Clean Energy 101: Thermal Batteries

This guide by RMI explains the function, types, and potential of thermal batteries as a decarbonization tool for industrial heating and grid stability. It details how these systems convert renewable electricity into stored heat using abundant materials, offering a cheaper and less complex alternative to hydrogen for high-temperature industrial processes.

• Thermal batteries address the challenge of decarbonizing industrial heating, which accounts for approximately 20 percent of global energy consumption and often requires temperatures exceeding 1,000°C for processes like steelmaking and glassmaking.
• The technology operates through a five-step process: charging with renewable electricity, converting that electricity to thermal energy via resistive heating, storing it in high-heat capacity media (such as graphite, bricks, or crushed rock), maintaining the temperature through insulation, and delivering the heat on demand.
• Thermal batteries are categorized into three main types: latent phase change (e.g., ice-based or cryogenic), sensible non-phase change (e.g., molten-salt, hot silicon, or graphite), and thermo-chemical (e.g., salt hydrate or adsorption solar heating).
• Compared to lithium-ion batteries or hydrogen, thermal batteries use abundant, cheap materials like salt and clay bricks and avoid the storage and transport risks associated with hydrogen's small molecular size and emissions issues.
• Investment in industrial decarbonization peaked at $5 billion in 2023 and remained consistent in 2024, with new investment in thermal batteries specifically spiking to over $350 million in 2024.
• Widespread adoption is hindered by practical barriers, including the lack of access to location- and time-specific wholesale electricity pricing and the high cost of the pipes, insulation, and pumps required to move heat.

APA

RMI (2025). Clean Energy 101: Thermal Batteries. https://rmi.org/resources/clean-energy-101-thermal-batteries/

Chicago

RMI. Clean Energy 101: Thermal Batteries. 2025. https://rmi.org/resources/clean-energy-101-thermal-batteries/.

Wikipedia

{{cite report |author=RMI |title=Clean Energy 101: Thermal Batteries |date=3 February 2025 |url=https://rmi.org/resources/clean-energy-101-thermal-batteries/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmi2025clean, author = {{RMI}}, title = {{Clean Energy 101: Thermal Batteries}}, institution = {RMI}, year = {2025}, month = feb, url = {https://rmi.org/resources/clean-energy-101-thermal-batteries/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }