Electricity Generation Structure Research Articles

China's nuclear power in the context of decarbonization of the global energy industry

The global structure of energy resource consumption is analyzed. It is shown that the total consumption of energy resources in the 20th century increased almost 15 times and amounted to about 118 PWh in 2000. Of these, more than 80% were fossil (natural) energy carriers, 13 % were renewable energy sources and more than 6 % were nuclear power. This trend has continued for many years. Renewable energy sources and nuclear power are projected to dominate the growth of global energy consumption, meeting on average more than 90 % of the additional demand. China ranks first in the world in terms of GDP and the rate of development of the electric power complex, as well as in terms of production volume and the rate of development of nuclear power. The structure of electricity generation by fuel type in countries (TOP 5, 2021) with high energy consumption has been analyzed. It is shown that the main players in this market are three countries: China (30 %), USA (13 %) and India (6 %). The volume of electricity production in China is almost three times larger than in the EU countries and almost 7 times larger than in Russia. The structure of nuclear energy and China's achievements in this field are considered. It is shown that in the context of nuclear technologies (creation of fourth-generation reactors, development of technologies close to the full closed cycle of nuclear waste processing) China is already ready to significantly expand the scope of nuclear energy. Special attention is paid to the safety of nuclear facilities operations. The main problem China will face is the absence of an insurmountable barrier between civilian and military use of such technologies. This poses a serious threat to the ecology and life safety of the country. In the long term, nuclear power must also solve the problem of safe, long-term disposal of radioactive waste. It is shown that in the future China needs to re-examine its nuclear program in the context of cooperation with International Nuclear Security Organizations.

Energy transition in Poland and Spain against changes in the EU energy and climate policy

The European Union climate policy and the subsequent energy transition are expected to cause fundamental changes in individual EU countries, their economies, and industrial sectors. Furthermore, in order to achieve them, high financial outlays are essential. The main purpose of the article is to present a comparative analysis of the pace, directions, and main factors of the energy transition in Poland and Spain against the changes in the EU energy and climate policy. In particular, the subject of the study is the changes in the fuel structure of electricity generation (energy mix) and the changes in the concentration of energy generation. The analysis concentrates on Poland and Spain against the background of the group of EU27 countries. The study adopted a long-term perspective (1990–2020). The methodology used taxonomic measures of variability of structures and measures of concentration, as well as measures of descriptive and mathematical statistics. The result of the research proves that the EU common climate and energy policy has explicitly accelerated changes in the energy mix, both in the EU27 and in the studied countries, including those traditionally based on coal. The concentration analysis demonstrated an increase in diversification resulting in a significant increase in the share of renewable and low-carbon sources. The taxonomic analysis additionally proved that there was a parallel process towards making the energy mix of the studied countries more similar to the EU27. The limitation of the research is the adopted triangulation arrangement of the studied structures (EU27, EU15, countries that accessed the EU after 2004), enforced in this pilot research, but possible to expand the field of perception in subsequent research. What serves as a proof of the originality of the study is the fulfilment of research gaps in the long-term study of the degree of changes in the concentration of the energy mix structure of EU countries, and especially the study of the degree of intensity of its similarity. The application value of the study is its use in the energy policies of countries traditionally based on coal for the indication of the taken position, the goals, and ways to achieve them based on the experience of other countries.

