Hydro Resources Research Articles

From Curtailed Renewable Energy to Green Hydrogen: Infrastructure Planning for Hydrogen Fuel-Cell Vehicles

Problem definition: Hydrogen fuel-cell vehicles (HFVs) have been proposed as a promising green transportation alternative. For regions experiencing renewable energy curtailment, promoting HFVs can achieve the dual benefit of reducing curtailment and developing sustainable transportation. However, promoting HFVs faces several major hurdles, including uncertain vehicle adoption, the lack of refueling infrastructure, the spatial mismatch between hydrogen demand and renewable sources for hydrogen production, and the strained power transmission infrastructure. In this paper, we address these challenges and study how to promote HFV adoption by deploying HFV infrastructure and utilizing renewable resources. Methodology/results: We formulate a planning model that jointly determines the location and capacities of hydrogen refueling stations (HRSs) and hydrogen plants as well as electricity transmission and grid upgrade. Despite the complexity of explicitly considering drivers’ HFV adoption behavior, the bilevel optimization model can be reformulated as a tractable mixed-integer second-order cone program. We apply our model calibrated with real data to the case of Sichuan, a province in China with abundant hydro resources and a vast amount of hydropower curtailment. Managerial implications: We obtain the following findings. (i) The optimal deployment of HRSs displays vastly different spatial patterns depending on the HFV adoption target. The capital city, a transportation hub, is excluded from the plan under a low target and only emerges as the center of HFV adoption under a high target. (ii) Promoting the HFV adoption can overall help reduce hydropower curtailment, but the effectiveness depends on factors such as the adoption target and the grid upgrade cost. (iii) Being a versatile energy carrier, hydrogen can be transported to various locations, which allows for strategic placement of HRSs in locations distinct from hydrogen plant sites. This flexibility offers HFVs greater potential cost savings and curtailment reduction compared with other alternative fuel vehicles (e.g., electric vehicles) under current cost estimates. Funding: W. Qi acknowledges the support from the National Natural Science Foundation of China [Grants 72242106 and 72188101] and the Natural Sciences and Engineering Research Council of Canada [Grant RGPIN-2019-04769]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2022.0381 .

Возможности и проблемы энергогенерации в Республике Тыва

RELEVANCE. The energy sector forms the basis for functioning of other economic sectors and social services. Presentday technologies of energy generation are based on using coal, gas, oil, hydro, nuclear and renewable sources. PURPOSE. Analysis of the current state of energy generation in the Republic of Tyva, identification of drivers for development and optimization of its structure. RESULTS. A review is made of the current global trends in energy generation. Directions for diversifying energy generation sources are proposed, e.g. using both imported and coal seam gas as well as hydro resources along with coal. CONCLUSIONS. Focusing on only one energy source reduces the energy security of the region. Energy shortages and the presence of costly diesel-based power generation hinder the economic development of the Republic of Tyva. In the republic that has extensive coal reserves, coal generation has to introduce modern “clean coal” technologies. A high share of thermal power plants in the structure of the coal-fired generation capacity will allow the development of cogeneration using innovative, environmentally friendly Russian technologies. Options for solving the challenge of energy shortage in Tuva in the future until 2035 are proposed.

Frequency, duration, severity of energy drought and its propagation in hydro-wind-photovoltaic complementary systems

Analyzing low-renewable-output events, termed “energy droughts” is crucial for renewable energy systems. However, due to the challenges in hydropower regulation and complex spatiotemporal correlations among resources, the assessment and contributions of various resources to energy droughts in hydro-wind-photovoltaic (PV) energy systems (HWPSs) remain unexplored. To address these issues, this study evaluated energy droughts and compound resource droughts rather than single-resource in HWPSs, exploring the propagation. Assessments of frequency, duration, and severity relied on weather-to-resource conversion models and total power obtained through complementary operation. Estimating propagation probability from resource to energy droughts was achieved via the C-vine copula, quantifying resource contributions to drought propagation. Results of a case study in the Yalong River Basin indicated that (1) short-lived compound resource droughts have been increasingly frequent recently, peaking during winter or summer. After incorporating hydro energy resources, the severity and annual average occurrence of compound droughts decreased (from 18.56 to 5.24 events/year). (2) Complementary operation effectively reduced the probability of drought propagation. (3) Hydro and PV energy resources were pivotal contributors to drought propagation, contributing 49.1 % and 40.1 % when representing 53.4 % and 22.5 % of the total system capacity, respectively. Therefore, the study offers valuable insights into energy drought warnings and risk mitigation.

