Table of contents

The research and application of efficient clean energy is the most important energy saving and emission reduction measure in China at the present stage, and the technological progress of clean energy power generation has also attracted the attention of experts and scholars all over the world. Therefore, the 2022 7^th International Conference on Clean Energy and Power Generation Technology (CEPGT 2022) was successfully held during December 9^th-11^th, 2022 in Zhenjiang, China (virtual form), providing a shared platform for the international academic and engineering community.

The International Conference on Clean Energy and Power Generation Technology is an international academic conference. Everyone interested in the fields related to Clean Energy and Power Generation Technology were welcomed to join the online conference and give comments and raise questions to the speeches and presentations.

The online conference consisted of Keynote Speeches, Oral Presentations, and Academic Investigation, attracting about 50 individuals from all over the world. We have invited six sophisticated professors from different countries and regions to perform keynote speeches. Among them, Prof. Marc A. Rosen from Ontario Tech University, Canada delivered a wonderful keynote speech on Hydrogen Energy Systems: A Pathway to Sustainable Energy and Sustainable Development. Through hydrogen energy systems, the energy carrier hydrogen is a key facilitator of sustainable energy and can contribute significantly to attaining sustainability and sustainable development. As easily accessible fossil fuel supplies become increasingly scarce and environmental concerns escalate, hydrogen energy is likely to become increasingly important. With the world's energy sources becoming less fossil fuel-based, hydrogen and electricity are expected to be the two dominant energy carriers for the provision of end-use services in a hydrogen economy. In this presentation, the role of hydrogen as an energy carrier and facilitator of sustainable energy was described and illustrated, and hydrogen energy systems that can contribute to a sustainable world were reviewed and discussed. All keynote speakers made brilliant speeches and shared unique professional experience and insights, triggering heated discussion in the conference.

CEPGT 2022 received a great many submissions in the areas related to clean energy and power generation technology. Each submission was reviewed by at least two expert reviewers and the committee picked out some excellent papers that are included in the proceedings, covering but not limited to the following topics: Hydrogen and Fuel Cell, Green Energy Technology, Renewable Energy, Hydroelectric Power Generation, etc.

On behalf of the Conference Organizing Committee, we would like to thank the Technical Program Committee members and external reviewers for their hard work in reviewing and selecting papers. And we would like to acknowledge all of those who supported CEPGT 2022. Particularly, our special thanks go to the editors and other members Journal of Physics: Conference Series. We deeply appreciate their efforts in making the conference successful.

The Committee of CEPGT 2022

List of Committee member is available in the pdf.

All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

• Type of peer review: Single Anonymous

• Conference submission management system: Morressier

• Number of submissions received: 52

• Number of submissions sent for review: 47

• Number of submissions accepted: 23

• Acceptance Rate (Submissions Accepted / Submissions Received × 100): 44.2

• Average number of reviews per paper: 2

• Total number of reviewers involved: 10

• Contact person for queries:

Name: Xuexia Ye

Email: xx.ye@keoaeic.org

Affiliation: AEIC Academic Exchange Information Centre

The high rate and long life performance of the lithium ion batteries are affected by serious volume change and low conductivity of the active electrode material during the charging and discharging. Herein, bimetal sulfides embedded in N-doped carbon polyhedral nanocages (SnS@CoS@NCNTs) are successfully designed by employing porous metal-organic frameworks (MOFs) as precursors. Benefiting from the abundant active sites of metal sulfide, the catalytic properties of CoS, and the high conductivity of porous carbon, SnS@CoS@NCNTs electrode materials exhibit excellent performance. The electrode delivers the initial specific capacity of 1112 mA·h·g⁻¹ and the remarkable capacity of nearly 440 mA·h·g⁻¹ after 300 cycles in current density of 1 A·g⁻¹, which may be caused by the synergistic effect of bimetal sulfides and N-doped carbon polyhedral nanocages to enhance the structural stability and ion/electron conductivity. This work provides a feasible method for constructing bimetal-sulfide/carbon composites with excellent electrochemical performance.

