Renewable EnergyPub Date : 2024-11-19DOI: 10.1016/j.renene.2024.121889
Haoxiang Zhang , Zhenyu Huang , Xuexin Wang , Chen Li , Youbo Liu , Junyong Liu
{"title":"Capacity investment portfolio optimization considering EV charging flexibility: A heuristic algorithm-informed system dynamics approach","authors":"Haoxiang Zhang , Zhenyu Huang , Xuexin Wang , Chen Li , Youbo Liu , Junyong Liu","doi":"10.1016/j.renene.2024.121889","DOIUrl":"10.1016/j.renene.2024.121889","url":null,"abstract":"<div><div>Orderly charging of electric vehicles (EVs) functions as a flexible tool for peak shaving to help integrate renewable energy sources effectively. Coordinating investments in charging resources and generation resources can enhance social benefits while ensuring the charging needs of EVs are met. This study aims to optimize the long-term investment strategies for these resources using a heuristic algorithm-informed system dynamic (SD) approach. Firstly, a SD model is developed to simulate the long-term interactions among generation resources, EVs, and power demand, capturing their dynamic relationships. Then, the fixed feedback functions of investment parameters in the SD model are replaced with an optimization model, enabling parameter optimization for environmental and economic objectives. Given that the process must quantify the aforementioned long-term interrelationships with potential high-order, nonlinear feedback loops, the solution is implemented using Particle Swarm Optimization (PSO). Data from a specific province in China was used for the case study. The results show that the optimized investment portfolio reduced carbon costs and total investment by 2.4% and 22%, respectively, while total social costs decreased by 17% compared to the pre-set investment strategy. Lastly, we also conducted sensitivity analysis and algorithm comparison.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"238 ","pages":"Article 121889"},"PeriodicalIF":9.0,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable EnergyPub Date : 2024-11-19DOI: 10.1016/j.renene.2024.121950
Chi Wei Su , Xin Yue Song , Junyi Dou , Meng Qin
{"title":"Fossil fuels or renewable energy? The dilemma of climate policy choices","authors":"Chi Wei Su , Xin Yue Song , Junyi Dou , Meng Qin","doi":"10.1016/j.renene.2024.121950","DOIUrl":"10.1016/j.renene.2024.121950","url":null,"abstract":"<div><div>In the global energy transition context, climate crisis events are poised to reshape the energy market landscape, leading to pronounced upheavals and significantly increased risks in the global energy market. This paper focuses on the U.S. and employs quantile connectedness to analyse the spillover effects among climate policy uncertainty (CPU) and renewable and non-renewable energy from January 2013 to October 2023. The research outcomes indicate that the influence of the interconnected network of variables is more pronounced in extreme market conditions compared to average market conditions. In extreme conditions, non-renewable energy continues to serve as the primary transmitter, while CPU and renewable energy only transition to a transmitter role during specific periods. Consequently, the government should implement more proactive policy measures to optimise the energy consumption structure and progressively transition to renewable energy to achieve long-term environmental sustainability.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"238 ","pages":"Article 121950"},"PeriodicalIF":9.0,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable EnergyPub Date : 2024-11-18DOI: 10.1016/j.renene.2024.121863
Qiulei Cheng , Song Tian , Haitian Long , Yingang Gui , Qiang Yi , Shoutai Li , Ping Wang , Mingyuan Gao , Yuhua Sun
{"title":"Energy self-sufficient power supply method for trackside detection sensors","authors":"Qiulei Cheng , Song Tian , Haitian Long , Yingang Gui , Qiang Yi , Shoutai Li , Ping Wang , Mingyuan Gao , Yuhua Sun","doi":"10.1016/j.renene.2024.121863","DOIUrl":"10.1016/j.renene.2024.121863","url":null,"abstract":"<div><div>With the swift expansion of China's high-speed railway network and the escalation of train speeds, the assurance of operational safety has become paramount. The state of the tracks is crucial for ensuring the safety of high-speed trains, rendering precise track assessment essential. Nonetheless, investigations on the utilization of electrified rails for powering sensors along the tracks are still few. This paper presents a method for supplying power to trackside detecting sensors via electrified rail, grounded on the operational principles of railway signal lamp control. An energy management circuit was initially developed, with resistance and other parameters meticulously adjusted to achieve optimal energy efficiency and output voltage. Furthermore, experiments were conducted to measure the length of charging and discharging of the energy storage capacitor under various operational conditions. The findings indicate that the energy management circuit module effectively powers a point rail crack-detecting sensor, maintaining operation for over 5 min and satisfactorily fulfilling detection criteria. In comparison to conventional approaches, the proposed energy self-sufficient power supply approach offers advantages such as maintenance-free longevity, enhanced efficiency, and greater environmental sustainability.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"238 ","pages":"Article 121863"},"PeriodicalIF":9.0,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable EnergyPub Date : 2024-11-17DOI: 10.1016/j.renene.2024.121898
