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, Available online , doi: 10.16516/j.ceec.2024-266
Abstract:
Objective The structure of the wind power generation system is complex, and in order to achieve efficient testing and control algorithm verification of the wind power generation system, it is necessary to simulate the wind power generation system in real time. At present, there is a lack of domestic real-time simulation and verification platform for wind power generation systems in the market. Method A hardware-in-the-loop co-simulation system architecture based on Bladed and HiGale was proposed, and the real-time co-simulation of Bladed and HiGale through BHTM was realized for hardware-in-the-loop testing of wind power system controllers. Result In this paper, a typical semi-direct drive permanent magnet synchronous motor wind power generation unit is taken as an example, and a hardware-in-the-loop accompanying test model is built, which is mainly composed of wind field model, mechanical transmission and electrical model, and the co-simulation platform was used to test the performance of the hardware under three working conditions: grid-connected control, pitch control and low-voltage ride-through. Conclusion On the one hand, the experimental results verify the effectiveness of grid-connected control and pitch control algorithms. On the other hand, it is also proved that the platform can provide reliable technical support in the development and testing stage of wind power generation systems, which is of great engineering significance for improving system R&D efficiency and saving R&D costs.
, Available online , doi: 10.16516/j.ceec.2024-413
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Objective The hydrogen production system based on solar electrolysis of water is limited by the volatility and intermittency of solar energy, the conversion efficiency of the photovoltaic system, and the performance of the electrolysis cell. Through the performance and stability analysis of a hydrogen production system based on solar electrolysis of water, it can provide data support for technology research and development, promote the optimal design of system components, and then accelerate the commercialization process of solar electrolytic water to hydrogen technology, and help scale up the application of hydrogen energy industry. Method This paper proposed a solar photovoltaic (PV) cell indirectly coupled electrolyzer hydrogen production system. The research included the effects of light intensity and ambient temperature on the output performance of PV cells, analyzed the role of the storage battery in stabilizing the input power of the proton exchange membrane electrolyzer, and verified and evaluated the performance of the proposed system based on the summer climatic data of Tianjin city. Result Studies have shown that an increase in light intensity at a constant ambient temperature increases the PV power. When the light intensity is constant, the increase in ambient temperature will lead to a decrease in PV power generation. The battery can well stabilize the power of the electrolytic tank. Conclusion Through the dynamic analysis of the all-day operation of the hydrogen production system based on solar electrolysis of water, it is verified that the system contributes to the stable hydrogen production around the clock, which provides a valuable reference for the large-scale photovoltaic cell indirectly coupled electrolyzer hydrogen production system.
, Available online , doi: 10.16516/j.ceec.2025-062
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Objective In view of the urgency of global greenhouse gas emission reduction, comprehensive research on CO2 capture technologies, widely applied in coal-fired power generation, steel, cement, oil refining, and chemical industries, has been conducted. This research aims to provide technical support for effectively controlling CO2 emissions and promoting low-carbon development. Method This paper introduced the principles, advantages, disadvantages, and application status of four CO2 capture technologies: absorption, membrane separation, cryogenic separation, and adsorption. It also summarized the principles, advantages, disadvantages, and research progress of temperature swing adsorption, pressure swing adsorption, and pressure-temperature swing adsorption. Result The research found that each technology and method has its own advantages and disadvantages. The absorption and adsorption methods are considered to be more economical. However, the widely used chemical absorption method is prone to problems such as equipment corrosion, solvent loss, and high energy consumption. In contrast, the adsorption method utilizes adsorbents to capture CO2, which does not cause equipment corrosion, and the adsorption and regeneration processes are easy to operate. Among the adsorption methods, desorption by temperature swing adsorption is complete, but it has large energy consumption. Pressure swing adsorption has low energy consumption but relatively limited adsorption capacity. While pressure-temperature swing adsorption shows potential in balancing energy consumption and adsorption effectiveness. Conclusion In the chemical industry, CO2 capture via small modular equipment can satisfy the small-scale CO2 capture demands of particular experiments. This approach is characterized by low investment costs and easy installation. However, future research should focus on the development of new capture technologies that are highly efficient and energy-saving, or the optimized integration of current technologies. Such efforts aim to reduce costs, boost capture efficiency, thereby making a positive contribution to global greenhouse gas emission reduction and sustainable development.
, Available online , doi: 10.16516/j.ceec.2024-410
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Objective In case of hydrogen leakage, it can quickly diffuse and mix with the surrounding air, forming a combustible vapor cloud, which may cause combustion and explosion accidents. Numerical simulation of this process can effectively help engineers and workers reduce risks. Method Using Fluent computational fluid dynamics software, simulation and analysis were conducted on various hydrogen-related facilities of the "Delingha PEM Water Electrolysis for Hydrogen Production Project", such as H2 release ports, O2 release ports, 20 MPa high-pressure tube bundles, and 2.8 MPa large-capacity storage tanks, to evaluate the consequences of continuous leakage incidents under environmental wind speed and temperature conditions. Result The results indicate that: 1) the H2, O2 release ports do not pose a risk of hydrogen explosion or create an oxygen-rich environment outside the hydrogen production plant. The main potential hazards are ignition sources such as naked fire and sparks that could trigger fires. It is recommended to install static elimination devices, and, whenever possible, recycle oxygen; 2) Regarding the high-pressure tube bundles and storage tanks, the differences are that the hydrogen leakage rate of high-pressure tube bundles are fast, and the leakage time of the storage tanks is long. It is recommended to install thermal imaging hydrogen detection and alarm devices in conjunction with the construction of protective walls, limit access for personnel, and prohibit operators from carrying ignition sources and non-explosion-proof apparatus into hazardous areas. Conclusion The patterns of hydrogen leakage and diffusion across different scenarios offer strong theoretical support the design of the hydrogen leakage safety warning system during the project implementation phase and for risk reduction.