Emergency coordinated control of multiple VSC‐HVDC for improving power system transient frequency and steady‐state frequency

AbstractWith the penetration of the high proportion of power electronics interfaced energy resources, the frequency stability issue in power systems is becoming increasingly prominent. This paper proposes a coordinated control strategy of multiple voltage source converter based high voltage direct current transmission (VSC‐HVDC) to simultaneously improve the transient frequency and steady‐state frequency after a severe disturbance. Firstly, a modified average system frequency response (MASFR) model is constructed with reserve power limitation, which takes into account the frequency responses of different types of generators (thermal, hydro and new energy resources). Secondly, according to the frequency stability requirements, the corresponding constraints, which consider the overload capacity of VSC‐HVDC, the AC transmission capacity and the frequency of AC grids on both sides of VSC‐HVDC, are formulated. Thirdly, for the transient frequency control, the coordinated optimization control model of multiple VSC‐HVDC is established, which aims to minimize the control energy considering the transient frequency threshold. For the steady‐state frequency control, the coordinated optimization control model is fomulated, which aims to minimize the control cost while considering the steady‐state frequency threshold. The two control schemes achieve seamless and smooth switching. Finally, the correctness and effectiveness of the proposed control strategy are verified in the improved IEEE 39 bus system.

Multicriteria GIS-based assessment of biomass energy and hydropower potentials in Nigeria

The deployment of hybrid renewable energy systems remains the quickest way to salvage the dwindling grid supply in Nigeria and improve energy access. The assessment of biomass and hydro potentials across the geopolitical zones of the country to determine the optimal locations for a Biogas fired thermal plant for energy generation is thoroughly addressed in this paper. Multiple Geographical Information System (GIS) approaches were used to assess the energy potentials of crop and forest residues for biomass, as well as waterbodies, and waterlines for a hydrothermal power plant. The study applies the inverse distance weighting and weighted overlay multicriteria decision analysis. Forest areas, waterbodies, distance from water sources and road accessibility were considered for locating the biomass and hydrothermal facilities within multiple ring buffer distances of 200 m–2000 m from the combined biomass and hydropower resources. The result shows four states with potentials to host biomass-hydrothermal power plants in Nigeria; Niger, Kaduna, Bauchi and Taraba states with biomass potentials of 831.9 tonnes/yr, 1173.27 tonnes/yr, 322 tonnes/yr and 739.48 tonnes/yr, respectively and inland waterways. It further shows that these plants can be optimally located within 2000 m from the source of the biomass and hydro resources. This paper recommends the utilization of these results to carry out feasibility studies and make informed decisions on the exploration of these resources for power generation. It also advocates for a control in the commercialization of forest residues to sustain the production from these hybrid plants and supports the Nigerian bio-energy policy that proposes to effectively utilize the Nigeria's non-fuelwood as substitute to felling of trees.

МОДЕЛЬ ОПТИМАЛЬНОГО РОЗПОДІЛУ ГІДРОРЕСУРСІВ ГЕС З РЕЗЕРВУВАННЯМ ПОТУЖНОСТЕЙ ДЛЯ НАДАННЯ ДОПОМІЖНИХ ПОСЛУГ АВТОМАТИЧНОГО ВІДНОВЛЕННЯ ЧАСТОТИ

