Share Of Electricity Generation Research Articles

New Functions of VSC Based HVDC Transmission Systems that Can Effectively Support the Future South-East European Grid with Low Inertia and Large Amount of Res Generation

Abstract The energy mix in South-East Europe is nowadays mainly composed by hydro and fossil fuels generation almost equally distributed in the share of electricity generation. Wind and solar PV generation play a very marginal role playing cumulatively less than 7% of the total generation, while fossil fuels exceed 52% of the total generation. A Multi-Terminal HVDC grid between the different countries in South-East Europe may provide various operational and socio-economic gains. In this paper are presented some grid specific challenges and explored some new functions of HVDC transmission systems based on VSC technology that can effectively support the grid with large amount of RES. The paper aims to explore how the VSC converters can improve the system’s voltage stability and provide the necessary frequency control when the inertia in the grid is very low and how the HVDC transmission system can accomplish transferring the primary and secondary reserves solving the rising problems related to dispatchability and inertia response in RES based power grids.

Assessing Economic Complementarity in Wind–Solar Hybrid Power Plants Connected to the Brazilian Grid

The share of electricity generation from Variable Renewable Energy Sources (VRES) has increased over the last 20 years. Despite promoting the decarbonization of the energy mix, these sources bring negative characteristics to the energy mix, such as power ramps, load mismatch, unpredictability, and fluctuation. One of the ways to mitigate these characteristics is the hybridization of power plants. This paper evaluates the benefits of hybridizing a plant using an AI-based methodology for optimizing the wind–solar ratio based on the Brazilian regulatory system. For this study, the hybrid plant was modeled using data collected over a period of 10 months. The measurements were obtained using two wind profilers (LIDAR and SODAR) and a sun tracker (Solys 2) as part of the EOSOLAR R&D project conducted in the state of Maranhão, Brazil. After the power plant modeling, a Genetic Algorithm (GA) was used to determine the optimal wind–solar ratio, considering costs with transmission systems. The algorithm achieved a monthly profit increase of more than 39% with an energy curtailment inferior to 1%, which indicates economic complementarity. Later, the same methodology was also applied to verify the wind–solar ratio’s sensitivity to solar energy pricing. The results show that a price increase of 15% would change the power plant’s optimal configuration.

Fast frequency response services in low inertia power systems—A review

To fight global warming, the share of electricity generation from renewable sources is increasing in the energy mix. The replacement of conventional generation plants with inverter-based generation sources has led to a reduction in the system inertia and also change the nature of the frequency control in power systems. Thus, many system operators have introduced new techniques to enhance the system frequency stability such as the Fast Frequency Response (FFR) services. This paper reviews the state-of-the-art of most common tools proposed in the literature for participation in the FFR services as well as the challenges that are still facing each FFR tool. Furthermore, some of the control strategies proposed in the literature for each FFR tool have also been discussed and compared. Finally, some recommendations related to the adoption of FFR services in future power systems have been provided.

The development options of nuclear power under carbon dioxide emissions constraints

The aim of the work is forecasting the development of nuclear power in Russia and the world for the period up to 2050 under various scenarios of constraints on carbon dioxide emissions. A brief comparative analysis of the main characteristics of the forecasts of the International Energy Agency (IEA) and the International Renewable Energy Agency (IRENA) has been carried out. Additionally, calculations were performed using the mathematical models of the world energy system GEM and GEM-Dyn developed at the ISEM SB RAS. The optimal ratio of nuclear and non-nuclear energy sources has been determined. It is shown that nuclear power, including nuclear power plants operating on a closed fuel cycle, along with renewable energy sources, is an effective technology that can solve the problem of reducing carbon dioxide emissions. Calculations have shown that in the sustainable development scenario, the capacity of nuclear power plants in Russia in the period from 2020 to 2050 can increase by 2.7 times, and their share in electricity generation can reach 21–25% in 2030 and 26–35% in 2050. The average annual growth rate (for 30 years) of the installed capacity of nuclear power plants in Russia in the sustainable development scenario is 3.1% compared to 2.7% for the world as a whole. In the GEM and GEM-Dyn calculations performed by the authors, the scale of nuclear energy use turned out to be about 30% higher than in the scenarios of the International Energy Agency due to more conservative estimates of the opportunities for improving the performance of renewable energy sources and taking into account the need to back-up their capacity.