, Available online , doi: 10.16516/j.ceec.2025-040
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Objective As hydrogen energy has gained new momentum recently, analyzing the economic and social impacts of developing a hydrogen energy sector can inform further policy formation and investment decision making in this regard. Method Considering the increasingly important role of East Asia Summit (EAS) region in both economic growth and green energy transition, we developed a demand-driven model for the hydrogen energy supply chains to comprehensively and quantitatively evaluate the economic and social impacts hydrogen energy development in the EAS region. Result This model provides estimates of the capital investment required, the number of new jobs created, the potential carbon emissions reduction, the subsidies needed in the early stages of development, and the impacts on key energy security indicators. Conclusion We find that hydrogen energy development has a significant job creation effect, and that the total investment the fiscal burden appear to be manageable for countries in the EAS region. In addition to substantial carbon emissions reduction, positive social impacts also include general improvements in energy security indicators.
, Available online , doi: 10.16516/j.ceec.2024-292
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Introduction The efficiency of existing compressed air energy storage is not high enough, and the site selection is limited by the gas storage condition, which is not beneficial to the large-scale replication of compressed air energy storage. In order to improve the efficiency of compressed air energy storage, a gas turbine-based binary cycle gas compression energy storage system was proposed. Method The compression and expansion process of the gas turbine was decoupled, and dual-working substance gas storage system with constant pressure variable volume operation method in a gas chamber was utilized. Energy storage and power generation could be realized through coordinated operation of the air working substance energy storage loop and CO2 working substance energy storage loop. Preliminary thermodynamic calculations and engineering feasibility analysis were conducted on the binary cycle gas compression energy storage system based on 50 MW industrial gas turbine. Result The results show that the energy storage efficiency of the system is about 80%, reaching the level of pumped hydro energy storage, higher than that of conventional gas compression energy storage, but lower than that of lithium-ion battery energy storage. The cost level of the system is between pumped hydro energy storage and lithium-ion battery energy storage, slightly lower than that of salt cavern compressed air energy storage. Conclusion For regions with abundant fuel resources such as natural gas and hydrogen energy, the gas turbine-based binary cycle gas compression energy storage system can be applied in the scenarios such as high energy consuming industries, new energy bases, and electricity grid, and it has good engineering feasibility as well as commercial competitiveness potential.
, Available online , doi: 10.16516/j.ceec.2024-398
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Objective FeCrAl alloys have shown promise as candidate materials for accident tolerance fuel cladding because of their excellent high-temperature strength, irradiation resistance, and mature fabrication technology. There are fewer studies related to the thermal and irradiation creep of FeCrAl alloys due to the high cost, long cycle time and difficult testing of neutron irradiation. The thermal and irradiation creep behavior of FeCrAl alloys were examined. And, the effects of irradiation dose rate, temperature and stress on the creep rate and parameters of the creep constitutive equations were analyzed. Method The creep simulations were performed on several FeCrAl samples with different grain sizes over a wide range of temperature, stress, and irradiation dose rates, using LAMMPS molecular dynamics simulator. Result The results show that the irradiation creep rate is significantly lower, compared to the thermal creep rate. As stress rises, the thermal creep rate increases exponentially, and the stress exponent increases roughly from 0.9 to 2.0 at the turning point of 0.8 GPa. The irradiation creep rate increases linearly with stress and dose rate, that is, the exponents of both dose rate and stress for irradiation creep are very close to 1.0. Besides, higher temperatures accelerates the linear increase of irradiation creep rate with dose rate, and the irradiation creep pre-factor becomes larger. Conclusion The creep of FeCrAl alloys under conditions of high temperature and irradiation is mainly attributed to the thermal creep behavior. Higher temperatures and stresses accelerate the irradiation creep process.
, Available online , doi: 10.16516/j.ceec.2024-427
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Objective The paper aims to focus on the field of nuclear fusion energy, conducting an in-depth study of related technologies and the development trends of industry chains. By reviewing the development history, analyzing the current situation, and predicting future trends, the paper comprehensively examines the development trends of energy technology and industry chains. Method Based on multiple authoritative industry surveys, data analysis was conducted to organize the development history and current status of the nuclear fusion industry, analyze the trends in technological innovation and the distribution of technology fields, discover the intrinsic connections between technology, policy, and capital, predict the future direction of the industry, and reveal the development trends of the industry through data analysis. Result The study indicates that private enterprises are gradually becoming an important force in the nuclear fusion industry. Investors' confidence in the potential of nuclear fusion energy is continuously strengthening. Policies issued by governments around the world have greatly promoted the vigorous development of the nuclear fusion industry. American companies have the broadest involvement in various technological fields of nuclear fusion, with a proportion of involved fields 1.7 times that of the second-ranked United Kingdom, and significantly higher than other countries. Almost all nuclear fusion companies have targeted power generation as their main market. In the derivative fields, industrial heat accounts for 28.6% of the derivative market choices in the entire survey, becoming the mainstream choice for most companies. There is a mutually reinforcing supportive relationship between technology, policy, and capital. Conclusion Looking at the development patterns of the nuclear fusion industry in recent years, technological innovation will continue to advance, capital will continue to expand, and policies around the world will remain optimistic.
, Available online , doi: 10.16516/j.ceec.2024-251
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Objective During the development of China nuclear power industry, a variety of foreign developed reactors have been introduced, therefore the severe accident mitigation strategies in China is multifarious. By analyzing the engineering practice and the economic feasibility for each strategy, the references for the selection of severe accident mitigation strategies for future nuclear power plants in China are given. Method The development and the engineering practices of severe accident mitigation strategies were studied, and the economy analysis of these strategies were conducted with the consideration of the system main equipment costs, supporting space construction costs and the economic impact of the nuclear emergency process. Result Among all the strategies, the passive cavity injection cooling system with the design scheme of in-containment refueling water storage tank as the water source has the lowest engineering cost, the extended core catcher has the shortest nuclear emergency time requirement and the lowest economic losses caused during the accident mitigation process. Conclusion For nuclear power plants located far away from densely populated areas, the passive cavity injection cooling system can be chosen to reduce the overall engineering cost. For nuclear power plants located near densely populated areas or large industrial zones, the extended core catcher is the best choice.
