Operation Of Power Plants Research Articles

Optimal Scheduling of Virtual Power Plants Under a Multiple Energy Sharing Framework Considering Joint Electricity and Carbon Trading

The virtual power plant (VPP) is an excellent approach for mitigating the intermittency and fluctuation of renewable energy sources. The present work proposes an optimal scheduling model for VPPs to leverage the benefits of joint electricity and carbon trading from the perspective of multiple energy-sharing mechanisms. First, the optimal sharing scheduling model of the electric, thermal, and hydrogen energy was established. The model integrates various components, including wind turbines, photovoltaic units, electrolytic cells, combined heat and power units, hydrogen-doped gas boilers, electric energy storage, thermal storage tanks, and hydrogen storage tanks. Then, the model incorporates a tiered carbon trading mechanism to minimize operating and trading costs. Finally, numerical results indicate that, compared with the independent operation of virtual power plants and the lack of joint electricity and carbon trading, the optimal scheduling scheme proposed in this paper reduces the total cost and carbon emissions of the three VPPs by 3.3% and 49.7%, respectively. This demonstrates that the proposed model can effectively reduce the total operating expenses of VPPs by facilitating the allocation of electric, thermal, and hydrogen energy and achieving low-carbon emission operations.

After the battle: Emergent norms and the silencing of dissent in a Norwegian wind power community

In the small municipality of Åfjord on the Norwegian coast, home to one of Europe's largest onshore wind power installations, we observed a shift in critical attitudes towards a specific wind power development plan. Initially considered legitimate standpoints within an ongoing debate over land use, these viewpoints transformed into silenced opinions, or acquiescence, as the project progressed from the planning stage to fully operational wind power plants. A demand for consensus emerged within the local community. Through qualitative analysis of in-depth interviews with concerned stakeholders and community members, we employ a social norm perspective to explore the catalysts behind that shift and discuss potential consequences of the transformation. The article transcends the conventional explanatory approach to opinions on wind power development and provides valuable insights to the field of research on social acceptance. Specifically, it demonstrates that key drivers of acceptance, such as economic spin-off effects, can evolve into codes dictating legitimate behaviour and opinions in host communities. This poses a potential threat to the free exchange of opinions and local democracy.

To the selection of battery parameters for a M1 category hybrid vehicle

Background: To optimize the operation of a hybrid vehicle power plant, it is necessary to correctly select the parameters of its traction battery, which significantly affect the control algorithm and charge-discharge balance. The presence of a methodology that allows one to make a reasonable choice depending on the characteristics of the target vehicle, the conditions and modes of its operation will make it possible to increase energy efficiency indicators.Aims: The work aim was to develop a methodology for calculating the parameters of a hybrid vehicle traction battery using the energy charge-discharge balance of its power plant.Matherials and methods: A mathematical model of the charge-discharge energy balance has been proposed. Using this model, it is possible to make appropriate calculations on the amount of energy expended by the power plant when a vehicle moving through the stages of the European urban cycle, and analyze various algorithms for controlling it to achieve maximum energy efficiency, as well as select capacity and pover of traction battery. The basis for the calculations was the cycle described in UN Regulation No. 83.Results: The process of energy accumulation in a traction battery is considered, and criteria for choosing an algorithm for the operation of the vehicle’s power plant are indicated. The energy of vehicle movement in the urban cycle was determined, taking into account the operating time of the units, and the charge-discharge energy balance was calculated, which, in turn, made it possible to find the proper battery capacity. It has been established that the battery charge value at the end of the cycle should be equal to the initial value, which allows the use of a lower capacity battery and ensure maximum energy efficiency of the power plant. Also, based on the calculation results, recommendations were made regarding the optimization of the specific energy and weight-size parameters of the battery.Conclusions: The proposed methodology allows for a reasonable choice of а hybrid vehicle power plant parameters to ensure its energy efficiency.