БІОЕНЕРГЕТИКА ЯК ФАКТОР НАЦІОНАЛЬНОЇ БЕЗПЕКИ В УМОВАХ ВОЄННОГО СТАНУ

The purpose of the article is to study the current state of the fuel and energy system, its vulnerability to wartime risks, and analysis of the potential of bioenergy in solving the problem of strengthening the national security of Ukraine by recognizing the critical importance of energy security. The relationship between the definitions of "national security" and "energy security" as components of a part and a whole is revealed. The hypothesis about the critical importance of energy security in the national security system is formulated, considering the importance of the energy sphere for all elements of both economic and social segments without exception. The characteristics of the fuel and energy complex were studied as part of a retrospective analysis. The system of factors that increase the parameters of the vulnerability of the national energy system has been decomposed. The structure of electricity generation in Ukraine, which corresponds to the signs of a high level of centralization, is analyzed. Attention is focused on the need to diversify sources of energy in order to strengthen positions in energy security and, therefore, in national energy security. Special attention is paid to bioenergy development as part of implementing the strategic task of building a combined energy supply system. The influence of the latter on national security was studied through the disclosure of factors of direct influence (diversification of the resource base, substitution of imported energy carriers, strengthening of stability in the conditions of wartime challenges due to the production of stable and predictable electricity; the ability to balance the energy system), as well as highlighting positive external effects (reduction of anthropogenic impact on the environment, diversification of agricultural production, increasing the level of socio-economic development of rural areas, development of innovations, creation of new jobs). A list of the main directions of the regulatory influence of the state on the processes of changing the energy balance in the direction of expanding the share of bioenergy as a driver of the development of decentralized generation based on the combination of socio-ecological and economic imperatives of the development of the national economy, which corresponds to the concepts of sustainable development and national security requirements, is given.

Electricity generation and CO2 emissions in China using index decomposition and decoupling approach

Over the past three decades, energy and economic growth have been joined by enormous environmental pollution and growing global concerns. It is necessary to check the factors' effects impacting CO2 emissions and decouple CO2 from economic growth for the biggest emitter China. This study uses the logarithmic mean Divisia index extended by introducing electricity substitution factors (i.e., activity, population, electricity intensity, electricity overall, generation structure, energy efficiency, and fuel emission factor effects) and is then combined with Tapio's decoupling method to analyze the CO2 emission drivers, states and sectorial emissions for the years 1991–2020. The findings show that: (1) population and activity effects are the main driving factors in increasing CO2 emissions by adding trade and electricity generation structure effects. (2) Decoupling states presented the two decoupling states through electricity CO2 emissions and economic growth effects, showing that expansive negative decoupling is dominant. This shows that both factors show an increasing return to scale. (3) Individual factors and sectorial decoupling indexes show long-run variations and relationships between them, which means that industrial structure adjustment will help mitigate CO2 emissions and sustain economic development. Finally, based on empirical findings, the results suggest more ambitious targets for emerging low-carbon technologies that could help the rapid decarbonization of China's electricity sector.

On the Feasibility of Building Mini-Thermal Power Plant Using Local Fuels in the Conditions of the Republic of Belarus. Part 1. State of Use of Local Fuels in Heat Supply Systems

As part of ensuring the country's energy security and pursuing a policy of decarbonization of the economy in the Republic of Belarus, the maximum use of its own fuel and energy resources (FER) is expected. However, the question of choosing the type of heat source in centralized heat supply systems when using local fuels (LF) remains open. The commissioning of the Belarusian Nuclear Power Plant and the relatively high specific cost of electricity generating capacities using local fuels tip the scales to the use of boiler houses as heat sources. However, world experience in the development and application of heating, as the most energy-efficient solution in the field of heat supply, requires a more thorough study of this problem. The paper presents an overview of the use of local fuels in Belarus and a number of European countries with developed centralized heat supply. Based on the analysis of open source data, the paper provides information on the state of use of local fuels in district heating systems of the Republic of Belarus and a number of European countries that have experience in the widespread use of solid biomass and where it constitutes a significant share in the structure of thermal and electrical energy production in relation to other fuel and energy resources. The main aspects of the energy programs of a number of European countries with the largest share of thermal and electrical energy generation using local fuels are presented. It has been revealed that the energy program of Finland is of the greatest interest for Belarus, where the share of nuclear energy in the structure of electrical energy production, just like in the Republic of Belarus, is approaching to 40 % and the energy strategy assumes an increase in the share of thermal power plants using local fuels in the structure of heat and electricity generation.

