Operating Reserve Research Articles

Optimal size selection of combined diesel generator/fuel cell/photovoltaic system components using a multi‐objective strategy and sea lion optimization algorithm

AbstractOne of the challenges of the production sector of the electricity industry at present is how to meet the needs of electricity consumption in the country by using and localizing new power plant units. The main purpose of the presented paper is to offer an optimum arrangement for a combined diesel generator/FC/PV system for an off‐grid supply of electricity in a community in Shache, China. A multi‐objective scheme of the combined system is suggested with consideration of the unpredictability in solar radiation, load, and operating reserve (OR). The multi‐objective optimization has been established to make the TNPC (total net present cost) and LPSP (probability of power supply loss) minimum. In this study, the decision variables are the number of diesel generators (DG), photovoltaic (PV) panels, fuel cells (FC), electrolyzers, and hydrogen tanks. To get more authentication, the impact of several criteria on the size issue has been analyzed. The incorporation of a hydrogen production system lowers the overall expense of the combined systems, according to the modeling results. Plus, the operational reserve has a greater effect on the Pareto front in comparison with solar energy and load uncertainty.

Assessment of the resource base of Rumex tianschanicus Losinsk. in the mountain regions of southeastern Kazakhstan

Inventory of stock economically valuable plant species is one of the urgent tasks in the regional cadastral assessing of plant resources. The results of this will be applied to conduct state monitoring and the flora cadastre in the Republic of Kazakhstan. Genus Rumex L. belongs to Polygonaceae Juss. family and represented by 27 species in the flora of Kazakhstan including 15 medicinal which used in folk and official medicine. For the first time undertaken a cadastre assessment of current ecological state of the flora and plant resources in Almaty region, the stocks of plant raw material of the valuable medicinal Rumex tianschanicus, have been identified and taken into account in 2021-2022 years on the 3 floristic territories (24. Dzhungarsky Alatau, 25. Zailiysky Kungei Alatau, 25a. Ketmen-Terskey Alatau) and 4 administrative (Eskeldinsky, Kegensky, Raiymbeksky, Uigursky) districts. The resource survey of the territories carried out by a route-reconnaissance method using generally accepted resource-study and geobotanical methods. On the surveyed territory the total operational reserve of air-dry underground part of Rumex tianschanicus was 169.5 tons on 113.3 hectares with a total volume of possible annual harvesting of 17.0 tons of air-dry plant raw materials. For commercial harvesting thickets were isolated ridges of Ketmen (Uigur district) and Terskey Alatau (Raiymbek district) which located within 25a floristic region in the southeast of the Almaty region.

Optimal Power Generation and Voyage Scheduling in Shipboard Power Systems Considering Load Characteristics-Based Operating Reserve Management

Optimal Power Generation and Voyage Scheduling in Shipboard Power Systems Considering Load Characteristics-Based Operating Reserve Management

Ресурсный потенциал плодов растений рода Vaccinium L. на территории Тулунского района Иркутской области

Cranberries (V. vitis-idaea L.), blueberries (V. myrtillus L.) and blueberries (V. uliginosum L.) grow on the territory of the Tulunsky district of the Irkutsk region. At the same time, cranberries and blueberries have significant resource potential. The article presents the biological and operational reserves of these species. Since it is practically impossible to use the entire operational reserve, then, based on the average bio-productivity and taking into account the maximization of income, we offer the most optimal possible volumes of blanks. It should be noted that the yield of wild products varies significantly, so the data from year to year can vary greatly. Keywords: RESOURCE POTENTIAL, LINGONBERRIES, BLUEBERRIES, BLUEBERRIES, YIELD

The role of electricity market design for energy storage in cost-efficient decarbonization

The role of electricity market design for energy storage in cost-efficient decarbonization

An Analysis of the Effects of Renewable Energy Intermittency on the 2030 Korean Electricity Market

