Capacity Of Renewable Energy Sources Research Articles

Flexibility index and decreasing the costs in energy systems with high share of renewable energy

Recent European Green Deal includes decision to become carbon neutral and even carbon negative region in order to tackle the climate crisis. Main technical challenge and a key factor in techno-economic analysis of the energy system of the future, based on variable renewable energy sources, is their variable production and its integration. In order to deal with this problem in long-term energy planning, different approaches have been tried, focusing on overcapacity, storage capacities and sectors coupling with heating and transport. In this research, different flexibility options, storage and demand response technologies are modelled on a national energy systems level. With the case study area modelled in EnergyPLAN model, the goal of the research is to show how each flexibility option influences the economically feasible generation capacities of renewable energy sources, storage technologies and demand response in order to reach a certain share of renewable energy in final energy consumed. To follow the numerous possible configurations of the system, flexibility index for each option and a flexibility vector for each scenario are introduced. Results show which flexibility options play key role in important steps of energy transition to 70%, 80%, 90% and 100% RES energy system.

Simulation and Techno-Economic Analysis of On-Grid Battery Energy Storage Systems in Indonesia

The limited capacity of renewable energy sources in the grid utility is a challenge. Increasing the capacity of renewable energy sources is supported by energy storage in the grid. The Battery Energy Storage System (BESS) allows storing more electricity from New and Renewable Energy (EBT) sources to meet load requirements. This paper designs a techno-economic study of various battery technologies using HOMER (Hybrid Optimization Modeling Software) software simulation. Simulations are made for grid-connected photovoltaic systems in Indonesia. HOMER is used to find the energy cost ($ / kWh) for each type of battery technology and battery system size. The simulation is designed using 1MWp PV component parameters, inverter, energy storage to be compared, residental load, and connected to the grid. The results will help to determine which technology and battery size is more suitable for the system. The findings from this paper resulted in the lowest Levelized Cost Of Energy (LCOE) of $ 1.03 in solar power generation.

Challenges of High Renewable Energy Sources Integration in Power Systems—The Case of Croatia

This paper presents a high-level overview of the integration of renewable energy sources (RES), primarily wind and solar, into the electric power system (EPS) in Croatia. It presents transmission system integration aspects for the particular case of this country. It explains the current situation and technical characteristics of the current conventional generation units and currently installed wind energy capacities. Based on the current situation future development scenario is determined and used to evaluate the impacts of the wide-scale integration of renewables. Grid connections aspects, power balancing, market participation, and inertia reduction aspects are considered. Furthermore, some specifics of both solar and wind integration are discussed identifying problems and potential solutions. Primarily through the provision of the inertial response of both solar and wind and through better forecasting of wind production. Finally, the outlook for the Croatian power system is given, that will most probably double its RES capacity in the coming 3-year period and a certain level of investments and changes of current operational practices will need to be provided.

Оцінювання впливу генерування ВДЕ на показники надійності роботи мереж операторів систем розподілу

The article analyzes the regulations for assessing the quality of electricity supply, which is especially important for distribution system operators in terms of the introduction of incentive tariffs. The influence of the increase in the installed capacity of RES on the normative indicator of the duration of power supply interruptions — SAIDI was determined, and also the change of the indicator of the average duration of power supply failures (min) from the year and region was analyzed. Correlation analysis was performed for a number of operators of distribution systems for the impact of renewable energy generation on SAIDI, in the periods 2013—2016 and 2017—2020. It is determined that in the period from 2013 to 2016, the growth of the installed capacity of renewable energy sources had almost no effect on the normative indicator of the duration of power outages — SAIDI. And since 2017, due to the choice of sub-optimal connection points and / or a sharp increase in the installed capacity of renewable energy sources, SAIDI is increasing. Graphs of dependence of increase of the established capacity of renewable energy sources on areas of Ukraine in the period from 2013 to 2020 are constructed. For clarity, a graph of the dependence of the installed capacity of renewable energy sources for a number of distribution system operators on the year of implementation of such capacity for two periods, namely 2013—2016 and 2017—2020. The schedule of dependence of the annual indicator of average duration of failures in power supply on areas of Ukraine in the period from 2013 to 2020 is constructed. The regions with the largest installed capacity of renewable energy sources as of the end of 2020 were selected for plotting and correlation analysis. The conclusion on the influence of renewable energy sources on the reliability of electricity supply to distribution system operators is made.

