Applied Energy最新文献

{"title":"Joint peak power and carbon emission shaving in active distribution systems using carbon emission flow-based deep reinforcement learning","authors":"Sangyoon Lee ,&nbsp;Panggah Prabawa ,&nbsp;Dae-Hyun Choi","doi":"10.1016/j.apenergy.2024.124944","DOIUrl":"10.1016/j.apenergy.2024.124944","url":null,"abstract":"<div><div>Distribution optimal power flow (D-OPF) with peak load shaving function is crucial for guaranteeing economical and reliable operations of active distribution grids with various distributed energy resources. However, conventional D-OPF methods reduce only the power operation cost without considering carbon emission reduction, which may lead to a slowdown in achieving global carbon neutrality. To resolve this issue, this study proposes a deep reinforcement learning (DRL)-assisted D-OPF framework realizing dual-peak shaving of power and carbon emission for low-carbon active distribution system operations based on the notion of carbon emission flow (CEF). The proposed framework aims to minimize the total power operation costs of substation and gas-turbine (GT) generators. It also aims to reduce the total carbon emission cost via mitigation of peak power and carbon emission in the CEF-based D-OPF framework with both power and carbon emission peak constraints. A key feature of the proposed framework is the adoption of the DRL method for the CEF-based D-OPF problem to determine economical and eco-friendly peaks of power and carbon emission under dynamically changing distribution system operations. Furthermore, a D-OPF optimization-based reward function for the DRL agent is designed to yield no constraint violations for the D-OPF problem during the agent’s training phase. Numerical examples conducted on the IEEE 33-node and IEEE 69-node distribution systems with GT generators, solar photovoltaic systems, and energy storage systems demonstrate that, in contrast with CEF-free and CEF-integrated optimization methods with fixed power and/or carbon emission peaks, the proposed method further reduces the total carbon emission and cost.</div></div>","PeriodicalId":246,"journal":{"name":"Applied Energy","volume":"379 ","pages":"Article 124944"},"PeriodicalIF":10.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721110","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}

{"title":"Effects of hydrogen dilution on performance and in-plane uniformity of large-scale PEM fuel cell with low anode catalyst loading","authors":"Ling Xu ,&nbsp;Liangfei Xu ,&nbsp;Yangbin Shao ,&nbsp;Xiyuan Zhang ,&nbsp;Zunyan Hu ,&nbsp;Jianqiu Li ,&nbsp;Minggao Ouyang","doi":"10.1016/j.apenergy.2024.124992","DOIUrl":"10.1016/j.apenergy.2024.124992","url":null,"abstract":"<div><div>Enhancing hydrogen utilization is crucial for improving the efficiency of Proton Exchange Membrane (PEM) fuel cells. However, the widespread implementation of ultra-thin PEMs introduces a challenging objective: balancing hydrogen utilization with hydrogen dilution, which can adversely affect performance. To achieve this balance, understanding the impact of hydrogen dilution on fuel cell performance is critical, particularly for commercial large-scale fuel cells with low anode catalyst loadings, where significant research gaps remain. This study aims to fill these research gaps by investigating the performance and current distribution of a 291 cm² fuel cell with an anode platinum loading of 0.1 mg/cm² under varying hydrogen molar fractions (HMFs) and hydrogen stoichiometric ratios (HSRs). The results reveal that hydrogen dilution affects performance through three primary mechanisms: decreasing anode hydrogen partial pressure, exacerbating hydrogen supply non-uniformity, and altering the water balance. Notably, the latter two factors interact and collectively affect in-plane uniformity, leading to complex performance characteristics under hydrogen dilution conditions. Furthermore, the performance loss due to hydrogen dilution observed in this study is more pronounced than previously reported, primarily due to low catalyst loading and in-plane non-uniformity resulting from scale expansion. Nevertheless, at medium to low current densities and high HSR conditions, where the impact of hydrogen dilution is diminished, moderate hydrogen dilution can be permitted to enhance hydrogen utilization. Based on the data collected, this study maps the boundary for hydrogen dilution constrained by performance loss, offering valuable insights into the design and optimization of future control strategies.</div></div>","PeriodicalId":246,"journal":{"name":"Applied Energy","volume":"379 ","pages":"Article 124992"},"PeriodicalIF":10.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721170","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}