Republic of Korea has unique geographical characteristics similar to those of an island, resulting in an isolated power system. For this reason, securing sufficient operating reserves for the system’s stability and reliability in the face of the intermittency of increasing variable renewable energy (VRE) is paramount, and this will pave the way to achieving the nation’s decarbonization target and carbon neutrality. However, the current reserve-operation method in Republic of Korea does not take into account energy-system conditions, such as the intermittency of the VRE. Therefore, this paper presents an analysis of the impact of changes in reserve-operation methods on the electricity market in the future Republic of Korean power system, with the increased levels of VRE that are currently envisioned. Specifically, three reserve-operation methods, including Korea’s current reserve-power-operation standards, were applied to the two power-system plans announced by the Korean government to analyze the annual generator operation and costs. The analysis results show that securing reserves proportional to the VRE would exert negative effects, such as increased power-generation costs and the curtailment of nuclear and VRE generation. These results can contribute to the estimation of operational reserves needed for high levels of VRE and to the design of new the Korean reserve market, to be introduced in 2025.

Optimal Allocation of Energy Storage Capacity in Distributed Micro-grid Based on Improved Whale Algorithm

At present, the setting of monitoring nodes for optimal allocation of energy storage capacity in micro-grid is generally target-based, with slow allocation speed and weak pertinence, which can easily lead to the increase of the final difference adjustment coefficient and affect the final allocation effect. Therefore, the research and analysis on the optimal allocation method of distributed micro-grid energy storage capacity based on the improved whale algorithm are proposed. According to the actual disposal requirements and standards, the basic operation frequency and reserve capacity of the micro-grid are determined, the multi-level monitoring node deployment form is set, the monitoring range is expanded, and the speed and pertinence of configuration are improved to complete the layout of energy storage capacity monitoring nodes. The optimal allocation model of the improved whale calculation of grid energy storage capacity is constructed. The optimal allocation is realized by constraint programming. The test results verify that the energy storage power of the micro-grid will be enhanced with the increase of the frequency modulation times of energy storage calculated by the whale calculation optimization configuration test group. In this context, the difference adjustment coefficient of the micro-grid configuration becomes lower, only 1.03, indicating that in the process of practical application, the energy storage capacity configuration of micro-grid is optimized. The frequency modulation fluctuation is slowed down, the running frequency is faster, and the method has practical application value.

Modeling demand flexibility impact on the long-term adequacy of generation systems

This paper proposes a novel probabilistic model for quantifying the impact of demand flexibility (DF) on the long-term generation system adequacy via Sequential Monte Carlo Simulation (SMCS) method. Unlike load shedding, DF can be considered an important instrument to postpone bulk consumption from periods with limited reserves to periods with more generating capacity available, avoiding load shedding and increasing the integration of variable renewable generation, such as wind power. DF has been widely studied in terms of its contribution to the system’s social welfare, resulting in numerous innovative approaches ranging from the flexibility modeling of individual electric loads to the definition of aggregation strategies for optimally deploying this lever in competitive markets. To add to the current state-of-the-art, a new model is proposed to quantify DF impact on the traditional reliability indices, such as the Loss of Load Expectation (LOLE) and the Expected Energy Not Supplied (EENS), enabling a new perspective for the DF value. Given the diverse mechanisms associated with DF of different consumer types, the model considers the uncertainties associated with the demand flexibility available in each hour of the year and with the rebound effect, i.e., the subsequent change of consumption patterns following a DF mobilization event. Case studies based on a configuration of the IEEE-RTS 79 test system with wind power demonstrate that the DF can substantially improve the reliability indices of the static and operational reserve while decreasing the curtailment of variable generation cause by unit scheduling priorities or by short-term generation/demand imbalances.

