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Purpose – Striving to achieve the goal of carbon neutrality before 2060 indicates that China, as the most extensive power system in the world and a country based on coal power, is imperative to improve the technical level of electric power utilization. This paper aims to explore the nonlinear evolution mechanism of power technology progress under the constraints of net-zero carbon dioxide emissions in China. Design/methodology/approach – This paper, first, based on China’s provincial panel data from 2000 to 2019, uses global direction distance function to measure power technological progress. Second, the threshold regression model is used to explore the nonlinear relationship between carbon emission reduction constraints on electric power technological progress. Findings – There is a significant inverted U-shaped relationship between China’s provincial carbon emission reduction constraints and electric power technological progress. Meanwhile, the scale of regional economic development has a significant moderating effect on the relationship between carbon emission reduction constraints and power technological progress. Research limitations/implications – This paper puts forward targeted suggestions for perfecting regional carbon emission reduction policy and improving electric power technological progress. Originality/value – Based on the global directional distance function, this paper extracts power as a production factor in total factor productivity and calculates the total factor electric power technological progress. This paper objectively reveals the influence mechanism of carbon emission reduction constraints on electric power technology progress based on the threshold regression model.

This paper addresses the optimal sizing of Hybrid Renewable Energy Systems (HRESs), encompassing wind, solar, and battery systems, with the aim of delivering reliable performance at a reasonable cost. The focus is on mitigating unscheduled outages on the national grid in Iraq. The proposed On–off-grid HRES method is implemented using MATLAB and relies on an iterative technique to achieve multi-objectives, balancing reliability and economic constraints. The optimal HRES configuration is determined by evaluating various scenarios related to energy flow management, electricity prices, and land cover effects. Consumer requirements regarding cost and reliability are factored into a 2D optimization process. A battery model is developed to capture the dynamic exchange of energy among different renewable sources, battery storage, and energy demands. A detailed case study across fifteen locations in Iraq, including water, desert, and urban areas, revealed that local wind speed significantly affects the feasibility and efficiency of the HRES. Locations with higher wind speeds, such as the Haditha lake region (payback period: 7.8 years), benefit more than urban areas (Haditha city: payback period: 12.4 years). This study also found that not utilizing the battery, particularly during periods of high electricity prices (e.g., 2015), significantly impacts the HRES performance. In the Haditha water area, for instance, this technique reduced the payback period from 20.1 to 7.8 years by reducing the frequency of charging and discharging cycles and subsequently mitigating the need for battery replacement.

In the analogy where achieving the “carbon peaking and carbon neutrality” goals (the “dual carbon” goals) is compared to a battle, energy is the main battlefield, and electric power the main force. The low-carbon transformation path of the electric power industry exerts fundamental impact on progress towards carbon peaking and carbon neutrality of the whole society. Therefore, this paper first analyzes challenges and opportunities faced by the electric power industry to achieve the “dual carbon” goals; secondly, on the basis of deep low-carbon, zero-carbon and negative-carbon scenarios of the electric power industry, this paper quantifies and delves into the consumption structure of primary energy and final energy, as well as the future development positioning and trend of different categories of energy. Based on the research results, this paper proposes low-carbon transformation path of the electric power system at the stages of carbon peaking, deep low-carbon and carbon neutrality, and analyzes the trend of power supply cost changes in different scenarios. On this basis, a series of implementation key points and measures are proposed to adapt to green and low-carbon transformation of the electric power industry, covering areas such as coal-fired electric power development positioning, new energy development and utilization, diversified supply and demand, new energy industry chain, and power supply costs, and so forth.

The article presents the results of studying the electric and thermal efficiency of mobile photovoltaic and photothermal devices (MPVD and MPTD) based on crystalline silicon with a power of 60W panel, designed for the production of electricity and hot water for the domestic needs of rural residents. Our experiment conducted in natural conditions was carried out in the heliopolygon of the Physical-Technical Institute in July of the summer season. The device was manually adjusted and measurements were carried out in the directed mode. Reflectors are installed on the side of the photovoltaic panel (PV) in order to increase the intensity of sunlight in MPTD. As a cooling system, heat collector (HC) is installed in the back of the PV. The HC of the photothermal panel (PVT) is fundamentally different from the system of HC in other works. During the experiment carried out in natural conditions, the effects of the reflectors installed on the front surface of the photothermal device’s PV and the heat collector attached to the back side were determined. Thermal efficiency was 5.5-6 times higher than electric efficiency for PVT panels. And 90% of the solar energy falling on the surface of the photothermal device is converted into useful energy.