Evaluation of the Impact of Green Hydrogen Blending Scenarios in the Italian Gas Network: Optimal Design and Dynamic Simulation of Operation Strategies

Blending hydrogen (H2) produced from Renewable Energy Sources (RES) in the existing Natural Gas (NG) network is a promising option for the deep decarbonization of the gas sector. However, blending H2 with NG significantly affects the thermophysical properties of the gas mixture, changing the gas supply requirements to meet the demand. In this work, different scenarios of green hydrogen blending (Blend Ratio BR equal to 5/10/15/20%vol) are analyzed at national level with different temporal constraints (hour/day/week/month/year) based on real gas demand data in Italy, addressing both design requirements (RES and electrolyzer capacity) via Linear Programming (LP) and carrying out dynamic simulations of different operational strategies (constant or variable blend). Although H2/NG blending provides a huge opportunity in terms of deployed H2 volume, higher BRs show rapidly increasing design requirements (1.3-1.5 GWe/%vol and 2.5-3 GWe/%vol for electrolysis and RES capacity respectively) and a significative increase of the total gas mixture volume (0.83 %/%vol) which hinders the CO2 reduction potential (0.37 %/%vol). A variable blend operation strategy (allowing a variation of BR within the analysed period) allows to balance a variable H2 production from RES. Wider temporal constraints imply several beneficial effects such as relaxing design constraints and avoiding the implementation of an external storage, thus reducing the cost while maintaining the same amount of injected gas. The Levelized Cost Of Hydrogen (LCOH) is preliminarily estimated around 7.3 $/kg for yearly scenarios (best-case), although shorter temporal constraints entail significative excess hydrogen which would increase the LCOH if not deployed for other applications.

Global Electricity Interconnection With 100% Renewable Energy Generation

Under the United Nations ‘Net-Zero 2050’ target, transition towards a 100% renewable energy (RE) sourced power grid has become an ever more attractive pathway. However, the inherent fluctuations and intermittency of RE generation, particularly wind and solar, would inevitably pose great technical and economic barriers to their massive integration into the energy supply. A global interconnected electricity grid to utilize the complementarity of diverse demand patterns and RE sources provides an appealing solution. With detailed datasets, this paper is therefore to assess the economic benefits of such a global electricity grid with 100% RE generation using the state-of-the-art Ultra High Voltage Direct Current transmission technologies. The global electricity grid is split into 14 regions with 20 potential interconnection routes and regional geographical centroid is treated as equivalent node for inter-regional distance calculation. Global hourly meteorological re-analysis data of up to seven years with spatial resolution of ${0.25}^{\circ }\times {0.25}^{\circ }$ (approximate $28 \text {km}\times 28\text {km}$ ) is used to generate regional representative generation power series. With the minimum annual system cost for meeting demand in 2050, an integrated planning and power dispatch model is presented to determine the additional regional capacities of RE sources, storage systems, and the interconnectors from 2030, and in which load curtailment is incorporated and ‘ $N$ -1’ security are much stricter than those traditionally applied. The paper provides a comprehensive analysis with 24 cases based on different supply portfolios which show a 20% cost saving through specific global interconnections thereby lending support to the concept of a Global Electricity Grid.

Analytical Approach for Fast Frequency Response Control of VSC HVDC

The importance of the auxiliary control of power electronic devices such as HVDC and FACTs is growing owing to the increase in the generation capacity of renewable energy sources. This paper presents a temporary frequency support strategy using the electrostatic energy in voltage-sourced converter-type high-voltage direct current systems. An analytical derivation for selecting the optimal droop constant to improve the frequency nadir was established. The optimal droop constant was derived via system frequency response analysis by using the support termination time. Furthermore, the optimality of the support was computed using numerical equations. Modified outer control loops were implemented in the master controller to utilize the proposed method in voltage-sourced converter control. The effect of the fast frequency support control strategy was verified via a time-domain electromagnetic transient program simulation based on case studies. To examine the practical applicability of the proposed strategy, the parameter robustness was investigated by performing deviated system parameter simulations. The results validated the proposed strategy.