{"title":"A copula-based whole system model to understand the environmental and economic impacts of grid-scale energy storage","authors":"Fan He ,&nbsp;Matthew Leach ,&nbsp;Michael Short ,&nbsp;Yurui Fan ,&nbsp;Lirong Liu","doi":"10.1016/j.apenergy.2024.124935","DOIUrl":"10.1016/j.apenergy.2024.124935","url":null,"abstract":"<div><div>Energy storage is important in future power systems. However, the role of grid-scale energy storage in the power system and in the whole socio-economic system is unclear. A copula-based whole system model is developed to explore the economic and environmental effects of grid-scale energy storage, thus supporting the decision-making at micro and macro levels. A power system optimisation model is linked with an input-output model, and the copula function is embedded in the model to reflect the multiple and interactive uncertainties from electricity demand, emission constraints, and sector disaggregation. We conducted case studies on China and the UK in 2025 considering different storage technologies (Pumped hydro, Battery, Flywheels storage) to show the differences related with power systems and economic structures. We find that increasing energy storage capacity leads to increase in renewable generation capacity (solar generation in China and wind generation in the UK). Thus, it can reduce their total economy-wide carbon emissions. Uncertainty in sector disaggregation will have a large impact on carbon emissions in some extreme cases, especially in those sectors closely linked to the power sector and with high emission intensity.</div></div>","PeriodicalId":246,"journal":{"name":"Applied Energy","volume":"379 ","pages":"Article 124935"},"PeriodicalIF":10.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704646","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}

{"title":"A field test and evaluation of radiative cooling performance as applied on the sidewall surfaces of residential buildings in China","authors":"Ze-Ye Wang ,&nbsp;Xian Wu ,&nbsp;Ming-Liang Qu ,&nbsp;Li-Wu Fan ,&nbsp;Zi-Tao Yu ,&nbsp;Shu-Qin Chen ,&nbsp;Jian Ge ,&nbsp;Liang Wang ,&nbsp;Sheng-Juan Dai","doi":"10.1016/j.apenergy.2024.124961","DOIUrl":"10.1016/j.apenergy.2024.124961","url":null,"abstract":"<div><div>To investigate the energy-saving effect of radiative cooling materials when applied to the external surfaces of the side walls of buildings, the present study was carried out in a typical room-split multi-story residential building in Zhejiang province, China. The field test was conducted for a period of 259 days across all four seasons. Two types of rooms (middle rooms and side rooms) were selected to set up the control and experimental groups. By measuring the heat fluxes through the walls of both the control and experimental rooms, the effective cooling power of the radiative cooling materials was determined. The results show that the average cooling power calculated from the two sets of the middle rooms is 0.8 W/m² and 1.0 W/m², and the average cooling power of the side room is 1.0 W/m². A model of the residential building was then developed using EnergyPlus code. The measured effective cooling power of radiative cooling was embedded into the model via the “Other Equipment” module that resolves the issue of deviation in the prediction of energy-saving effect due to the spectral selectivity of radiative cooling materials at different angles. After verifying with the measured results, the model was used to evaluate the energy-saving performance of the radiatively-cooled sidewalls. Compared with traditional sidewalls, the energy-saving rate during the cooling season (from May to October) was found to be up to 1.5 % when radiative cooling is applied on the sidewalls of residential buildings in “hot summer and cold winter” regions in China.</div></div>","PeriodicalId":246,"journal":{"name":"Applied Energy","volume":"379 ","pages":"Article 124961"},"PeriodicalIF":10.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721111","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}