Increasing the energy performance of rolling stock is one of the most relevant railway transport. One of the ways to achieve these tasks is to determine the optimal parameters of the traction drive of the rolling stock, with which you can create computer simulation models. In this article, the optimal parameters of an asynchronous traction motor of an electric rolling stock are determined. Determination of the parameters of the ATM is necessary to create a computer simulation model that allows reproducing electromagnetic processes in a traction electric drive and converters, as well as processing functions of the simulation results obtained that are adequate to the real conditions of use on electric rolling stock of converters with various control algorithms in traction and regenerative braking modes. In the article, the modes of idling, short circuit and rated load are used to determine the parameters of the ATM in relation to the T-shaped replacement circuit using the method of separation of losses in the engine. Losses in traction converters and traction gearboxes are taken into account in accordance with the power developed by the ATM. The results obtained can be used in a computer simulation model designed to reproduce electromagnetic processes in a traction electric drive and converters, when determining the energy characteristics of electric locomotives with asynchronous traction motors.

In this paper, balancing electricity production using renewable energy such as wind power, PV cells, hydropower, and CHP (combined heat and power) with biomass is carried out in relation to electricity consumption in primarily one major region in Sweden, SE-3, which contains 75% of the country’s population. The time perspective is hours and days. Statistics with respect to power production and consumption are analyzed and used as input for power-balance calculations. How long periods are with low or high production, as well as the energy for charge and discharge that is needed to maintain a generally constant power production, is analyzed. One conclusion is that if the difference in production were to be completely covered with battery capacity it would be expensive, but if a large part of the difference were met by a shifting load it would be possible to cover the rest with battery storage in an economical way. To enhance the economy with battery storage, second-life batteries are proposed to reduce the capital cost in particular. Batteries are compared to hydrogen as an energy carrier. The efficiency of a battery system is higher than that of hydrogen plus fuel cells, but in general much fewer precious materials are needed with an H2/fuel-cell system than with batteries. The paper discusses how to make the energy system more robust and resilient.

Energy from biogas is widely available, inexpensive, and often contributes to waste management, making it one of the most promising renewable energy sources. The main factors influencing this process’ efficiency include the substrates’ chemical composition, temperature, and digester load. This paper presents the possibilities offered by a biogas plant built at a farm specialising in dairy cows. The dependence of the power generated in the micro biogas plant on its technical parameters was analysed in detail. Studies carried out by the authors in an agricultural microgas plant (with an electrical output of 40 kW) have shown that they are designed to maintain continuous energy production, despite changing process parameters such as digester mass level, biogas height, temperature or slurry flow into the digester. However, from the point of view of the amount of electricity generated, changes would have to be made to the design of the biogas plant. Firstly, a more powerful generator would have to be installed to cover the electricity requirements of the equipment installed in the biogas plant so that power close to the rated capacity of the biogas plant is still sent to the grid. Secondly, replacing the two existing agitators of the digestion mass (9 kW each) with more agitators of lower power (e.g., four agitators of 4.5 kW each) would be necessary. These should be programmed so that one of the agitators operates at any given time (the operating time of a given agitator should depend on the composition of the digestate).

The paper describes a new possible method of diagnostics of the current technical condition of equipment using a mathematical model based on fuzzy expert estimates and the theory of fuzzy sets. The specifics of the task is determined mainly by the type of the obtained estimates, namely: causal relationships between the controlled parameters of the transformer equipment and defects that could entail their change and the possibility of further operation of the facility. At the same time, attention is paid to the problem of the degree of consistency of expert opinions that affects the quality of the assessment of the current technical condition of the studied object. The paper provides a comparative analysis of the arithmetic mean estimates and median estimates of the consistency of expert opinions. It is shown that the significant drawback of the arithmetic mean approach is its instability towards outliers of individual opinions moving the resulting value under the influence of the “dissident expert opinions”. On the other hand, the median estimate is free of such shortage; it is more outlier-resistant and simply discards a part of radically outlying expert opinions. For the first time, the Kemeny median has been used for technical diagnostics. Kemeny median is based on the introduction of a metric to the set of expert opinions, and axiomatic introduction of the distance between them. Also, the paper formulates a criterion on how to determine the optimal number of experts in the group.