, Available online , doi: 10.16516/j.ceec.2024-169
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Objective The safety of nuclear power is a key concern of the international community. As an important system of transmission medium and heat exchange, nuclear power pipelines have many safety problems. Corrosion of pipeline walls will lead to leakage or rupture, which will cause accidents and threaten personnel lives and public safety. Therefore, nuclear power pipeline corrosion detection is of great significance for the safe operation of nuclear power. Method The corrosion detection of pipeline wall is usually done by piezoelectric ultrasound, which requires couplant, and cannot be applied in the high temperature and unattended environment of nuclear power plants. Electromagnetic acoustic transducer (EMAT) excites and receives ultrasonic waves with the way of electromagnetic coupling, which doesn’t need couplant, and it is applicable for high temperature and unattended scenarios. In this paper, a thickness measurement method with shear waves by EMAT is proposed, and applied to the corrosion detection of the inner wall of nuclear power pipelines. The shear wave probe of EMAT is optimized to obtain signals with higher signal-to-noise ratio, which are filtered and denoised by wavelet to get the actual thickness of the measured pipeline. Result The result shows that this method achieves measurement errors within 1%, indicating high detection accuracy suitable for corrosion detection on the inner walls of nuclear power plant pipelines. Conclusion By conducting corrosion detection on pipeline walls, problems can be identified early, and preventive maintenance measures can be taken to extend the equipment's lifespan, reduce maintenance costs, and enhance the safety of nuclear power operation.
, Available online , doi: 10.16516/j.ceec.2024-180
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Objective The study aims to comprehensively and systematically explore the current development status of molten salt reactor (MSR) technology, clarify the advantages of MSR as the fourth-generation nuclear power technology, and analyze the major challenges facing its commercialization. By analyzing the development history, technical classification, and research and development progress in various countries, the study provides valuable references for the future development of MSR technology. Method Using the research methods of literature review and comparative analysis, the development history of MSR technology was reviewed, the different types of MSR technology were classified in detail, and the latest progress in MSR technology research and development in countries such as the United States, China, Russia, France, and Canada was deeply analyzed. Meanwhile, based on actual cases such as the MSRE experimental reactor and the TMSR project, the key technical progress and major challenges of MSR technology were discussed. In addition, the impact of international cooperation and technological innovation on the development of MSR technology was also analyzed. Result It is found that MSR technology has been widely concerned globally due to its advantages of high safety and high fuel utilization rate. The United States has verified the engineering feasibility of MSR through the MSRE experimental reactor, and China has made important progress in molten salt preparation and purification in the TMSR project. Russia, France, Canada, and other countries have also made significant achievements in the field of MSR technology. However, the commercialization of MSR technology still faces many challenges, including supply chain construction, fuel supply, regulatory framework adaptation, waste treatment, safety assurance measures, and complex maintenance and operation. Conclusion Although MSR technology faces many challenges, its advantages in safety, fuel utilization rate, and design flexibility give it broad development prospects. International cooperation and technological innovation are key factors in promoting the progress of MSR technology. With the continuous advancement of related technologies, these challenges are gradually being resolved. In the future, MSR technology is expected to become an important support for the global energy structure transformation, playing a crucial role in improving fuel utilization, reducing nuclear waste generation, and enhancing reactor safety. As research deepens and technology matures, MSR technology is expected to achieve commercialization and contribute to the global clean energy transition.
, Available online , doi: 10.16516/j.ceec.2024-099
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Objective The safe operation of nuclear power equipment is crucial for nuclear power plants (NPPs), and the losses caused by accidents are immeasurable. Therefore, effective anomaly detection for nuclear power equipment is necessary. Considering the limitations of fixed thresholds and manual detection methods, which are difficult to adapt to the dynamic changes in time series data, this paper proposes an anomaly detection method based on POT for multivariate statistical processes. Method This paper adopted PCA to construct an anomaly detection model, where the SPE statistic of the model served as the initial threshold for the POT algorithm. Subsequently, the portion exceeding the initial threshold was fitted with a generalized Pareto distribution to determine the final dynamic threshold. An anomaly warning was issued when the anomaly score exceeded the final threshold. By combining multivariate statistical process control (MSPC) with extreme value theory (EVT), this method used MSPC to discover anomalies in the operating data of NPPs quickly and improved the sensitivity and reliability of anomaly detection by modeling and analyzing extreme events, so that it can quickly detect anomalies in high-dimensional operating data of NPPs. Result In the simulation experiment results, the proposed method has a higher accuracy and recall rate than conventional multivariate statistical and POT methods. In experiments with actual operating data from different equipment in NPPs, the method's effectiveness in anomaly detection has been demonstrated. Conclusion By combining MPSC with EVT, the anomaly detection method proposed in this paper can not only detect anomalies caused by changes in data relationships but also avoid false detection in traditional MSPC by determining the final threshold using the POT method. This method can handle high-dimensional time series operating data of NPPs, improve the efficiency of anomaly detection, ensure the safe and efficient operation of NPPs, and improve their economic benefits.
, Available online , doi: 10.16516/j.ceec.2024-364
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Introduction In order to improve the deep peak shaving ability of coal-fired units, a deep peak shaving system for coal-fired units coupling non-afterburning compressed air energy storage is proposed in this paper. Method The system stored electric energy by compressing air during the low load period of the power grid to reduce the external power supply, and released the electric energy, stored by compressing air, during the peak load period of the power grid to increase the power supply. Result Taking a 2×350 MW supercritical primary intermediate reheat coal-fired unit as an example, the calculated internal rate of return on project capital is 7.45%, indicating that the system has a certain level of economic viability. Conclusion At this stage, coal-fired units coupling non-afterburning compressed air energy storage may have some disadvantages in terms of initial investment, and this scheme can significantly improve the bi-directional peak shaving ability of coal-fired units. Moreover, it does not require modifications to the existing equipment of the units, thus avoiding adverse effects on their operation. It has a certain application prospect in the field of deep peak shaving of coal-fired units.
