these sources are considered harmless to the atmosphere, as there are little or virtually no fumes discharged, and toxic gases such as carbon dioxide, carbon monoxide, and sulfur dioxide. Renewable electricity would be a major advantage for power generation in the near future so we will reuse these assets to generate useful electricity. The paper discusses these and other issues with the implementation of renewable energy and assess the potentials of Azerbaijan in adapting this type of energy in the future.

Transition economies have less ambition to achieve the 2030 Sustainable Development Goals in comparison with developed economies. However, if to compare the benchmarks under Goal 9 “Affordable and clean energy” for Ukraine with the trends of its energy balance, the satisfaction of the relevant ambitions is possible only with a comprehensive approach. Purpose of the study is to analyse the multifaceted innovative intersectoral cooperation and inclusion of energy-tourism projects in the regional socio-economic and ecological programs, in accordance with the reference benchmarks under SDGs in Ukraine. The paper has outlined an approach to activation the relationship between renewable energy and tourism sphere, on the example of solar power plants in the Dnipro region. Implementation of the proposed, in the study, part of the regional program will create opportunities: for tourism sphere – improving the tourist image of the region, increasing in the number of domestic tourists, creating new jobs, increasing in volume of tourist services, increasing in revenues from tourism to regional and local budgets; for renewable energy sphere: also improving an image and information policy, increasing in number of future customers, generating additional income, improving indicators of social and environmental effectivness. The proposals set out in the paper will serve in the future as basis for the development of the ideas of energy-tourism symbiosis within the European Green Deal.

The increasing share of volatile renewable energy in the electricity grid increases the importance of load flexibility and Demand Response for balancing electricity supply with demand. Flexible loads in office buildings (e.g. educational buildings) are heating, ventilation, and air conditioning (HVAC) systems. This paper focuses on ventilation systems as flexible loads for providing ancillary services to the grid. A number of studies consider ventilation system control based only on demand or discuss possibilities of improving system performance. Previous studies provide little or no information about ventilation system flexibility, e.g. amount of power modulation, the rate of change, and the duration of how long the power level can be held. The described information is required by aggregators to provide load aggregation services for transmission system operators (TSO). This paper proposes a robust and model-free approach to estimate ventilation system flexibility according to CO2 concentration in extracted air. The proposed approach includes power regulation boundaries for the ventilation system and duration estimation when operating at the selected boundary. A case study is conducted on a ventilation system, which services an auditorium of an educational building. The current paper analyzes the proposed robust approach for estimating ventilation system flexibility and compares estimation to measured results.

This paper concentrates on the organizational and communication aspects of development of the smart grid technologies. The paper highlights the potential of decentralised electricity generation for generating electricity from less energy-intensive and cost-efficient sources. It shows that renewable and unconventional energy sources may be integrated into decentralised electricity grids – the generation lines that have an intelligent grid. In addition, the paper focuses on the benefits and risks of different smart grid applications and their impact. We show that smart grids have the potential to minimise costs, but the use of smart grid technology also affects the level of risk, so the organizational and communication aspects are of a great importance.

The paper describes special aspects of using the wind power plants (wind turbines) in the power grid. The paper provides the classification and schematic presentation of AC wind turbines, analyzes the role, place and performance of wind power plants in Smart Grid systems with a large share of renewable energy sources. The authors also reviews a detailed analysis of existing AC wind turbines in this paper. Recommendations are given for how to enhance the wind power plants in smart grids in terms of reliability, and introduce the hardware used in the generation, conversion and interface systems into the existing power grid. After the wind power plants had been put online, the relevance of the Smart Grid concept for existing power grids was obvious. The execution of such projects is assumed to be financially costly, requires careful study, and development of flexible algorithms, but in some cases this may be the only approach. The analysis of using wind turbines shows that the structural configuration of wind power plants can be based on the principles known in the power engineering. The approaches may differ, not fundamentally, but in engineering considerations. it is necessary to point out that the method of controlling dual-power machines is quite comprehensive so that their wide use will face operational problems caused by the lack of highly professional specialists in electric drives. Therefore, it seems advisable to use square-cage asynchronous generators in wide applications. The paper shows that as the renewable energy sources are largely used in power grids, there is an issue of maintaining the power generation at a required level considering the variability of incoming wind energy. This results in the malfunctions in the operation of relay protection devices and emergency control automatics (RP and ECA), and the complicated control. Also, the standards of the CIS countries and regulatory documents miss the requirements for the wind turbine protections, taking into account their specialty causing the inefficient standard protective logic, which does not work correctly in a number of abnormal and emergency operating modes, and especially Smart Grid in power grids.