Prospects for the application of a small wind power device with a vertical axis in the Jizzakh region

In recent years, renewable energy sources, especially wind energy, have been widely used around the world. Big projects are being implemented in Uzbekistan for the development of wind energy in the next decade. Large wind power plants are being built in different regions of the country such as Navoi, Bukhara, and Karakalpakstan. In these wind power plants, horizontal type wind energy devices are mainly used for the production of electricity. Horizontal-axis wind energy devices are used not only in the production of large capacities, but also in providing local consumers with small capacities. However, the share of electricity generation or supply of local consumers with the help of small vertical axis wind energy devices is much smaller. In this article, analyzing the potential of wind energy in Jizzakh region, the prospects of using small vertical wind energy devices are theoretically researched.

RESEARCH OF BROWN COAL BURNING PROCESSES IN THE VORTEX FIREPLACE BY COMPUTER MODELING

As part of the course for European integration in Ukraine, a new Energy Strategywas approved to reduce the share of coal among primary sources to 12.5 % by 2035, the share ofelectricity generation at TPPs and CHPs to 3 2%. In 2021, Ukraine joined the EU's Green Dealstrategy with a commitment to completely stop coal production and close coal energy and close coalenergy by 2050.At the same time, coal energy has advantages - significant reserves of domestic coal (first inEurope and eighth in the world), which make it a guarantor of energy independence.Given the growing share of "green" generation in Ukraine, the share of pulverized coalproduction should be kept at least 30% of total energy productionThe use of expensive imported natural gas in Ukraine's fuel balance stimulates the developmentof industrial and small energy based on cheap local fuels and combustible waste. The use of cheapcoal, peat, wood waste can reduce the cost of heat production in housing and communal services,industrial enterprises.Combustion of low-grade fuels is constrained due to the complexity of organizing a sustainablecombustion process.Local fuels are characterized by high humidity and ash content, low heat of combustion. Thezone of autogenous (self-sustaining) combustion is defined by the limits: combustible - more than25 %, moisture - less than 50 %, ash - less than 60% by working weight.Vegetation and wood are the starting point for the stages of metamorphism (carbonization):plant residues, peat, brown coal, coal, anthracite. Characteristics of humolites, the organic part of the fuel, by stages of metamorphism. Fuels ofdifferent types and different degrees of carbonization - peat, lignite is peroxidized and contain a lotof oxygen in the combustible mass, have the lowest thermal stability and the highest yield of volatilesubstances.In the process of metamorphism, oxygen is removed and the thermal stability of the organicmatter of the fuel is increased.

Impact of COVID-19 Response Measures on Electricity Sector in Jordan

With the wide spread of new variants of coronavirus that cause the infectious disease COVID-19, governments around the world typically respond by imposing restrictions on people’s activities that range from partial to full lockdowns. This has severe implications on all economic activities, which is manifested by the changes in energy demand. In this study, the impact of COVID-19 on the electricity sector in Jordan is analysed through quantifying the strictness of the government response measures to contain the spread of the pandemic, as calculated by the stringency index, with the electricity demand by the different sectors. Results showed that the minimum peak load in 2020 decreased by 13% as compared to that of 2019. The most affected sectors were the domestic sector, whose share in consumption increased by 8%, and the commercial and hotel sector, whose share decreased by 19%. The concept of an energy-weighted stringency index was introduced to account for the impact of government response measures on the different sectors. The analysis was applied for all Jordan as well as for the three electricity distribution regions. Results also showed that despite measures taken to contain spread of the pandemic, the share of electricity generation by renewables increased from 15% in 2019 to 24% in 2020.