Synergetic Scheduling Energy and Reserve of Wind Farms for Power Systems with High-Share Wind Power

With wind and other variable renewable energy (VRE) generation gradually becoming the main power source, it is difficult to ensure the flexible and secure operation of the system by completely relying on conventional sources to balance the uncertainty and volatility of VRE. The increase of VRE penetration leads to the shortage of operation reserves, and wind power is allowed to participate in reserve services. However, the output of wind power is uncertain, and how to ensure the reliability and sustainability of wind power reserves is still an open question. A robust energy and reserve dispatch method considering the flexibility of wind power is proposed to solve this problem. To effectively measure the output and reserve margin of wind power under uncertain scenarios, (1) the grid connection coefficient of wind turbine generators (WTGs) is defined, and the uncertainty set considering active wind power curtailment is established; and (2) based on two kinds of WTG control methods, the reserve model of wind farms is established. The model links the reserve capacity between the base scenario and uncertain scenarios through the reserve coefficient, which ensures that the wind power reserve determined in the base scenario is still deliverable in any uncertain scenario. The robust scheduling model determines the optimal dispatching and reserve plan of conventional units and wind farms by balancing the system operation economy and the schedulable reserve of wind power. The column-and-constraint generation algorithm is used to solve the model. The effectiveness of the proposed model is verified by the illustrative results of the IEEE normal system.

The interaction of wholesale electricity market structures under futures with decarbonization policy goals: A complexity conundrum

Competitive wholesale electricity markets can help facilitate energy system decarbonization by incentivizing investments in clean energy technologies that meet evolving system needs. We explore market structure impacts on generator operations and deployment by risk-averse, heterogeneous investor firms using the Electricity Markets and Investment Suite – Agent-based Simulation (EMIS-AS) model. We apply clean energy targets of 45%–100% by 2035 considering energy, ancillary services, capacity, and clean energy credit products and pricing and eligibility rules. Results highlight a complexity conundrum, whereby finding the “right” market design to achieve decarbonization goals and avoid unintended consequences can be a highly-nuanced, non-incremental challenge. Carefully designed energy-only markets can achieve the same clean energy targets as capacity market structures but with different revenue and profitability outcomes. Operating reserve demand curve-based scarcity pricing can substitute capacity markets for similar deployment outcomes. Carbon pricing alone is most effective at achieving decarbonization levels at low clean energy targets, and clean energy credit markets and carbon pricing are substitutionary at high clean energy targets. Restricting technology participation in capacity and operating reserve markets can impact deployment and operations, even for nonrestricted technologies. Adding an inertia product with fast frequency response yields insufficient provision at high clean energy targets, but work is needed to understand frequency requirements and capabilities.

Application of an Operating Reserve Demand Curve in ERCOT in the South Korean Electricity Market to Accommodate High Penetration Levels of Renewable Energy

Application of an Operating Reserve Demand Curve in ERCOT in the South Korean Electricity Market to Accommodate High Penetration Levels of Renewable Energy

Estimating the Operating Reserve Demand Curve for Efficient Adoption of Renewable Sources in Korea

As the proportions of variable renewable sources (VRSs) such as solar and wind energy increase rapidly in the power system, their uncertainties inevitably undermine power supply reliability and increase the amount of operating reserve resources required to manage the system. However, because operating reserves have the characteristics of a public good and their value is related to the social cost of blackouts, it is difficult to determine their market price efficiently, which leads to inefficiencies in procuring operating reserves. This study estimates the operating reserve demand curve (ORDC) of the Korean power system to provide an effective basis for measuring the proper value and quantity of operating reserves needed to meet the reliability standard. A stochastic dynamic optimization model is applied to incorporate the probabilistic characteristics of VRS and the inter-hour constraint, which is necessary for analyzing load-following reserves. An econometric model and the Monte Carlo simulation method are used to generate the forecast profiles of solar and wind generation. The results indicate that the proper amount of hourly operating reserves needed in 2034 is approximately 4.4 times higher than that in 2020 at the current reserve offer price. The ORDC of 2020 has a price-inelastic shape, whereas the ORDC of 2034 has a price-elastic shape because the reserve requirement varies considerably with its offer price level in the high-VRS penetration case. This variability is due to alternatives, such as VRS curtailment or load shedding, which can replace the reserve requirement. This study also showed that VRS curtailment is an effective balancing resource as an alternative to reserves.