In this study, the temperatures of the front glass, back sheet, and solar cell (SC) in the rear electrical contact of the PV module during heating, and the open circuit voltage and short circuit current corresponding to these temperatures were experimentally investigated. Measurements were conducted in the city of Termez in conditions of an air temperature of 30ºC and solar radiation intensity of 850-950W/m2 . Two mono c-Si PV modules with the same electric power were selected for the experiment. Three K-type chrome and alumn combined thermocouples were used to measure the temperatures in the layers of the first PV module. During the observations, it was found that the temperature of the PV module glass differs from the back sheet temperature by ~20ºC, and from the temperature of the back electrical contact of the SC by ~25ºC. Also, according to the temperature difference, the open circuit voltage of the PV module decreased from 21V to 19.3V, and the short circuit current increased from 0.65A to 0.75A. During the experiment, the values of electric power changed by ~11-11.6W.

The needs of the population and industry for electrical energy are limited by oil and gas reserves, which leads to the need to use renewable energy sources. Myanmar is one of the developing countries in Asia. Its specific power consumption is low compared to neighboring countries. Currently, one of the most important tasks of the electric power industry is to ensure reliable, uninterrupted power supply to all industrial and domestic facilities. At the same time, the development of small solar photovoltaic installations (PMT), operating both in parallel with the grid and in autonomous mode, can improve the power supply of closely located consumers more efficiently and faster than the development of a large power system. Therefore, the work devoted to the improvement of the equipment of a small solar photovoltaic installation is relevant and of great practical importance.

Aim/purpose - The aim of the article is to present the essence of ex post approach to sectoral regulation, to show the advantages and disadvantages of ex post regulation and to answer the question whether it is worth using in the electricity sector. Design/methodology/approach - For this purpose, a critical analysis of expert literature was made and an empirical analysis of countries that have applied ex post regulation in the electricity sector in the European Union. Two research methods were used: a case study and a comparison of changes in price and quality of services. The research period covered the period 2000-2016. Findings - It was found that ex post regulation reduces regulatory costs, does not adversely affect the quality of service and long-term rates, gives businesses the freedom of decision-making and the ability to react quickly to changes in the economy. The main disadvantages of ex post regulation are the tendency for companies to over-estimate bills for consumers, the difficulty of pursuing claims by consumers and the need to shift regulatory risk to consumers. Research implications/limitations - In the paper there was identified a research gap, i.e. the effects of ex post regulation in the electricity sector in European Union countries where such regulation was applied. Identifying the research gap will help us understand what are the advantages and disadvantages of ex post regulation and will create a model for when it is good moment to implement this in the economy. Besides identifying the research gap, further studies will be required over ex post regulation. Originality/value/contribution - The additional value of the paper is the study of ex post regulation, its essence and types. The article analyzed the effects of ex post regulation in the electricity sector and provided valuable insights into the potential risks associated with this approach to economic regulation.

Aim/purpose - This paper attempts to appraise the potential of water resources for Cameroon and the standard of living conditions confronting people in the country. Design/methodology/approach - A simple descriptive method of data analysis is adopted using analytical tools such as percentages, tables, and means to achieve the objectives of the inquiry. Data for the study were generated from personal observations in one hand and collected from water resources literature, on the other hand. Findings - With the help of the data gathered, the paper establishes that despite the existence of abundant water resources in Cameroon the standard of living conditions of people with respect to basic needs of survival such as drinking water, improved sanitation services, and electricity supply is far below expectation. Research implications/limitations - The main implication of the study is that in spite of the surplus volume of water resources (325.96 km3 or 95.12% of annual total water resources) endowment in Cameroon, the population benefits marginally from it due to the mismanagement of resources and misplacement of priorities as obtained in most sub-Saharan African countries. One limitation of this study is that the use of limited primary data in the investigation offers no room toward establishing the extent of water resources allocation to the various users of water in the country. Originality/value/contribution - The paper suggests that the government of Cameroon should encourage the population to run community basic social services projects and subsidize the activities of such ventures in kind through technical assistance or in cash.

The urgency of the task is to develop a heat exchanger-regenerator designed for high- temperature heating of gaseous media, which are used in various technological schemes of the petrochemical, gas processing, energy and other industries. The developed heat exchanger has high performance due to the developed heat exchange surface, reliability due to the fact that the inner and outer pipes are movable relative to each other with linear dimensions compensation, it is simple to manufacture, does not require the use of an intermediate heat carrier, can be used as a heating coolant combustion products of untreated, low-grade gaseous fuel. At the same time, it is possible to equip the developed apparatus with a convection heat exchanger for more efficient use of the heat of the fuel combustion products. The article describes the proposed design, the principle of operation of this heat exchanger-regenerator. A review of the technical literature has been carried out, the main advantages of the device are shown in comparison with the currently known domestic and foreign counterparts. The paper presents the main calculated dependencies used in the design, as well as the results of the calculations. The possibility of using the proposed heat exchanger as part of a gas turbine unit used as an autonomous power source is considered, as well as information about technological processes in which it can be used. In conclusion, we can say that the developed heat exchanger has high performance, differs in the ability to work at high temperatures without violating the integrity of the structure, does not require the use of an intermediate heat carrier, and is to be used in many industries.