Zhaozhao Tang , Davina Vallabh , Yaodong Wang , Ye Huang , Jing-Cheng Han , Yang Zhou , Linlin Wang , Muhammad Ahmad , Maryam Yousaf , Yuchen Wang , Yuefei Huang
{"title":"Net-zero farming: Trigeneration with carbon capture and storage","authors":"Zhaozhao Tang , Davina Vallabh , Yaodong Wang , Ye Huang , Jing-Cheng Han , Yang Zhou , Linlin Wang , Muhammad Ahmad , Maryam Yousaf , Yuchen Wang , Yuefei Huang","doi":"10.1016/j.renene.2024.121898","DOIUrl":"10.1016/j.renene.2024.121898","url":null,"abstract":"<div><div>Aiming to achieve net-zero farming, this study explores the potential of anaerobic digestion of various biowastes to produce biogas for meeting the energy demands of a dairy farm, including electricity, heating, and cooling. Two options were investigated: Option 1 focuses solely on meeting the farm's energy demand, while Option 2 focuses on a big system that utilizes all available biowastes to produce biogas, with surplus electricity sold back to grid. These options were modelled using ECLIPSE software and evaluated in terms of practicality, environmental impact, and economic viability. Option 2, employing trigeneration, achieved an overall efficiency of 80.0 %, significantly higher than Option 1's 48.4 %. However, the efficiencies of the combined heat and power (CHP) system for Option 1 and 2 were 62.2 % and 81.1 %, respectively, both higher than their corresponding trigeneration. Option 2 also produced a greater annual carbon dioxide offset of 4206 Ton CO<sub>2</sub>-eq compared to 299 Ton CO<sub>2</sub>-eq for Option 1 by leveraging digestive fertilizers and carbon capture and storage technology (CCS). Finally, it was found that the payback period for Option 1 was projected at 11 years while Option 2 would require 12 years, with anticipated profits of £124,900 and £891,900 for Options 1 and 2, respectively.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"238 ","pages":"Article 121898"},"PeriodicalIF":9.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable EnergyPub Date : 2024-11-17DOI: 10.1016/j.renene.2024.121927
Xiaofeng Zhang , Yuting Liu , Yu Zhan , Renshi Yan , Jin Mei , Ang Fu , Fan Jiao , Rong Zeng
{"title":"Multi-scenario optimization and performance evaluation of integrated energy system considering co-scheduling of EVs and stationary energy storage","authors":"Xiaofeng Zhang , Yuting Liu , Yu Zhan , Renshi Yan , Jin Mei , Ang Fu , Fan Jiao , Rong Zeng","doi":"10.1016/j.renene.2024.121927","DOIUrl":"10.1016/j.renene.2024.121927","url":null,"abstract":"<div><div>As the mobile energy storage and load-side demand response device, energy dispatch potential of electric vehicles (EVs) in energy supply system is yet to be fully explored. This study presented a multi-energy incorporating integrated energy system (IES) with carbon capture system and power-to-gas for residential building and EVs, five optimal scheduling strategies considering EVs charging/discharging, co-dispatch of EVs and IES, and stationary battery characteristic are proposed. Optimization objectives, such as annual total cost (ATC), annual carbon emission (ACE) and total grid interaction (TGI), considering configuration and operation scheduling for IES under five scenarios can be determined through augmented ε-constraint and entropy weight-TOPSIS method, furthermore the impacts of carbon tax, battery degradation cost and the number of EVs on system performances are also studied. The results indicated that optimal ATC of IES is 6361.8 thousand yuan in Case 4 considering EVs ordered charging/discharging, optimum ACE and TGI are 4711.5 t and 2850.7 MWh in Case 5 with EVs ordered charging/discharging and state of fixed battery. Peak values and durations for charging/discharging electricity of fixed battery decrease in Case 4 and 5. This research offers a innovative idea for optimal design and operational management of integrated energy system with EVs orderly charging/discharging.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"237 ","pages":"Article 121927"},"PeriodicalIF":9.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable EnergyPub Date : 2024-11-17DOI: 10.1016/j.renene.2024.121865
Cristina Harumi Enokida , Deisi Cristina Tapparo , Fabiane Goldschmidt Antes , Ricardo Luis Radis Steinmetz , Flaviane Eva Magrini , Igor Vinicius Machado Sophiatti , Suelen Paesi , Airton Kunz
