{"title":"Progress in underground thermal energy storage: research contents, hotspots, and development trends","authors":"Renfeng Wei , Yong Li , Yanfeng Liu","doi":"10.1016/j.apenergy.2025.126725","DOIUrl":null,"url":null,"abstract":"<div><div>Existing reviews on underground thermal energy storage (UTES) are often fragmented and lack analysis of the spatial-temporal evolution of research hotspots. This study aims to provide an objective and comprehensive analysis of the developmental trajectory and research trends in the global UTSES field. This study utilizes 7705 documents published over the past 30 years as its data source to conduct bibliometric and content analysis using knowledge graph techniques. It focuses on three core issues: research frontiers and technology maturity, core bottlenecks, and future trends and cost characteristics. The aim is to overcome the limitations of traditional qualitative reviews and establish a data-driven, multi-dimensional analytical framework. The results indicate that the UTES field has undergone three stages of development: embryonic, stable growth, and rapid expansion, with large-scale commercialization expected by 2065. Aquifer thermal energy storage (ATES) focuses on heat-fluid-solid coupling optimization. Borehole thermal energy storage (BTES) emphasizes the integration of phase-change materials (PCMs) with renewable energy. Energy piles (EPs) serve as a critical key link between underground structures and energy systems. Rock thermal energy storage (RTES) is shifting toward high-temperature material innovations, with EP demonstrating significantly higher research intensity. The cost ranking is as follows: EP < (BTES, abandoned mine type; ATES, with existing well reuse) < (BTES, without existing wells) < (ATES, without existing wells) < RTES. Through quantitative analysis and prediction models, this study provides a scientific basis for UTES technological innovation, collaboration establishment, and policy formulation. Moreover, it significantly enhances the scientific rigor of thermal storage system design and engineering translation efficiency.</div></div>","PeriodicalId":246,"journal":{"name":"Applied Energy","volume":"401 ","pages":"Article 126725"},"PeriodicalIF":11.0000,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Energy","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0306261925014552","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0
Abstract
Existing reviews on underground thermal energy storage (UTES) are often fragmented and lack analysis of the spatial-temporal evolution of research hotspots. This study aims to provide an objective and comprehensive analysis of the developmental trajectory and research trends in the global UTSES field. This study utilizes 7705 documents published over the past 30 years as its data source to conduct bibliometric and content analysis using knowledge graph techniques. It focuses on three core issues: research frontiers and technology maturity, core bottlenecks, and future trends and cost characteristics. The aim is to overcome the limitations of traditional qualitative reviews and establish a data-driven, multi-dimensional analytical framework. The results indicate that the UTES field has undergone three stages of development: embryonic, stable growth, and rapid expansion, with large-scale commercialization expected by 2065. Aquifer thermal energy storage (ATES) focuses on heat-fluid-solid coupling optimization. Borehole thermal energy storage (BTES) emphasizes the integration of phase-change materials (PCMs) with renewable energy. Energy piles (EPs) serve as a critical key link between underground structures and energy systems. Rock thermal energy storage (RTES) is shifting toward high-temperature material innovations, with EP demonstrating significantly higher research intensity. The cost ranking is as follows: EP < (BTES, abandoned mine type; ATES, with existing well reuse) < (BTES, without existing wells) < (ATES, without existing wells) < RTES. Through quantitative analysis and prediction models, this study provides a scientific basis for UTES technological innovation, collaboration establishment, and policy formulation. Moreover, it significantly enhances the scientific rigor of thermal storage system design and engineering translation efficiency.
期刊介绍:
Applied Energy serves as a platform for sharing innovations, research, development, and demonstrations in energy conversion, conservation, and sustainable energy systems. The journal covers topics such as optimal energy resource use, environmental pollutant mitigation, and energy process analysis. It welcomes original papers, review articles, technical notes, and letters to the editor. Authors are encouraged to submit manuscripts that bridge the gap between research, development, and implementation. The journal addresses a wide spectrum of topics, including fossil and renewable energy technologies, energy economics, and environmental impacts. Applied Energy also explores modeling and forecasting, conservation strategies, and the social and economic implications of energy policies, including climate change mitigation. It is complemented by the open-access journal Advances in Applied Energy.