Severe weather conditions not only damage electric power infrastructure, and energy systems, but also affect millions of users, including residential, commercial or industrial consumers. Moreover, power outages due to weather-related natural disasters have been causing financial losses worth billions of US dollars. In this paper, we analyze the impact of power outages on the revenue of electric power suppliers, particularly due to the top five weather-related natural disasters. For this purpose, reliable and publicly available power outage events data are considered. The data provide the time of the outage event, the geographic region, electricity consumption and tariffs, social and economic indicators, climatological annotation, consumer category distribution, population and land area, and so forth. An exploratory analysis is carried out to reveal the impact of weather-related disasters and the associated electric power revenue risk. The top five catastrophic weather-related natural disaster categories are investigated individually to predict the related revenue loss. The most influencing parameters contributing to efficient prediction are identified and their partial dependence on revenue loss is illustrated. It was found that the electric power revenue associated with weather-related natural disasters is a function of several parameters, including outage duration, number of customers, tariffs and economic indicators. The findings of this research will help electric power suppliers estimate revenue risk, as well as authorities to make risk-informed decisions regarding the energy infrastructure and systems planning.

Introduction. The relevance of the research topic is conditioned by the need to comprehend the historical experience, the place and role of the Far East in the process of Russian modernization. Methods. The theoretical and methodological basis of the study is the concept of modernization. Modernization is understood as a process in which traditional societies are transformed into industrial, modern ones. Analysis. Studying the history of the Russian Far East electrification makes it possible to distinguish three stages of the region electrification during the period under study: the first stage is the late 19th c. – the late 1920s; the second stage is the late 1920s– 1930s; the third stage is the late 1930s–1940s. Results. The periodization of the history of the Far East electrification proposed in the study in the late 19th – mid 20th centuries is based on the stages of the country’s economic development and the specifics of the Russian Far East technical modernization. The paper reveals that the Russian Far East electrification was heavily influenced by economic-geographical and historical factors. The article establishes that electrification plays an important role in creating a technical basis for forming a regional economy of the industrial type with predominance of extractive industries and the military-defense industry.

Bistable vibration energy harvesters are sensitive to impulsive excitations widely existed in environments, and the favorable large-orbit snap-through oscillation possesses high energy conversion efficiency and output voltage. The enhanced averaging method (EA) with Jacobian elliptic functions provides an analytical, efficient tool of guiding the structural design and parameters optimization of bistable harvesters excited in impulsive environments. However, the EA method still suffers some limitations: the predicted transient dynamics undergo undesired sudden jump at the end moment of the snap-through regime, and; phase error occurs during the intrawell regime when large initial velocity is applied. To address these limitations, an improved EA method is proposed in this paper. The transient dynamics in the snap-through and intrawell regimes are separately approximated via two-piecewise expressions, leading to high-fidelity estimation of the vibration amplitude and critical moment dividing the snap-through from intrawell dynamics which occur later in the time. A novel, more accurate estimation of the vibration phase is derived. The prediction performance of the improved EA method is validated via numerous comparisons with the EA method and numerical simulations. It shows that the improved EA method effectively eliminates the aforementioned limitations induced by EA method, providing high-fidelity reconstruction of the transient dynamics of the bistable harvesters excited in impulsive environments.

The energy conservation achieved by utilizing waste heat in the energy and industrial sectors has became more and more important after the energy crisis in the 1970s because it plays a vital role in the potential energy-efficiency improvement. In this regard, cogeneration (combined heat and power, CHP) systems are thus becoming attractive due to the energy, economic, and environmental policies for pursuing stable electricity supply, sustainable development and environmental pollution mitigation in Taiwan. The objective of this paper is to present an updated analysis of CHP systems in Taiwan during the period from 1990 to 2010. The description in the paper is thus based on an analysis of electricity supply/consumption and its sources from CHP systems during the past two decades, and centered on two important regulations in compliance with CHP systems (i.e., Energy Management Law and Environmental Impact Assessment Act). Based on the total net power generation from CHP systems (i.e., 35,626 GWh) in 2011, it was found that the carbon dioxide reduction benefits were estimated to be around 20,000 Gg.