The publication is devoted to the development of a mathematical model for the optimal allocation of hydro resources among hydroelectric units of HPPs for the production of electric energy and the provision of automatic frequency res-toration reserves with an asymmetric adjustment range. The concept of building a mathematical model for the optimiza-tion problem is presented. The main goal of the optimization is to maximize the benefit of the power generation com-pany from the use of available hydro resources for the production of electricity and the provision of services for the regulation of IPS of Ukraine modes. Areas of determining the main characteristics of the operation mode of hydro-power units of HPPs were studied and a system of restrictions on the load capacity of hydrounits was formed. A system of restrictions to control the balance of water resources in the reservoir and a system of restrictions to control the val-ues of water runoff for hydroelectric power stations have been defined. For the level of the power generating company, a system of restrictions on the control of the minimum values of the volumes of electricity and ancillary services for the fulfillment of already concluded agreements, as well as a system of restrictions on the control of the volumes of electric-ity and ancillary services within the predicted volumes of market demand, has been formed. The structure is substanti-ated and the components of the target function are described. Approaches to solving the problem of forecasting the amount of electrical energy imbalances on the balancing market of Ukraine are defined. Peculiarities of the process of finding optimal solutions regarding the loading levels of hydropower units with available hydro resources have been studied. The presence of the effects of "economic impracticality of the full use of available water resources" was noted, and the main consequences of the manifestations of this effect were investigated. References 12, figures 3, tables 2.

Complementary assessment and design optimization of a hybrid renewable energy system integrated with open-loop pumped hydro energy storage

The intermittent nature of renewable energy resources is a major obstacle in utilizing such resources for power generation despite their abundance. In this paper, a dynamic analysis of an integrated system based on photovoltaic (PV) panels and wind turbines coupled with pumped hydro energy storage is presented. When the power generation exceeds the power demand, surplus electricity is used to pump the water to the upper reservoir. The natural inflow of the river obviates the necessity for oversized reservoirs and saves costs. A recently introduced multi-objective equilibrium optimizer algorithm is developed to find the optimal size of the integrated hybrid energy system. The objectives are to minimize the levelized cost of electricity and maximize the reliability of the proposed system. The results show that the correlation between solar and wind power generation in the selected location is mildly strong with a value of 0.3. The total energy generation from hydro, solar, and wind resources are 77,508.7 kWh, 103,323 kWh, and 47,375.4 kWh, respectively. Comparing the results with other algorithms indicates that the equilibrium optimizer has a better performance in finding the optimal design.

Evaluation of Energy Complementarity Between Wind, Solar and Water Resources in the Municipality of Lages (Santa Catarina, Brazil)

Purpose: Evaluate the energy complementarity between hydro, wind, and solar resources, and size a wind system and a photovoltaic system to meet the same production of the CGH Caveiras, (Lages/SC). Methods: Wind and solar systems were sized in order to meet the production of CGH Caveiras, from commercial models of equipment and considering data from 2017 to 2019. To assess complementary, data from the same period were obtained from the river monitoring station of ANA and the meteorological station of INMET. Results and Conclusion: In order to meet the demand of CGH Caveiras, only 1 medium sized wind turbine or 915 photovoltaic modules of the chosen models for the study would be necessary, and both systems could be used to compensate for periods of low hydroelectric production. The complementarity was confirmed through Pearson coefficients, where -0.39 was obtained between hydro and wind, and -0.32 between hydro and solar. Temporal complementarity indices, in turn, indicate complementarity between hydro and solar (κhs = 0.778) and between hydro and wind (κhe = 0.611). Research Implications: Both wind and solar resources exhibit complementarity with the hydro patterns of the study area, and either of the proposed systems, wind or photovoltaic solar, could be used in a hybrid manner with the existing hydroelectric system, especially during periods of droughts. Originality/value: Considering the scarcity of energy complementarity studies in Santa Catarina, as well as the impact of climate change on the hydrological regime and hydroelectric power generation, research of this nature is essential for the region’s energy security.

Is the Existing Hydropower Development Policy, 2001 Investment Friendly?