Reactive power control of photovoltaic power generation systems by a wide‐area control system for improving transient stability in power systems

AbstractAs the installed capacity of renewable energy sources is increasing, the role of inverters is becoming more important in the maintenance of power system stability. Therefore, in this study, we propose the use of a wide area control system (WACS) to control the inverters of photovoltaic (PV) systems in a coordinated manner to improve transient stability. In this method, we select PV systems whose reactive power injections are deemed to suppress the acceleration of the critical generator, based on a time‐domain simulation for each possible fault before the fault occurs. When a fault occurs, we trigger the reactive current injections with the selected PV systems that is, the WACS operates as an event‐based emergency control system. Numerical simulation results demonstrate that this method can further improve transient stability compared with an autonomous reactive current support function that is applied to existing PV inverters. The proposed WACS could be a promising approach to address the transient instability phenomena under unscheduled power flow conditions by periodically updating the control table based on real‐time information.

Enhancing hosting capacity of intermittent wind turbine systems using bi‐level optimisation considering OLTC and electric vehicle charging stations

Worldwide, the hosting capacity of renewable energy sources (RES) is remarkably expanded in distribution systems. One of the most auspicious RES is wind turbine systems (WTSs), which can improve the performance of distribution systems. In turn, the integration of high WTS penetrations can also deviate the system operation away from the standard condition. To tackle this issue, we propose a method for enhancing the hosting capacity of multiple WTSs considering their intermittent generations in distribution systems. The proposed method considers the operation of the on-load tap changer (OLTC), allowing to solve voltage problems efficiently. Especially, the proposed method optimises the charging/discharging power of electric vehicles (EVs), which can contribute positively to regulating WTS intermittent generation. Additionally, the reactive power support of WTSs, complying with the IEEE 1547:2018 standard, is incorporated in the planning model of WTSs. To solve such an optimisation problem, a bi-level optimisation algorithm is developed based on the gravitational search algorithm. Comprehensive simulation results are performed on the 69-bus distribution feeder interconnected to four EV stations. Based on the results, the proposed approach can efficiently enhance/increase the hosting capacity of WTSs in distribution systems, thanks to the consideration of OLTC, reactive power support of WTSs and EVs.

Design of Isolated Microgrid System Considering Controllable EV Charging Demand

Microgrid construction is promoted globally to solve the problems of energy inequality in island regions and the use of fossil fuels. In the application of a microgrid system, it is important to calculate the capacities of renewable energy sources and storage systems (ESSs) to ensure economic feasibility. In some microgrids that have recently had environmental challenges, there are island regions where the policy is to consider both the installation of the microgrid system and the supplement of electric vehicles (EV). However, an EV load pattern that does not match the solar radiation pattern may increase the required ESS capacity. Therefore, in this study, we designed and analyzed a method for reducing the microgrid system cost using a controllable EV charging load without the requirements of vehicle-to-grid technology and real-time pricing. The power system operations at similar capacities of photovoltaic and ESS were shown by applying EV charging control steps in 10% increments to analyze the effect of EV charging demand control on the microgrid. As a result of the proposed simulation, the amount of renewable power generation increased by 2.8 GWh over 20 years only by moving the charging load under the same conditions. This is an effect that can reduce CO2 by about 2.1 kTon.

Green Economy as a Paradigm of Sustainable Development of the Republic of Kazakhstan

The aim of the paper is to analyse the green economy as a paradigm of sustainable development of the Republic of Kazakhstan. The paper found that the use of alternative energy is an integral part of the development of the green economy. It is determined that the total capacity of renewable energy sources in the world until 2024 will increase by 50%. The necessary elements of the transition to the green economy are the development of new financial instruments, namely, payments for ecosystem services, green banking, stocks and bonds, markets for the sale of intellectual property in environmental technologies.