Solar photoelectric energy converted into electricity requires large surface areas with incident light and flexible materials to capture these light emissions. Currently, sunlight rays are converted to electrical energy using silicon polymeric material with efficiency up to 22%. The majority of the energy is lost during conversion due to an energy gap between sunlight photons and polymer energy transformation. This energy conversion also depends on the morphology of present polymeric materials. Therefore, it is very important to construct mechanisms of highest energy occupied molecular orbitals (HOMO)s and the lowest energy unoccupied molecular orbitals (LUMO)s to increase the efficiency of conversion. The organic and inorganic solar cells used as dyes can absorb more photons from sunlight and the energy gap will be less for better conversion of energy to electricity than the conventional solar cells. This paper provides an up-to-date review on the performance, characterization, and reliability of different composite polymeric materials for energy conversion. Specific attention has been given to organic solar cells because of their several advantages over others, such as their low-energy payback time, conversion efficiency and greenhouse emissions. Finally, this paper provides the recent progress on the application of both organic and inorganic solar cells for electric power generations together with several challenges that are currently faced.

O artigo discute o processo de introdução da energia elétrica na cidade de São Paulo no início do século XX. A Proclamação da República marcou o início da modernização das empresas de serviços urbanos, com a introdução da eletricidade. Foi neste contexto que dois grupos iniciaram uma intensa batalha no setor elétrico paulista: o grupo nacional da Companhia Brasileira de Energia Elétrica (CBEE) - conhecido também como Docas de Santos - e o canadense Light. A falta de uma legislação federal para o setor de energia elétrica legou às Câmaras Municipais o poder concedente para os serviços de eletricidade, garantindo que as relações políticas entre vereadores e empresários tivessem decisivo papel na instalação de tais serviços. Assim, o artigo descreve o processo de introdução da eletricidade em São Paulo mediante os debates sobre a regulamentação dos serviços públicos, desvendando os critérios políticos ou ideológicos que levaram a conformação de tais leis.This paper discusses the introduction of electric power in the city of São Paulo during the beginning of the 20th century. The Brazilian Republic Proclamation (1889) established the beginning of the public services companies' modernization, which through the enterprises fusion and the arrival of foreign capital allowed the electric power introduction in the main Brazilian cities. Two rival groups started a competition in the São Paulo's electric sector: the national enterprise Companhia Brasileira de Energia Elétrica (CBEE) - so called as Docas de Santos - and the Canadian company Light. The inexistence of a federal legislation to electric power services had transformed municipal decisions in deterministic guidelines for utility bids, making municipal lobbying a key instrument in utility concessions. Hence, this paper issues describe the electric power introduction in the city through the debates about the utilities' rules, analyzing the political or ideological criteria that build the São Paulo's laws for electricity sector.

In this paper we will present the differences between the production of electricity using wind turbines and the production of electric power by most other possible ways.Because thermoelectric power plants are the most widely used on a world scale, it will start by comparing the wind turbine with different types of thermal power plants. The wind turbine is the installation that allows the kinetic energy of the wind to be transformed into mechanical or electrical energy. The regenerative kinetic energy of the wind acts on the blades, moving the turbine propeller, turning it into mechanical rotational energy. This is in turn transformed into a further generator into electricity and delivered to the public energy grid.

This paper presents the analysis of possibilities to use municipal waste for energy production. Household waste utilization options are evaluated at the economic, ecological and social criteria. The paper also includes household waste generation projections, and estimation of the possible levels of generated energy. Article in Lithuanian. Buitinių atliekų naudojimo energijai gaminti galimybių analizė Anotacija. Tyrimo tikslas – nustatyti buitinių atliekų naudojimo perspektyvas Lietuvoje, prognozuojant buitinių atliekų susidarymo tempus, surinkimą ir analizuojant jų deginimo galimybes energijai gaminti, vadovaujantis ekonominiais, ekologiniais ir socialiniais kriterijais. Ekonominis vertinimas atliekamas pagal 3 kriterijus: 1) šiukšlių deginimo stoties technologinė kaina, Lt/kW; 2) investicijos, generuojamos energijos vienetui, Lt/MWh; 3) išlaidos dujoms tokiam pačiam kiekiui energijos pagaminti, Lt. Ekologinis įvertinimas atliekamas pagal sudeginto kuro kiekio ir išsiskyrusių teršalų santykį. Socialinis vertinimas atliekamas gyventojų apklausos būdu. Įdiegus Lietuvoje šiukšlių deginimo stotis per 25 metus būtų galima sudeginti 20,63 mln. tonų šiukšlių ir pagaminti 4756 GWh elektros ir 16223 GWh šilumos energijos. Reikšminiai žodžiai: kuras, buitinės atliekos, panaudojimo kriterijai, elektros energija, šiluminė energija, investicijos.