The paper assesses the relevant problems of the global energy paradigm, with emphasis on ensuring energy security. To solve this problem, the state and prospects of world energy markets and the forecast for their development are analyzed. The paper substantiates the importance of improving energy efficiency in Russia. It also analyzes and displays the most important aspects of global energy problems, highlights the dynamics of the global balance of energy consumption, analyzes the development of renewable energy sources. The study determined the place of fuel and energy sector in the global economy. Forecasts of global electricity consumption are presented. The paper focuses on the need for measures that contribute to overcoming energy threats in the global energy market.

Currently, Vietnam‘s energy source structure is being changed by which renewable energy sources play more important role to meet the electricity demand and reduce greenhouse gas emissions from fossil energy sources. Vietnam’s energy development strategy determines to build some renewable energy centers, of which Ninh Thuan is the first province designated to become a national renewable energy center. This is based on Ninh Thuan’s endowment as a province having the largest renewable energy potential in Vietnam. Development of a large renewable energy center allows power system planners to overcome the mismatch in timescales associated with developing transmission power grid and renewable energy generation. Besides, renewable energy center can facilitate a significant pipeline of large-scale renewable energy and storage projects. However, Ninh Thuan province is far away from the major load centers of Vietnam so the calculation and analysis of economic indicators need to be studied. This paper will present the results of the analysis of economic indicators of major renewable electricity sources in Ninh Thuan (onshore wind power, offshore wind power, solar power) to provide scientific arguments for developing a renewable energy center in Vietnam. Also the paper addresses the problem of the large-scale penetration of renewable energy into the power system of Vietnam. The proposed approach presents the optimization of operational decisions in different power generation technologies as a Markov decision process. It uses a stochastic base model that optimizes a deterministic lookahead model. The first model applies the stochastic search to optimize the operation of power sources. The second model captures hourly variations of renewable energy over a year. The approach helps to find the optimal generation configuration under different market conditions.

This paper aims to present a feasibility study for clean production, storage and distribution of large amounts of hydrogen, starting from low-cost available renewable electrical energy. Paraguay and Brazil own equally the binational company ITAIPU Hydroelectric Plant (14 GW, about 96,000 GWh/year of production). 50% of this energy corresponds to Paraguay: however, since its energy demand is quite low, a large amount of this energy is sold to Brazil, receiving a compensation of 10 $/MWh. In this context, seeking for ways of adding value to generated electricity, this paper assesses the potential of clean H2 production by water electrolysis, simulating the use of one generator unit of the mentioned company (700 MW) and discussing two alternatives for the produced hydrogen: a) using it for ammonia production as base for fertilizers; b) using it for passenger cars. A detailed thermo-economic analysis is performed using a dedicated software developed by the authors. The results show that production is economically feasible for both cases, moreover the process is completely clean and significant amounts of oxygen are produced, potentially representing an additional revenue for the process.

The relevance of this study is caused by the need to solve problems of sustainable use of natural resources in the Arctic region when implementing projects with international participation. The paper highlighted a number of the most significant problems of the region, which destroy the ecological balance. The areas of development of the natural resources of the Arctic region have been determined with the participation of countries interested in this, in particular, China, which is striving to become the leading export world power and influence the sustainable use of natural resources in the Arctic region. The paper analyzes the interests of China in the Arctic, identifies the strategy of China’s behavior and the main directions of international cooperation with the countries of Northern Europe and North America in the Arctic region. China is increasingly pursuing its Arctic policy, and international cooperation is an important way for China to strengthen its research and economic potential in the Arctic. The dominant interests of China in the Arctic are: the development of polar scientific research; the creation of a transport and logistics system; development of hydrocarbon energy and mineral resources; development of systems based on renewable energy sources; maintaining ecological balance, including through the development of a green economy in the region; environmental protection. In this regard, China is taking active steps to establish strong bilateral and multilateral relations with Western countries, the so-called Arctic G8 countries, and seeks to promote its interests in the region under consideration, including through large investments in the Arctic projects of these countries.

