This editorial article reviews the Special Issue "Low-grade thermal energy utilization: technologies and applications," which presents state-of-the-art research on the management and utilization of low-grade thermal energy. Low-grade thermal energy, often considered waste, has gained increasing attention due to the need for decarbonization and energy security. The Special Issue includes over 50 high-quality articles covering various technologies and applications for harnessing this energy resource. The articles are categorized into heat pumps, power cycles, thermoelectric generators (TEGs), thermal storage, solar thermal energy utilization, and other thermal energy technologies. Heat pumps are used to upgrade heat sources, with studies focusing on their integration with seasonal heat storage and solar thermal systems. Power cycles, such as the organic Rankine cycle (ORC), Kalina cycle, and Stirling cycle, are explored for converting low-grade heat into electricity. TEGs are highlighted for their modular design and efficiency in direct heat-to-electricity conversion. Thermal storage technologies, including phase change materials and sensible storage, are discussed for managing thermal loads. Solar thermal energy utilization technologies, such as solar-assisted heat pumps and photothermal conversion, are also covered. The Special Issue also addresses other thermal energy technologies, including heat pipes, thermally regenerative electrochemical cycles (TREC), and thermal management systems for cooling high-power devices. These studies demonstrate the potential of low-grade thermal energy in enhancing energy efficiency, reducing environmental impact, and supporting sustainable energy systems. The research highlights the importance of innovative technologies and integrated systems in optimizing the utilization of low-grade thermal energy for various applications. The findings provide valuable insights and guidance for future research and development in this field.This editorial article reviews the Special Issue "Low-grade thermal energy utilization: technologies and applications," which presents state-of-the-art research on the management and utilization of low-grade thermal energy. Low-grade thermal energy, often considered waste, has gained increasing attention due to the need for decarbonization and energy security. The Special Issue includes over 50 high-quality articles covering various technologies and applications for harnessing this energy resource. The articles are categorized into heat pumps, power cycles, thermoelectric generators (TEGs), thermal storage, solar thermal energy utilization, and other thermal energy technologies. Heat pumps are used to upgrade heat sources, with studies focusing on their integration with seasonal heat storage and solar thermal systems. Power cycles, such as the organic Rankine cycle (ORC), Kalina cycle, and Stirling cycle, are explored for converting low-grade heat into electricity. TEGs are highlighted for their modular design and efficiency in direct heat-to-electricity conversion. Thermal storage technologies, including phase change materials and sensible storage, are discussed for managing thermal loads. Solar thermal energy utilization technologies, such as solar-assisted heat pumps and photothermal conversion, are also covered. The Special Issue also addresses other thermal energy technologies, including heat pipes, thermally regenerative electrochemical cycles (TREC), and thermal management systems for cooling high-power devices. These studies demonstrate the potential of low-grade thermal energy in enhancing energy efficiency, reducing environmental impact, and supporting sustainable energy systems. The research highlights the importance of innovative technologies and integrated systems in optimizing the utilization of low-grade thermal energy for various applications. The findings provide valuable insights and guidance for future research and development in this field.