Approaches to assessing the resource potential of Central Asia in a climatic resource-constrained environment

The object of research in the article is the methodology of evaluation and calculation of the wind energy resource for the design of wind power plants in Central Asia. This methodology is based on the approach for determining the wind resource in conditions of insufficient climate data developed by REC “RES” of Peter the Great St. Petersburg Polytechnic University. The energy industry of Central Asia, like the world energy industry, seeks to increase the use of facilities based on renewable energy sources, which is caused by several factors: environmental, economic, social, and so on. The global energy industry is implementing a “green” energy transition, largely due to government policy, thereby several strategies and decisions have been adopted in Central Asia. At the moment, the installed capacity of renewable energy sources in Central Asia is 13747 GW. The methodology for evaluation of wind energy resources has been developed, and a resource potential has been calculated in the city of Aktau in Kazakhstan. The methodology includes a 3-level evaluation system and calculation in the WindPRO software. This methodology guarantees the accuracy of calculating the wind resource up to 90-95%.

Optimisation of a hydrogen production – storage – re-powering system participating in electricity and transportation markets. A case study for Denmark

The power capacity of renewable energy sources is constantly increasing through the installation of new units, primarily comprising the most mature technologies such as wind and solar energy converters, as well as through the implementation of innovative technologies that are currently at an infant stage of development. The aim of this study was to investigate the prospects of implementing hydrogen technologies in the electricity network as an electricity production unit or/and utilise the produced hydrogen as transportation fuel. Three main scenarios were identified to be the most appropriate for this: (1) Support of the electrical grid via a fuel cell; (2) participation of a hydrogen production and fuel cell system in the electricity and transportation markets; and (3) participation in the transportation market. The results indicated that a fuel cell generator providing ancillary services is not economically viable in the investigated case study, while implementing a hydrogen production unit with a hydrogen fuel selling price between 4 and 114 €/kgH2, depending on the electrolyser’s power input, will yield positive results. For the third scenario, the hydrogen fuel price ranged between 3.6 and 15.0 €/kgH2. This research shows that hydrogen technologies can be used in the electricity and transportation markets from a technical point of view. However, from an economic point of view, a hydrogen system used only for a single application does not seem to be financially appealing. This suggests that reducing the investment cost and/or limiting operating costs is mandatory to support this type of investment.

ОПРЕДЕЛЕНИЕ ОПТИМАЛЬНОЙ СТРУКТУРЫ ВЕТРОСОЛНЕЧНЫХ ЭЛЕКТРОСТАНЦИЙ В МОНГОЛЬСКОЙ ЧАСТИ ПУСТЫНИ ГОБИ

Актуальность работы обусловлена интенсивным экономическим развитием стран Северо-Восточной Азии, увеличением их потребности в электроэнергии и целесообразностью повышения экономической и экологической эффективности электроснабжения за счет реализации проектов электроэнергетической интеграции. При этом важную роль может играть широкомасштабное внедрение возобновляемых источников энергии. Цель: определение оптимальной структуры ветросолнечных электростанций в монгольской части пустыни Гоби (соотношения мощностей электростанций разных типов и выработки ими электроэнергии) для разных сочетаний экономических и климатических условий. Методы: систематизация климатической и метеорологической информации, предварительная оценка эффективности энергоисточников разных типов по критерию стоимости производимой электроэнергии, математическое моделирование структуры и режимов работы энергосистемы. Математическая модель учитывает случайный характер поступления солнечной и ветровой энергии. Результаты. Показано, что произведенная фотоэлектрическими преобразователями и ветротурбинами электроэнергия с учетом стоимости ее транспорта по линиям электропередачи конкурентоспособна на электроэнергетических рынках Китая и других стран Северо-Восточной Азии. Для различных значений прихода солнечной радиации и скорости ветра определены оптимальные соотношения между мощностями возобновляемых источников энергии, производством электроэнергии фотоэлектрическими преобразователями и ветротурбинами, а также поставками электроэнергии из энергосистемы Китая для компенсации неравномерности выработки возобновляемых источников энергии. Показана экономическая эффективность совместного использования солнечной и ветровой энергии в монгольской части пустыни Гоби за исключением некоторых районов с низкими скоростями ветра. Совместное использование солнечной и ветровой энергии позволяет снизить суммарные затраты на систему электроснабжения более чем на четверть по сравнению с вариантом использования только солнечной энергии.

