Pub Date : 2025-02-22DOI: 10.1016/j.energy.2025.135224
Jianyang Sun , Chengguo Su , Jingchao Song , Chenchen Yao , Zaimin Ren , Quan Sui
To address the mismatch between renewable energy resources and load centers in China, this study proposes a two-layer capacity planning model for large-scale wind-photovoltaic-pumped hydro storage energy bases integrated with ultra-high-voltage direct current transmission lines. The model introduces a multi-mode operational framework, enhancing its adaptability to diverse regional conditions and operational scenarios. Additionally, it explicitly incorporates ultra-high-voltage direct current operational constraints, ensuring realistic and robust transmission planning. The outer-layer focuses on capacity optimization, while the inner-layer employs an 8760-h time-series simulation to comprehensively evaluate operational performance under varying conditions, offering a practical and generalizable solution for renewable energy base planning. The case study shows that: (1) Integrated operation of wind and photovoltaic power with pumped hydro storage enhances transmission stability and efficiency, achieving a power supply guarantee rate over 90 % and curtailment rate below 15 %. (2) Under free transmission mode, the transmission curve is smooth and stable, with power supply guarantee rate surpassing 99 % and curtailment rate under 4 %. (3) Due to temporal mismatches between renewable generation and load demand in Northwest China, the agreed transmission curve mode reveals that pumped hydro storage alone is insufficient to meet external transmission needs, requiring gas turbine units for collaborative regulation.
{"title":"Capacity planning for large-scale wind-photovoltaic-pumped hydro storage energy bases based on ultra-high voltage direct current power transmission","authors":"Jianyang Sun , Chengguo Su , Jingchao Song , Chenchen Yao , Zaimin Ren , Quan Sui","doi":"10.1016/j.energy.2025.135224","DOIUrl":"10.1016/j.energy.2025.135224","url":null,"abstract":"<div><div>To address the mismatch between renewable energy resources and load centers in China, this study proposes a two-layer capacity planning model for large-scale wind-photovoltaic-pumped hydro storage energy bases integrated with ultra-high-voltage direct current transmission lines. The model introduces a multi-mode operational framework, enhancing its adaptability to diverse regional conditions and operational scenarios. Additionally, it explicitly incorporates ultra-high-voltage direct current operational constraints, ensuring realistic and robust transmission planning. The outer-layer focuses on capacity optimization, while the inner-layer employs an 8760-h time-series simulation to comprehensively evaluate operational performance under varying conditions, offering a practical and generalizable solution for renewable energy base planning. The case study shows that: (1) Integrated operation of wind and photovoltaic power with pumped hydro storage enhances transmission stability and efficiency, achieving a power supply guarantee rate over 90 % and curtailment rate below 15 %. (2) Under free transmission mode, the transmission curve is smooth and stable, with power supply guarantee rate surpassing 99 % and curtailment rate under 4 %. (3) Due to temporal mismatches between renewable generation and load demand in Northwest China, the agreed transmission curve mode reveals that pumped hydro storage alone is insufficient to meet external transmission needs, requiring gas turbine units for collaborative regulation.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"320 ","pages":"Article 135224"},"PeriodicalIF":9.0,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488560","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}
Pub Date : 2025-02-22DOI: 10.1016/j.energy.2025.135174
Ning Wang , Baobao Hu , Yiheng Pang , Zhiguo Qu , Yun Wang
Escalating the self-humidification ability of polymer electrolyte membrane fuel cell is of paramount significance to automobile and portable applications, particularly for ambitious humidifier-free goal. In this study, detailed humidification mechanisms are explored for steady-state and startup scenarios through three-dimensional multiphase modeling. Model validations for different inlet humidities and current density evolutions of startup are strictly performed, five proposed operating strategies are quantitatively compared, in which the crucial influence of anode and cathode self-humidification cycles are evaluated. The dynamic characteristics of both preheating and self-heating modes during startup are also investigated under humidifier-free design. The results indicate that anode self-humidification cycle plays a more important role than the cathode one. The thin membrane fuel cell performance is insensitive to the anode relative humidity due to enhanced self-humidification. Additionally, the observed current density overshoot after startup is attributed to rapid oxygen consumption, followed by a gradual increase due to continuous electrolyte hydration. The fundamentals of dynamic self-humidification during different voltage/current-density startups are similar, determined by transient water accumulation and current density evolution. Moreover, self-heating mode shows lower output voltage due to sluggish catalyst activity, while it can alleviate the steep oxygen concentration drop during startup, compared with the preheating one.