Atmospheric 14CH4, 14CO2 and 37Ar measurements around a Swiss pressurized water reactor during an annual revision period

Since the 1980s, radiocarbon (14C) has gained attention as a valuable tool to quantify the amount of fossil and non-fossil emissions of CO2 and CH4 in the atmosphere. Since the 1970s, however, important 14C emissions in the atmosphere also occur through the operation of nuclear power plants. The limited knowledge about these emissions challenges the use of 14C as a universal source apportionment tool. Depending on the reactor type, 14C is emitted in different forms; in particular, pressurized water reactors emit 14C as a mixture of 14CH4 and 14CO2. However, few atmospheric 14C measurements close to nuclear power plants are available, which mostly address 14CO2 emissions. Argon-37 (37Ar) can also be produced in nuclear reactors; however, its atmospheric measurement is challenging, resulting in limited available data. In this study, we sampled ambient air during 20–75 min into 18 individual bags around the pressurized water reactor in Gösgen, Switzerland, at the beginning of the annual revision period in 2019, when 14C and 37Ar emissions can be expected due to the depressurization of the reactor. These samples were analyzed for 14CH4, 14CO2 and partly for 37Ar. About 1 km downwind of the stack, we found background-corrected activities up to 1900, 370, and 93 mBq m−3 respectively. Considering corresponding background activities of 0.3, 48 and 2 mBq m−3 for 14CH4, 14CO2, and 37Ar, this represents an excess of about 6300, 7.4, and 47 times, respectively. Using an atmospheric dispersion model, we satisfactorily simulated the 14CH4 and 14CO2 activities in the surroundings of the reactor during this event. Our measurements emphasize the importance of nuclear power plants in the interpretation of atmospheric 14C measurements and show that pressurized water reactors represent a serious limitation in the use of 14C for source apportionment of CH4 sources. Our results also provide insights into the approximate magnitude of civilian 37Ar emissions from nuclear facilities specifically during maintenance operations.

Detecting Geothermal Operational Asset Anomalies Using the Locality-Sensitive Hashing (LSH) Algorithm

Geothermal power plants are crucial for sustainable energy generation, necessitating the reliable maintenance of their operating assets. This research proposes an approach for asset maintenance through anomaly detection using the Locality- Sensitive Hashing (LSH) algorithm. The accuracy and coverage of traditional anomaly detection approaches in geothermal power plants may be constrained by sensor monitoring systems. The LSH algorithm is used to improve detection skills and get a full understanding of the state of important assets. The proposed method utilizes historical sensor data collected during geothermal power plant operations. This data is transformed into hash codes using LSH, effectively capturing similarities between various operational states and asset conditions. By comparing the hash codes of the current operational state with a library of precomputed hash codes representing typical operating conditions, the LSH algorithm can identify deviations indicating potential irregularities. This facilitates early detection of anomalies, even in large-scale databases, enabling prompt maintenance interventions. The application of anomaly detection using the LSH algorithm provides benefits such as improved asset maintenance planning, reduced downtime, and increased operational safety. By leveraging data-driven analysis and the effectiveness of LSH, geothermal operators can detect faults early, enabling prompt interventions and optimizing reliability and efficiency. By leveraging historical sensor data and the efficient similarity approximation capabilities of LSH, the proposed approach enables early diagnosis of problems, improving maintenance planning and optimizing geothermal operations. Keywords: geothermal assets, locality-sensitive hashing, asset condition, fault detection, reliability

Two-stage distributionally robust optimization operation of virtual power plant considering the virtual energy storage of electric vehicles