Nepal is endowed with an abundance of hydro resources. Its gross hydropower potential is estimated to be 83,290 MW technically. Out of which, 42,133 MW is ascertained as economically exploitable. However, in the span of 112 years, only around 2,900 MW is harnessed. It is obvious that the development of hydropower is a public policy-related matter. Previous studies exhibit several complications in hydropower development policy, 2001 such as private sector participation in electricity trade, lack of one window system, term of project, hedging mechanisms, foreign direct investment, and so forth. In this regard, this study aims to investigate its efficiency and effectiveness through quantitative research design. Herein, for the sake of empirical research three independent variables namely, Financial Incentives Sufficiency (FIS), Return on Investment Sufficiency (RoIS), and Market Access Sufficiency (MAS), and one dependent variable namely, Investment Friendliness (IF) was dealt. To collect the opinion of respondents a set of questionnaires comprising 11 questions was developed and approached to 108 informants from 25 diverse sectors of the hydro-industry. Herein, deductive reasoning was persuaded. For analyzing data, statistical tools such as arithmetic mean, standard deviation, factor analysis, Chi-Square tests, Mann Whitney "U" test, and Kruskal-Wallis "H" test were computed. Based on empirical analysis this study concludes that the hydropower development policy, of 2001 is investment-friendly. However, the study manifested a number of rooms that were to be addressed as changing the expectations of investors. On this ground, the findings of this study will be applicable with a view to formulating a more investment-friendly hydropower policy in the future.

Energy potential assessment and techno–economic analysis of micro hydro–photovoltaic hybrid system in Goda Warke village, Ethiopia

Abstract Rural Ethiopia has significant untapped potential for hydro and solar energy generation systems. However, challenges arise from seasonal variations and unfavourable topographic positions of flowing rivers, hindering the efficient exploitation of these resources. Despite the country’s abundance in hydro and solar energy resources, >75% of the population still lack access to electricity from the national grid. This work deals with energy resource potential assessment and techno–economic analysis of micro hydro–photovoltaic (PV) hybrid systems, considered in the case study of Goda Warke village, located in the Yaya Gulele district. A novel framework is proposed that utilizes the Natural Resource Soil Conservation Service curve number method to assess the energy potential of micro-hydro energy in ungauged basins, specifically at the exit point of the Girar River basin catchment. The average monthly flow rate in the basin is 0.975 m3/s, while the area exhibits a solar radiation potential of 5.39 kWh/m2/day. Energy policy promotes expanding access to modern energy sources and utilization of indigenous energy resources. Simulation results indicate that the hydro/PV/diesel generator (DG)/battery and hydro/PV/battery systems are the most optimal choices based on net present cost, with the inclusion of a DG for economic comparison. Micro-hydro energy covers most of the electric load in the area, achieving a capacity factor of 47.5%. The cost of energy and net present cost were found to be sensitive to variables such as the price of diesel fuel, pipe head loss, and the growth of the village load. The optimized system demonstrated a hydro energy potential of 1405.37 MWh/year and a PV energy output of 274.04 MWh/year, resulting in a levelized cost of energy of 0.0057 and 0.049 $/kWh for the hydro and PV components, respectively.

A real time integrated modelling and control of modified pumped storage governor-PSS damping action for random renewable penetration

The modern power system network is continuously being penetrated by asynchronous intermittent renewable generations like solar and wind sources. Also, hydro plants can be an integral part for future power generation along with pumped storage units, but their governors need to be modified to provide adequate damping torque. So, to meet these challenges a coordinated strategic control of a new two degree of freedom pumped storage hydro governor with power system stabilizer has been proposed here to damp rotor angle oscillations in power system. The modified governor can provide good regulation along with tracking of error signal and power system stabilizer is modified to provide fast response along with reduced transient and steady state error. The proposed control action is optimally coordinated by a modified differential evolution with gray wolf optimizer algorithm. A two area four machine and 39 bus modified New England hydro dominated system have been taken in this work. Proposed controller's performance has been justified by different critical oscillatory conditions as random solar and wind penetrations with time and frequency analysis. These experimentations have been conducted in MATLAB Simulink and verified with real time simulation based in OPAL-RT 4510. For optimal coordination a multi objective function has been considered here including minimization of speed and real power deviation, undershoot and overshoot with settling time. This control action is simple, easy to implement, less costly and much efficient to damp oscillations and will enhance usability of existing hydro resources.