Impeller imbalance is an unavoidable problem in the process of the operation of wind turbines, and it often has a serious impact on the safety and stability of wind turbines, thus shortening their life cycle. Aiming at the current problems, such as high cost and instability caused by the impeller imbalance in wind turbines, this paper proposes an assessment method for impeller imbalance in wind turbines based on image processing and headroom analysis. Firstly, the deep-learning image-processing technology is used to convert the video monitoring data into numerical data, and then the comprehensive imbalance index of the three blades based on the numerical data is calculated, so as to determine if an impeller imbalance problem exists or not. The proposed method was validated with the operation data of wind turbines in field and good results were achieved.

For the humidification-dehumidification desalination unit to perform more efficiently, a two-stage humidification-dehumidification heat pump desalination system was proposed. So as to improve the heat and mass transfer effect between seawater and moist air, the two-stage humidifier was employed to recover the waste heat of seawater discharged from the first stage humidifier. The models of a one-stage and two-stage humidification heat pump seawater desalination system were built using Aspen Plus simulation software. Multi-condition simulation studies were carried out for different inlet seawater temperatures, liquid-gas mass ratios, and refrigerant flow rates of the heat pump. According to the comparative examination of the simulation's outcomes, it is concluded that: with the increase in inlet seawater temperature and liquid-gas flow ratio, the two-stage humidifier system's recovery rate and gain output ratio are superior to those of the first-stage humidifier system, and the inlet seawater temperature and circulating airflow needed for the two-stage humidifier system to perform at its best are less demanding than those for the first-stage humidifier system., indicating that the two-stage humidifier dehumidification desalination technology of the heat pump has great performance improvement and a broad application prospect.

Building a County Energy Internet (CEI) is crucial for achieving green and low-carbon transition and sustainable development of county energy systems. This paper proposes a bi-level collaborative planning method for CEI to configure devices' capacities in multiple regional CEIs (RCEIs) and plan the interconnected networks simultaneously. Firstly, the models of multi-energy devices and networks are constructed. Then, an optimal partitioning method based on a clustering algorithm is proposed to divide the CEI into multiple RCEIs by considering the load distribution pattern and complementary characteristics. On top of that, a bi-level planning model for CEI is established, wherein the lower-level problem aims at configuring the capacities of devices in RCEIs through mixed-integer linear programming (MILP), while the upper-level problem is the determination of the interconnected multi-energy network topologies by searching the minimum spanning tree. This two-level planning problem is resolved iteratively, in which the network topologies of CEI and energy imbalance in each RCEI are shared information. Case studies on the modified CEI validate the effectiveness and practicality of the proposed method.

After diesel fuel injection, when spray droplets in the air hit the wall, four types of impingement states will be formed: stick, rebound, spread, and splash. There are already many models describing the impingement of droplets on the wall. In order to analyze the impact of the droplet-wall model on the formation of oil film, this paper constructed a three-dimensional model of the diesel combustion in engine's cylinder. The main part of the model was the simulation of the diesel fuel injection process, and different droplet collision models were used to calculate their influence on oil film formation of engine's piston.

Nuclear power generation technology is obviously a safe and economical way of generating power in modern society. As the low temperature heat source, the condenser of the nuclear power technology condenses the steam into condensate water and then establishes a certain degree of vacuum at the exhaust port of the turbine. The operation of condenser is critical to the nuclear power generation technology. In this paper, the influences of the arrangement of tube bundles on the condenser of nuclear power generation technology were investigated. Three types of condensers, including the church window type, the centripetal type, and the UT type, were analyzed using Ansys Fluent software. The steam flow velocity distribution, air concentration distribution, temperature distribution, and heat transfer coefficient distribution were studied. Under specific design conditions, the flow velocity in the church window type was large, the exhaust air concentration was small, the maximum flow rate distribution was relatively reasonable, and the air concentration distribution was more concentrated. The performances of the centripetal type and the UT type were slightly worse, and the steam condensation was less. In contrast, the condensation of the church window type was large, the relative performance was high, and the heat transfer performance was better.