Virtual Power Plant (VPP) is a key to aggregate various distributed energy sources. With the vigorous rise of various distributed energy sources, the direct access of large-scale electric vehicle load will increase the complexity of VPP coordinated operation. Hence, this paper proposes a VPP optimization method for Electric Vehicle Virtual Energy Storage (EV-VES). Firstly, the travel characteristics of electric vehicles are analyzed, and EV-VES model is established to coordinate and manage the charge-discharge behavior of EV. Secondly, the “carbon charge rate” model of energy storage (ES) is introduced to establish the relationship between carbon emission and electricity price, and the VPP operation model considering the “carbon charge rate” of energy storage is established. Finally, the two-stage robust optimization operation model of VPP is constructed, Wasserstein distance is used to describe the confidence set of uncertain probability distribution of wind power generation and load, and the uncertainty of system source and load are described by the confidence set. The Column and Constraint Generation (C&CG) algorithm was used to determine the optimal operational benefit solution. The effectiveness of the proposed VPP optimal operation model was validated through case study.

Effect of hydrogen addition on the methane-air combustion under normal and reversed gravity

The existing scientific and technical results in the field of methane-air flames stabilization by adding hydrogen under various gravitational conditions were analyzed in relation to ensuring the safe operation of rocket and space power plants. Experimental setup was created for the purpose of studying the combustion stability of such fuel compositions under the various gravity conditions. The extended ranges of stable combustion rates were obtained experimentally at different percentages of hydrogen added to methane-air mixture under the both normal and reverse gravity conditions. The existence of a lean methane-hydrogen-air flame under reverse gravity in contrast to normal gravity conditions was observed. The influence of hydrogen addition on the dynamics and flame shape at such conditions was studied. The greater influence of hydrogen in ensuring stable combustion of a lean flame under reverse gravity than under normal gravity was demonstrated. Furthermore, the findings substantiated the rationale for utilizing hydrogen to expand the operational stability of burner devices.

Environmental Impact of Wind Farms

The aim of this article is to analyse the global environmental impact of wind farms, i.e., the effects on human health and the local ecosystem. Compared to conventional energy sources, wind turbines emit significantly fewer greenhouse gases, which helps to mitigate global warming. During the life cycle of a wind farm, 86% of CO2 emissions are generated by the extraction of raw materials and the manufacture of wind turbine components. The water consumption of wind farms is extremely low. In the operational phase, it is 4 L/MWh, and in the life cycle, one water footprint is only 670 L/MWh. However, wind farms occupy a relatively large total area of 0.345 ± 0.224 km2/MW of installed capacity on average. For this reason, wind farms will occupy more than 10% of the land area in some EU countries by 2030. The impact of wind farms on human health is mainly reflected in noise and shadow flicker, which can cause insomnia, headaches and various other problems. Ice flying off the rotor blades is not mentioned as a problem. On a positive note, the use of wind turbines instead of conventionally operated power plants helps to reduce the emission of particulate matter 2.5 microns or less in diameter (PM 2.5), which are a major problem for human health. In addition, the non-carcinogenic toxicity potential of wind turbines for humans over the entire life cycle is one of the lowest for energy plants. Wind farms can have a relatively large impact on the ecological system and biodiversity. The destruction of animal migration routes and habitats, the death of birds and bats in collisions with wind farms and the negative effects of wind farm noise on wildlife are examples of these impacts. The installation of a wind turbine at sea generates a lot of noise, which can have a significant impact on some marine animals. For this reason, planners should include noise mitigation measures when selecting the site for the future wind farm. The end of a wind turbine’s service life is not a major environmental issue. Most components of a wind turbine can be easily recycled and the biggest challenge is the rotor blades due to the composite materials used.

Aspects of commercialization of small nuclear power plants in Russia and Mongolia

Subject. The article considers prospects for the development of nuclear energy, global problems of energy supply. Objectives. The aim is to identify the socio-economic efficiency of creation and operation of low-power nuclear power plants. Methods. The study employs methods of systems, comparative, structural, and logical analysis. Results. We analyzed prospects for the operation of low-power nuclear power plants, revealed their advantages and disadvantages, proposed recommendations to increase the level of usefulness and reduce the cost of low-power nuclear power plants. Conclusions. Small-scale nuclear power plants have the potential to provide a more sustainable and secure energy future for the world.