{"title":"Self-humidification characteristics of steady-state operation and startup for humidifier-free polymer electrolyte membrane fuel cell","authors":"Ning Wang , Baobao Hu , Yiheng Pang , Zhiguo Qu , Yun Wang","doi":"10.1016/j.energy.2025.135174","DOIUrl":"10.1016/j.energy.2025.135174","url":null,"abstract":"<div><div>Escalating the self-humidification ability of polymer electrolyte membrane fuel cell is of paramount significance to automobile and portable applications, particularly for ambitious humidifier-free goal. In this study, detailed humidification mechanisms are explored for steady-state and startup scenarios through three-dimensional multiphase modeling. Model validations for different inlet humidities and current density evolutions of startup are strictly performed, five proposed operating strategies are quantitatively compared, in which the crucial influence of anode and cathode self-humidification cycles are evaluated. The dynamic characteristics of both preheating and self-heating modes during startup are also investigated under humidifier-free design. The results indicate that anode self-humidification cycle plays a more important role than the cathode one. The thin membrane fuel cell performance is insensitive to the anode relative humidity due to enhanced self-humidification. Additionally, the observed current density overshoot after startup is attributed to rapid oxygen consumption, followed by a gradual increase due to continuous electrolyte hydration. The fundamentals of dynamic self-humidification during different voltage/current-density startups are similar, determined by transient water accumulation and current density evolution. Moreover, self-heating mode shows lower output voltage due to sluggish catalyst activity, while it can alleviate the steep oxygen concentration drop during startup, compared with the preheating one.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"320 ","pages":"Article 135174"},"PeriodicalIF":9.0,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488562","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}
Pub Date : 2025-02-22DOI: 10.1016/j.energy.2025.135222
Nan Chen, Junheng Gao, Lihui Gao, Shuanghao Yang, Shouyan Chen
In light of the high penetration of renewable energy sources into the grid and the associated power curtailment phenomenon, this paper proposes a multi-energy conversion scheduling strategy for an electric-heat-gas-cooling integrated energy system. To mitigate the operational constraints and environmental impact of conventional cogeneration units, this study integrates a concentrating solar power plant equipped with a thermal storage system into the conventional cogeneration framework. Moreover, considering load-side uncertainties, flexible electric and thermal loads are incorporated into system scheduling to enhance system adaptability and operational flexibility. Finally, a mixed-integer programming algorithm is employed to solve the optimization problem. Simulation results demonstrate that incorporating the flexible load scheduling strategy reduces daily operational costs by 2.82%, power curtailment losses by 22.07%, and decreases the peak-to-valley difference of electric loads by 14.68%. Integrating concentrating solar power plant into system operation reduces daily operational costs by 3.70%, cuts carbon emissions by 20.30%, and lowers daily gas purchases by 11.49%. These findings validate the feasibility and effectiveness of the proposed approach.