, Available online , doi: 10.16516/j.ceec.2024-287
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Introduction International Hydrogen Council predicts that hydrogen energy will account for 18% of the total global end-use energy demand by 2050. In the technical path of green hydrogen preparation, the electricity cost of photovoltaic (PV) power generation is a key factor affecting the cost-effectiveness of hydrogen production by water electrolysis. Method Based on the solar resource data of typical regions in China, a levelized cost of energy (LCOE) calculation model was constructed to analyze the PV power generation costs at current and limit module costs, and quantify the marginal impact of photoelectric conversion efficiency improvement on LCOE. Result The results indicate that: with an annual effective power generation hours of 1 200, LCOE for crystalline silicon photovoltaic cell system can be reduced to CNY 0.133 per kWh; However, the LCOE threshold of CNY 0.1 per kWh can be achieved for perovskite solar cell, crystalline silicon-perovskite tandem cell and dual tandem cell system with higher theoretical conversion efficiency when the annual power generation hours are 1 008, 1 092 and 864 respectively. When the LCOE for PV power generation is less than CNY 0.1 per kWh, the cost of hydrogen production by water electrolysis can be reduced to CNY 6.16 per kg. Conclusion With the reduction of module cost and the improvement of conversion efficiency, the LCOE for PV power generation in more than 90% of areas in China will have the potential to break through RMB 0.1/kWh. Within this cost range, green hydrogen will show a competitive advantage in production cost compared with traditional grey hydrogen and is expected to become the mainstream hydrogen source. This paper provides a quantitative basis for the industrialization of photovoltaic hydrogen production technology, and has an important reference value for optimizing the transformation path of energy structure and realizing the coordinated development of environmental benefits and economic benefits.
, Available online , doi: 10.16516/j.ceec.2024-297
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Introduction The development of information technology leads the development trend of the new era. Information technology promotes the progress of nuclear power generation technology to intelligentization and even smartization, while also ensuring the safe development of nuclear power generation. Method The positioning association of information, nuclear power generation, and the intelligentization of nuclear power generation was provided. The application of information technology in future nuclear power generation was studied. The development trend of advanced nuclear power generation was analyzed. Result The future nuclear power generation should first be information-based nuclear power generation, followed by intelligent nuclear power generation, and then possibly smart nuclear power generation. The characteristics of 5G low delay can make the nuclear power generation system more accurate, and the nuclear system can be accurately adjusted to operate faster and respond in time. Cloud computing can also find problems in nuclear power generation's complex mass of data. Big data can analyze the root causes of problems in a timely manner. Quantum technology can enhance the core fuel function. Artificial intelligence machine data capture and neural networks learn to process and apply information more precisely. Conclusion Informationization is also a new quality productivity revolution, and information technology promotes the progress of nuclear power generation technology to intelligent development. The intelligence of nuclear power generation is the future trend of advanced nuclear power generation development. The upgrading of information technology is the leading driver of nuclear power generation. Ensuring nuclear power generation safety requires the assistance of information. Network information technology is the central link to build a comprehensive nuclear and solar energy system.
, Available online , doi: 10.16516/j.ceec.2024-289
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Introduction The coordinated development of electricity and hydrogen is a key pathway to achieving dual carbon goals and serves as a crucial support for building a new power system. To promote the sustainable development and market promotion of China’s hydrogen energy industry, the multi-dimensional business operation models and development strategies for electric-hydrogen complementary and collaborative systems are proposed. Method Firstly, the paper comprehensively reviewed the development trends in the electric-hydrogen field both domestically and internationally, and summarized the current status of typical electric-hydrogen projects. Secondly, the profitability mechanisms for electric-hydrogen complementary and collaborative system were analyzed, including the research on diverse hydrogen sales models, the exploration of electricity market revenue, and the assessment of carbon reduction economic value. Based on this basis, multi-dimensional business models for the electric-hydrogen complementary and collaborative system tailored to China's national conditions were proposed, and profitability was calculated under the boundary conditions such as different market conditions and electricity price mechanism. Result The study shows that the electricity pricing mechanism in the spot market significantly guides hydrogen storage, helping to compensate for the efficiency losses in the electric-hydrogen conversion. Integrated utilization of electrolyzers and fuel cells for ancillary services is one of the key strategies to enhance profitability. Coordinating renewable energy hydrogen production with hydrogen sales can substantially improve overall economic benefits, and is also an effective transition from hydrogen sales profitability strategies to future electricity market revenues. Conclusion Based on China's energy endowment characteristics and regional distribution, it is recommended that different regions explore the development of business models for electricity-hydrogen complementary and coordinated systems tailored to local conditions. These include clarifying market-oriented policy directions, guiding large-scale development, and expanding diverse end-use applications.
, Available online , doi: 10.16516/j.ceec.2024-278
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Introduction The construction of beautiful China should show the beauty of modernized engineering, and more importantly, it should rely on the excellent traditional Chinese culture. The paper aims to study the design method to improve the existing industrial buildings with culture and aesthetics, which is limited by process modeling and engineering economy. Method Through case study and engineering practice, we studied the aesthetic design cases of power projects at home and abroad, summarized the three perspectives of traditional regional culture, scientific and technological innovation culture, and diversified fusion culture, and applied them to the design ideas of "Distant Shadows - Rising Clouds - Sky" for the new 2×1000 MW project of CHN Energy Yueyang Power Plant. Result Through the design practice of typical projects, the engineering aesthetic design method of "cultural empowerment expression", "innovation-driven design" and "sharing and integration development" is refined. Conclusion We expect to take the Yueyang Power Plant as a starting point to explore the feasible way for culture as a conceptual starting point and innovation foothold to empower engineering aesthetics, especially in the overall planning and architectural design of thermal power plants.