The development of international civil liability legal regime for nuclear damage and their inspiration for domestic law-making

As International Atomic Energy Agency has stated in its Handbook on Nuclear Law, “Even in situations for which the highest standard of safety has been achieved, the occurrence of nuclear accidents cannot be completely excluded.” Therefore, the international legal framework for nuclear damage compensation liability has been evolving since the establishment of Nuclear Energy Agency of Organization for Economic Co-operation and Development (OECD NEA) and International Atomic Energy Agency (IAEA). Over the years, various international treaties have been enacted to address the compensation of nuclear damage and to establish liability regimes for nuclear incidents. To date, these treaties have established a series of legal principles of nuclear damage liability, such as the sole liability principle, the strict liability principle, the financial guarantee principle etc., which have been developing since establishment. This paper offers an overview of the historical development of the principles of these international treaties for nuclear damage liability and thus draws upon both primary and secondary sources, including treaties, official documents, academic literature, and reports by international organizations. Including the legislation study methodology, comparative methodology is also adopted in this paper to analyze the changes and trend of these principles. The paper reveals that the Paris Convention, which was established in 1960, was the first attempt to establish a comprehensive legal regime for nuclear damage liability. Most of the principles of this Convention have been inherited by subsequent international treaties and domestic legislations. With the awareness of protecting public’s rights having been significantly strengthened, the range of compensation has been broader, the matters of immunity from liability for operators of nuclear power plants have been reduced, the limitation of the compensation amount has been higher etc. In conclusion, the international legal regime for nuclear damage liability has been showing a shift from protecting the development of the nuclear industry to a joint protection of both public health and rights and the nuclear industry, which should be paid attention to and deeply learnt by domestic legislators of all states for the establishment and perfection of their domestic legislation in this field.

Studi Medan Elektromagnetik pada Pembangkit Listrik Tenaga Surya

This research investigates the electromagnetic field (EMF) characteristics generated by solar power plants, focusing on their potential environmental and health impacts. The study employs a dual methodology combining direct measurements using gaussmeters and computer simulations using COMSOL software to map electromagnetic fields around solar power installation components. Measurements were taken under two conditions: during solar power plant operation and non-operation, to establish comparative baseline data. The research found significant variations in electromagnetic field intensity based on operational status and distance from components, particularly near inverters and cable networks. Results indicate that EMF levels are higher during operation, with field strength decreasing exponentially with distance from the source. These findings contribute to understanding EMF distribution patterns in solar installations and provide valuable insights for implementing appropriate mitigation strategies to ensure safe operation within established exposure standards.

Development of ultrasonic phased array technique for inspection of fir-tree type turbine blade root and disc-rim in nuclear power plant

ABSTRACT Steam turbines are crucial in both nuclear and thermal power plants, serving a key role in electricity generation. However, the operational lifespan of these turbines is often limited by failures in the turbine blade roots and disc rims due to fatigue, stress corrosion cracking and creep. Usage of reliable non-destructive technique during in-service inspection of turbine assembly is very important for decision making and safe operation of power plant. The conventional ultrasonic technique which is being employed currently suffers from access limitation, high inspection time and false calls during defect detection due to complex geometry of blade roots and disc rims. To address these issues, an advanced ultrasonic inspection technique using phased array technology was developed, specifically tailored for fir-tree type blade roots and disc rims. Ultrasonic Simulation studies were performed to determine the optimal parameters for phased array probes, ensuring the effective detection and precise sizing of crack-like defects. This manuscript presents the findings from these simulations, along with experimental results from phased array inspections of turbine blade root and disc rim mockup of turbine assembly in nuclear power plant.