Technical and economic analysis of biogas and solar photovoltaic (PV) hybrid renewable energy system for dairy cattle barns

Novel to this study, modular hybrid renewable energy systems comprising of biogas and solar photovoltaic (PV) are designed for various dairy cattle barns located in Konya, Erzurum and İzmir provinces of Turkey. It is estimated that the grid-connected system including PV and biomass are more feasible than the stand-alone biomass system in terms of net present cost, return on investment, cost of energy and annual worth. Thirteen independent variables are used to predict the contribution of electricity generation from the modular hybrid renewable energy systems to Turkey's gross domestic product. Optimum annual worth of different cattle barns is chosen as an independent econometric variable. Linear, ridge, lasso and elastic net regression models are generated. Among these regression models, ridge regression gives the highest coefficient of determination as 0.92, and the lowest root mean squared error value of 0.463 (million $). The lowest net present cost values of grid-connected barn systems with five different cattle capacities are found as $36942, $54219, $270119, $721516 and $3097716, respectively. It is found that total installed cost of solar energy has the strongest effect on the share of electricity generation in terms of the effect on the gross domestic product, which is calculated as 97%.

How flexible electricity demand stabilizes wind and solar market values: The case of hydrogen electrolyzers

Wind and solar energy are often expected to fall victim to their own success: the higher their share in electricity generation, the more their revenue in electricity markets (their “market value”) declines. While market values may converge to zero in conventional power systems, this study argues that “green” hydrogen production can effectively and permanently halt the decline by adding flexible electricity demand in low-price hours. To support this argument, this article further develops the merit order model and uses price duration curves to include flexible hydrogen electrolysis and to derive an analytical formula for the minimum market value of renewables in the long-term market equilibrium. This hydrogen-induced minimum market value is quantified for a wide range of parameters using Monte Carlo simulations and complemented with results from a more detailed numerical electricity market model. It is shown that—due to flexible hydrogen production alone—market values across Europe will likely stabilize above €19 ± 9 MWh−1 for solar energy and above €27 ± 8MWh−1 for wind energy in 2050 (annual mean estimate ± standard deviation). This is in the range of the projected levelized cost of renewables, and other types of flexible electricity demand may further increase renewable market values. Market-based renewables may hence be within reach.

Forecasting seasonal electricity generation in European countries under Covid-19-induced lockdown using fractional grey prediction models and machine learning methods

Balances in the energy sector have changed since the implementation of the Covid-19 pandemic lockdown in Europe. This paper analyses how the lockdown affected electricity generation in European countries and how it will reshape future energy generation. Monthly electricity generation from total renewables and non-renewables in France, Germany, Spain, Turkey, and the UK from January 2017 to September 2020 were evaluated and compared. Four seasonal grey prediction models and three machine learning methods were used for forecasting; the quarterly results are presented to the end of 2021. Additionally, the share of electricity generation from renewables in total electricity generation from 2017 to 2021 for the selected countries was compared. Electricity generation from total non-renewables in the second quarter of 2020 for France, Germany, Spain, and the UK decreased by 21%–25% compared to the same period of 2019; the decline in Turkey was approximately 11%. Additionally, electricity generation from non-renewables in the third quarter of 2020 for all countries, except Turkey, decreased compared to the same period of the previous year. All grey prediction models and support vector machine method forecast that the share of renewables in total electricity generation will increase continuously in France, Germany, Spain, and the UK to the end of 2021. The forecasting methods provided by this study open new avenues for research on the impact of the Covid-19 pandemic on the future of the energy sector.

Environmental Impact Assessment of Coal Gasification in Hydrogen Production

Increasing industrialization and population demands for higher energy use as electricity. Coal has a broader share in electricity generation but there is problem of GHG emission due to direct coal combustion. Coal gasification is adopted as a cleaner technology in place of traditional method of generating electricity and hydrogen production. This study develops an assessment method to evaluate the pollutant emissions generated from coal gasification process. Life cycle assessment (LCA) is a method used for evaluation of greenhouse gas emission quantity and fossil energy consumption. A system boundary of cradle to production stage is chosen for the study. The result shows that during coal mining and cleaning process CO2 emission has higher contribution compared to CH4and N2O. In this stage, total CO2 emission is 19.976 kg in which diesel alone emits 72.46 % of CO2. During transportation of coal, train transport medium has lower CO2 emission as 5.413 kg while road transportation emits 8.144 kgCO2. Production phase suggests that carbon capture and storage condition is suitable for environmental protection as it reduces CO2, CH4 and N2O emission.