In this paper, method selecting optimal location for large scale photovoltaic (PV) power plant in Imo State is carried out. Ten local government areas (LGAs) in Imo were selected out of the 27 LGAs in the state. Also, five parameters were used for ranking the selected LGAs for their suitability for large scale PV power plant. The five parameters are; (i) Global Irradiation On Horizontal Plane (kWh/m²) (ii) Available Energy (Kwh) (iii) Yearly Unit Cost of Energy (iv) Population (v) Land Mass (Km2). PVSyst software was used for the simulation of the PV energy generator output and unit cost at each of the selected LGA. The meteorological data used for the simulation was obtained from NASA website. Also, population density and land mass of each of the LGAs were obtained from Nigerian Population Commission publication. In all, Umuapu has the highest PV Site Suitability Factor (PVSSF) of 142 while Oguta has the least with 39. Consequently, the optimal site for large scaled PV power plant among the selected LGAs in Imo State is Umuapu. Accordingly, Umuapu has the PV Site Suitability Rank (PVSSR) of one (1) while Oguta has the poorest PVSSR value of 10.

This paper presents the construction of a model to support corporate managers in the energy sector. It is expected that the identification and measurement of parameters involved in decision making in this sector can assist managers in new projects of power generation. Knowledge management and strategic planning originate the resources necessary for correct alignment with the goals and expectations of organizations. It is thus possible to define different scenarios to be presented to managers. Through interviews with consultants and experts in the energy sector it was possible to define and validate a set of indicators which will be used in the proposed model. Hence a questionnaire to a representative sample of managers and others involved in the decision making processes of companies in the electricity power sector is filled in. In addition, contributions from researchers from Information Science, Electrical Engineering and Administration are of prime importance as well and are carried out in this work. The management model proposed is part of an ongoing research on strategic planning and on decision-making to enterprises of power generation from renewable sources1.

The major source of energy comes from fossil fuels. The current situation in the field of fuel and energy is becoming more problematic as world population continues to grow because of the limitation of fossil fuels reserve and its pressure on environment. This review aims to find economic, reliable, renewable and non-polluting energy sources to reduce high energy tariffs in Russian Federation. Biofuel is fuel derived directly from plants, or indirectly from agricultural, commercial, domestic, and/or industrial wastes. Other alternative energy sources including solar energy and electric power generation are also discussed. Over 100 Mt of biomass available for energy purposes is produced every year in Russian. One of the downsides of biomass energy is its potential threatens to food security and forage industries. An innovative approach proved that multicomponent fuel (80% diesel oil content for motor and 64% for in stove fuel) can remarkably reduce the costs. This paper proposed that the most promising energy model for future is based on direct solar energy conversion and transcontinental terawatt power transmission with the use of resonant wave-guide technology.

The economy of Ghana has attained a middle-income status and is seeking to advance; hence, an analysis of the economy based on the supply chain management of energy is significant to provide the quantitative results and comprehensive information about how and where the energy use affects economic growth and development. This information is necessary to enable the government to respond promptly with measures that will improve the supply of energy to ensure the profitability and competitiveness of firms. The objective of this paper is to analyse the effect of electric power fluctuations on the profitability and competitiveness of SMEs, using SMEs operating within the Accra business district of Ghana as a case study. This research is a crosssectional survey and it adopted a mixed method approach. A sample of 70 Ghanaian SMEs was selected using a systematic sampling approach. Inclusion criterion for the selection of the SMEs was their location within the business district of Accra as well as their use of electricity in their main business operation. Data was collected with an interviewer-administered structured questionnaire which focused on the effect of power fluctuation on the operations of SMEs, especially on the profitability and its resulting effect on the firms’ competitiveness. The SPSS statistical package was used to group and analyse the data. The study is a single-factor analysis of the exogenous problems facing the Small and Medium Enterprise sector. The study found that without reliable energy supply, SMEs are unable to produce in increased quantities and quality leading to poor sales hence low levels of profitability. It is established that low profitability negatively affects Return on Assets (ROA) and Return on Investment (ROI) of SMEs. Consequently, if the level of profitability is high, it is expected that ROA and ROI will be high and vice versa. With high profits, SMEs are able to increase their competitiveness.