, Available online , doi: 10.16516/j.ceec.2024-044
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Introduction For the oxygen ion conductive solid fuel cell fueled by hydrogen, the paper proposed a SOFC-"GT+ST" system with the cathode and anode of the fuel cell entering the gas turbine and steam turbine respectively, and analyzed the impact of different parameters on system efficiency, providing reference opinions for hydrogen fuel cell and turbine coupling systems. Method A system model was established using the software Ebsilon. The model was compared with the SOFC-GT system under the given parameters. Additionally, the study investigated the effects of fuel utilization, compressor pressure ratio, air flow and SOFC inlet working fluid temperature on the total power generation efficiency of SOFC-"GT+ST" system. Result The results show that compared with the SOFC-GT system, the total power generation of the SOFC-"GT+ST" system increases to 73.3 MW, representing a 5.74% improvement over the original system, with a power generation efficiency of 60.13%. The fuel utilization of the fuel cell, the compressor pressure ratio, the cell inlet temperature and the air flow rate all affect the system’s total power generation efficiency. Among these factors, there is an optimal value for fuel utilization and a reasonable range for the air flow rate. Additionally, higher cell inlet temperature and compressor pressure ratio lead to higher power generation efficiency of the system. Conclusion Under the structure and parameters defined in this study, the optimal value of fuel utilization of fuel cell is 0.85, and the air flow value should be between 35 and 39 kg/s. The improved system can effectively enhance the total power generation efficiency of SOFC and turbine combined power generation system. The results of this study provide a reference for the selection of system parameters.
, Available online , doi: 10.16516/j.ceec.2024-031
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Introduction With the increase of renewable energy capacity installed each year, hydrogen production by water electrolysis has become an important way to consume renewable energy. Method This paper integrated the classical electrochemical model, conservation relationship, and empirical formula of alkaline electrolyzer to investigate the impact of temperature, pressure, current density, and other factors on the performance of water electrolysis system for hydrogen production. By analyzing the impact mechanism in relation to the electrolyzer structure, key materials, and operation conditions the study identifies a direction for optimizing the performance of current water electrolysis system for hydrogen production. Result The studied performance parameters include hydrogen yield rate, global efficiency, cell voltage, and hydrogen content in oxygen. The study found that increasing current density and raising the temperature both enhance the hydrogen production rate, while changes in pressure have a relatively minor impact. The paper combines physical mechanisms and practical operating experience to analyze the validity of some empirical parameters in the model. Conclusion Optimizing the electrolyzer structure and boosting the performance of catalysts are crucial for improving the current density. Operating the electrolyzer at too high a temperature exceeds the tolerance of the equipment materials, while operating at too low a temperature increases system energy consumption. Therefore, a balanced consideration is necessary. Increasing pressure means higher requirements for the equipment's sealing and the performance of basic materials, but producing high-pressure hydrogen also provides more options for downstream applications, potentially reducing investment in downstream compression and storage systems.
, Available online , doi: 10.16516/j.ceec.2024-124
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Introduction The Hunan-Guangxi Corridor, rich in wind resources, is a channel for cold air to move southward into Guangxi. Every winter, there are often severe weather conditions such as low temperatures and freezing, which can lead to problems such as ice coating on wind turbine blades, changes in material and structural properties, and changes in load, resulting in reduced service life of wind turbines and affecting power generation capacity. In Guangxi, the impact of cold wave and low temperature weather on wind power generation has received widespread attention. Low temperature conditions have a significant impact on the operation phase of wind farms. Currently, there are few studies that statistically analyze the operation of wind turbines under low-temperature conditions and their impacts. Method This paper utilized real-time observation data and 0.25 × 0.25 reanalysis data from the European Center ERA5, as well as data from wind energy companies in Guangxi on ice induced shutdowns and wind curtailment power losses. An analysis was conducted on the impact of the low temperature and freezing weather from December 15 to 24, 2023 on the high-altitude wind power generation in northern Guilin. Simultaneously, the formation mechanism and forecasting techniques of Guilin's severe low temperature and freezing weather were analyzed. Result It is found that there is a correlation between environmental temperature, air humidity, and wind power loss, and a correlation formula is derived. Conclusion This research provides a foundation for further prediction and early warning of low temperature weather and wind power generation in Guilin high-altitude wind farm. Using temperature forecasting products from numerical forecasting, the number of daily shutdowns and power losses in the future can be predicted in advance, assisting in wind power forecasting. At the same time, high-precision freezing disaster weather forecast and warning can optimize customer resource allocation, reduce customer property losses, and ensure personnel and equipment safety.
, Available online , doi: 10.16516/j.ceec.2024-231
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Introduction In recent years, under the continuous promotion of carbon peaking and carbon neutrality policy, offshore wind power hydrogen production has made great progress in China as an important technology for renewable hydrogen production. The article reviews the technological routes, development status and challenges in the offshore wind power hydrogen production industry within China. Based on the analysis, it presents targeted countermeasures and recommendations, aiming to provide a foundation of insights and references for the future application and advancement of offshore wind power in the region. Method Through an investigation of the research and development progress in offshore wind power hydrogen production technologies both domestically and internationally, the technological advancements and constraints were analyzed across three key dimensions: offshore wind-to-hydrogen systems, electrolytic hydrogen production technologies, and offshore hydrogen storage and transportation solutions. By evaluating the current overall development status of the industry, the current development advantages and constraints of the industry were analyzed from the aspects such as policy frameworks, market structures, and technological pathways. Result The analysis highlights the existing strengths and development constraints of the industry. Notably, the industry demonstrates a diversified development trajectory, positively influencing the renewable hydrogen sector and promoting continuous advancements in electrolyzer capacity. Nonetheless, several critical challenges persist, including the absence of breakthroughs in core technologies, dependence on imported key components, elevated life cycle costs, and gaps in regulatory and policy support. These factors collectively represent significant barriers to the sustained growth and advancement of the offshore wind-powered hydrogen production industry. Conclusion It is concluded that in the process of actively developing the offshore wind power hydrogen industry, the hidden bottleneck constraints should be guarded against, from the perspective of policy standards, industrial layout, core technology, etc., China should scientifically design and reasonably layout, to promote the development of the combination of offshore wind power and hydrogen industry, and to help achieve the carbon peaking and carbon neutrality goals.