{"title":"Enhancing the methane production from methane hydrate by cyclic N2–CO2 gas injection and soaking method: Significance of the slow diffusion-controlled process","authors":"Masahiro Yasue ,&nbsp;Yoshihiro Masuda,&nbsp;Yunfeng Liang","doi":"10.1016/j.apenergy.2024.124912","DOIUrl":"10.1016/j.apenergy.2024.124912","url":null,"abstract":"<div><div>Methane hydrate (MH) is a crucial lower-carbon energy resource in climate mitigation and current energy transition. A depressurization technique has been mainly attempted to produce methane gas. Simultaneously, the exchange of CH₄ from gas hydrates by N₂–CO₂ has been studied to enhance methane gas production and CO₂ sequestration. We conducted experiments with hydrate-bearing cores by applying the cyclic injection and soaking method. An N₂–CO₂ gas (ca. 60 mol% CO₂) was injected into a core during the injection period, and the core was allowed to stand stationary during the soaking period. Concurrently, a numerical model was developed to simulate the gas production performance of the cyclic injection and soaking method. This model considers a two-stage process for the gas replacement phenomena between CH₄ and (N₂ + CO₂) in the hydrate: an almost immediate replacement at the hydrate surface followed by a more gradual diffusion-controlled replacement in the subsurface hydrate layer. The rapid replacement is modeled by phase equilibrium between the vapor phase and the hydrate surface. The diffusion due to the difference in concentration of each gas component between the surface hydrate layer and the inner hydrate describes the slow gas replacement phenomenon. By repeating four cycles of soaking and injection, the experiments achieved a high CH₄ recovery factor of 67.7 % and a high exchange ratio of 54.7 %. About 18 % of the CO₂ injected gas was sequestrated. The soaking process enhanced methane recovery by 1.5 times in the recovery factor compared to the first injection production and almost half of the CH₄ molecules in MH were extracted. Our simulations demonstrated excellent agreement with experimental results, confirming the soaking process is very efficient for methane recovery. From the production history matching, the diffusion coefficient of CH₄ molecules in the solid-state MH during slow replacement phenomena was estimated to be on the order of 10⁻¹⁹ m²/s, significantly smaller than those of previous research.</div></div>","PeriodicalId":246,"journal":{"name":"Applied Energy","volume":"379 ","pages":"Article 124912"},"PeriodicalIF":10.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704831","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}

{"title":"Cooling demand reduction with nighttime natural ventilation to cool internal thermal mass under harmonic design-day weather conditions","authors":"Mingtong Li ,&nbsp;Xiong Shen ,&nbsp;Wentao Wu ,&nbsp;Kristen Cetin ,&nbsp;Finn Mcintyre ,&nbsp;Liangzhu Wang ,&nbsp;Lixing Ding ,&nbsp;Daniel Bishop ,&nbsp;Larry Bellamy ,&nbsp;Meng Liu","doi":"10.1016/j.apenergy.2024.124947","DOIUrl":"10.1016/j.apenergy.2024.124947","url":null,"abstract":"<div><div>Cooling demand is steadily increasing across different climate zones due to global warming. A potential solution for cooling demand reduction is applying nighttime natural ventilation to cool internal thermal mass. However, a simplified and accurate modelling framework to assess the technique is still missing. The goal of the study is to build that framework integrated with a validated internal thermal mass model and apply the framework to quantify the cooling demand reduction potential in a space with different thermal mass and envelope configurations and in different climate zones. Results show that using Granite as internal thermal mass is three times more effective than concrete to reduce peak cooling load. Adding too much internal thermal mass can create adverse effects on cooling load reduction. The optimum thickness of internal thermal mass is between 28 and 45 mm. Envelope construction also has an influence on the performance of nighttime cooling. Applying the technique in buildings with lightweight structures reduces peak cooling load by 35.9% more than heavyweight structures. As heavyweight structures delay the release of the daily absorbed heat and cause higher indoor air temperatures at night. The two belts between the Tropic of Cancer and 60 degrees north latitude, and between the Tropic of Capricorn and 45 degrees south latitude are suitable for nighttime natural ventilation of internal thermal mass, achieving the annual cooling demand reduction above 1.25 kWh m⁻². In Dessert climate zones, the technique exhibits an extraordinary potential to reduce cooling demand, up to 6.67 kWh m⁻² per year.</div></div>","PeriodicalId":246,"journal":{"name":"Applied Energy","volume":"379 ","pages":"Article 124947"},"PeriodicalIF":10.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721112","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}