The Environmental Impact of Changes in the Structure of Electricity Sources in Europe

The limited use of non-renewable energy sources facilitates a reduction in the negative environmental impact of electricity production. The policies of European countries aim to change the structure of electricity sources, focusing particularly on non-renewable sources. The aim of this study was to assess changes in the structure of electricity generation depending on the energy sources used in 34 European countries in the years 1990–2020 in terms of their environmental impact. This study was conducted using cluster analysis: a method applied in multivariate comparative analyses. Such an approach provided a new, broader outlook on changes in the structure of electric energy production in Europe. A total of nine homogeneous groups of countries were distinguished in terms of energy transformation. The ecological scarcity method 2013 was applied to assess the environmental impact of electricity production in the analyzed countries. In the investigated period, the negative environmental impact of electricity production in European countries decreased. The median of the volume of this impact, determined based on the structure of production in 1990, for the analyzed countries was 464 UBP/1 kWh. In the following years, the value of the median dropped to 413 UBP/1 kWh (2000), 322 UBP/1 kWh (2010), and 204 UBP/1 kWh (2020), respectively. The diversification of the countries in this respect also decreased, which resulted in a reduction in the number of clusters from eight in 1990 to two in 2020.

ПРОБЛЕМИ ЕНЕРГОЗАБЕЗПЕЧЕННЯ СУЧАСНОГО ТА МАЙБУТНЬОГО ГРОМАДСЬКОГО ЕЛЕКТРОТРАНСПОРТУ УКРАЇНИ

This article discusses the common issues of energy supply faced by most municipal enterprises of urban electric transport in Ukraine, which have been affected to some extent by military aggression, impacting their primary function of passenger transportation. The energy supply situation in Ukraine is a matter of global concern, making the topic of this article highly relevant. The article analyzes the structure of electricity generation in the unified power system of Ukraine, revealing that the cheapest electricity is produced by nuclear and hydroelectric power plants in the country, while the most expensive, known as "green" electricity, is generated by solar and wind power plants. Additionally, the article presents a diagram illustrating the changes in funding that occurred in 2023 among the ministries and departments of Ukraine compared to the budget of the previous year. An analysis is provided regarding the prospects of increasing funding for the energy sector of Ukraine during this period. Moreover, the article offers recommendations to municipal enterprises and city councils on post-war procurement of energy-efficient rolling stock for the country's public transport enterprises. These recommendations are based on the analysis of energy consumption indicators for various types of electric passenger transport, including traditional and modern hybrid urban electric transport capable of covering a certain portion of the route without being connected to power wires, thanks to battery packs. Such vehicles can be electric buses or trolleybuses with autonomous operation. The ecological aspect of these hybrid electric transport types is also considered. Hybrid electric transport models are expected to replace city transport powered by internal combustion engines. The article also separately examines the project for renewing the rolling stock of electric transport in the city of Kharkiv, which is the authors' hometown, and explores the possibilities for municipal transport enterprises in this city to increase their entrepreneurial activity by providing charging services to other electric vehicles owned by citizens under private ownership rights. The authors have developed a scheme for the development of charging infrastructure for electric cars, electric bicycles, and other similar vehicles.

Social, Economic, and Environmental Effects of Electricity and Heat Generation in Yenisei Siberia: Is there an Alternative to Coal?

The energy sector is one of the most important pollutants in the atmosphere and causes significant emissions of greenhouse gases. In Russia, coal is the main contributor to the fossil fuel consumption of thermal power plants and boilers, thus affecting atmospheric air pollution by releasing particulate matter and nitrogen oxides, which are strongly associated with a negative impact on human health. This problem is especially acute for the resource regions of Yenisei, Siberia, a 2.5+ mln sq km macro-region in the very heart of Russia. In this paper, we analyze the impact of the structure of electricity and heat generation on emissions of pollutants and climate-active gases in Yenisei, Siberia, and give an overview of their social, ecological, and economic effects. More than 75% of electricity in Yenisei, Siberia, is produced by hydroelectric power plants that do not pollute the atmosphere. The rest of the electricity is generated in the cogeneration mode by thermal power plants, which are cores of the heat supply designs of cities. The share of individual coal-powered heat sources is still high. A detailed analysis of existing equipment and technologies at existing thermal power plants is needed to select options for their modernization to reduce emissions while keeping coal in use. Our calculations for the biggest cities of Krasnoyarsk Krai show that investments in the transition to heating with pellets will require RUB 184.7 million for Nazarovo and RUB 313.9 million for Kansk. At the same time, switching to electric heating is more than twice as expensive: RUB 498.6 million for Nazarovo and RUB 847.5 million for Kansk. The additional costs will range from RUB 21 to RUB 45.4 thousand per household per year for the pellet variant and from RUB 56.8 to RUB 122.5 thousand per year for electric heating, which could triple the annual heating costs. Thus, these options are unlikely to be implemented without direct state support. We argue that creating an attractive living environment in Yenisei, Siberia, must begin with intensive public investment in mitigating the environmental externalities caused by coal emissions.

