Until the early 1990s, the domestic power industry was a natural monopoly. This was caused by the specificity of the operation of the electricity transmission and distribution sub sectors, technical challenges of coordinating the operation of generating units and transmission networks, requirements regarding long-term forecasting of the industry development, and returns to scale. In view of the above, the objective of the presented paper is to assess the economic situation of energy companies operating in a competitive electricity market. The article analyses the main areas of activity of the energy companies, i.e.: the areas of production, transmission, distribution, and sales. In addition, the market shares of the various energy companies, in terms of generating capacity and the amount of the energy produced, were analyzed. Furthermore, the technical and economic situation of enterprises operating in the power sector was also subjected to analysis. The mentioned analysis has revealed that the profit received from the main activity of the enterprises (i.e. the sale of electricity) has decreased in recent years. What is more, the energy sector must adapt to legal and regulatory changes related to the intensification of the decarbonization policy pursued by the European Commission. Therefore, national energy should focus on developing skills in the areas of innovation, such as: electro mobility, energy storage, energy management, etc.

This paper shall present and explain the key aspects related to the issue of combined heat and power generation (CHP – Combined Heat and Power or Cogeneration). The cooperation with the water treatment plant launched allowed a closer look at the described technology as well as allowed the analyses and survey. The survey on the efficacy of the selected components of the cogeneration system was based on two cogeneration units fuelled with biogas produced in the sewage fermentation.

In this paper, the results of correlations between air temperature and electricity demand by linear regression and Wavelet Coherence (WTC) approach for three different European countries are presented. The results show a very close relationship between air temperature and electricity demand for the selected power systems, however, the WTC approach presents interesting dynamics of correlations between air temperature and electricity demand at different time-frequency space and provide useful information for a more complete understanding of the related consumption.

Time-of-use (TOU) electricity pricing has been applied in many countries around the world

to encourage manufacturers to reduce their electricity consumption from peak periods to

off-peak periods. This paper investigates a new model of Optimizing Electricity costs during

Integrated Scheduling of Jobs and Stochastic Preventive Maintenance under time of-use

(TOU) electricity pricing scheme in unrelated parallel machine, in which the electricity price

varies throughout a day. The problem lies in assigning a group of jobs, the flexible intervals

of preventive maintenance to a set of unrelated parallel machines and then scheduling of jobs

and flexible preventive maintenance on each separate machine so as to minimize the total

electricity cost. We build an improved continuous-time mixed-integer linear programming

(MILP) model for the problem. To the best of our knowledge, no papers considering both

production scheduling and Stochastic Preventive Maintenance under time of-use (TOU) electricity

pricing scheme with minimization total Electricity costs in unrelated parallel machine.

To evaluate the performance of this model, computational experiments are presented, and

numerical results are given using the software CPLEX and MATLAB with then discussed.

Ensuring the security of power generation systems is a pillar of the proper functioning of each state. Energy security is fundamental to ensure both economic growth and social welfare. As energy storage has not developed in an efficient extent, covering the current and prospective power demand is a major challenge for transmission system operators. Moreover, the activities that are to be taken should be technically and economically justified and need to meet the requirements of environmental protection. Cooperation between neighboring countries in the field of electricity exchange is among the activities undertaken to ensure the safety of the power generation systems. The integration of electricity markets is one of the key challenges of the European Union’s energy policy. The European Commission issued a directive on interconnection, according to which the capacity of interconnections should total 10% of installed capacity until 2020 (and 15% until 2030) in each Member State. The main objective of this study is to assess the changes in electricity imports and exports in 2003–2018 and to investigate the current level of cross-border exchanges between Poland and the neighboring countries. This paper also answers the question of whether Poland will fulfil the obligations set by the European Commission. In addition, the paper presents the risks and the challenges related to fulfilling the mentioned commitments. The results of the study indicate that the development and modernization of network infrastructure in the field of cross-border exchange are necessary because, in the context of the forecasted increase in electricity demand, Polish generation units will not be able to meet the demand.