Due to the axial asymmetry of the volute structure, the circumferential inhomogeneity of the flow at the volute outlet exists, leading to the deviation of the flow in the nozzle and impeller from the ideal state. In this paper, a numerical study of a SCO2-radial inflow turbine is carried out to simulate the flow inside the turbine with the asymmetric and symmetric volute respectively. The results show that the use of a pear-shaped symmetric cross-section volute can effectively reduce the circumferential inhomogeneity of the flow, simplify the vortex structure inside the volute, reduce the flow losses and improve the efficiency of the turbine.

The cascades phase change heat storage (CLTES) and trans-critical CO₂ Rankine cycle were combined to study the effects of the number of phase change materials in series on heat storage on the performance of waste heat recovery systems in order to overcome the influence of heat source volatility. In terms of net work, 3-CLTES is 12.5% higher than 2-CLTES, but with 30.4% more heat exchange area. Compared with 4-CLTES, the net output work decreased by 2.6%, and the heat transfer area increased by 6.7%.

The output power of photovoltaic (PV) power plant is influenced by the fluctuation of meteorological conditions, which, coupled with the intermittent nature of the power output, has raised concerns about the stability of power grid. According to the variations in meteorological conditions, PV power prediction technology can predict the PV output power in advance to decrease the influence of PV power generation on the stable operation of the power grid. In this paper, the PV power prediction model is built on Matlab simulation software with a BP neural network algorithm. After that, the power prediction calculation of a PV power station is carried out under the operation conditions of sunny and cloudy days. The results show that, in the periods of prediction, the power curve of the predicted value is close to the power curve of the real value, which demonstrates the great accuracy of the BP prediction model established in this paper.

A natural cellulosic biomass pretreatment process was established to use ionic liquid (IL) for efficient zymolysis and subsequent bioethanol production, the IL 1, 3-Dimethylimidazolium dimethyl phosphate/Tween-80 ([Mmim][DMP]/T80) was selected in view of its high pretreatment function. The productivity of reducing sugars from mulberry twigs pretreated with the IL at 130°C for 0.33 h reached 74.72% after zymolysis for 48 h, while only a 14.62% conversion rate for the sample pretreated by water. The fermentability character of the hydrolyzate, witdrawn from zymolysis, was fermented into bioethanol using Saccharomyces cerevisiae. This kind of microbe could efficiently utilize glucose to produce ethanol with the yield of 0.382 g/g glucose in 30 h fermentation. In conclusion, the ionic liquid pretreatment at low temperatures shows promise as a pretreatment reagent for natural lignocellulosic biomass.

Wind turbine, photovoltaic and other power supply connected to the grid operation brings new critical problems to traditional reactive power optimization. Considering the safety and stability of operation, a reactive power optimization model with two objectives of minimum voltage offset and minimum network loss is established. In MATLAB, the reactive power optimization simulation analysis of the IEEE33 system connected with a wind turbine and photovoltaic is carried out, and the MOPSO algorithm is used to solve the reactive power optimization model. The multi-objective MOPSO algorithm is optimized to improve the stability of power grid operation and reduce the fluctuation of power flow. The network loss is reduced, and the effectiveness of the strategy is verified.

Hybrid energy storage systems are increasingly envisaged to be used in the construction of microgrids to alleviate the intermittency of renewable energy output and achieve large-scale penetration into the power grid. The hydrogen-electric coupled system (HECS) combines long-term hydrogen storage with short-term battery storage and realizes the conversion of multiple energy flows through power to gas and gas to power. However, the optimal scheduling of such a hybrid energy storage system is more complex than a single one. Faced with this issue, this paper proposed a HECS scheduling method based on the storage degradation cost to solve the power distribution problem. Furthermore, to reduce the impact of source-load uncertainty, the improved k-medoids method is used to extract representatively typical and extreme scenarios from the annual data to evaluate the economy and reliability of the system operation. According to the simulation result, we can conclude that the proposed method achieves cost-optimal scheduling by maximizing hydrogen production in the on-grid mode and reducing the battery cycle cost in the off-grid mode. Compared with the state machine control strategy, the proposed method has lowered the operation cost in all simulation scenarios and shows its effectiveness. Finally, the results show that the operation cost can be reduced by applying a demand response program, especially in the off-grid mode.