, Available online , doi: 10.16516/j.ceec.2024-244
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Introduction As one of the new energy storage technologies, vertical gravity energy storage has become a research hotspot in the field of energy storage because of its high safety and environmental friendliness. Systems based on the traditional rotary motors can only transport a single heavy load and cannot meet the various power level requirements of the power grid by changing the number of different loads transported. The application of linear motors, however, can effectively address this issue. Therefore, the vertical gravity energy storage systems using linear motors have garnered significant attention. Method This paper introduced the basic working principle of vertical gravity energy storage systems using linear motors and summarized the current system structures and the design of linear motors within these systems. Result The results show that due to the long-distance movement of the vertical gravity energy storage device and the large mass of the load block, a linear motor with large thrust and magnet and coil windings mounted on the mover is required. Current research focuses on consequent-pole linear vernier hybrid machines, flux-switched permanent magnet linear motors, and linear switched reluctance motors. All three types of motors are suitable for vertical gravity energy storage systems due to their unique characteristics and advantages. Conclusion It is evident that compared with the traditional rotary motor systems, systems using linear motors offer numerous advantages, and will gradually become the mainstream solution for vertical gravity energy storage technology. Given the system characteristics of vertical gravity energy storage, the selection of linear motors is crucial. If the structure of linear motors is specifically designed for vertical energy storage systems, the excellent performance of the storage system will be better leveraged to promote the widespread application of vertical gravity energy storage technology.
, Available online , doi: 10.16516/j.ceec.2024-319
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Introduction With the proposal of the "carbon peak" and "carbon neutrality" goals, the global push for the transformation of the energy structure is accelerating the construction of new power systems dominated by renewable energy. The intermittency and instability of the new energy sources connected to the grid place higher demands on energy storage technologies. Gravity energy storage, as a novel physical energy storage technology, has broad prospects for development. However, its output power lacks stability, and the power curve urgently needs to be optimized. Method This paper analyzed the operation process of a shaft-based gravity energy storage system and established physical, efficiency, and power models. Based on these three fundamental models, an overall model for multi-objective optimization was developed with the goals of stabilizing power output and minimizing fluctuation rates. Constraints were set by combining the three models with real-world conditions to determine the optimal parameter configuration for the weight during operation. Result Simulation verification of the energy storage system shows that the established overall model effectively optimizes the output power curve at the grid demand power levels of 30 MW, 40 MW, and 50 MW. The optimized fluctuation rates are 3.9%, 4.6% and 8.7%, respectively. Conclusion Based on the proposed optimization model, under the condition of constant medium mass of the weight, the output power fluctuation increases as the grid demand power level rises. When the power level increases by 20 MW, the power fluctuation rate increases by 4.8%. Under the condition of constant grid demand power level, the output power fluctuation rate decreases as the medium mass of the weight increases. When the mass of the weight increases from 80 t to 150 t, the power fluctuation rate at 40 MW decreases by 4.2%. The model demonstrates good feasibility and provides valuable guidance for future vertical gravity energy storage projects.
, Available online , doi: 10.16516/j.ceec.2024-247
Abstract:
Introduction As a new type of energy storage means, shaft-type gravity energy storage technology has unique advantages of low environmental pollution, low construction cost and high efficiency, and has a wide application prospect, but the research on the power generation characteristics and influencing factors of the system itself is still imperfect. The power generation efficiency of the shaft-type gravity energy storage system is one of the important indicators of the energy storage system. Method In this paper, through the mathematical modeling of the efficiency model of the shaft-type gravity energy storage system, the influencing factors of efficiency in case of three different heavy block fall curves were studied, and the influence trend of these factors on the power generation efficiency of the system was explored through simulation experiments, and then the efficiency characteristics of the three velocity curves were compared and analyzed. Result The results show that the falling speed has a significant effect on the efficiency of the system, and the power generation efficiency can be improved by reducing the speed appropriately. The height of the shaft and the mass of the heavy block have little effect on the efficiency of power generation. For the three velocity curves, the power generation efficiency of trapezoidal and triangular velocity curves was less affected by other factors, while the parabolic velocity curve was more sensitive to the influence of other factors, and the power generation efficiency was relatively smaller, and the trapezoidal velocity curve has the highest system efficiency under the same conditions. Under the premise of heavy blocks with large weights, the power generation efficiency of the three velocity curves was less affected by other factors. Conclusion Therefore, using heavy blocks with large weights, reducing the maximum falling speed of heavy blocks, and adopting the trapezoidal velocity curve can significantly improve the power generation efficiency to achieve better system performance.
, Available online , doi: 10.16516/j.ceec.2024-219
Abstract:
Introduction In the context of the "30·60" carbon peak and neutrality targets, this paper’s purpose is to address the problem of poor power balance performance in integrated energy systems caused by the uncertainty and discontinuity of renewable energy. Method This paper constructed a hydrogen-electricity coupling link that included hydrogen production from electrolyzed water coupled with gas hydrogen blending technology and hydrogen storage, established a punishment mechanism for wind and solar curtailment, and constructed an optimization and scheduling model for integrated energy system that included hydrogen-electricity coupling link. To address the problems of getting stuck in local optima and slow convergence speed during the solution process, the Pied Kingfisher Optimizer (PKO) algorithm was introduced. Result The model aims to minimize the total system cost as the objective function, and solves for the optimal scheduling results of the output of each energy network unit; Compared with traditional optimization algorithms, PKO has a faster convergence speed and is better able to achieve the goal of global optimal solution. Conclusion Case analysis indicates that using the model and method proposed in this paper reduces the total cost by 15.04% and 6.99% respectively compared to other schemes, effectively improving the utilization level of new energy in the integrated energy system, reducing the total system cost, and making it more economical.