{"title":"Typhoon related cascading fault chain dynamic evolution model and risk mitigation in distribution systems","authors":"Ying Du ,&nbsp;Junxiang Zhang ,&nbsp;Yuntian Chen ,&nbsp;Haoran Zhang ,&nbsp;Haoran Ji ,&nbsp;Chengshan Wang ,&nbsp;Jinyue Yan","doi":"10.1016/j.apenergy.2024.124903","DOIUrl":"10.1016/j.apenergy.2024.124903","url":null,"abstract":"<div><div>The resilience of distribution system is severely influenced by typhoon disasters and the secondary disasters such as floods and debris flows. The cascading propagation of typhoon disasters, coupled with the cascading propagation of faults in distribution systems, creates a dual-coupling dynamic that results in large-scale faults. The key to mitigating losses from typhoon-related cascading faults lies in understanding the potential paths of cascading propagation and taking corresponding measures to preemptively interrupt the chain propagation. In this paper, based on the analysis of actual typhoon related fault data of Guangzhou, China, we created the knowledge graph of the typhoon related cascading fault chains and modeled the chain formation mechanism, successfully integrating the distribution systems and the typhoon disaster propagation systems. We also achieved the dynamic evolution of typhoon related cascading fault chains by using system dynamics. In the case studies of Guangzhou, we selected three typical typhoon related fault scenarios, and then the proposed model is utilized to capture the fault cascading pathway, which can help mitigate typhoon related fault risks in distribution systems.</div></div>","PeriodicalId":246,"journal":{"name":"Applied Energy","volume":"379 ","pages":"Article 124903"},"PeriodicalIF":10.1,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721169","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}

{"title":"Performance of district energy system under changing climate: A case study of Shenzhen","authors":"Pengyuan Shen ,&nbsp;Yuchen Ji ,&nbsp;Menglei Zhong","doi":"10.1016/j.apenergy.2024.124986","DOIUrl":"10.1016/j.apenergy.2024.124986","url":null,"abstract":"<div><div>The impacts of climate change on the economic performance of different district energy systems (DES) are rarely evaluated. In this research, the performance of both conventional and combined heat and power systems (CCHP) are simulated and compared by modeling and analyzing the DES. Building simulation is conducted by using the downscaled future hourly weather data in the period of 2050–2060 under two future climate scenarios. Optimal sizing and operation schedule of the DES are determined in both current and future climate. Lifetime annualized heating and cooling per area cost (HC) is used to compare the economic performance of the district system. It is found that the annul cooling load in RCP4.5 and RCP8.5 increases by 6 % and 9.68 %. The HC of the conventional system ranges from 122.72 Yuan/m² to 141.1 Yuan/m² with a range of profit rate from 5 % to 20 % under various climate scenarios, and that number for the CCHP is from 72.36 Yuan/m² to 95.24 Yuan/m². Compared with the conventional system, the optimal CCHP system charges 32.5 % to 41 % less on the building end users if the lifetime profit rate is to be maintained between 5 % to 20 %.</div></div>","PeriodicalId":246,"journal":{"name":"Applied Energy","volume":"379 ","pages":"Article 124986"},"PeriodicalIF":10.1,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704645","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}