The article presents the results of laboratory measurements of U_d breakdown voltages in a high-voltage vacuum insulating system for different pressures, contact gaps, type of electrode contacts and type of residual gas inside the discharge chamber. First of all, the electrical strength of the discharge chamber with a contact system terminated with contact pads made of W ₇₀Cu ₃₀ and Cu ₇₅Cr ₂₅ material was compared for selected values of contact gaps. It was found that below a pressure of p = 3.0 x 10 ^-1 Pa the electrical strength reaches an approximately constant value for each of the set contact gaps d. Analytical relationships were determined to calculate this value for each of the contact pads used. Above a pressure of p = 3.0 x 10 ^-1 Pa, the measured values of U_d breakdown voltages decrease sharply. The values of breakdown voltages in the discharge chamber with residual gases in the form of air, argon, neon and helium were also determined for selected values of contact gaps d. Depending on the residual gases used, significant differences were noted in the values of pressure p at which the loss of insulating properties in the discharge chamber occurred. These values were 3.3 x 10 ^-1 Pa for argon, 4.1 x 10 ^-1 Pa for air, 6.4 x 10 ^-1 Pa for neon, and 2.55 x 10 ⁰ Pa for helium, respectively.

In this paper, selected aspects of the national technical level of electric energy supply security is shown. An analysis and assessment of the electric power infrastructure in area of generation, transmission and distribution in aspects of electric energy security is conducted. The profile of the generation sector and grid infrastructure in the area of transmission and distribution is shown. The present and future situation in a range of operation of electric power infrastructure in the area of generation, transmission and distribution in the frames of the National Electric Power System in the electric energy supply security context is determined. The level of national electric energy supply security in area of generation and grid infrastructure is assessed. Threats of electric energy supply security are described and the catalogue of essential actions for the assurance of electric energy supply security are proposed. In the area of electricity generation, at present there is no danger to the electricity supply security in normal load conditions, but there is a high probability that it will occur in the future (after 2025) when the forecasted increase in electricity demand takes place and the new stringent environment protection requirements (Directive IED, BAT conclusions, Winter Package) enter into force. The network infrastructure in area of transmission and distribution is admittedly adapted for presently occurred typical conditions of electric energy demand and the realization of internal tasks in normal conditions, but can create a potential threat for electric energy supply security. In the context of the forecasted increase of electric energy demand, inadequate power generation sources in the National Electric Power System and available through intersystem connections, their uneven location on the territory of Poland in the shortage of proper network transmission capacities, the necessity of improvement of the quality and electric energy supply reliability to final consumers and the intensive development of renewable energy sources, the present network infrastructure in area of transmission and distribution will be insufficient.

The second decade of the 21st century is a period of intense development of various types of energy storage other than pumped-storage hydroelectricity. Battery and thermal storage systems are particularly rapidly developing ones. The observed phenomenon is a result of a key megatrend, i.e. the development of intermittent renewable energy sources (IRES) (wind power, photovoltaics). The development of RES, mainly in the form of distributed generation, combined with the dynamic development of electric mobility, results in the need to stabilize the grid frequency and voltage and calls for new solutions in order to ensure the security of energy supplies. High maturity, appropriate technical parameters, and increasingly better economic parameters of lithium battery technology (including lithium-ion batteries) result in a rapid increase of the installed capacity of this type of energy storage. The abovementioned phenomena helped to raise the question about the prospects for the development of electricity storage in the world and in Poland in the 2030 horizon. The estimated worldwide battery energy storage capacity in 2030 is ca. 51.1 GW, while in the case of Poland it is approximately 410.6 MW.

The paper presents a thermal-economic analysis of a 900 MW coal-fired power unit for ultra-supercritical parameters with internal steam reheat. The subject of the study was the cycle proposed as the "initial thermal cycle structure" during the completion of the project "Advanced Technologies for Energy Generation" with the steam parameters of 650/670 °C/30 MPa. Two configurations of internal reheat were analysed: with a four- and seven-section exchanger. The effect of reheat on the operation of the power unit under a partial load was also analysed, and preliminary calculations of the heat exchange area of the internal reheat were made.

This article describes a thermodynamic analysis of an oxy type power plant. The analyzed power plant consists of: 1) steam turbine for supercritical steam parameters of 600 °C/29 MPa with a capacity of 600 MW; 2) circulating fluidized bed boiler, in which brown coal with high moisture content (42.5%) is burned in the atmosphere enriched in oxygen; 3) air separation unit (ASU); 4) CO2 capture installation, where flue gases obtained in the combustion process are compressed to the pressure of 150 MPa. The circulated fluidized bed (CFB) boiler is integrated with a fuel dryer and a cryogenic air separation unit. Waste nitrogen from ASU is heated in the boiler, and then is used as a coal drying medium. In this study, the thermal efficiency of the boiler, steam cycle thermal efficiency and power demand were determined. These quantities made possible to determine the net efficiency of the test power plant.