The paper will discuss the potential of renewable hydrogen as an energy storage medium for the decarbonisation of multiple sectors and for the energy system security. The author will particularly focus on the applications related to the building industry with perspectives to be further developed. The paper will cover the most up-to-date initiatives addressing the combination of hydrogen production based on water electrolysis and solar energy methods with the possibility of hydrogen implementations for energy storage, transportation and stationary applications such as combined heat and power (CHP) plants or fuel cell electric generators. The opportunity to reach improved efficiency and cost-effectiveness in the energy transition will be presented on the example of the two selected case studies: the world’s first full-scale wind power and hydrogen plant and the most up-to-date on-going project chosen by Fuel Cells and Hydrogen Joint Undertaking. They will be analysed in purpose to draw the conclusions regarding the options and limitations of the actual renewable hydrogen based energy storage systems tested in the real life situation. The second aim of the paper is to formulate the recommendations for the further action in this field, including the reduction of some non-technological barriers.

This paper presnts biomass as a renewable energy source and defines the resources as well as the ways through biomass energy is converted into fuels, the technologies used for extracting the energy from biomass as well as the advantages and disadvantages that appear by using of biomass as a energy source. In addition,it is known hydrogen is an important alternative energy vector and a bridge to a sustainable way fot the energy future. Hydrogen is an energy carrier and can be obtained by different production technologies from a large variety of primary energy sources. At present, many researches are focused on getting energy from biomass, a sustainable and non-polluting way to replace fossil fuels, because the biomass can be considered as the best option with high potential, which meets energy requirements and could insure fuel supply in the future. Biomass and residual biomass can be used to produce hydrogen rich gas sustainably. Biomass pyrolysis and gasification offers an efficiency and economical route for the renewable hydrogen production and this is also discussed in the paper.

How to supply electricity to the remote areas has become a very pressing issue for some countries which do not have the ability to connect all power grids to the whole country temporarily. At the same time, with the increase of fossil fuel costs and the continuous development of renewable energy generation technology, the construction of a hybrid renewable energy microgrid system seems to become an economic and technical approach to resolve the power shortage problem in the remote areas of some countries. Based on the analysis of local natural resources and load conditions, this paper designed a microgrid system which contains the wind turbines, PV systems, a diesel generator and an energy storage module to meet the power supply needs of the small town Amdjarass in Chad. Then the authors optimized the capacity of this microgrid and estimated the cost of this system with the utilization of HOMER software. In the end, this paper set the optimal configuration scheme with the target of the lowest COE and analyzed the sensitivity of some important parameters which could affect the economic performance.

This paper proposes a new optimal operation of Microgrids (MGs) in a distribution system with wind energy generators (WEGs), solar photovoltaic (PV) energy systems, battery energy storage (BES) systems, electric vehicles (EVs) and demand response (DR). To reduce the fluctuations of wind, solar PV powers and load demands, the BES systems and DR are utilized in the proposed hybrid system. The detailed modeling of WEGs, solar PV units, load demands, BES systems and EVs has been presented in this paper. The objective considered here is the minimization of total operating cost of microgrid, and it is formulated by considering the cost of power exchange between the main power grid and microgrid, cost of wind and solar PV energy systems, cost of BES systems, EVs and the cost due to the DR in the system. Simulations are performed on a test microgrid, and they are implemented using GAMS software. Various case studies are performed with and without considering the proposed hybrid system.

The paper deals with the problems of balancing the United Energy System of Ukraine caused by high renewable energy penetration and the impact of the COVID-19 pandemic on the energy sector. The paper analyses the trends in renewable energy development, the dynamics and structure of electricity consumption and export in pre-epidemic and epidemic periods and identifies the main challenges to operational security of the United Energy System of Ukraine. The methodical approach to improve the methodology for estimation of country’s energy security level by considering the index of developing capacities for balancing the United Energy System of Ukraine is suggested. In addition, proposals have been made to reduce threats to the stable work of the United Energy System of Ukraine by putting into operation of energy storage capacities, promoting the development of мaneuvering renewable energy capacities, and implementation of other appropriate measures in this field.