Comparison of Three Different Learning Methods of Multilayer Perceptron Neural Network for Wind Speed Forecasting

In the world, electric power is the highest need for high prosperity and comfortable living standards. The security of energy supply is an essential concept in national energy management. Therefore, ensuring the security of electricity supply requires accurate estimates of electricity demand. The share of electricity generation from renewables is significantly growing in the world. This kind of energy types are dependent on weather conditions as the wind and solar energies. There are two vital requirements to locate and measure specific systems to utilize wind power: modelling and forecasting of the wind velocity. To this end, using only 4 years of measured meteorological data, the present research attempts to estimate the related speed of wind within the Libyan Mediterranean coast with the help of ANN (artificial neural networking) with three different learning algorithms, which are Levenberg-Marquardt, Bayesian Regularization and Scaled Conjugate Gradient. Conclusions reached in this study show that wind speed can be estimated within acceptable limits using a limited set of meteorological data. In the results obtained, it was seen that the SCG algorithm gave better results in tests in this study with less data.

Sustainable renewable energy supply networks optimization – The gradual transition to a renewable energy system within the European Union by 2050

In order to achieve the goal of a carbon neutral EU by 2050 and meet the climate targets of the Paris Agreement, a sustainable, efficient, competitive and secure energy system needs to be developed. This paper presents the synthesis of sustainable renewable energy supply networks within the EU-27, proposing a stepwise energy transition in the transport and power sectors, achieving a carbon net neutral target by 2050. A multi-period mixed-integer programming model is developed, with the objective of maximizing sustainability net present value, considering different biomass and waste resources for the production of biofuels, renewable electricity, hydrogen, food and bioproducts, employing different types of technologies. The results show that, with further development of existing technologies, the goal of a carbon-neutral EU can be achieved without compromising food production. Wind farms have proven to be the most promising solution at present for the rapid expansion of electricity generation from renewable energy sources, while the importance of solar photovoltaics is increasing over the years, reaching the 43% share of electricity generation from RES in 2050. Moreover, the energy transition within the EU could have a significant positive impact on the economic, environmental and also social aspects of sustainability, with more than 1.5 million new job opportunities created across the EU over the next 30 years.

Uncertainty analysis of the future cost of wind energy on climate change mitigation

We conduct uncertainty analysis on the impacts of the future cost of wind energy on global electricity generation and the value of wind energy to climate change mitigation. We integrate data on global onshore and offshore wind energy cost and resources into the Global Climate Assessment Model (GCAM), and then propagate uncertainty based on distributions derived from an expert elicitation study on the future cost of onshore and offshore wind energy. The share of wind energy electricity generation in 2035, without a global policy on CO2 emissions, ranges between 4% and more than triple the 2019 share of 5.3%. Under a 1.5°C cap, this range is wider, with shares up to 34%. This range of uncertainty implies the need for flexible systems and policies, allowing large amounts to be deployed if needed. We explore whether a breakthrough in wind energy could prevent the demand for natural gas as a bridge technology to a low carbon economy, and find that uncertainty in wind energy is only pertinent for medium-stringency policies, such as a $60/t carbon tax. Under this scenario, there is a 95% chance that the cost of wind energy will be low enough to lead to an immediate reduction in the share of natural gas. In contrast, under a business-as-usual scenario without a breakthrough in cost, natural gas is highly likely to continue increasing in share of electricity generation. Under a 1.5°C cap, natural gas will decrease in share regardless of wind energy cost.