The increasingly stringent requirements for wastewater treatment enforce the adoption of technologies that reduce pol-lution and minimize waste production. By combining the typical activated sludge process with membrane filtration, biolog-ical membrane reactors (MBR) offer great technological potential in this respect. The paper presents the principles and ef-fectiveness of using an MBR at the Głogów Małopolski operation.Physicochemical tests of raw and treated wastewater as well as microscopic analyses with the use of the FISH (fluorescence in situ hybridization) method were carried out. More-over, the level of electric energy consumption during the operation of the wastewater treatment plant and problems related to fouling were also discussed. A wastewater quality analysis confirmed the high efficiency of removing organic impurities (on average 96% in case of BOD5 and 94% in case of COD) and suspension (on average 93%).

This paper proves that the trend of development of modern transport in the world is to maximize the level of providing the personal use of electric vehicles. This mechanism would also partially solve the environmental problems of mankind. To implement this idea, some global automakers have announced the decision of the full transition of production to electric vehicles. At the same time, for effective functioning of the electric-vehicle market, adequate infrastructure needs to be created. There is a positive trend in the annual growth of the charging-station network in developed countries, that characterizes the charging-station market as dynamic and promising, but mostly chaotic and imbalanced at the regional level.
The main hypothesis of the research is about the independence between the level of electric-vehicle market development and networks of charging stations. The object of the study is the Washington (USA) electric-vehicle market, as it is the market segment with the highest development characteristics.
To test the hypothesis, the authors provided a multifactor analysis of the local electric-vehicle market and the existing charging infrastructure. A comprehensive analysis of the electric-vehicle market and the charging-station network in Washington (USA) was performed, and the market characteristics were defined accordingly: the degree of electric-vehicle spread in the regional localities; the level of charging-station-network coverage and concentration; the ratio of electric vehicles to charging stations.
Authors identified the tendency of the state location to innovations connected with electric vehicles. Clusterization and recommendations according to the level of development of the electric-vehicle market aimed to balance and grow the total electric-vehicle market and connected infrastructure.

The paper presents the characteristics of the attitude that students have towards electric cars and the significance of distinguished attitude elements in creating interest in the purchase of such vehicles. Electric cars are the new type of vehicles that have an electric motor and use the electricity stored in batteries. They are introduced to the market, but for various reasons the volume of sales is not high. So far, it is not sufficiently known how electric vehicles are assessed by Poles. The presented research is an attempt to know what the attitude towards this type of vehicle. The attitude model tested in this research includes three areas: knowledge about them, emotions that they evoke and potential behaviors. The participants were students of Rzeszów University of Technology – a group of young people who are potential consumers of new technologies. The obtained results indicate that electric cars are rather unknown. At the same time, they arouse great interest and their image is very positive. The attitude characteristics towards this type of vehicle is supplemented by perceived limitations: too high of a purchase price, lack of sufficient information about them and unsatisfactory technical parameters, mainly the long time needed to recharge the battery and the insufficiently long distance with one recharge. The interest in the purchase is dependent on positive emotions, and the lack of sufficient information is an obstacle in thinking about buying such a vehicle. Understanding the attitudes of Polish students towards electric cars can be helpful in adapting information about such cars to potential customers, which in turn may affect the level of interest and sales volume.

Energy is a basic industry for any economy and ensures the country’s security, including economic

security. The purpose of the article is to analyze the reform of the energy sector in Ukraine

for successful integration into the energy sector of the European Union. The state of the energy

industry from 2003 to 2018 is analyzed. The following main reasons for the decrease in electricity

generation in Ukraine are identified – a decrease in production volumes, the annexation of Crimea

and the anti-terrorist operation in the east of Ukraine, a decrease in the volume of energy output

from Thermal Power Plants due to aging capacities, difficulties with raw materials, low efficiency,

which, however, has a good effect on the environment due to a decrease carbon dioxide emissions.

The directions of reforming the electric power industry of Ukraine are considered in the context of

“industry-market-company”. Four electricity market models are analyzed and the new model of the

competitor’s market for electricity in Ukraine with contract market, spot market, the balancing market

is substantiated. The structure of the segments of the new electricity market and the participants

are proposed. More than half of the electricity market is provided by nuclear power, which ranks

the 5th in the world in terms of installed capacity. The analysis of the performance indicators of the

nuclear company for 2007–2019 showed significant reserves for the company’s growth, which are

being successfully implemented through strategic development projects and phased corporatization

of the company as a tool of unbundling. The main challenges of implementation a new market

model are analyzed and solutions are proposed.