In this paper, we integrate technological, institutional, and financial approaches towards expansion of the smart grid technology. We turn to China as the major producer and consumer of energy with an increasing focus on renewables. China’s electricity market has experienced a number of reforms while trying to address the economic and environmental challenges. In order to identify the basic requirements for the Chinese power sector, we look into the underlying trends of the energy mix, regulatory policies, and financial flows. Understanding these facets allows one to suggest directions for the further development of the Chinese power sector in the light of the smart grid concept. Indeed, the smart grid concept has no strict definition and, therefore, requires simultaneous consideration of multiple factors. The analysis shows that ensuring smooth transfer of electricity across the regions is a quintessential condition for smart grid development and the promotion of renewable energy in China. As the role of the state-owned enterprises still remains the most important one in the sector, private initiatives should be supported. Therefore, financial incentives are needed to guide the shifts in the energy mix and maintain efficient energy generation and consumption in China.

PE Elektroprivreda Srbije (Electric Power Industry of Serbia - PE EPS) is of a strategic importance for national economy. Long-term policy of depressed electricity price has caused a number of distortions, mainly through direct impact on the operations of EPS and a number of other effects such as irrational consumption, high energy intensity, low charges, high level of technical and commercial losses, etc. Serbia still has the lowest electricity price in Europe, but regulated price model provides a certain profit level for EPS. The aim of this paper is to show the potential that the electric power industry as a branch can have if the Government provides the conditions for its sustainable operation.

PE Elektroprivreda Srbije (Electric Power Industry of Serbia - PE EPS) is of a strategic importance for national economy. Long-term policy of depressed electricity price has caused a number of distortions, mainly through direct impact on the operations of EPS and a number of other effects such as irrational consumption, high energy intensity, low charges, high level of technical and commercial losses, etc. Serbia still has the lowest electricity price in Europe, but regulated price model provides a certain profit level for EPS. The aim of this paper is to show the potential that the electric power industry as a branch can have if the Government provides the conditions for its sustainable operation.

The intermediate load electric power stations become more and more interesting for theelectric power market in Romania. In this context, the Combined Cycle Power Plants came as a veryattractive solution. This paper presents the results of a study regarding the use of the aeroderivativePratt & Whitney FT8-3 gas turbine, available in Romania, for the electric power generation in aCombined Cycle Power Plant. It is also analyzed the Combined Heat in Power generation with FT8-3gas turbine when saturated steam or hot water are required.

Water in some form plays a critical role in geothermal projects, given current technology. This paper explores inconsistencies in treatment of water and geothermal resources at the federal and state levels, and discusses legal and practical issues the developer should consider, relating to use of water, geothermal resources, and alternative sources of water supply. The developer is urged to incorporate water resource planning into project planning beginning at the project feasibility stage, and to seek creative solutions, possibly in cooperation with key stakeholders in the project area, to secure needed fluid resources.

It is known that mechanical work, and in turn electricity, can be produced from a difference in the chemical potential that may result from a salinity gradient. Such a gradient may be found, for instance, in an estuary where a stream of soft water is flooding into a sink of salty water which we may find in an ocean, gulf or salt lake. Various technological approaches are proposed for the production of energy from a salinity gradient between a stream of soft water and a source of salty water. Before considering the implementation of a typical technology, it is of utmost importance to be able to compare various technological approaches, on the same basis, using the appropriate variables and mathematical formulations. In this context, exergy balance can become a very useful tool for an easy and quick evaluation of the maximum thermodynamic work that can be produced from energy systems. In this short paper, we briefly introduce the use of exergy for enabling us to easily and quickly assess the theoretical maximum power or ideal reversible work we may expect from typical salinity gradient energy systems.

The methods of determination of electric energy consumption norms that can be used for forecasting the own needs of DC traction substations are offered in the paper.

En un contexto de fuerte crisis económica y medioambiental, la Biblioteca Rector Gabriel Ferraté (BRGF), de la Universitat Politècnica de Catalunya (UPC), ha conseguido un ahorro en energía eléctrica superior al 33 % a pesar de producirse en un momento en el que la biblioteca ha ampliado significativamente sus prestaciones. Detallar las acciones del plan interno que ha determinado este ahorro es el objetivo principal de este artículo, pero además también se pretende dar a conocer las colaboraciones y gastos que han sido necesarios para ello, cuáles han sido las limitaciones impuestas a tales acciones o cual es el futuro esperado en este campo en la BRGF y en las bibliotecas de la UPC. Todo esto, con la voluntad de poner de manifiesto la importancia de un tema tan inédito en la bibliografía dedicada a las bibliotecas y, sobre todo, con el ánimo de que alguna(s) de estas acciones puedan ser útiles y aplicables a otras bibliotecas tanto universitarias como de cualquier otro ámbito.In a context characterized by a huge economic and environmental crisis, the Rector Gabriel Ferraté Library (BRGF) at the Polytechnic University of Catalonia (UPC) has managed to save more than 33% in electricity, in spite of having expanded its services significantly . The main aim of this paper is to review the action taken under the internal plan that has achieved this saving, while also to inform about the collaborations and expenses required, the difficulties met, or the prospects for the future in this area in the BRGF and UPC libraries. We stress the importance of this topic – currently ignored in the literature on libraries – and, especially, in the hope that some of the measures taken may be useful and applicable in other libraries, both in universities and elsewhere.