{"title":"Economic dispatch of integrated energy systems taking into account the participation of flexible loads and concentrated solar power plants","authors":"Nan Chen, Junheng Gao, Lihui Gao, Shuanghao Yang, Shouyan Chen","doi":"10.1016/j.energy.2025.135222","DOIUrl":"10.1016/j.energy.2025.135222","url":null,"abstract":"<div><div>In light of the high penetration of renewable energy sources into the grid and the associated power curtailment phenomenon, this paper proposes a multi-energy conversion scheduling strategy for an electric-heat-gas-cooling integrated energy system. To mitigate the operational constraints and environmental impact of conventional cogeneration units, this study integrates a concentrating solar power plant equipped with a thermal storage system into the conventional cogeneration framework. Moreover, considering load-side uncertainties, flexible electric and thermal loads are incorporated into system scheduling to enhance system adaptability and operational flexibility. Finally, a mixed-integer programming algorithm is employed to solve the optimization problem. Simulation results demonstrate that incorporating the flexible load scheduling strategy reduces daily operational costs by 2.82%, power curtailment losses by 22.07%, and decreases the peak-to-valley difference of electric loads by 14.68%. Integrating concentrating solar power plant into system operation reduces daily operational costs by 3.70%, cuts carbon emissions by 20.30%, and lowers daily gas purchases by 11.49%. These findings validate the feasibility and effectiveness of the proposed approach.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"320 ","pages":"Article 135222"},"PeriodicalIF":9.0,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-22DOI: 10.1016/j.energy.2025.135228
Yubao Li , Ruisi Zong , Juhuang Song , Zhiwei Chen , Chunbiao Yang , Lingfei Qi , Jinyue Yan
Micro-energy harvesting technologies are expected to replace traditional chemical batteries, providing stable and continuous clean energy for low-power wireless sensors. However, the voltage generated by micro-energy harvesting systems is often irregular and chaotic, making it unsuitable for direct use in electronic devices. To address this issue, this paper proposes an adaptive duty cycle interface circuit based on the Perturb and Observe (P&O) method, aiming to reduce the fluctuation of the output voltage while also implementing charging and discharging protection control for the battery. Experimental data have verified the feasibility of the voltage regulation strategy proposed in this paper, when the input voltage is constant and the target output voltage varies within the range of 1.2 V–4.2 V, the output voltage fluctuation of the P&O-based adaptive duty cycle control strategy is limited to 0.034 V. Moreover, when the input voltage is between 1 and 50 V, the maximum fluctuation of the output voltage is 0.344 V and the maximum deviation is 9.3 %. When the wind speed is between 3 and 7 m/s, the energy conversion efficiency ranges from 24.4 % to 56.8 %. At a moderate wind speed of 7 m/s, the power generation can reach 6835.2 J/day, and 2460.68 kJ/year. To prevent battery discharge when there is no energy input and overcharging due to continuous charging, this paper uses an analog-to-digital converter (ADC) and a logic gate circuit to implement charging and discharging protection control for the battery, ensuring protection during charging and preventing battery discharge.
{"title":"An energy management strategy integrating high-efficiency voltage regulation and charge protection for ambient energy harvesting system","authors":"Yubao Li , Ruisi Zong , Juhuang Song , Zhiwei Chen , Chunbiao Yang , Lingfei Qi , Jinyue Yan","doi":"10.1016/j.energy.2025.135228","DOIUrl":"10.1016/j.energy.2025.135228","url":null,"abstract":"<div><div>Micro-energy harvesting technologies are expected to replace traditional chemical batteries, providing stable and continuous clean energy for low-power wireless sensors. However, the voltage generated by micro-energy harvesting systems is often irregular and chaotic, making it unsuitable for direct use in electronic devices. To address this issue, this paper proposes an adaptive duty cycle interface circuit based on the Perturb and Observe (P&O) method, aiming to reduce the fluctuation of the output voltage while also implementing charging and discharging protection control for the battery. Experimental data have verified the feasibility of the voltage regulation strategy proposed in this paper, when the input voltage is constant and the target output voltage varies within the range of 1.2 V–4.2 V, the output voltage fluctuation of the P&O-based adaptive duty cycle control strategy is limited to 0.034 V. Moreover, when the input voltage is between 1 and 50 V, the maximum fluctuation of the output voltage is 0.344 V and the maximum deviation is 9.3 %. When the wind speed is between 3 and 7 m/s, the energy conversion efficiency ranges from 24.4 % to 56.8 %. At a moderate wind speed of 7 m/s, the power generation can reach 6835.2 J/day, and 2460.68 kJ/year. To prevent battery discharge when there is no energy input and overcharging due to continuous charging, this paper uses an analog-to-digital converter (ADC) and a logic gate circuit to implement charging and discharging protection control for the battery, ensuring protection during charging and preventing battery discharge.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"320 ","pages":"Article 135228"},"PeriodicalIF":9.0,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479016","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}