International legal and economic aspects of joint use of the Paz River hydro-resources by the USSR, Finland and Norway in the 1920–1940s

The article deals with the fact that international legal relations of joint use of hydro resources of border rivers by Soviet Russia, Finland and Norway in 1920–1944 is an understudied topic among domestic and foreign researchers. This is largely due to the fact that the international legal interaction between the countries was contradictory, and the problems of security of border territories caused concern and could not create normal conditions for regional economic cooperation in this area.

Ensemble Learning Framework for DDoS Detection in SDN-Based SCADA Systems.

Supervisory Control and Data Acquisition (SCADA) systems play a crucial role in overseeing and controlling renewable energy sources like solar, wind, hydro, and geothermal resources. Nevertheless, with the expansion of conventional SCADA network infrastructures, there arise significant challenges in managing and scaling due to increased size, complexity, and device diversity. Using Software Defined Networking (SDN) technology in traditional SCADA network infrastructure offers management, scaling and flexibility benefits. However, as the integration of SDN-based SCADA systems with modern technologies such as the Internet of Things, cloud computing, and big data analytics increases, cybersecurity becomes a major concern for these systems. Therefore, cyber-physical energy systems (CPES) should be considered together with all energy systems. One of the most dangerous types of cyber-attacks against SDN-based SCADA systems is Distributed Denial of Service (DDoS) attacks. DDoS attacks disrupt the management of energy resources, causing service interruptions and increasing operational costs. Therefore, the first step to protect against DDoS attacks in SDN-based SCADA systems is to develop an effective intrusion detection system. This paper proposes a Decision Tree-based Ensemble Learning technique to detect DDoS attacks in SDN-based SCADA systems by accurately distinguishing between normal and DDoS attack traffic. For training and testing the ensemble learning models, normal and DDoS attack traffic data are obtained over a specific simulated experimental network topology. Techniques based on feature selection and hyperparameter tuning are used to optimize the performance of the decision tree ensemble models. Experimental results show that feature selection, combination of different decision tree ensemble models, and hyperparameter tuning can lead to a more accurate machine learning model with better performance detecting DDoS attacks against SDN-based SCADA systems.

ANALYTICAL REVIEW OF MODERN NON-CONVENTIONAL ENERGY SOURCES

The structure of the world energy economy has developed in such a way that 80 % of the electricity consumed is obtained by burning fuel at power plants, where the chemical energy of the fuel is first converted into heat, heat into work, and work into electricity. Hydropower also provides a significant percentage (about 15 %), the rest is covered by other sources, mainly nuclear power plants. Human needs are growing, there are more and more people, and this causes gigantic volumes of energy production and growth rates of its consumption. Today, traditional energy sources (various fuels, hydro resources) and technologies for their use are no longer able to provide the required level of energy availability of society, because these are non-renewable sources. And although the explored reserves of natural fuels are very large, the problem of depletion of natural reserves at the current and projected rates of their development is moving into a real and near future. Even today, a number of fields, due to depletion, turn out to be unsuitable for industrial development, and for oil and gas, for example, one has to go to hard-to-reach, remote territories, to ocean shelves, etc. The forecast proves that while maintaining the current volumes and growth rates of energy consumption at 5–7 %, fossil fuel reserves will completely run out in 70–150 years. Another factor limiting a significant increase in energy production through fuel combustion is the ever-increasing environmental pollution from energy production waste. These wastes are significant in mass and contain a large number of various harmful components. This is where acid rain comes from, the disappearance of ozone, the poisoning of farmland and water bodies. Moreover, nature is no longer able to process these pollution and self-repair by natural physico-chemical and microbiological methods.
 In nuclear power, environmental problems of a different kind arise. They are associated with the need to exclude the ingress of nuclear fuel into the environment and the reliable disposal of nuclear waste, which, with the current level of development of technology and technology, is associated with great difficulties.
 No less harmful is the thermal pollution of the environment, which can lead to global warming of the Earth's climate, melting of glaciers and rising sea levels.
 In the light of the above, the widespread practical use of non-traditional and renewable energy sources, which are also environmentally friendly and do not pollute the environment, is becoming increasingly relevant.
 The article briefly presents an analytical review of modern non-traditional and renewable energy sources.