Matching Analysis of Technical Parameters and Safety Standards for Nuclear Replacement of Coal-Fired Units

In the context of the growing share of renewable energy and the impending decommission of a large number of coal-fired units, nuclear energy is the only green energy that can replace coal power for a stable, clean, efficient, and large-scale power supply. This article compares the differences between coal power and nuclear power in terms of thermal system, thermal cycle, turbine parameters, and safety. It discusses the possibility of replacing the boiler of a coal power plant with nuclear power, that is, replacing the boiler of a coal power plant with a nuclear reactor for generation/heating/cogeneration. For coal-fired units with similar capacity that do not use a reheat cycle (at or below high pressure) and nuclear power units (such as a high-temperature gas-cooled reactor), as well as coal-fired units with a reheat cycle (ultra-high pressure and above) and nuclear power units (such as pressurized water reactors), there are great differences in steam parameters. In terms of steam turbines, the size of nuclear power units is relatively larger, requiring additional dehumidification measures. In addition, the safety factors and management methods considered in the site selection, construction, and operation of nuclear power plants are more stringent and complex, and comprehensive analysis and evaluation are needed in aspects such as waste treatment and accident emergency response. Except for the relevant provisions of the American Society of Mechanical Engineers code for pressure vessels, nuclear power units are not compatible with coal-fired units in terms of safety standards. Therefore, considering comprehensively, it is believed that the scheme of nuclear power replacing coal-fired units for power generation/heating/cogeneration program is not feasible at present.

Insights into the precipitation-dominated creep behavior of a 25Cr20Ni-Nb-N austenitic heat-resistant steel via interrupted creep

The creep behavior of austenitic heat-resistant steels (A-HRS) determines their application and safe operation in modern advanced ultra-supercritical power plants. To date, understating of the creep behavior and corresponding microstructural evolution has relied on creep rupture tests, therefore, the evolution of complex precipitates and their effects on properties remains debated. Here, a series of interrupted and ruptured creep tests were conducted on 25Cr20Ni-Nb-N (HR3C) steel at 700 °C under the stress of 180 MPa, 150 MPa and 120 MPa. It was found that the creep deformation was predominantly controlled by dislocation gliding that interacted with the secondary Z-phase dispersions in grain interior. While the associated fracture mechanism was the intergranular fracture dominated by wedge cracking that was accelerated by the σ-phase and coarse M23C6 at grain boundaries. It was further demonstrated that the creep strengthening was dominated by the shearing mechanism originated from the secondary Z-phase dispersions. Conversely, the contribution of Orowan bowing from M23C6 and primary Z-phase became negligible as their coarsened size. Furthermore, it was clarified that the dominant strengthening of the secondary Z-phase and the subgrains to the microhardness development, whereas the contribution of M23C6 and σ-phase is slight.

Technical efficiency of SO2 scrubbers with byproduct contracts

This paper explores the impact of synthetic gypsum, a byproduct of sulfur dioxide (SO2) abatement, on the technical efficiency of SO2 scrubber technology. On average SO2 scrubbers are 60% efficient suggesting substantial emission reductions are possible by narrowing the efficiency gap. Gypsum marketability provides an economic incentive for improved power-plant operation of scrubbers with 8.8% average increases in technical efficiency. By contrast, we do not find any statistically significant evidence of innovative change in scrubbing technology.

Protection of Nuclear Power Plants from Fraudulent Items

At present a lot of problems with fraudulent items occurred. They disrupt the safety of industry, power engineering and other objects that are important for the life of human society. The article gives infor-mation on causes of occurrence of fraudulent items in nuclear power plants and shows that protection against fraudulent items needs to perform during the whole supply chain of critical items. In detail, it concentrates to the quality of awarding terms of references, which nuclear power plant operator prepares when it gives order to commercial supplier and of process of take-over control of the deliver commodity. Due to national security, the safety of nuclear facilities is also supervised by national nuclear regulatory body. During our research we processed checklists by which national nuclear regulatory body can reveal risks in awarding the contracts to commercial suppliers and in take-over control, and ensures improve-ment of these processes.