Pub Date : 2025-02-22DOI: 10.1016/j.energy.2025.135231
Yongqiang Xia, Tao Yu, Lei Yang, Bingbing Chen, Lanlan Jiang, Mingjun Yang, Yongchen Song
Hydrate-based CO2 storage in subsea sediments presents a promising solution for safe carbon sequestration, as CO2 hydrate caps effectively reduce CO2 leakage risk. However, the effectiveness of using large-scale hydrate caps to achieve substantial CO2 sequestration is still uncertain. This study developed a numerical model for CO2 sequestration in sediment environments. The distribution patterns of multi-state CO2 (i.e., free, dissolved, and hydrate states) and the effectiveness of hydrate caps were investigated using single-horizontal-well and dual-horizontal-well systems. The findings indicated that a higher injection rate expedited the formation rate of CO2 hydrate caps but reduced the dissolved CO2 sequestration efficiency within the hydrate formation zone and the free phase zone. At the same CO2 sequestration amount, a low-flow-rate prolonged injection strategy could mitigate the pressure accumulation near the well and broaden the distribution range of the hydrate cap. Smaller well spacing facilitated the formation of a larger hydrate cap during the dual-well CO2 sequestration, with the thickness of the hydrate cap increasing by approximately 12 m over 50 years after CO2 injection cessation. Furthermore, a low-permeability mud cap interfered with the processes of CO2 plume migration and heat transfer, exacerbating the stratum instability near the injection well within the hydrate formation zone. This study provided new insights into forming large-scale CO2 hydrate caps and contributed to developing the CO2 storage technology in subsea sediments.
{"title":"Multi-state CO2 distribution patterns for subsea carbon sequestration assisted by large-scale CO2 hydrate caps","authors":"Yongqiang Xia, Tao Yu, Lei Yang, Bingbing Chen, Lanlan Jiang, Mingjun Yang, Yongchen Song","doi":"10.1016/j.energy.2025.135231","DOIUrl":"10.1016/j.energy.2025.135231","url":null,"abstract":"<div><div>Hydrate-based CO<sub>2</sub> storage in subsea sediments presents a promising solution for safe carbon sequestration, as CO<sub>2</sub> hydrate caps effectively reduce CO<sub>2</sub> leakage risk. However, the effectiveness of using large-scale hydrate caps to achieve substantial CO<sub>2</sub> sequestration is still uncertain. This study developed a numerical model for CO<sub>2</sub> sequestration in sediment environments. The distribution patterns of multi-state CO<sub>2</sub> (i.e., free, dissolved, and hydrate states) and the effectiveness of hydrate caps were investigated using single-horizontal-well and dual-horizontal-well systems. The findings indicated that a higher injection rate expedited the formation rate of CO<sub>2</sub> hydrate caps but reduced the dissolved CO<sub>2</sub> sequestration efficiency within the hydrate formation zone and the free phase zone. At the same CO<sub>2</sub> sequestration amount, a low-flow-rate prolonged injection strategy could mitigate the pressure accumulation near the well and broaden the distribution range of the hydrate cap. Smaller well spacing facilitated the formation of a larger hydrate cap during the dual-well CO<sub>2</sub> sequestration, with the thickness of the hydrate cap increasing by approximately 12 m over 50 years after CO<sub>2</sub> injection cessation. Furthermore, a low-permeability mud cap interfered with the processes of CO<sub>2</sub> plume migration and heat transfer, exacerbating the stratum instability near the injection well within the hydrate formation zone. This study provided new insights into forming large-scale CO<sub>2</sub> hydrate caps and contributed to developing the CO<sub>2</sub> storage technology in subsea sediments.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"320 ","pages":"Article 135231"},"PeriodicalIF":9.0,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143509033","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}
Pub Date : 2025-02-22DOI: 10.1016/j.energy.2025.135030
Fatih Selimefendigil , Hakan F. Oztop
Modern energy technology systems including batteries, hydrogen storage units, electronic equipments and photovoltaic (PV) modules require effective cooling methods and thermal management techniques for performance improvements and safety of operation. In this study, a novel thermal management system for double PV units is proposed by using combined effects of inclined elastic fin in the T-shaped branching cooling channel and thermoelectric generator (TEG) modules. The FEM based numerical analysis is carried out for different Reynolds numbers (between 200 to 1200), fin lengths (between 0 and H), fin tilt (between 10 and 45), and fin position (yf between -H and H) where both rigid or elastic fin configurations are considered. Cell temperature drops of 14 °C and 15.48 °C are seen in PV1 and PV2 when Reynolds number (Re) is raised from 200 to 1200 using a rigid fin while average temperatures become 2 °C and 0.5 °C higher at the highest Re when elastic fin is used. Poor thermal transport is observed at the fin location of yf=−H. Fins and higher Re significantly lower the PV surface temperature of both PVs in double PV-TEG combined system. When elastic and rigid fins are used at the highest Re, the temperature of PV1 is lowered by about 14.5 °C and 16.7 °C compared to the reference configuration of the no-fin case at Re=200, while the temperature of PV2 is lowered by about 12 °C and 11.2 °C. PV’s performance is estimated using artificial neural network model for different flow rates, fin lengths, and fin inclinations (both elastic and rigid scenarios).