Analysis of Pakistan's electricity generation and CO2 emissions: Based on decomposition and decoupling approach

Electricity consumption plays an imperative role in the rising economy and carbon dioxide equivalent (CO 2eq ) emissions in Pakistan. This study employs the decomposition and decoupling methods in driving factors of CO 2es from electricity generation for the years 1990–2019. The study investigates the key driving factors in three ways: first, the study measures the CO 2eq emission from the electricity sector using the logarithmic mean Divisia index (LMDI) between population, activity, electricity intensity, total electricity, electricity generation structure, energy efficiency, and fuel emission factor effect. Second, Tapio's decoupling index method is employed to analyze the association between electricity CO 2eq emission and economic growth over the study period. Third, decoupling indexes of each factor are analyzed for future policies and sustainable growth. The results show that (1) the activity effect and the population is the key driving factors in rising CO 2eq emission by the contribution of trade and generation structure effect. (2) The decoupling states showed the five decoupling states using the effects of electricity CO 2eq emission and economy, presenting weak decoupling in the current period. (3) Each factor's decoupling states presents the long-run instability and relationship among them. Consequently, fossil fuel consumption in Pakistan should concentrate on promoting energy-conserving technology and industrial structure adjustment.

Inter-Provincial Electricity Trading and Its Effects on Carbon Emissions from the Power Industry

Electricity trading is an effective measure to minimize carbon emissions and alleviate the imbalance between reverse distribution of regional energy resources and power load. However, the effects of China’s electricity trading on carbon emissions have not been fully explored due to lack of complete and balanced inter-provincial power transmission data. Therefore, the electricity generation–consumption downscaling model, logarithmic mean Divisia index (LMDI) model, and random forest clustering algorithm within a general framework were used in the present study to explore the effect of electricity trading on level of carbon emissions. Comprehensive inter-provincial electricity transmission data were generated, driving factors including electricity imports and exports were decomposed at the national and provincial scales, and clustered provincial policy implications were evaluated. The results revealed that: (i) although economic activities were the main driving factor for increase in carbon emissions at the national level, 382.95 million tons carbon emissions were offset from 2005 to 2019 due to inter-provincial electricity importation, whereas electricity export increased carbon emission by 230.30 million tons; (ii) analysis at the provincial level showed that electricity exports from Sichuan and Yunnan provinces accounted for more than 20% of the nation’s total electricity flow. Notably, this high level of exports did not significantly increase carbon emissions in these provinces owing to the abundant hydropower resources; (iii) emission reductions were only observed at the national level if the carbon intensity of the exporting provinces was lower compared with that of importing provinces, or if the electricity trading was generated from renewable sources; (iv) the effect of electricity import on emissions reduction was markedly higher relative to the effect of electricity export in most provinces, which reflected the actual situation of sustaining optimization of electricity generation structure in provincial grids of China. These findings provide a basis for decision makers to understand the contributions of electricity trading to the changes in carbon emissions from electricity generation, as well as form a foundation to explore practicable carbon emission mitigation strategies in the power industry.