Investigation of Abnormal Level Control Oscillations in a BWR Feedwater System

In the long-term operation of nuclear power plants, the aging of systems, structures, and components can lead to maintenance issues that must be dealt with to maintain cost-effective plant operations. One common issue affecting the currently operated boiling water reactors is the onset of unexpected level oscillations in feedwater heaters. This phenomenon can cause excessive cycling of drain valves and lead to premature failures. In this work, we develop a dynamic model of a set of feedwater heaters to determine the root cause of oscillations observed in an operating plant. Simulation results of various transient scenarios were used to investigate the effects of the controller parameters, boundary conditions, and possible valve and instrument issues. The analysis led to the conclusion that the most likely causes of the observed self-sustained oscillations in the system are the nonlinear behaviors of the drain valve and the level transmitter induced by degraded equipment condition. A partial plug of the pressure line used for level sensing in the system can account for a significant deadtime in the level transmitter, a nonlinear effect shown to induce self-sustained oscillatory behaviors.

Damage to Steam Turbine Rotors Due to Asynchronous Connections of Electric Generators to the Unified Power System

The article aims to contribute to the ongoing study of damage to steam turbine rotors resulting from asynchronous connection of electric generators to the unified power system. At the present time, the assessment of the residual life of steam turbine equipment is based on the study of the degradation of the mechanical properties of steels and the analysis of the thermal stress state. The aim of this work was to determine the impact of such vibrations on the mechanical properties of rotors and their damage. This goal was achieved by solving the following tasks: developing a 3D model of the K-1000-60/3000 LMZ turbine unit shaft based on design documentation; calculating the stress-strain state of the shaft resulting from asynchronous connections using finite element analysis; and evaluating the level of metal damage in the rotors due to torsional vibrations. The developed mathematical model used a classical approach, replacing the working blades and bandage fastenings with concentrated masses and moments of inertia. The most important results are the calculated rotor damages that occur due to asynchronous connection of the turbogenerator to the unified power system with a synchronization angle of 30°. The greatest damage to the rotor metal was found in the shaft section between the steam turbine and the electric generator. The significance of the results obtained is that the use of this data will improve meth-ods for assessing the remaining life of turbogenerators. This, in turn, will improve the reliability and safety of power plant operations.

Технико-экономические показатели энергокомплекса при использовании ветроэнергетических установок для покрытия собственных нужд ТЭЦ

In accordance with the Russia Energy Strategy until 2035, within the framework of the implementation of energy-saving technologies in the power-generating sector, it is planned to use hybrid energy, which is one of the ways of transition from conventional generation to generation with a high share of renewable energy sources. However, to implement such complexes, it is necessary to conduct research that considers the natural and climatic characteristics of the region, its resource capabilities, as well as the mutual influence of conventional and renewable energy sources in the structure of generating equipment capacities. The wind potential at the construction site has been analyzed to assess the feasibility of incorporating wind turbines. Based on the technical characteristics of wind turbines and meteorological conditions, the model of wind turbines to be installed has been selected. Technical and economic indicators of the energy complex operation, providing for the use of wind power plants to partially cover the house load of CHPs have been obtained. The indicators are determined on an annual, monthly basis using the physical method of attributing the total fuel costs for heat and electricity output in case of their combined production. Operation of wind power plants as a part of the energy complex with CHP in winter has a positive effect on the process of thermal efficiency of combined heat and power generation, and in summer, on the contrary, leads to deterioration of the efficiency indicators. Relatively small fuel savings per year when using wind power plants as a part of the energy complex with CHP does not allow to consider the project cost-effective. The obtained results should be considered when making system-wide decisions on the development of renewable energy sources in parallel operation with fossil fuel power plants.

Estimation of the Put Option Value for Solar Power Plant Operators Participating in the Renewable Portfolio Standard (RPS) Spot Market

Estimation of the Put Option Value for Solar Power Plant Operators Participating in the Renewable Portfolio Standard (RPS) Spot Market