Nowadays, the world is facing a common problem of resource scarcity, so the search for a new clean energy source is the trend of the future. China is rich in marine resources and is close to the centers of electricity consumption. Offshore wind power as a future clean energy source is thus a new avenue to pursue today. Now, one of the technical issues limiting the expansion of offshore wind power is the reliable and economical transmission of long-range electricity to onshore power grids. However, traditional high-voltage DC transmission is no longer suitable for large, long-distance offshore wind farms due to its economics, the difficulty of compensating for offshore reactive power, and the complexity of large-scale system coupling. The flexible HVDC transmission method based on MMC (Modular Multilevel Converter) has become the development direction for HVDC transmission due to its high output quality and economic advantages. MMC is the core device for flexible HVDC transmission. In order to improve the output voltage quality and ensure the stability of the transmission process, the selection of a suitable modulation method is a basic condition. Among the existing applied modulation methods, this paper took NLM (nearest level modulation) based on MMC as the research object. It was verified through principal analysis and simulation that this method could not only achieve multi-level output but also that the more sub-module (SM) investment, the higher the output waveform quality.

In recent years, all research on symmetrical double side cathode solid oxide fuel cell (SDSC-SOFC) has mainly focused on electrochemical and mechanical properties. However, there is a lack of research on the contact resistance of SDSC-SOFC. The sintering model of SDSC-SOFC is established first, and then based on the sintering model, the impact of the pre-tightening force is considered. The effects of end plate thickness and pre-tightening force on contact resistance are analyzed. In order to improve the mass power density of SDSC-SOFC, an end plate thickness of 30 mm is recommended. The average contact resistance of the cathode decreases with the increase of the pre-tightening force, but the decreasing rate is reduced. When the pre-tightening force is greater than 400 N, the impact of the pre-tightening force on the average cathode contact resistance can be ignored.

The fully coupled aerodynamic-hydrodynamic-mooring numerical model of floating offshore wind turbine(FOWT) has been established. The complex conditions such as second-order wave force, full-field turbulent wind, and mooring break have been taking into account. Using OrcaFlex and FAST to calculate the dynamic response of FOWT under the combined action of wind, wave and current. The time-domain response of floating foundation, mooring tension, blade root contact force, aerodynamic power, and wind rotor thrust are obtained. And the effect of the turbulent wind and mooring break at different positions on the FOWT are studied. The results show that compared with the platform motion and mooring tension, the aerodynamic power and rotor thrust are more sensitive to the turbulent wind, and there are fluctuations in amplitude and multiple peaks in the frequency spectrum. Compared with the leeward side, the mooring break on the windward side is a more dangerous situation, and it is easy to cause the collapse of platform and the break of the remaining mooring. The mooring break on the leeward side is relatively safe, and it will produce a drift in the sway direction, and have little impact on the safety of the wind turbine.

The unpredictability for wind power interprets the critical factor limiting its large-scale penetration in microgrids. Gaussian and Cauchy distributions describe both the arbitrary and vague characteristics of wind power to evaluate wind power unpredictability. Afterward, the wind power is presumed an undefined arbitrary variable, and a multi-objective optimization model concerning the credibility density function is developed to balance the economics and the reliability of microgrids. For the solution of the model, the NSGA-II algorithm is applied to seize the Pareto front. By fully deliberating the cognitive uncertainty of the dispatchers, the evidence-theory-based decision-making is employed to drive the eventual scheduling from the Pareto set. The emulation performances substantiate the appropriateness and efficacy of the proffered model with unpredictable wind power by providing a compromise scheme between economics and reliability.