Optimal pricing strategy for electric vehicle battery swapping: Pay-per-swap or subscription?

Electric vehicles (EVs) contribute to carbon emission reduction, but the limitations of existing charging technologies impose a bottleneck to their further diffusion. Addressing the root issues of long waiting time and range anxiety, battery swapping demonstrates great market potential. A swapping service provider may choose between two pricing strategies based on battery rental: pay-per-swap and subscription. This study establishes a game-theoretical model to portray a simplified EV replenishment market including one charging station, one swapping station, and one battery renter, and explores the optimal pricing strategy. To capture the influence of consumer preferences, the model considers high versus low opportunity cost of time. In either scenario, consumers choose between charging and swapping to maximize surplus utility. Equilibrium prices, demands, and profits under pay-per-swap and subscription strategies are obtained through backward induction. The results indicate that pricing strategy choice-making hinges on provider-side operating cost, battery depreciation and reserve size, as well as consumer-side time sensitivity and opportunity cost. Numerical and extended analyses suggest that the subscription strategy is conducive to initial market development, whereas the more consumer-friendly pay-per-swap strategy is preferred afterwards.

Wood industry clusters and their optimal location for the efficient use of forest raw materials

World experience in the creating of clusters in different industries has shown their effectiveness. This paper investigated the resource potential for creating a cluster designed for wood processing and to process wood waste from the timber industry of the Krasnoyarsk Territory of Russia. Static indicators were assessed, representing a quantitative characteristic of forest raw material resources: total and operational reserves of wood available in the region. While studying the state and use of forest resources, significant reserves of forest resources and secondary raw materials were revealed. Main indicators of the forest industry of the region over recent years were analyzed. The main systemic issues hindering the development of the timber industry were exposed. It was concluded that the region has raw material potential and industrial infrastructure necessary for the formation and sustainable development of a cluster for processing waste from the timber industry. Analysis of the producers and harvesters of forest products’ locations revealed potential wood industry clusters, and areas suitable for cluster economic development were proposed. The average figures of the nearest neighbor were used and analyzed to examine the spatial distribution of raw material harvesters and enterprises that produce finished products with respect to transport infrastructure, staffing, and raw material availability.

Operating Dynamic Reserve Dimensioning Using Probabilistic Forecasts

The rapid integration of variable renewable energy sources (VRES) into power grids increases variability and uncertainty of the net demand, making the power system operation challenging. Operating reserve is used by system operators to manage and hedge against such variability and uncertainty. Traditionally, reserve requirements are determined by rules-of-thumb (static reserve requirements, e.g., NERC Reliability Standards), and more recently, dynamic reserve requirements from tools and methods which are in the adoption process such as Dynamic Assessment and Determination of Operating Reserve ( <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DynADOR</uri> ), Dynamic Reserves Dimensioning ( <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DRD</uri> ), and <uri xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RESERVE</uri> , among others. While these methods/tools significantly improve the static rule-of-thumb approaches, they rely exclusively on deterministic data (i.e., best guess only). Consequently, these methods disregard the probabilistic uncertainty thresholds associated with specific days and their weather conditions (i.e., best guess plus probabilistic uncertainty). This work presents practical approaches to determine the operating reserve requirements leveraging the wealth information from probabilistic forecasts. Proposed approaches are validated and tested using actual data from the California Independent System Operator (CAISO) system. Results show the benefits in terms of risk reduction of considering the probabilistic forecast information into the dimensioning process of operating reserve requirements.

The influence of models assessing the state in task of ensuring balance reliability on managerial decisions when the ups planning

Various models of assessment a random state are considered. The solution problem of substantiating power reserves is associated with the need to redistribute generating capacities between the EPS territorial zones. It is shown that this need leads to almost the same values of operational power reserves when using various models of assessing state. This is confirmed by experimental calculations on many models of estimated EPS schemes for various parameters.