Korišćenje alata za tržišno modelovanje pri analizi benefita po elektroenergetski sistem izgradnjom novog interkonektivnog dalekovoda

The goal of this paper is to introduce the market modeling tool Antares and to point out possibilities of its utilisation in cost-benefit analysis of energy projects. Market modeling of power systems represents a detailed modeling of generating units, consumption and cross-border connections with neighboring systems in order to find economically optimal dispatching of power plants by which the total consumption will be satisfied. In this paper, two power systems connected by cross-border transmission lines will be modeled (in one of them there is a large amount of installed capacity of renewable energy sources). The benefits of reinforcing cross-border connection embodied in avoiding curtailment of available renewable energy due to low energy consumption and lack of energy storage systems will be analyzed, along with corresponding benefits of reduced CO2 emissions due to the ability to transfer green energy into neighboring power systems through increased cross-border capacity.

On the role of electric vehicles towards low-carbon energy systems: Italy and Germany in comparison

Electric vehicles can play a major role in the transition towards low-carbon energy systems, but the related increase in electricity demand inevitably affects the strategic planning of the overall energy system as well as the definition of the optimal power generation mix. With this respect, the impact of electric vehicles may vary significantly depending on the composition of both total primary energy supply and electricity generation sector. In this study Italy and Germany are compared to highlight how a similarity in their renewable shares not necessarily leads to similar results in CO2 emissions reduction. Different energy scenarios are simulated with the help of EnergyPLAN software assuming a progressive increase in renewable energy sources capacity and electric vehicles penetration. Results show that, for the German case, the additional electricity required leads to a reduction in CO2 emissions only if renewable capacity increases significantly, whereas the Italian energy system benefits from transport electrification even at low renewable capacity. With a sixfold increase in renewables capacity and assuming a complete electrification of private transportation where electric vehicles charging strategy is regulated to enhance renewable integration, CO2 emissions can be reduced by 22% and 39% for Italy and Germany respectively. However, this comes along with a remarkable renewable surplus, respectively equal to 15% and 28% of the total national production unless large-scale energy storage systems are deployed.

Forecasting of Turkey's greenhouse gas emissions using linear and nonlinear rolling metabolic grey model based on optimization

Abstract This study aims to contribute to the development of energy policies for Turkey's greenhouse gas (GHG) emissions in the future. For this purpose, linear and nonlinear metabolic grey models are combined with the optimization technique to obtain more accurate forecasting results. Optimization technique provides estimation of the parameters in metabolic grey model (MGM(1,1)) and nonlinear metabolic grey model (NMGM(1,1)). In this study, MGM(1,1), NMGM(1,1), optimized metabolic grey model OMGM(1,1), and optimized nonlinear metabolic grey model (ONMGM(1,1)) are applied for prediction of Turkey's GHG emissions including the Land Use, Land Use Change and Forestry (LULUCF), excluding LULUCF and from the energy sector. The ONMGM(1,1) gives more accurate results than the others from 1995 to 2016. The MAPE values of the ONMGM(1,1) are 4.80%, 4.14% and 5.19% for Turkey's GHG emissions with LULUCF, without LULUCF and from the energy sector, respectively. On the other hand, results of the ONMGM(1,1) show that the annual growth rates are forecasted as 0.56%, 0.66% and 0.49% for Turkey's GHG emissions with LULUCF, without LULUCF and from the energy sector, respectively, from 2017 to 2025. Furthermore, Turkey's highest GHG emissions with LULUCF, without LULUCF and from the energy sector are estimated by MGM(1,1) as 606.9 Mt of CO2 equivalent, 726.4 Mt of CO2 equivalent and 585.2 Mt of CO2 equivalent in 2025, respectively. According to Turkey's Intended Nationally Determined Contribution (INDC), target of its GHG emissions including LULUCF is estimated as 934 Mt of CO2 equivalent in a Business-As-Usual scenario and 790 Mt of CO2 equivalent in a Mitigation scenario for the year 2025. Therefore, this study presents lower values of Turkey's GHG emissions with LULUCF than the values of Turkey's INDC for the year 2025. Additionally, results of this study present that energy sector has the largest share of Turkey's GHG emissions from 2017 to 2025. Therefore, Turkish Government should develop policies to use energy more efficiently and to increase the capacity of renewable energy sources in electricity generation. Especially, Turkey's ambition to increase the share of renewable energy in total is very assertive. This can be seen from the Turkey's 11th Development Plan. According to the Plan, the share of total renewable energy and natural gas in total electricity generation is going to be increased from 32.5% in 2018 to 38.8% in 2023 and to be decreased from 29.85% in 2018 to 20.7% in 2023, respectively.