En un context de forta crisi econòmica i mediambiental, la Biblioteca Rector Gabriel Ferraté (BRGF), de la Universitat Politècnica de Catalunya (UPC), ha aconseguit un estalvi en energia elèctrica superior al 33 % malgrat produir-se en un moment en què la biblioteca ha ampliat significativament les seves prestacions. Detallar les accions del pla intern que ha determinat aquest estalvi és l'objectiu principal d'aquest article, però a més també es pretén donar a conèixer quines col.laboracions i despeses han calgut, quines han estat les limitacions imposades a les accions o quin és el futur esperat en aquest camp a la BRGF i a les biblioteques de la UPC. Tot això, amb la voluntat de posar de manifest la importància d'un tema tan inèdit en la bibliografia dedicada a les biblioteques i, sobretot, amb l'ànim que alguna(es) d'aquestes accions puguin ser útils i aplicables a altres biblioteques tant universitàries com de qualsevol altre àmbit.n a context characterized by a huge economic and environmental crisis, the Rector Gabriel Ferraté Library (BRGF) at the Polytechnic University of Catalonia (UPC) has managed to save more than 33% in electricity, in spite of having expanded its services significantly . The main aim of this paper is to review the action taken under the internal plan that has achieved this saving, while also to inform about the collaborations and expenses required, the difficulties met, or the prospects for the future in this area in the BRGF and UPC libraries. We stress the importance of this topic – currently ignored in the literature on libraries – and, especially, in the hope that some of the measures taken may be useful and applicable in other libraries, both in universities and elsewhere.

The resort of low potential energy for buildings heating and preparation of domestic hot water (DHW) are discussed in this paper. Real heat pump system, which was designed and mounted for individual house heating and DHW preparation, was analyzed. The purpose of this research was to explore the seasonal factor of performance for heat pump. Manufacturer and salespeople claim that the coefficient of performance (COP) for their offered equipment is 4.5 or even higher. They also calculate the energy transformation through the entire season referring to it. Actually, it is likely that the COP cannot be used when calculating the seasonal energy transformation in reality. Electricity that is seasonally consumed and the heat that is produced in all the period should be analyzed in this context. The results of this exploration show that the real seasonal factor of performance is 3.02. With reference to experience of financial support for that type of heating systems in various European countries, there is a great necessity to create similar support schemes in Lithuania. The methodology of assessing the seasonal heat pump’s factors for performance also should be prepared in Lithuania. Article in Lithuanian. Realus šilumos siurblio sezoninis energijos transformacijos koeficientas Anotacija. Žemo potencialo energijos (žemės, vandens, oro) naudojimas pastatams šildyti ir karštam vandeniui ruošti – labai aktualus šių dienų klausimas. Tyrimo objektu pasirinktas individualus gyvenamasis namas Kauno rajone. Pastatas yra vieno aukšto,140 m2 šildomo ploto, 180 m2 bendro ploto. Tyrimas buvo atliekamas tiesioginio matavimo metodu, naudojant apskaitos prietaisus. Pastatui šildyti ir karštam vandeniui ruošti suprojektuotas ir įrengtas dirva/vanduo tipo šilumos siurblys, kurio deklaruojama šiluminė galia, esant grindų šildymo sistemai (veikiančiai 35/25 °C režimu), yra 11 kW, elektrinė galia – 2,45 kW. Tiriamojo objekto šilumos siurblio realus sezoninis (20 mėnesių) transformacijos koeficientas (SPF) yra 3,02, o pagaminta 1 kWh šiluminės energijos kainuoja 10,6 ct (vertinant pagal 2009 m. dviejų laiko zonų tarifą ir elektrinių viryklių elektros energijos kainas). Reikšminiai žodžiai: šilumos siurblys, šiluminė energija, elektros energija, transformacijos koeficientas.