, Available online , doi: 10.16516/j.ceec.2024-218
Abstract:
Introduction With the proposal of "carbon peak, carbon neutrality" goal, the concept of low-carbon environmental protection has been raised to a new height. As energy terminals, the parks have become an important carrier of low-carbon emission reduction. Method Aiming at the operation economy of the integrated energy system in the parks with electricity-gas-heat coupling and the problem of wind and light curtailment, an operation method of the integrated energy optimization in the parks based on electricity-to-gas （P2G） conversion was proposed. The electrolysis tanks, methane reactors and hydrogen fuel cells were introduced to replace the traditional P2G, providing an effective method for new energy consumption. Result In order to further reduce the carbon dioxide emissions in the parks, a stepped carbon trading mechanism based on the carbon excess rate was introduced. Taking the daily operating cost of the parks as the optimization target, an optimal scheduling model was established to set constraints to satisfy the supply/demand balance of the integrated energy system and the operation of the equipment in the parks. The results show a 12.4% reduction in system operating costs, a 16.2% reduction in system carbon emissions, and a 29.3% and 25.7% increase in wind and photovoltaic utilization, respectively. Conclusion The CPLEX business solver is used as a solution, and the proposed strategy is compared and verified to effectively improve the economy and low carbon of the integrated energy system in the parks by setting up multiple operation scenarios, which provides a strong support for the parks to achieve the goal of carbon emission reduction.
, Available online , doi: 10.16516/j.ceec.2024-140
Abstract:
Introduction The frame gravity energy storage system has a wide range of application prospects due to its high economic benefits, low system costs, and unrestricted geographical conditions. Method The paper studied the profit variation rules of the frame gravity energy storage system throughout its life cycle in detail by applying the leveled net present value of electricity (LNPVE) model. The paper, based on the net present value of capital flow in gravity energy storage systems, first built a levelized revenue of electricity (LROE) model which includes initial investment, discount rate, feed-in tariff, and government subsidies; then, built the LNPVE model on the basis of the LROE model and the levelized cost of electricity (LCOE) model; and finally explored the changes of LCOE, LROE, LNPVE, total net present value income and total discounted cost when the discount rate, feed-in tariff, service life and charge-discharge efficiency of the system change, to comprehensively consider the impact of different parameters on the economic efficiency of the system. Result The increase in the discount rate, service life, and charge-discharge efficiency of the system will improve the economic efficiency of the system. In addition, as the service life of the system increases, the LNPVE of the system decreases while the total net present value income increases. Therefore, it is more appropriate to comprehensively consider multiple factors when evaluating the economic efficiency of the system. Conclusion The LNPVE model studied here can provide a reference for the construction and profit analysis of frame gravity energy storage systems.
, Available online , doi: 10.16516/j.ceec.2024-139
Abstract:
Introduction Gravity energy storage, as a new form of energy storage, plays an increasingly important role in balancing power supply and demand, responding to intermittent energy fluctuations, and other aspects of the power system. Method Focusing on the gravity energy storage system based on ground structure and slope gravity energy storage, the paper analyzed in detail the research status of these two forms of gravity energy storage both domestically and internationally. Firstly, compared with traditional energy storage forms, the working principle and advantages of gravity energy storage were provided. Then, the research status and economic cost analysis of the gravity energy storage system based on ground structure and slope gravity energy storage structures were presented. Then, two typical types of slope gravity energy storage system structures, i.e. mountain mining car type and mountain cable car type, were introduced in detail, and the effect of parameters such as slope and weight on system efficiency and cost performance was explained. Finally, prospects and suggestions were given for the technical characteristics of gravity energy storage systems. Result The gravity energy storage system based on the ground structure is stable and has a high initial investment cost, making it suitable for users with large power fluctuations. The slope gravity energy storage features low construction cost and simple operation and is suitable for users in high mountain terrain with low power demand. Conclusion With the gradual maturity of gravity energy storage technology and its continuous cost reduction, it will play an important supporting role in the construction of power systems as a new type of energy storage in the future.
, Available online , doi: 10.16516/j.ceec.2024-108
Abstract:
Introduction During the hydrogen production process at hydrogen refueling stations, the mixture of ethanol and hydrogen can easily form a combustible gas, which may explode if ignited by sparks or high temperatures. In order to reduce the risk of explosion during hydrogen production and storage at hydrogen refueling stations, experimental research is essential. Method The explosion characteristic parameters were analyzed for hydrogen-ethanol-air mixture with different equivalence ratios and ethanol blending ratios at 1 bar and 400 K. By calculating the flammability limit and deflagration index of mixed gas, the degree of explosion hazard was evaluated, and effective safety measures were formulated to reduce the risk of explosion. Result The experimental research results show that an increase in the equivalence ratio will shorten the explosion time, making it ultimately tend to a stable value. The stable explosion times corresponding to hydrogen volume fractions (30%, 50%, 70%) are 0.03 s, 0.025 s, and 0.019 s. The maximum explosion pressure, maximum pressure rise rate, and deflagration index all increase and then decrease with the increase of equivalence ratio, reaching their peak at an equivalence ratio of 1.3. The flammability limit of the mixed gas continues to decrease with the addition of ethanol, and the decrease in UELmixture (upper flammability limit of mixture) is significantly higher than that in LELmixture (lower flammability limit of mixture). In addition, the maximum pressure rise rate and deflagration index show a significant decreasing trend with the addition of ethanol, and the maximum deflagration index calculated for this research is 11.85 MPa·m/s. Conclusion The research results have revealed the effect of equivalence ratio and blending ratio on the explosion characteristics of mixed fuels, providing a solid theoretical basis for reducing explosion risks in hydrogen production and storage processes at hydrogen refueling stations.