Probabilistic Energy Flow Calculation through the Nataf Transformation and Point Estimation

With the increasing capacity of renewable energy sources, uncertainties regarding renewable energy and other dynamic loads in integrated energy systems (IESs) are increasing. Thus, it is necessary to study the probabilistic energy flow (PEF) of IESs. However, existing PEF calculation methods such as the point estimate method (PEM) are computationally inefficient when there are many random variables and estimated points; moreover, relatively large errors can occur when the estimated points are outside their limits. Hence, this paper presents a calculation method that addresses these problems. Because there are correlations among the variables, the Nataf transformation is employed to control the correlation quickly and effectively. A model for an IES that is interconnected with natural gas and electricity systems and accounts for the uncertainties of wind plants, photovoltaic power plants, and dynamic gas loads is presented. Correlations between wind plants and photovoltaic power plants are handled using the Nataf transformation. Finally, a modified PEM is developed to solve the PEF. For situations in which the estimated points exceed their boundaries, the power transformation and equal constraint transformation methods are used. The results of time-domain simulations demonstrate the effectiveness of the proposed approach.

Application of the Least Square Support Vector Machine for point-to-point forecasting of the PV Power

<p>In today's industrial world, the growing capacity of renewable energy sources is a crucial factor for sustainable power generation. The application of solar photovoltaic (PV) energy sources, as a clean and safe renewable energy resource has found great attention among the consumers in the recent decades. Accurate forecasting of the generated PV power is an important task for scheduling the generators and planning the consumption patterns of customers to save electricity costs. To this end, it is necessary to develop a global model of the generated power based on the effective factors which are mainly the solar radiation intensity and the ambient weather temperature. As a result of the wide numerical range of these parameters and various weather conditions, a large training database must be used for developing the models, which results in high-computational complexity of the algorithms used for training the models. In this paper, a novel algorithm for point to point prediction of the generated power based on the least squares support vector machine (LS-SVM) has been proposed which can handle the large training database with a very fewer deal of computation and benefits from reasonable accuracy and generalization capability. </p>

The Impact of Emerging Renewable Energy on Capacity Mechanisms in Power Systems and Expert Opinion

With the increasing energy demand, the growing capacity of renewable energy sources and the impact of developing competition, it is desirable to manage the market with appropriate investments along with the electricity market and optimum load distribution. In line with this demand, supply security and energy quality play an important role day by day. This includes the production capacity and the long-term security of the system, reflecting the system's ability to stand in unexpected events and sudden load changes. The demand side seems to have insufficient support to the market for new capacity planning to ensure this coverage. This problem can be solved by producing additional capacity. Basically, it is aimed to reduce investment risk for production companies and / or investors and to provide higher supply security and lower price fluctuations to consumers. The concern of not investing in electricity generation capacity to meet the maximum load level has led to investments in capacity utilization in the form of capacity mechanisms of developed and developing states. In this study, an academic analysis of the capacity mechanism of the renewable energy resources and the capacity analysis of the capacity mechanism were made and expert opinions were presented, the latest developments in the energy market were examined and the reliability solutions that could be appropriate to the national electricity market were proposed