Природные ресурсы девясила высокого (Inula helenium L.) на территории Восточного Казахстана

This article presents the results of research on the assessment of natural resources of a medicinal plant used in both scientific and folk medicine – high-grade elecampane on the territory of East Kazakhstan. In the course of the research, two promising cenopopulations (Ushbulak and Seleznevskaya cenopopulations) of high-grade elecampane on the territory of the Listvyaga and Ulbinsky ridges were identified for the procurement of medicinal raw materials. The biological and operational reserves of rhizomes and roots, as well as the volume of annual raw material procurement, have been determined. Due to the location of the thickets of Inula helenium in the Ushbulak cenopopulation near the village of Ushbulak, the herbage is partially disturbed by cattle grazing, which affects the growth of Inula helenium in the herbage. The results obtained can be used to clarify the possible resources of an important medicinal plant and to develop measures for the protection of this species in East Kazakhstan.

긴급 에너지 자립 섬에서 신재생에너지 연계 ESS의 예비력 공급에 따른 분산전원의 최적용량 산정

In this paper, we introduce a linear programming model to find optimal capacity for distributed power generating units and energy storage systems (ESSs) directly connected to solar photovoltaic systems or wind turbine generators. The ESSs are used to relieve the variability of renewable generators and provide operating reserves. The proposed optimization model minimizes the total annualized cost including construction and operation costs for generators and ESSs. A renewable portfolio standard and carbon dioxide emissions reduction target are applied to the optimization model as environmental policies. To examine the impacts of implementing the environmental policies and providing operating reserves by the ESSs, case studies are conducted, and results are compared. The optimal results obtained from the proposed model show that the total cost is reduced, and installed capacity of fossil-fired generators is smaller compared to when ESSs do not provide operating reserves.

К изучению ресурсов лекарственных растений Атырауской области

The study of medicinal plant resources is important for the organization of a system of rational environmental management and environmental monitoring. Resource surveys of the natural territories of the Atyrau region were carried out to determine the potential for procurement of medicinal raw materials. Thickets suitable for harvesting were identified for 10 species of medicinal plants. The localization sites of thickets, the yield of plant raw materials (for air-dry weight), abundance and operational reserves were determined. The following areas of thickets and volumes of potential collection of raw materials were established: Peganum harmala — 22.5 hectares and 116.95 tons; Alhagi pseudoalhagi — 228.0 hectares and 196.05 tons; Alhagi persarum — 12.3 hectares and 13.21 tons; Scabiosa isetensis — 12.3 hectares and 4.2 tons; Artemisia terrae-albae — 40.2 hectares and 13.43 tons; Tanacetum santolina — 2.3 hectares and 0.9 tons; Helichrysum arenarium — 15.4 hectares and 2.1 tons; Anabasis aphylla — 126.0 hectares and 24.89 tons; Glycyrrhiza glabra — 36.2 hectares and 20.48 tons; Althaea officinalis — 88.0 hectares and 14.24 tons. The obtained information on plant resources can be used in planning and organizing raw materials for the needs of the pharmaceutical industry of Kazakhstan.

Population Structure of Species of the Trifolium L. Genus in the Pasture Territory of Shirvan (Azerbaijan)

The place of research is the pasture territories of 11 administrative districts of Azerbaijan. The names of plant groups were carried out according to the dominant species, the abundance — according to the Drude scale. The age indices and indices of clover efficiency were studied. Biological and operational stocks of Trifolium L. species were determined in the Shirvan districts. Research results data: Trifolium medium — 8399.5 t; T. caucasicum — 12000 t; T. canescens — 47973 t; T. campestre— 4315 t; T. bonannii — 1119 t; T. tumens — 3164.4 t. The total biological stock of representatives of the Trifolium L. genus is 76.971 tons, of which 10%, i. e. 7.69 tons are operational reserves. This indicates that these species are valuable fodder plants.