Сountry’s energy policy in context of the world economy’s ecologization

Acceleration of economic processes in the world necessitates a rapid response to change, which when considering the transition to greening the economy should be reflected in the country’s energy policy. The object of research in this article is the fuel and energy sector of the world, and the subject of research - energy policy. The purpose of the scientific article is to assess the development trends of the fuel and energy complex of Ukraine in modern conditions and identify key trends in its development; determination of the main directions of energy policy and diplomacy of the country in the conditions of world economy’s greening. Research methods used: method of analysis, synthesis, systematization, comparison, abstract-logical method, statistical methods of research of economic processes. The main results were: determination of fuel reserves of Ukraine and its natural resource potential; analysis of final energy consumption and identification of trends in the level of energy intensity of GDP; assessment of the electricity generation structure in Ukraine and changes in the share of renewable energy sources; establishing ways to encourage greening of industry and prospects for implementing an environmental approach; determining the directions of energy policy and diplomacy of Ukraine in the context of the world economy’s greening. Thus, in modern business conditions, an important condition for the effective functioning of any economic system has become flexibility and the ability to quickly adapt to market conditions. Therefore, the development of an extensive system of tasks of the state’s energy strategy with those developed in accordance with the realities of a particular management system is the key to successful energy policy. And establishing cooperation in the energy sector will allow us to adopt the experience of developed countries and integrate into the European and global energy community. The ecological vector of energy systems development has been an integral trend for many years and will soon become a constant for the effective development of the country. Therefore, the implementation of preventive measures to green economy is an urgent issue of Ukraine's energy policy.

Techno-economic analysis of a nuclear-wind hybrid system with hydrogen storage

Climate change and increasing electricity demand have changed the electricity generation structure to include more renewable energy. To keep the global temperature increment within 2 °C, the fraction of renewable energy in the energy mix will continuously increase. High penetration of wind and solar energy challenges the electricity grid as they are not dispatchable. Hybrid energy systems with energy storage have the opportunity to meet the challenge due to their stability and flexibility in energy dispatching. However, their performances and economics remain questionable and quantitative analyzes are needed. In this work, Hybrid Nuclear-Renewable Tool (HyNuRT) code is developed to analyze the technical and economic performance of a hybrid nuclear-wind system with hydrogen storage. In the code, technical models of wind turbines, nuclear units, and hydrogen production and storage units are developed and coupled to economical evaluation models. The economic model considered features of a small modular reactor which is more suitable to couple with renewable energy due to its lower power output and modular fabrication. The novelty of this method is to estimate system performance of typical months of the year with stochastic real-time data and predict system economic value including the construction phase. This method is computational time-saving and makes optimization possible in a relatively short time. The work analyzed the techno-economic performances of conservative and balanced cases to evaluate their performances and economic values by real grid demand data. Results show balanced case can increase the internal return rate by 2.1% with missing only limited peak demand. Comparison of hybrid nuclear-wind systems with and without hydrogen storage show that with assumptions in this work, hydrogen storage shows its advantage on both to meet the grid demand and increase the economic return by 1% while not strongly impacting the cash flow. The results show hybrid system with hydrogen storage can enhance both the system performance and the economic value under proper configuration.

Modelling Long-Term Transition from Coal-Reliant to Low-Emission Power Grid and District Heating Systems in Poland

Energy systems require technological changes towards climate neutrality. In Poland, where the power system is dominated by outdated coal-fired power plants, efforts to minimize the environmental impact are associated with high costs. Therefore, optimal paths for the development of the energy sector should be sought in order to achieve ambitious long-term strategic goals, while minimizing the negative impact on the consumers’ home budget. A methodology and a model for the development of the electricity and heat generation structure were developed and implemented in market allocation (MARKAL) modelling framework. Two scenarios were presented, i.e., business as usual (BAU) and withdrawal from coal (WFC) scenarios. The calculations showed a significant role of nuclear energy and offshore wind power in the pursuit of climate neutrality of electricity generation. In the BAU scenario, the model proposes to stay with coal technologies using carbon capture and storage systems. Withdrawal from coal (WFC scenario) makes it necessary to replace them by gas-fired power plants with CO2 sequestration. Solar energy can be used both in electricity and district heating. In order to build on the latter technological option, appropriate energy storage techniques must be developed. Geothermal energy is expected to be the key option for district heat generation in the long-term horizon. The proposed development paths guarantee a significant reduction in greenhouse gases and industrial emissions. However, complete climate neutrality is uncertain, given the current degree and dynamics of technological development.