{"title":"Cooling of double PV-TEG combined units by using a T-shaped branching channel equipped with an inclined elastic fin","authors":"Fatih Selimefendigil , Hakan F. Oztop","doi":"10.1016/j.energy.2025.135030","DOIUrl":"10.1016/j.energy.2025.135030","url":null,"abstract":"<div><div>Modern energy technology systems including batteries, hydrogen storage units, electronic equipments and photovoltaic (PV) modules require effective cooling methods and thermal management techniques for performance improvements and safety of operation. In this study, a novel thermal management system for double PV units is proposed by using combined effects of inclined elastic fin in the T-shaped branching cooling channel and thermoelectric generator (TEG) modules. The FEM based numerical analysis is carried out for different Reynolds numbers (between 200 to 1200), fin lengths (between 0 and H), fin tilt (between 10 and 45), and fin position (yf between -H and H) where both rigid or elastic fin configurations are considered. Cell temperature drops of 14 °C and 15.48 °C are seen in PV1 and PV2 when Reynolds number (Re) is raised from 200 to 1200 using a rigid fin while average temperatures become 2 °C and 0.5 °C higher at the highest Re when elastic fin is used. Poor thermal transport is observed at the fin location of yf=−H. Fins and higher Re significantly lower the PV surface temperature of both PVs in double PV-TEG combined system. When elastic and rigid fins are used at the highest Re, the temperature of PV1 is lowered by about 14.5 °C and 16.7 °C compared to the reference configuration of the no-fin case at Re=200, while the temperature of PV2 is lowered by about 12 °C and 11.2 °C. PV’s performance is estimated using artificial neural network model for different flow rates, fin lengths, and fin inclinations (both elastic and rigid scenarios).</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"320 ","pages":"Article 135030"},"PeriodicalIF":9.0,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479219","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}
Pub Date : 2025-02-22DOI: 10.1016/j.energy.2025.135215
Chen Zhuo , Li Wei , Pan Zhangrong , Liu Chenchen , Wang Huiyuan , Guo Junhong
Changes in environmental conditions, such as radiation and temperature, driven by climate change, will significantly impact photovoltaic (PV) power generation. In this paper, we utilize 14 models in the NASA Earth Exchange Global Daily Downscaled Projections (GDDP) climate model ensemble to analyze the spatial and temporal trends of PV potential and photovoltaic drought under the SSP2-4.5 and SSP5-8.5 scenarios during future carbon peak (2026–2035) and carbon neutrality (2056–2065) periods in China. The results indicate that, compared to the baseline period (2005–2014), the spatial variation of future annual mean PV capacity factor shows a declining trend in the western region, but increases in the southeastern region. Furthermore, the change in capacity factor during the carbon neutrality period is greater than during the carbon peak period, particularly under the SSP5-8.5 scenario. Seasonally, the most significant changes in PV capacity factor occur in autumn and winter. Under the SSP5-8.5 scenario during the carbon neutrality period, the change in autumn PV capacity factor exceeds 3 %. Regarding intra-annual variability, during the carbon peak period, the intra-annual variability of PV capacity factor declines in most parts of China, particularly in some southeastern regions, decreasing by over 5 %. Conversely, in the carbon neutrality period, intra-annual variability will increase in northeastern and central regions, with increases exceeding 4 %. This implies that these regions may face greater challenges in balancing supply and demand and managing stability in their power systems. Similar to climatic extreme events, the spatial-temporal characteristics of photovoltaic “drought” are analyzed. During the carbon neutrality period, the frequency of photovoltaic droughts (PVDF) in China is projected to decrease by approximately 10 % compared to historical periods, while the severity of photovoltaic droughts (PVDS) will significantly increase, rising by 17 % (36 %) under the SSP2-4.5 (SSP5-8.5) scenarios. Regionally, the frequency, duration, and severity of photovoltaic drought events in most regions of China are all diminishing, while there will be an increase in the northwestern and northeastern regions, with the severity metric rising by 63 % and 49 %, respectively. This indicates that the situation regarding photovoltaic droughts will become increasingly severe in these regions.