On the Feasibility of Building Mini-Thermal Power Plant Using Local Fuels in the Conditions of the Republic of Belarus. Part 2. Role of Mini-Thermal Power Plant in Heat Supply Systems of Cities and Settlements in Belarus

. Within the framework of ensuring the country's energy security and pursuing a policy of decarbonization of the economy in the Republic of Belarus, it is assumed to maximize the use of its own fuel and energy resources (TER). 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 unit cost of power generation capacities running on LF inclines the scales to use boiler houses as heat sources. Based on the world experience in the development and application of heating as the most energy-efficient solution in the field of heat supply, this problem has been studied in the conditions of Belarus. It is shown that the electric capacity of mini-thermal power plants using traditional LF connected to the unified system of the country is less than 100 MW, and the main technologies implemented at mini-thermal power plants using LF in the Republic of Belarus are traditional steam power plants with water steam as the working fluid (11 power plants) and steam power plant with organic Rankine cycle (ORC) (3 power plants). Geographically, mini- thermal power plants operating on LF are located evenly throughout the entire territory of the Republic of Belarus. The number of hours of use of the installed capacity of renewable energy sources (RES) of the Republic of Belarus has been determined. Energy sources based on organic waste and biomass (over 4,000 hours per year) and on hydro resources (about 3,500 hours per year) have a clear advantage, for which indicator of the number of hours of installed capacity use is much higher than for solar and wind power installations. In addition, biomass generating capacities have the lowest coefficient of electricity supply to the combined energy system. Based on the analysis of modern trends in the development of energy, technical and economic “attractiveness factors” for the construction of heating systems for heat supply on LF in the conditions of Belarus have been formulated, which, in addition to traditional factors (substitution of imported fuel – natural gas and oil), include improvement of the quality and reliability of energy supply to consumers in remote locations, development of polygeneration, reduction of losses of electric energy for its transport, participation in covering the electric load schedule of the unified power system, and also indicated the possibility of creating an energy hub on the basis of a mini-thermal power plant, structured for the integration of energy sub-sectors, distributed generation sources and the option of generating “green” energy carriers.

Integrating hydro and wind resources for effective congestion management in a hybrid electricity market

Congestion management in deregulated electricity systems threatens system security and reliability. Integration of renewable energy sources, unpredictable wind power, load demand, and the requirement for quickly deployable reserves make congestion management more difficult. While deciding the dispatch of the generating units, many factors have to be considered for the economic, secure, and reliable operation of the power system. This study presents a congestion management strategy that has been developed specifically for hybrid power systems. Within a pool and bilateral power supply market structure, it introduces a generator rescheduling-based congestion management technique. Ensuring safe bilateral transactions between these companies is crucial. Renewable sources affect congestion management dynamics, according to the research. The optimization issue includes operational limitations for scenarios with and without renewable source units. Monte Carlo simulation (MCS) was used to sample hourly wind speed from the Weibull PDF wind model. GAMS CONOPT solver used the model. General Algebraic Modeling System (GAMS)-MATLAB interface imported the model into MATLAB to extract the response. The best combination of renewable sources is 2 hydro + 1 wind unit as savings of congestion cost are $1403.6/h and $1855.18/h in case 1 (3-line congestion) and case 2 (2-line congestion), respectively. Results were accomplished by updating the IEEE-24 bus reliability test system with hydro and wind generators.