Electricity Markets Instability: Causes of Price Dispersion

The creation of a single competitive EU energy market is aimed at establishing a fair price in the integrated market space. However, electricity markets in European countries remain rather fragmented, and the marginal pricing method, which is the basic one used in the market, conditions a persistent price dispersion in the search for market equilibrium. This study examines the dispersion of electricity prices in 40 bidding zones in 26 European countries by means of quartile analysis. The geographic orientation of the markets, direction of electricity flows, and structure of electricity generation are considered as the causes of this dispersion. In the study, the geographical boundaries of the electricity markets are determined using the methods of correlation analysis of prices and transitive closure of commercial electricity flows. This makes it possible to single out highly integrated, moderately integrated, poorly integrated, and non-integrated markets. Using cluster analysis, electricity markets are classified according to the structure of electricity generation and direction of flows, with the identification of five clusters based on the dominant type of generation and three clusters based on the dominant direction of electricity supply. For each factor under investigation, the intragroup price dispersion is established. The results of the study have allowed to build a three-dimensional matrix that provides for determining the directions of changes in electricity prices when moving between its quadrants.

Future CO2 emission trends and radical decarbonization path of iron and steel industry in China

China has set new ambitious national determined contributions (NDC) target to reach the peak of CO2 emissions by 2030, and strive to achieve carbon neutrality by 2060. This urges radical efforts for all industries to neutralize or zeroize their CO2 emission, especially for the iron and steel industry. Here, we establish a comprehensive model to explore the potential CO2 emission pathways of China's iron and steel industry based on NDC and climate target in line with the Paris Agreement. Four scenarios are constructed: business as usual (BAU), NDC, 2-degree, and 1.5-degree. We predict the total CO2 emission from 2015 to 2050 will fall from 1690.82 Mt to 1475.75 Mt, 1249.39 Mt, 484.77 Mt, and 252.13 Mt under those four scenarios, respectively. To achieve 2-degree and 1.5-degree targets, iron and steel industry requires radical decarbonization. To explore the key factors behind the carbon neutrality of steel production, we apply Logarithmic Mean Divisia Index (LMDI) for the 1.5-degree scenario and find that steel production, breakthrough technologies and production structure will become the important factors. To effectively evaluate the CO2 emissions of steel production, we have set up a CO2 emission evaluation indicator system including comprehensive CO2 emission indicator, crude steel CO2 emission indicator, and section CO2 emission indicator. CSC model shows that low discount rates and high carbon prices will make low-carbon technologies cost-beneficial. Accordingly, we further discuss the potential barriers and strategies related to hydrogen steelmaking, carbon capture and storage (CCS), and electricity generation structure revolution to the iron and steel industry.

Generation Structure, Prices, and Tariffs in the Russian Electric Power Industry in 2009-2018

The paper aims to summarize and analyze the statistical data on the generation structure and price behavior in the Russian electric power industry and, based on the analysis, make a statistical contribution to the discussion on the outcomes of the electricity reform in Russia. A brief review of this topic is provided. The study states that the electric power industry should be regarded as a combination of four sub-industries when regulation, market design, and industrial organization problems are discussed. These four sub-industries are generation, transmission, distribution, and sales because of different regulations applied to these businesses. The main trends in the retail price index and some other indexes in the four sub-industries are observed from 2009 to 2018. The trends in electricity consumption and generation structure are discussed as essential components of economic processes in the industry. The findings suggest that the four sub-industries make different contributions to the overall growth of the electricity supply costs for end consumers. Most growth was determined by regulated government-granted monopolies in network businesses (transmission and distribution companies). The sales business is represented in the research by suppliers of last resort.

TARIFFS IN ENERGY: CURRENT FACTORS AND THE CONCEPT OF CHANGE

Factors acting on tariffs are characterized including the state of utilization of existing natural energy resources, the structure of electricity generation, energy efficiency, energy balance, the role of society in energy development and globalization. It has been concluded that in Georgia, as well as in the world, there is a tendency to increase tariffs. This is due to the need for increased and continuous investment in the extraction (production) of increasing amounts of energy resources, the t ightening of environmental requirements, and so on. According to the author, in order to improve the technical and economic indicators in the field and reduce tariffs, it is necessary to introduce scientific-technological and managerial progress at a higher rate compared to the existing challenges