The paper looks at an analysis of the tendency of changes in the fuel structure of electricity

generation and thus resulting changes in carbon dioxide emissions. Forecasts drawn up by various

institutions and organizations were selected for the analysis. Firstly, on the basis of statistical data

contained in (IEA 2017a, IEA 2008) and with the use of Kay’s indicators, the impact of changes in

energy intensity of the national income and energy mix on changes in carbon dioxide emissions per

capita in 2006–2015 for the OECD countries and Poland were analyzed. A small effect of changes

was found in the fuel mix in this period of time on the emissions. The main impact was due to changes

in the energy intensity of the national income and changes in the national income per capita.

Next, selected fuel scenarios for the period up to 2050 (60) were discussed – WEC, IEA, EIA, BP,

Shell, with a focus on the WEC scenarios. These have been developed for various assumptions with

regard to the pace of economic development, population growth, and developments of the political

situation and the situation on the fuel market. For this reason, it is difficult to assess the reliability

thereof. The subject of the discussion was mainly the data on the fuel structure of electricity generation

and energy intensity of national income and changes in carbon dioxide emissions. The final

part of the paper offers a general analysis of forecasts drawn up for Poland. These are quite diverse,

with some of them being developed as part of drawing up the Energy Policy for Poland until 2050,

and some covering the period up to 2035. An observation has been made that some forecasts render

results similar to those characteristic of the WEC Hard Rock scenario.

Energy storage, as a flexible resource that comprehensively supports network operation, will grow increasingly indispensable as the share of renewables increases.

The discrete Fourier transform (DFT) is the main method of electrical harmonic analysis since it’s easily realized in an embedded system. But there were some difficulties in performing synchronized sampling. The spectral leakage caused by asynchronous sampling affects the accuracy of harmonics analysis. Using window functions and interpolation algorithms can improve the accuracy of harmonics analysis. An approach for electrical harmonic analysis based on the interpolation DFT was proposed. A window function reduces DFT leakage and the interpolation algorithm modifies the calculation results of frequency, amplitude and the initial phase angle. The simulation results indicate that, by using the interpolation DFT electrical harmonic analysis method based on the Hanning window or the Blackman window, the error of calculating amplitudes and frequencies is not greater than 0.5%.

In the recent times, lot of research work carried out in the field of fuel cells explicitly divulges that it has the potential to be an ultimate power source in upcoming years. The fuel cell has more storing capacity, which enables to use in heavy power applications. In these applications, power conditioning is more vital to regulate the output voltage. Hence, we need a dc-dc converter to provide a constant regulated output voltage for such high-power system. Currently, many new converters were designed and implemented as per the requirement. This paper has made comparative study on several topologies of the quadratic high gain dc-dc converter and the applications where these topologies can be used when the fuel cell is given as a source. Also, we have compared various parameters of all the converters considered and generated the results with steady-state and dynamic study. In this article, we briefed the types of analysis carried on the dc-dc converter to study its performance. Moreover, various application of fuel cell is presented and discussed. This paper will be a handbook to the researchers who start to work on high gain dc-dc converter topologies with quadratic boost converter as a base. This article will also guide the engineers to concentrate on the fuel cell components where it needs to be explored for optimizing its operation.

Electromobility and electric cars are the words that began to gain significance in the social discourse in Poland especially intensively since 2017. Then, along with the announcement of the „Plan for the Development of the Electromobility Market in Poland”, government declarations appeared regarding one million electric cars that are to be used on Polish roads by 2025. It is already known today that such a result in Poland is impossible to achieve in the assumed time. According to the report of the Polish Alternative Fuels Association-PSPA (Polish EV Outlook 2020), in the event of introducing subsidies for the purchase of cars or subsidies, such as the possibility of 100% VAT deduction by buyers of such vehicles, the number of electric cars in Poland in 2025 could be over 280 thousand pcs. Without such government support, the Polish electric car park will be twice smaller. High prices of electric cars are one of the key barriers limiting Poles in making decisions related to the purchase of a vehicle. The aim of this article is to analyse the current state of the social environment in relation to the topic of ecological, electric cars. To what extent is it beneficial for the potential car owner to change from a traditional (petrol or diesel) car to an electric car due to purely financial benefits and other aspects? The article consists of an overview – presenting aspects related to the socio-economic benefits of buying an electric car. It also contains specific calculations regarding the profitability of using such a car in Polish conditions.