ADVANTAGES AND DISADVANTAGES OF RENEWABLE ENERGY SOURCES UTILIZATION

Renewable energy sources are still not the predominant energy resource in the energy sector, although in certain developed countries they participate in a significant share in electricity generation. It is estimated that world energy consumption from renewable energy sources exceeds 20% at the present and continues to grow. Renewable energy sources appear as an additional source of energy in the conventional electro-industry. The main reason for the increasing investment and exploitation of renewables is certainly environment preservation and environmental aspect of sustainability. This study seeks to expand the existing literature and contribute to a comprehensive understanding of the characteristics of renewable energy sources as a whole. Therefore, the purpose of this paper is to determine the advantages and disadvantages of renewable energy sources utilization in general, without considering the individual type of renewables, such as wind or solar energy. Thereby, the paper presents numerous advantages of using renewable energy in the electricity generation, such as environment preservation in terms of reduced greenhouse gas emissions or improvement of innovations and technical/technological development. There are also presented certain disadvantages of renewables in the production of electricity, such as dependence on weather conditions or low energy efficiency and low ability to produce electricity.

Generated power enhancement of the barrage type tidal power plants

The sudden rise in oil price in 1970s led various countries around the world to turn to renewable energy resources for electric power generation instead of fossil fuel-based power plants. Among different renewable power generations, wind and solar power plants have reached maturity and have been able to make a significant contribution to electricity supply. Tidal power plants have grown less due to high cost of investment. Hence, their share of electricity generation has been lower than that of wind and solar power plants. The potential of tidal energy is high and it is expected that tidal energy can play a key role for electricity production in the future power-system due to its accurate predictability. Two types of tidal power plants including barrage-type and current-type tidal power plants are developed for energy extracting from tides. The current-type tidal power plant generates electricity from the kinetic energy of tidal-currents in a way similar to wind-turbines, while the barrage-type tidal power plants are equipped with dam, barrage and reservoir in order to generate electricity from the potential energy of water stored in the reservoir. This paper proposes several methods for enhancing the generated power of barrage-type tidal power plants, which result in cost reduction of electricity generated by tidal power plants. At first, an optimum design procedure for calculating the optimum values of number of turbines, number of gates, sluice width, turbine tip diameter and turbine hub diameter is established based on the particle-swarm-optimization-algorithm, aiming to maximize the yearly produced energy. Then, the hourly optimum number of gates and turbines are calculated in the operation studies for maximizing the daily produced energy. Also, the utilization of hydro-pump is simulated as the third method of generated power enhancement. In addition, three operation modes of barrage-type power plants, including ebb-generation, flood-generation and double-effect generation are simulated and the best operation mode in terms of power generation is determined.

Integrated technical paradigm based novel approach towards photovoltaic power generation technology

Photovoltaic (PV) has been regarded as the most promising, technically viable large-scale renewable energy source for a sustainable society. However, as the demand for solar energy is generally rising, the world needs to fundamentally reconsider the development of PV generation technology. The objective of this study is to propose a comprehensive method to study the role of technological paradigms in the development of PV generation, and to contribute to PV generation policy recommendations and system management. A novel document data mining analysis system and the technological paradigm theory are used to conduct the study. PV generation technology paradigm composed of paradigm competition, diffusion and shift is established to explain the technological changes in the use of PV energy. In this paper, the autoregressive moving average model is used to make short-term forecasts of the PV generation installed capacity, and to compare with the data predicted by Prospective Industry Research Institute. The results show that the forecasting method herein is effective and reliable. Also, this paper discusses the benefits and barriers of PV generation technology. However, to achieve higher market share in electricity generation, more support policies, multi-level cooperation, technical support and capital investment are needed. Moreover, this study provides an analysis framework for the soft path analysis of PV generation technology to achieve sustainable PV technological development.

РОЗВИТОК АЛЬТЕРНАТИВНОЇ ЕНЕРГЕТИКИ УКРАЇНИ В КОНТЕКСТІ ЗАБЕЗПЕЧЕННЯ ЕНЕРГЕТИЧНОЇ ТА ЕКОЛОГІЧНОЇ БЕЗПЕКИ ДЕРЖАВИ.