ФОРМУВАННЯ ГРАФІКА ПРОПОЗИЦІЇ ГЕС НА РИНКУ «НА ДОБУ НАПЕРЕД» МЕТОДАМИ УМОВНОЇ ОПТИМІЗАЦІЇ ЗІ ШТРАФНИМИ ФУНКЦІЯМИ

Mathematical models are given for forming the schedule of electric energy supply from hydroelectric power stations for bidding in the "day-ahead" market segment. The formulation of the task of forming the supply schedule as a task of optimal use of available hydro resources for the production of electrical energy at hydroelectric power stations is described. The need to perform two-stage optimization based on price and non-price criteria is substantiated. It is proposed to consider non-price criteria by means of penalty functions in the objective function of optimization by price criteria. A system of basic technological limitations, as well as equations for control and adjustment of the reservoir filling level, is given. The results of practical calculations for both optimization options are presented. References 9, figures 3.

Risk Aversion and Hydro-energy Reservoirs Management under Monopolistic and Oligopolistic Industrial Structures

This article analyses management of hydropower dams within monopolistic and oligopolistic competition and when hydroelectricity producers are risk averse and face demand uncertainty. In each type of market structure we analytically determine the water release path at the closed-loop equilibrium. In the monopolistic case, we demonstrate that intertemporal allocation of hydro resources is done by additional pumping or storage depending on the relative abundance of water between different regions in order both to internalize the risk and to smooth the effect of uncertainty on electricity prices. In the oligopolistic case, we determine the conditions under which the relative scarcity (abundance) of water in the dam of a hydroelectric operator can favor additional strategic pumping (storage) in its competitor’s dams. Finally, we compare the effects of risk aversion on the output industry. We show, in monopolistic case, that the greater the generators’ risk aversion the larger the current water storage for future demands. In the oligopolistic case, however, the risk aversion increasing may be either in favor of reducing or increasing the total hydro output depending on demand uncertainty and market power parameters. We deduce that risk aversion coupled with market power may induce, under some condition, a misallocation of hydraulic resource across time.

GEORGIA’S ENERGY INDEPENDENCE

Every country wants to be energy independent. It is quite diffi cult to achieve or someƟ mes prac-Ɵ cally impossible. Georgia has declared its desire to have energy independence so that external poliƟ cal or eco-nomic factors will have less infl uence on the country's domesƟ c markets. Georgia was able to open up the energy trains of Russia as much as possible. Therefore, the ongoing war between Russia and Ukraine had less impact on Georgia compared to other European states. Achieving energy independence requires developing a well-thought-out plan and successfully achieving the milestones outlined in that plan. Georgia does not import electricity more than 8-10% each year, but thermal power plants that use natural gas as the main resource generate about 20-25% of electricity. Therefore, there is necessary to import natural gas from neighbouring countries for electricity generaƟ on. Today, there is a need to use renewable and abundant hydro resources, for which state support and appropriate measures are required.

ОПТИМИЗАЦИЯ РЕЖИМОВ РАБОТЫ ГЭС НА ОСНОВЕ ТЕОРИИ ПРЕДЕЛЬНОЙ ПОЛЕЗНОСТИ И ОЦЕНКИ СТОИМОСТИ ГИДРОРЕСУРСА

The purpose of this article is to solve the problem of optimizing the operation of a hydroelectric power station based on the theory of marginal utility and assessing the cost of a hydro resource, taking into account the characteristic modes of operation of a hydroelectric power station. In this work, a universal method, which combines an optimization method and a method for assessing marginal utility. The method developed by the authors involves use the adequate representation of the incremental rate characteristic and the determination of the cost of the hydro resource for the control of the operating modes of the HPP. Using the example of the Novosibirsk HPPs and TPPs, an assessment of the energy efficiency, proposing the concept of a developed methodology for determining the price of water for HPPs, will be obtained. Based on the results of the implementation of the developed approach at Novosibirsk HPPs, the electricity sales price competitive electricity market can be matched with the electricity sales price generated at TPP, which will be approximately 370 ¢/kWh