{"title":"Secure frequency regulation in power system: A comprehensive defense strategy against FDI, DoS, and latency cyber-attacks","authors":"Shaohua Yang ,&nbsp;Keng-Weng Lao ,&nbsp;Hongxun Hui ,&nbsp;Jinshuo Su ,&nbsp;Sheng Wang","doi":"10.1016/j.apenergy.2024.124772","DOIUrl":"10.1016/j.apenergy.2024.124772","url":null,"abstract":"<div><div>Maintaining frequency is crucial for the security of power systems, while deep cyber–physical interactions make frequency regulation susceptible to cyber-attack risks. False data injection (FDI) attacks, denial-of-service (DoS) attacks, and latency attacks are typical types of cyber-attacks prevalent in power systems, each capable of deteriorating system frequency through distinct mechanisms and posing serious security risks. However, existing studies on frequency regulation lack security aspects that can comprehensively address all these attack types. To fill this gap, this paper investigates a security strategy to safeguard power system frequency regulation. First, considering all these attacks, the system frequency regulation system is modeled to reveal the severity of cyber-security problems, specifically the failure to maintain frequency due to cyber-attacks. Moreover, a cyber-resilient control (CRC) strategy is developed to counter FDI, DoS, and latency attacks comprehensively. The CRC strategy involves a two-step process, including a safety surface and auxiliary trajectory control. The safety surface serves as a defensive barrier against multiple cyber-attacks, while the auxiliary trajectory control activates the safety surface’s defense capability, thereby ensuring the security of system frequency. Furthermore, rigorous proofs are given based on Lyapunov theorem, demonstrating that system stability can be guaranteed by the developed CRC strategy, even under multiple types of cyber-attacks. Finally, test results confirm the efficacy of the CRC strategy. For instance, it prevents pre-existing frequency oscillations and destabilization, and also reduces the maximum frequency deviation by approximately 96.61% under multiple cyber-attacks. Therefore, the developed CRC strategy can comprehensively defend against FDI, DoS, and latency cyber-attacks, significantly contributing to the power system security.</div></div>","PeriodicalId":246,"journal":{"name":"Applied Energy","volume":"379 ","pages":"Article 124772"},"PeriodicalIF":10.1,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704642","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}

{"title":"Feasibility-guaranteed machine learning unit commitment: Fuzzy Optimization approaches","authors":"Bala Venkatesh ,&nbsp;Mohamed Ibrahim Abdelaziz Shekeew ,&nbsp;Jessie Ma","doi":"10.1016/j.apenergy.2024.124923","DOIUrl":"10.1016/j.apenergy.2024.124923","url":null,"abstract":"<div><div>The unit commitment (UC) problem is solved several times daily in a limited amount of time and is commonly formulated using mixed-integer linear programs (MILP). However, solution time for MILP formulation increases exponentially with the number of binary variables required. To address this, machine learning (ML) models have been attempted with limited success as they cannot be trained for all scenarios, whereby they may contain false predictions leading to infeasibility, hindering their practical applicability. To overcome these issues, we first propose a hybrid deep learning model comprising a convolutional neural network (CNN) and bidirectional long-short-term memory (BiLSTM) to predict the UC decisions. Second, we incorporate these predictions as non-binding fuzzy constraints, enhancing the traditional UC model and creating an ML-fuzzy UC model. Two implementations of non-binding fuzzy constraints are studied. The first develops each ML decision variable as a separate fuzzy set, while the second creates one fuzzy set per hour, considering all decisions within. Introducing ML-UC decisions as non-binding fuzzy constraints ensures the ML-fuzzy UC model has a feasible solution if the basic MILP-UC problem does, while leveraging ML predictions. Moreover, the proposed model benefits from a reduced solution space, leading to substantial reductions in computing time. Results on IEEE 118-bus and Polish 2383-bus systems demonstrate 92 % and 89 % computation time reductions for both systems, respectively and achieve 100 % feasibility for both seen and unseen datasets when the basic MILP-UC problem has a feasible solution.</div></div>","PeriodicalId":246,"journal":{"name":"Applied Energy","volume":"379 ","pages":"Article 124923"},"PeriodicalIF":10.1,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704644","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}