Increased greenhouse gas emissions, climate change; loss of diversity of fauna and flora, depletion of mineral deposits, accumulation of huge volumes of industrial waste, increasing risks of shortages of some types of energy has led to the development and reaching new levels of renewable energy in many countries, mainly with strong economies. To date, a number of EU countries have virtually abandoned traditional nuclear energy, virtually curtailed fuel energy using nonrenewable fossil resources, and are working hard to develop new energy-saving technologies. In Ukraine, there is a similar tendency to reduce the production of electricity from thermal power plants and increase the share of renewable energy in total production. Unfortunately, in 2020 the structure of electricity production in Ukraine has changed and does not correspond to global trends in energy development. The share of electricity generation at TPPs has increased significantly, and the share of cleaner and cheaper NPP generation has decreased to 40%. There are a number of reasons for this, but we consider it urgent to return to the process of reducing TPP generation capacity. The dynamics of renewable energy development in the country is quite positive. Additional measures are also needed to ensure the safety of nuclear energy - to finally eliminate dependence on Russian fuel. Many countries have decided to abandon cars with internal combustion engines altogether. In Ukraine, the market for electric cars is also developing and the demand for such cars is growing every month. We are among the top 5 countries in terms of market development dynamics. The development of car designs with so-called "nuclear batteries" cannot be ruled out. There are many such technologies, but all of them are currently unfinished and limited in the use of security issues. It is necessary to stimulate the development of hydrogen and electric transport in our country at the legislative level. And last but not least: in order to form a philosophy of ecological consumption among the citizens of Ukraine, it is necessary to develop appropriate government programs, introduce them in education, science and industrial production

Development of a system for estimating and forecasting the rational resource-saving operating modes of TPP

The world energy crisis and environmental problems have prompted a rapid increase in the share of electricity generation by renewable sources. However, the operating modes of such energy facilities are rather uneven over 24 hours. Thus, for the energy sector of most developing countries, and as well as for part of developed countries, such fluctuations in the overall energy production balance lead to the forced limitation of the equipment capacity at TPPs or to the full shutdown of power units. The insufficient quantity of maneuvering capacities in the overall energy generating balance is a characteristic feature of the power systems of such countries as the Russian Federation, Ukraine, Macedonia, Bulgaria, Romania, Argentina, and others. The shortage of such capacities is often compensated for by the pulverized coal units with a power of 200–300 MW, whose operation is enabled at half-peak and peak modes. This equipment is not designed for such operations. Therefore, the development of a regime method of resource management has been proposed to prevent the premature exhaustion of TPP generating equipment. Based on technical auditing of the operational documentation of generating companies, a method has been suggested aimed at forecasting the rational resource-saving operational regimes of the high-temperature elements of power equipment by optimizing the ratio of the number of launches of the equipment from various thermal states. An optimization problem has been stated, which implies determining such a distribution of the process structural-technological parameters that would ensure the maximal preservation of equipment resource. The residual resource has been selected as the objective function of the optimization problem. The devised method has been represented in the form of a comprehensive system for estimating and forecasting the rational operational modes of the TPP high-temperature elements, which makes it possible to define individual resource indicators over the entire period of equipment operation for all possible future combinations of operational modes and to compile forecasts for thousands of different variants of power unit exploitation, implying the calculation of resource indicators for each of them

A State-of-the-Art Review on the Drive of Renewables in Gujarat, State of India: Present Situation, Barriers and Future Initiatives

Given the recent increasing public focus on climate change issues, the share of electricity generation by renewable energy resources is increasing day by day. Increased renewables share will give us robust, sustainable, and climate-friendly energy systems for the future. Renewable energy penetration with the current power systems needs substantial research, planning and development which are now the primary focus throughout the world. In this study, a global renewable energy scenario is explained in detail in contrast with India, considering a case study elucidating the comprehensive review of the Gujarat state in India. The primary focus is on Gujarat state’s actions plans to pertain to harvest renewable energy and maximizing its share in the energy mix. This study examines the actions and the policies adopted by the Gujarat government to overcome the potential barriers in order to support non-conventional as well as renewable energy development. It also investigates the numerous techno-economic and social constraints with possible solutions in promoting the deployment of upcoming renewable energy resources across Gujarat. This study can be used as a guideline for the government, policymakers, utilities, stakeholders and researchers to promote an increased renewable energy share in Gujarat as well as at other places around the globe.