Synergetic management of energy-water nexus system under uncertainty: An interval bi-level joint-probabilistic programming method

Synergic management of energy-water nexus (EWN) system is essential for coping with the dilemma of joint shortage of energy and water and supporting socio-economic sustainable development. The system is full of multiple uncertainties, making deterministic analysis methods infeasible. In this study, an interval bi-level joint-probabilistic programming (IBJP) approach is first developed through incorporating bi-level programming (BP) and interval joint-probabilistic programming (IJP) within a framework. IBJP has advantages in balancing the tradeoff between two-level decision makers under uncertainty, tackling uncertainties expressed as joint probabilities and interval values, and examining the risk of violating joint-probabilistic constraints. Then, the developed method is applied to planning China’s EWN system over a long-term planning horizon (2021–2050). Multiple scenarios related to different groups of constraint-violation levels for violating electricity demand and/or water availability constraints are examined. Results reveal that uncertainties associated with joint and individual probabilities have effects on the synergic management of EWN system. Results also disclose that limited water resource can promote electricity generation structure toward a low water-intensity, clean and sustainable pattern, in which the share of clean energy would increase to 66.25% by 2050 and the corresponding water withdrawal would save 41.20%.

Effects of carbon-nitrogen ratio on electricity generation, pollutant removal and microbial community structure of single-chamber MFCs in high salinity wastewater

In this study, five sets of single-chambered air cathode microbial fuel cells (MFC) were constructed. The effect of the carbon-nitrogen ratio on electricity generation and pollutant removal was discussed and the dominant strains in electrode biofilms were analyzed by high-throughput sequencing. The results showed that in terms of electricity generation performance, the increase of the carbon-nitrogen ratio was beneficial to the energy output at the carbon-nitrogen ratio of 3∶1, 4∶1, 5∶1, 6∶1 and 7∶1. When the carbon-nitrogen ratio was 7∶1, the open circuit voltage, internal resistance and maximum power density were 765 mV, 78.4 Ω and 7.33 W·m−3, respectively. Single-chamber MFCs could achieve simultaneous nitrification and denitrification, and the best removal effect of pollutants occurred at the carbon-nitrogen ratio of 4∶1, the corresponding removal rates of COD, ${\rm{NH}}_4^ + $ -N and TN were (86.17± 2.4)%, (96.98±1.8)% and (96.64±1.8)%, respectively. Microbial sequencing results showed that Thauera was the core genus of single-chamber MFC. With the increase of carbon- nitrogen ratio, the abundances of heterotrophic nitrification microorganisms in the cathode biofilms were 35.72%, 46.90%, 40.17%, 35.63% and 21.38 % in turns. The abundances of aerobic denitrifying bacteria were 35.72%, 52.60%, 49.59%, 45.08% and 21.38%, respectively. It is speculated that the heterotrophic nitrification-aerobic denitrification was the main pathway for nitrogen removal.

The assessment of the Bostanliq district (Uzbekistan Republic) based on the wind energy potential

The idea of achieving energy security and lowering the dependence on the global hydrocarbon market is at the top of the agenda in many countries. Most of them consider switching from traditional energy sources to renewable ones as one of the ways to reduce fuel import. This concept absolutely conforms to one of the UN Sustainable Development Goals (Goal no. 7, “Affordable and Clean Energy”). In May 2019, the Government of Uzbekistan Republic adopted the law on the Use of Renewable Energy Sources (RES). By 2030, Uzbekistan is going to increase the share of RES in the total structure of electricity generation up to 25 % (currently it is at 10 %), by building solar and wind farms with a total installed capacity of 5,000 MW and 3,000 MW, respectively. The energy-deficient Bostanliq district of the Tashkent region has become one of the places of interest, where transport infrastructure, recreation services, and renewable energy will be developed. The purpose of this study was a multivariate analysis, considering the meteorological, ecological, and socio-economic characteristics of the Bostanliq district, leading to the selection of the optimal location for the wind farm. The assessment map based on the results of this analysis made it possible to identify areas that are most suitable for the location of wind power plants. The assessment method, that was used in this work, is also applicable to other regions of the world.