, Available online , doi: 10.16516/j.ceec.2023-308
Abstract:
Introduction Wind turbine generator systems (WTGS) are prone to various types of failures due to the harsh operating environment. For the main bearing, a central component of the transmission system, it is difficult to detect and evaluate its early failure, and offshore operations are restricted by limited weather windows. How to accurately evaluate the operating conditions of the main bearings of offshore units has become a major difficulty for the industry. Method The study focused on the operation condition of the main bearing of an offshore direct-drive generator with a capacity of 7 MW. The transmission process of the wind wheel load in the transmission chain was deduced by the theoretical formula, and the radial load and axial load on the main bearing were obtained. Through the finite element calculation and analysis of the main bearing, the load distribution within the bearing raceway was obtained, which was mutually verified with the theoretical derivation, and the position of the vibration monitoring point was determined preliminarily. Result Finally, according to the position of the bearing measuring point, the vibration monitoring is carried out in the WTGS site, and a clear time-domain vibration curve is obtained. The vibration monitoring results such as the effective value of the vibration of the main bearing, the response frequency of the impact signal, and the acceleration envelope characteristics are analyzed. Combined with the detection results of the grease composition inside the bearing, the damage degree of main bearing's specific components is qualitatively judged. Conclusion This study has identified the measuring point position of the main bearing of multi-megawatt direct-drive offshore WTGS, and accurately assessed the operating condition of the main bearing, which can provide technical support for design and maintenance personnel.
, Available online , doi: 10.16516/j.ceec.2024-058
Abstract:
Introduction Energy is widely considered the fuel of industry and the lifeline of the national economy. The impressive economic and development achievement of Guangdong after reform and opening up relied heavily on the support and logistical backing from the development of its energy industry. Being a major energy consumer with limited resources and thus featuring low self-sufficiency in energy, Guangdong has always faced the threat of energy scarcity. After decades of development and transition, its energy sector is gradually evolving into a diversified new energy system composed of traditional thermal power, nuclear power, offshore wind power, and photovoltaic power generation. It has shifted from being a limiting factor in economic production to becoming an integral component of the province's high-tech manufacturing industry chain. Analyzing the economic contribution of energy sector from a macroeconomic perspective holds practical significance for formulating scientific energy industry development plans and promoting high-quality, coordinated development of energy and economy in Guangdong. Method Firstly, a research dataset was established by integrating the indicator data that represent the development of the energy sector and economy in Guangdong. Subsequently, both the vector autoregression model and the Feder two-sector production function model were employed to conduct a quantitative analysis of the overall economic contribution and spillover effects of Guangdong's energy sector. Result The analysis indicates that, during the late industrialization phase, a mutually reinforcing relationship existed between the energy sector and economic development in Guangdong. The production of the energy sector makes a significant overall contribution to economic growth, with notable spillover effects. However, the economic stimulus effect of energy investments is comparatively low. Conclusion The study empirically estimates the economic contribution of energy sector in Guangdong and based on the findings, suggests recommendations for high-quality development of Guangdong's energy sector. These can serve as references for the development planning and policy-making of Guangdong's energy development.
, Available online , doi: 10.16516/j.ceec.2023-294
Abstract:
Introduction Gas-steam combined cycle units have been widely used in combined heat and power, but their minimum power generation is limited by heat supply. Especially during the winter heating period in the north, gas-steam combined cycle units cannot reduce their output, thus impeding the grid integration of wind energy and causing wind curtailment. Method To address this issue, this paper investigates whether utilizing the operational flexibility of gas-steam combined cycle units in combined heat and power dispatch can promote wind power accommodation. To this end, a mathematical model was established to describe the diversified operating modes of gas-steam combined cycle units, then an economic dispatch model for combined heat and power considering wind power accommodation was constructed to co-optimize the unit commitment of coal-fired units, the operating modes of gas-steam combined cycle units, and the output distribution and reserve sharing among units. Result Case simulations revealed that during difficult periods of wind power accommodation, switching gas-steam combined cycle units from the two-on-one mode to one-on-one mode can reduce the wind curtailment rate by 1.28%, and switching them from extraction condensing to back pressure mode can reduce the wind curtailment rate by 4.55%. Conclusion Case analysis shows that making full use of the mode switching ability of gas-steam combined cycle units in combined heat and power dispatch can reduce the output of units during periods of high heat load, increase the wind power accommodation space to reduce the wind curtailment, increase the output ranges of units during periods of low heat load, thereby providing spinning reserve for the system and optimizing the reserve sharing among units.
Strategies for Improving the Safety and Operational Reliability of High-Voltage Frequency Converters
, Available online , doi: 10.16516/j.ceec.2023-184
Abstract:
Introduction "Energy saving and emission reduction" is the national technical requirement for industrial projects in recent years, and the frequency conversion technology can make process equipment adjust output under different working conditions, thereby saving resources. However, frequency converters are power electronic devices, and the failure rate of IGBT components is relatively high, and the requirements for the operating environment are harsh. Therefore, it is very important to improve the safety and operational reliability of high-voltage frequency converters. Method In the case of failure of individual power units of the high-voltage frequency converter, according to the neutral point drift technology, the position of the neutral point and the angle between the three-phase voltages are adjusted, so that the high-voltage frequency converter can bypass some faulty power units can still operate normally; Send the real-time status of the high-voltage inverter to the DCS, and realize the automatic bypass technology of the high-voltage inverter according to the logic configuration of the DCS; Set up a separate high-voltage inverter room to provide a relatively good operating environment for high-voltage inverters through air conditioning, ventilation, and air duct systems. Result After adopting the internal strategy and external environment strategy for the high-voltage inverter, the failure rate of the high-voltage inverter is reduced, and the safe operation time of the high-voltage inverter is prolonged. Conclusion The use of neutral point drift technology and the automatic bypass technology of the whole machine can reduce the failure probability and frequency of high-voltage inverters, and jointly improve the temperature and humidity conditions of the operating environment, which can increase the continuous and reliable operation time of the inverter, to greatly improve the safety and operation reliability of inverters.