Wind power has been widely utilized to support a considerable proportion of the power supply. However, wind power output is affected by weather and geographic factors to a large extent and therefore has the characteristics of being intermittent and random. To conduct subsequent studies on wind power output forecasting, a proper assessment of wind power output is required. We modified the traditional concept of three-vertex connected motifs from the perspective of magnitude, inspired by complex network and motif theory, and realized the wind power output fluctuation analysis. To testify to the effectiveness of the proposed method, an experiment based on the real-world wind power output of a wind farm was conducted. The network motifs' distribution of the experimental results was consistent with the real-world wind power output fluctuation, which verified the accuracy of the proposed method.

Industrial and commercial energy storage are widely used. Large industrial users can adjust the peak and valley power consumption during the summer peak power consumption to reduce the burden on transformers and to gain certain benefits from the peak and valley power difference. For users with important loads, the energy storage system is a alternative power supply to ensure the continuity of power supply for important loads. This paper systematically introduced the research progress based on the optimization of electrolyte and charging strategy in the field of improving the rapid charging of graphite anodes in recent years, which provided a reference for promoting the commercial application of rapid charging technology and the high-quality development of domestic energy storage technology. The high-power energy storage battery, in particular, can recover power supply as soon as possible after large-scale power system shutdown accidents or even power outages, reducing economic losses and social impact.

This paper investigated whether wind turbines have a residual life to ensure their continued safe and reliable operation after 20 years of design life. A modeling method for the load simulation of the wind turbine with a lack of design documents was proposed. A method for calculating the residual life of wind turbines based on site-specific load comparison analysis and uncertainty analysis was established. This method was applied to evaluate the residual life of 66 600 kW wind turbines at an old wind farm in northwest China. The equivalent loads of the turbine components were calculated under design conditions and actual operating conditions, and the residual lives of the turbine components were further evaluated by uncertainty analysis. The results showed that all components of these wind turbines had a residual life after operating over their 20-year design lives, and the wind farm could continue operating for at least 4.6 years.

Consider the current status of health (SOH) of lithium batteries, which presents challenging existing issues of accurately predicting and calculating. In this paper, an LSTM model and multi-optimization algorithm were used to estimate the battery health state. Taking advantage of the fast convergence speed and wide global optimization range of the optimization algorithm, optimized the number of layers and neurons in the LSTM model so the LSTM model was established, used to predict the health status of lithium batteries, and compared with the LSTM model prediction method without optimization. The results showed that the error of the battery health prediction model based on the proposed prediction model was less than 3%, the prediction accuracy was higher than the LSTM model without optimization, and the model had better accuracy and stability.

New energy storage is an important technology and fundamental equipment for building a new electric power system, an important support for achieving the goals of carbon peaking and carbon neutrality, and also a development focus for emerging strategic industries. In light of typical situations, such as a lack of station site resources and large-scale access to distributed new energy for power supply on a sea island, new energy storage is proposed to solve power supply capacity or quality problems in local areas and to replace or postpone power transmission and distribution investment. Considering the different life cycles of energy storage and power grid facility projects, we proposed an assessment method for the substitution effect of alternative energy storage on power grid functions based on the annual cost method and measured its cost-effectiveness under typical application scenarios.

Hybrid organic-inorganic halide perovskites solar cells have attracted extensive interest because of their outstanding properties, including an optimal band gap, high carrier mobility, and excellent optoelectronic merits. We study the electronic and crystal structural properties of hybrid organic-inorganic halide APbX3 (A = Cs, methylammonium (MA), formamidinium (FA), X = I, Br) perovskites using first-principles calculations based on density functional theory. We find that halide atoms and A-site cations strongly affect their structural and electronic properties. The radius of a halide atom and the size of an organic molecule determine their lattice parameters and bond length. A relatively large halide atom can increase the value of the lattice parameters (a and b). Meanwhile, the electronic properties (band gap & carrier effective mass) of the Pb-based hybrid halide APbX3 can be effectively modified by adopting appropriate A- and X-site atoms or organic sections. We predict that HOIPs may have outstanding potential in solar light harvesting with promoted power conversion efficiency due to a tunable band gap and excellent electronic properties.