{"title":"Spatiotemporal changes in PV potential and extreme characteristics in China under SSP scenarios","authors":"Chen Zhuo , Li Wei , Pan Zhangrong , Liu Chenchen , Wang Huiyuan , Guo Junhong","doi":"10.1016/j.energy.2025.135215","DOIUrl":"10.1016/j.energy.2025.135215","url":null,"abstract":"<div><div>Changes in environmental conditions, such as radiation and temperature, driven by climate change, will significantly impact photovoltaic (PV) power generation. In this paper, we utilize 14 models in the NASA Earth Exchange Global Daily Downscaled Projections (GDDP) climate model ensemble to analyze the spatial and temporal trends of PV potential and photovoltaic drought under the SSP2-4.5 and SSP5-8.5 scenarios during future carbon peak (2026–2035) and carbon neutrality (2056–2065) periods in China. The results indicate that, compared to the baseline period (2005–2014), the spatial variation of future annual mean PV capacity factor shows a declining trend in the western region, but increases in the southeastern region. Furthermore, the change in capacity factor during the carbon neutrality period is greater than during the carbon peak period, particularly under the SSP5-8.5 scenario. Seasonally, the most significant changes in PV capacity factor occur in autumn and winter. Under the SSP5-8.5 scenario during the carbon neutrality period, the change in autumn PV capacity factor exceeds 3 %. Regarding intra-annual variability, during the carbon peak period, the intra-annual variability of PV capacity factor declines in most parts of China, particularly in some southeastern regions, decreasing by over 5 %. Conversely, in the carbon neutrality period, intra-annual variability will increase in northeastern and central regions, with increases exceeding 4 %. This implies that these regions may face greater challenges in balancing supply and demand and managing stability in their power systems. Similar to climatic extreme events, the spatial-temporal characteristics of photovoltaic “drought” are analyzed. During the carbon neutrality period, the frequency of photovoltaic droughts (PVDF) in China is projected to decrease by approximately 10 % compared to historical periods, while the severity of photovoltaic droughts (PVDS) will significantly increase, rising by 17 % (36 %) under the SSP2-4.5 (SSP5-8.5) scenarios. Regionally, the frequency, duration, and severity of photovoltaic drought events in most regions of China are all diminishing, while there will be an increase in the northwestern and northeastern regions, with the severity metric rising by 63 % and 49 %, respectively. This indicates that the situation regarding photovoltaic droughts will become increasingly severe in these regions.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"320 ","pages":"Article 135215"},"PeriodicalIF":9.0,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143473913","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}
Pub Date : 2025-02-21DOI: 10.1016/j.energy.2025.135022
Yi Zeng , Yan Li , Zhongkai Zhou , Daduan Zhao , Tong Yang , Pu Ren , Chenghui Zhang
Accurate joint estimation of state of charge (SOC) and state of health is crucial for battery management systems. This paper proposes an innovative method employing a fractional-order model (FOM) in conjunction with a fractional-order filter for effective and precise online joint estimation of SOC and capacity. Motivated by the advantageous characteristics of FOMs in depicting the dynamic behavior of batteries, this paper establishes a first-order FOM. Subsequently, a fractional-order square-root cubature Kalman filter method is proposed for the online estimation of SOC and capacity. This method effectively addresses the potential non-positive definite covariance matrix issue during the iteration process. Additionally, this paper suggests using polynomials instead of binomials to compute fractional derivatives, aiming to further improve simulation accuracy. Besides, motivated by the impact of orders on modeling and state estimation under different battery aging and temperature conditions, through extensive experiments, the following findings are derived: (1) When the order of the state estimator is higher than the model order, it can significantly enhance the precision of state estimation. (2) The optimal order of the state estimator shows a decreasing trend with battery aging and increasing temperature. (3) Based on the experimental results, a order scheduling strategy can be established to provide a reference for the selection of the order. Finally, a comparative analysis is conducted between classical methods and the proposed method. Experimental results demonstrate that the proposed method makes the mean absolute error of SOC estimation about 2% and the capacity estimation errors typically remain below 3%, despite the degree of aging and temperatures.