{"title":"Anaerobic codigestion of livestock manure and agro-industrial waste in a CSTR reactor: Operational aspects, digestate characteristics, and microbial community dynamics","authors":"Cristina Harumi Enokida , Deisi Cristina Tapparo , Fabiane Goldschmidt Antes , Ricardo Luis Radis Steinmetz , Flaviane Eva Magrini , Igor Vinicius Machado Sophiatti , Suelen Paesi , Airton Kunz","doi":"10.1016/j.renene.2024.121865","DOIUrl":"10.1016/j.renene.2024.121865","url":null,"abstract":"<div><div>Anaerobic codigestion of animal manure and agro-industrial waste offers an efficient alternative to monodigestion, due to the synergy between different substrates. This study investigated the digestion of five types of waste: swine manure, cattle manure, poultry hatchery waste, bone and protein waste, and dissolved air flotation sludge. Biochemical Methane Potential tests and a codigestion trial in a CSTR reactor were conducted, with increases in organic loading rate (OLR). The genera <em>Clostridium_sensu_stricto_1</em> and DTU014, belonging to the phylum Firmicutes, predominated in the codigestion. The archaeal community was dominated by <em>Methanosaeta</em> and <em>Methanosarcina</em>. Genes encoding enzymes related to acetoclastic methanogenesis were predicted to be more abundant in the initial phases, demonstrating that despite fluctuations in physicochemical parameters an adaptation process occurred. The results showed that in an OLR of 3.67 kg<sub>VSadd</sub> m<sup>−3</sup><sub>reactor</sub> d<sup>−1</sup> exhibited the best performance, with a methane yield of 521 L<sub>NCH4</sub> kg<sub>VSadd</sub> d<sup>−1</sup> and a methane productivity of 1.91 L<sub>NCH4</sub> L<sub>reactor</sub><sup>−1</sup> d<sup>−1</sup>. Digestate analysis revealed an increase in nutrient concentration, particularly nitrogen, indicating its potential as a biofertilizer. This study confirms the feasibility of anaerobic codigestion for optimizing biogas production and utilizing waste with different characteristics, promoting a sustainable and circular economy approach for the agro-industrial and livestock waste management.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"238 ","pages":"Article 121865"},"PeriodicalIF":9.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable EnergyPub Date : 2024-11-17DOI: 10.1016/j.renene.2024.121941
Liu Tingli , Muhammad Ishtiaq , Shah Saud , Muhammad Qamar Rasheed
{"title":"Achieving sustainable development in emerging economies: Interplay between markets, resources, and environment","authors":"Liu Tingli , Muhammad Ishtiaq , Shah Saud , Muhammad Qamar Rasheed","doi":"10.1016/j.renene.2024.121941","DOIUrl":"10.1016/j.renene.2024.121941","url":null,"abstract":"<div><div>The rapid growth in economic activities, feeble resource utilizations, and financial assistance for energy extensive megaprojects alarm significant environmental challenges in emerging economies. Therefore, this research delves into investigating the effects of the stock market, financial development, renewable energy, economic complexity, natural resources, and globalization on environmental sustainability in emerging economies. The pooled mean group (PMG), mean group (MG), and dynamic fixed effect (DFE) estimation approaches are adopted to examine the long-run relationship, which accounts for cross-sectional dependence and slope heterogeneity among panels. The Dumitrescu-Hurlin panel Granger causality test was adopted to analyze the causal relationships among the modeled variables. The study's findings demonstrate that renewable energy, the stock market, economic complexity, and globalization have a negative impact on the ecological footprint. It demonstrates that renewable energy, the stock market, economic complexity, and globalization increase environmental sustainability in emerging economies by reducing ecological footprints. However, financial development and natural resources are positively related to ecological footprints, indicating that financial development and natural resource consumption boost ecological footprints, and their unsustainable use causes ecological problems. Additionally, the causal relationship shows that the stock market causes ecological footprints. Bidirectional causal links between renewable energy, natural resources, financial development, and globalization have been detected. Governments and policymakers need to establish policies to boost the sustainable use of both financial development and natural resources to enhance environmental quality in selected emerging economies.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"238 ","pages":"Article 121941"},"PeriodicalIF":9.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable EnergyPub Date : 2024-11-17DOI: 10.1016/j.renene.2024.121918
Zhongmei Tian , Wei Shi , Xin Li , Yonghui Park , Zhiyu Jiang , Ji Wu