The progressive processes of globalization and changes in the global, European and local economy require integrated efforts aimed at solving problems related to development at the national regional and the local level involving the environment, energy sources, climate and technological transformation issues. European Union Member States are given right to create an individual Energy mix. Coal will continue to play a major role in Poland’s energy mix during the next decades. Polish coal reserves can provide energy security for decades.

Despite crude oil and natural gas growth in fuel consumption, coal will continue to be the stabilizer of energy security for the country and play an important role in Poland’s energy mix in the years to come. However, further coal consumption requires investments in low carbon technologies which are of high efficiency and in high-efficiency cogeneration.

The validity of the full utilization of cogeneration potential should be highlighted. Operating cogeneration plants are more expensive than power plants but they are more efficient and generate less carbon emissions. In accordance with the assumptions of the Energy policy of Poland, a low-carbon economy with renewable Energy sources and nuclear Energy should be supported and developed, however the obsolete coal generators should be replaced with low-carbon high-efficient ones.

Scientists are focusing on the introduction of various types of renewable energy sources and the liberalization of energy markets in the regions of the country. The problems of preventing the achievement of goals and various strategies to achieve maximum energy conservation and overcoming the current economic and environmental crisis in Ukraine also remain unresolved. We can observe the experience of the leading countries in the electricity sector, which proves that reforming the electricity sector in Ukraine is inevitable. This, in turn, is a critical factor in stimulating economic and social growth and improving the competitiveness of the regions of Ukraine. Given the above, the necessity for the study of the level of efficiency (competitiveness) and the functioning of the regional energy markets of Ukraine is obvious.
This study shows that the efficiency of electricity in the western region is relatively low due to the lack of competition, the presence of an ineffective system of subsidizing the population with cheap resources, the non-transparency of trade operations, excessive regulation of state generation, the lack of a “balanced” system of market functioning, etc.

Within this study, resonance phenomenon, which is one of the crucial problems in mechanical constructions, has been analyzed with respect to oil starvation failure in a ball bearing. A unique test rig is designed, constructed, and placed in a laboratory ambience. A ball bearing on the electrical motor, which is a component of the test rig, has been selected for acquisition of data within triple sensing technology in vibration, acoustic, and electrical consumption through testing conditions. The target of that study is condition monitoring of oil starvation fault and resonance fault for comparison of various predictive maintenance methods. The testing was carried out within the electrical frequency of 40.5 Hz, which actuated the electrical motor in order to identify the rotation speed. According to the analyzed results, oil starvation fault and resonance fault is most accurately inspected by vibration analysis.

For the purpose of making of a solid body of an electric guitar the acoustic- and mechanical properties of walnut- (Juglans regia L.) and ash wood (Fraxinus excelsior L.) were researched. The acoustic properties were determined in a flexural vibration response of laboratory conditioned wood elements of 430 × 186 × 42.8 mm used for making of a solid body of an electric guitar. The velocity of shearand compression ultrasonic waves was additionally determined in parallel small oriented samples of 80 × 40 × 40 mm. The research confirmed better mechanical properties of ash wood, that is, the larger modulus of elasticity and shear modules in all anatomical directions and planes. The acoustic quality of ash wood was better only in the basic vibration mode. Walnut was, on the other hand, lighter and more homogenous and had lower acoustic- and mechanical anisotropy. Additionally, reduced damping of walnut at higher vibration modes is assumed to have a positive impact on the vibration response of future modelled and built solid bodies of electric guitars. When choosing walnut wood, better energy transfer is expected at a similar string playing frequency and a structure resonance of the electric guitar.

An electric power steering system (EPS) is a new type of steering system developed after a mechanical hydraulic power system (MHPS) and electric-hydraulic power steering system (EHPS). In order to coordinate and solve the portability and sensitivity of the steering system optimally, taking an induction power steering system as the research object, the control algorithm of induction motor control under the EPS is studied in this paper. In order to eliminate the feed-forward performance degradation caused by the change of feed-forward parameters, an on-line identification algorithm of feed-forward parameters is proposed. It can improve the control performance of online identification among three feed-forward parameters in the T-axle motor, it improves on the robustness of feed-forward control performance, at the same time it also gives simulation and test results. This method can improve the control performance of the three feed-forward parameter online identification of the T-axis motor and improve the robustness of feed-forward control performance. At the same time, simulation and test results are given. The simulation results show that the algorithm can significantly improve the response speed and control accuracy of EPS system control.