{"title":"Joint estimation of state of charge and health utilizing fractional-order square-root cubature Kalman filtering with order scheduling strategy","authors":"Yi Zeng , Yan Li , Zhongkai Zhou , Daduan Zhao , Tong Yang , Pu Ren , Chenghui Zhang","doi":"10.1016/j.energy.2025.135022","DOIUrl":"10.1016/j.energy.2025.135022","url":null,"abstract":"<div><div>Accurate joint estimation of state of charge (SOC) and state of health is crucial for battery management systems. This paper proposes an innovative method employing a fractional-order model (FOM) in conjunction with a fractional-order filter for effective and precise online joint estimation of SOC and capacity. Motivated by the advantageous characteristics of FOMs in depicting the dynamic behavior of batteries, this paper establishes a first-order FOM. Subsequently, a fractional-order square-root cubature Kalman filter method is proposed for the online estimation of SOC and capacity. This method effectively addresses the potential non-positive definite covariance matrix issue during the iteration process. Additionally, this paper suggests using polynomials instead of binomials to compute fractional derivatives, aiming to further improve simulation accuracy. Besides, motivated by the impact of orders on modeling and state estimation under different battery aging and temperature conditions, through extensive experiments, the following findings are derived: (1) When the order of the state estimator is higher than the model order, it can significantly enhance the precision of state estimation. (2) The optimal order of the state estimator shows a decreasing trend with battery aging and increasing temperature. (3) Based on the experimental results, a order scheduling strategy can be established to provide a reference for the selection of the order. Finally, a comparative analysis is conducted between classical methods and the proposed method. Experimental results demonstrate that the proposed method makes the mean absolute error of SOC estimation about 2% and the capacity estimation errors typically remain below 3%, despite the degree of aging and temperatures.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"320 ","pages":"Article 135022"},"PeriodicalIF":9.0,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479221","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}
Pub Date : 2025-02-21DOI: 10.1016/j.energy.2025.135165
Ali Keçebaş , Onur Vahip Güler , Aleksandar G. Georgiev , Emine Yağız Gürbüz , Azim Doğuş Tuncer , İstemihan Şahinkesen
This study investigates the impact of integrating an ethanol-based phase change material (PCM) cooling system on the performance of PV panels. The primary aim is to enhance thermal management and improve efficiency by utilizing ethanol's phase-changing properties within a glass dome selectively positioned over the PV panels. Experiments were conducted under controlled environmental conditions with varying absorber thicknesses (1.5 cm, 2 cm, and 2.5 cm) to assess their effects on PV performance. Energy and exergy analyses were employed to evaluate the thermal and electrical efficiencies. Results showed that the 2 cm thick ethanol-filled absorber significantly reduced surface temperatures, achieving an average front-side temperature of 51 °C and backside temperature of 45 °C. This configuration enhanced electrical efficiency to 18 % and thermal efficiency to 22 %. Ethanol-based absorbers demonstrated superior thermal management, maintaining optimal operating conditions and prolonging energy output. The front-surface placement of the cooling system further enhanced thermal and electrical performance by addressing overheating directly at the solar incidence point, though future research should focus on long-term durability and transparency concerns. The study concluded that integrating ethanol as a PCM in PV/T systems can effectively mitigate efficiency losses due to overheating. This innovative approach holds promise for advancing solar energy technology and improving PV panel reliability and efficiency. Future research should focus on the long-term stability and interactions of ethanol in PCM systems, performance under varied climatic conditions, and economic feasibility for large-scale applications.
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