{"title":"Numerical simulations of floating offshore wind turbines with shared mooring under current-only conditions","authors":"Zhongmei Tian , Wei Shi , Xin Li , Yonghui Park , Zhiyu Jiang , Ji Wu","doi":"10.1016/j.renene.2024.121918","DOIUrl":"10.1016/j.renene.2024.121918","url":null,"abstract":"<div><div>In recent years, with the continuous development of offshore wind power, reducing construction costs has become one of the key issues. Among them, the mooring system cost accounts for about 20%–30 % of the entire floating offshore wind turbine investment. The concept of shared mooring systems can potentially reduce the cost of floating offshore wind farms (FOWF). In this paper, research is carried out on the dynamic response of an FOWF under representative current conditions of the South China Sea. The comparative analysis focuses on the motion response of a single-spar Floating Offshore Wind Turbine (FOWT)and a dual-spar FOWF. A sensitivity analysis was performed on the length of the shared mooring line. The NREL 5-MW wind turbine with a spar platform is taken as a basis FOWT model for this work. The frequency-domain hydrodynamics is computed based on potential flow theory. The time domain analysis was simulated in a software for marine operations: SIMA(DNV). The viscous effect on the floater is modeled by the drag term in Morison's equation and the hydrodynamic force acting on the mooring line is computed using Morison's equation. Based on the finite element method, the mooring line is defined by a sequence of segments with homogeneous cross-sectional properties. The result shows that with the increase of the current return period, the two platforms move synchronously, and the movement increases almost linearly. Moreover, the motion response of the shared mooring platform is smaller than that of the single mooring platform under the same conditions, especially in the vertical direction. This paper contributes to improved fundamental understanding of shared mooring systems under complex marine environmental loads.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"238 ","pages":"Article 121918"},"PeriodicalIF":9.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable EnergyPub Date : 2024-11-17DOI: 10.1016/j.renene.2024.121923
Min Sun , Liangchang Peng , Hongshuai Lei , Jialei Zhang , Zheng Zhang , Qiang Chen , Guang Zhang , Jiquan Li
{"title":"A novel small-scale H-type Darrieus vertical axis wind turbine manufactured of carbon fiber reinforced composites","authors":"Min Sun , Liangchang Peng , Hongshuai Lei , Jialei Zhang , Zheng Zhang , Qiang Chen , Guang Zhang , Jiquan Li","doi":"10.1016/j.renene.2024.121923","DOIUrl":"10.1016/j.renene.2024.121923","url":null,"abstract":"<div><div>Carbon fiber reinforced plastic (CFRP) is widely used in horizontal axis wind turbines; however, their use in vertical axis wind turbines remains uncommon. To explore the advantages of CFRP composites in vertical axis wind turbines, this study introduces a new small vertical axis wind turbine constructed from CFRP. In particular, a vacuum assisted resin infusion process was used to fabricate a carbon fiber composite blade that exhibits high strength and significantly reduced mass compared to conventional blades. A two-dimensional numerical computational model of the vertical axis wind turbine was developed using the multiple reference system model. Wind tunnel experiments were conducted to validate the numerical calculations of the wind turbine. In addition, the effects of different parameters of different materials on the power output of the wind turbine were analyzed. The self-starting performance of the small vertical axis wind turbine was thoroughly examined. It was shown that the maximum power of the wind turbine equipped with carbon fiber blades was up to 14 times greater than that of the traditional wind turbine with resin blades. Furthermore, these turbines equipped with carbon fiber blades could self-start in light breezes and operate stably even at the tip speed ratio below one.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"238 ","pages":"Article 121923"},"PeriodicalIF":9.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renewable EnergyPub Date : 2024-11-17DOI: 10.1016/j.renene.2024.121934
ShiYong Zheng , Jiaying Li , Wen Lu , Muhammad Hafeez , Muhammad Tayyab Sohail , Muhammad Waqas Akbar , Razaz Waheeb Attar
{"title":"How does the productivity of renewable energy respond to institutional pressures and higher education?","authors":"ShiYong Zheng , Jiaying Li , Wen Lu , Muhammad Hafeez , Muhammad Tayyab Sohail , Muhammad Waqas Akbar , Razaz Waheeb Attar","doi":"10.1016/j.renene.2024.121934","DOIUrl":"10.1016/j.renene.2024.121934","url":null,"abstract":"<div><div>Over the past few decades, the share of renewable energy has escalated in the total energy mix due to its indispensable role in global mitigating efforts. Therefore, the focus of empirics has recently shifted towards the factors that can impact renewable energy. Nevertheless, the role of institutional pressures and higher education in fostering renewable energy production has yet to be analyzed. This study examines the nexus between institutional pressures, higher education, and renewable energy production in top polluted economies using the CS-ARDL model. The estimates imply that institutional pressures, higher education, environmental policy stringency, GDP, and ICT factors favorably impact renewable energy production. In the short run, only the GDP and financial globalization boost renewable energy production. To boost renewable energy production, policymakers should increase awareness by increasing the general level of education and strengthening the government's role in the successful implementation of these policies.</div></div>","PeriodicalId":419,"journal":{"name":"Renewable Energy","volume":"238 ","pages":"Article 121934"},"PeriodicalIF":9.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}